UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No         )

Filed by the Registrant  ☒                            Filed by a Party other than the Registrant  ☐

Check the appropriate box:

XERIS PHARMACEUTICALS, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

XERIS PHARMACEUTICALS, INC.

180 N. LaSalle Street, Suite 1600

Chicago, Illinois 60601

To our Stockholders:

You are cordially invited to attend a special meeting of the stockholders of Xeris Pharmaceuticals, Inc. (“Xeris”) to be held on September 14, 2021 at 8:00 a.m. Central Time. The special meeting will be held in a virtual-only meeting format. Only stockholders of record and beneficial owners of shares of our common stock as of the close of business on July 21, 2021, the record date, may attend and participate in the special meeting, including voting and asking questions during the special meeting. You will not be able to attend the special meeting physically in person. In order to attend the special meeting, you must register in advance at www.proxydocs.com/XERS prior to the deadline of September 13, 2021 at 4:00 p.m. Central Time. Upon completing your registration, you will receive further instructions via email, including a unique link that will allow you to access, and to vote and submit questions during, the special meeting. Details regarding how to attend and vote at the special meeting are more fully described in the accompanying proxy statement and your proxy card.

As previously announced, on May 24, 2021, Xeris entered into a transaction agreement (the “Transaction Agreement”) with Strongbridge Biopharma plc (“Strongbridge”), Xeris Biopharma Holdings, Inc. (“HoldCo”), and Wells MergerSub, Inc. (“MergerSub”). Under the terms of the Transaction Agreement, HoldCo will acquire the entire issued and to be issued ordinary share capital of Strongbridge (the “Acquisition”) pursuant to a scheme of arrangement under Chapter 1 of Part 9 of the Irish Companies Act 2014 (the “Act”) and a capital reduction under Sections 84 to 86 of the Act (collectively, the “Scheme”). As a result of the Scheme, Strongbridge will become a wholly owned subsidiary of HoldCo.

As consideration for the Acquisition, Strongbridge shareholders will be entitled to receive at the effective time of the Scheme (i) 0.7840 of a newly issued share of HoldCo common stock (“HoldCo common stock”) and (ii) one non-tradeable contingent value right (“CVR”), in exchange for each Strongbridge ordinary share held by such Strongbridge shareholders. Each CVR will represent a contractual right to receive future conditional payments worth up to an aggregate amount of $1.00, settleable in cash, additional shares of HoldCo common stock or a combination of cash and additional shares of HoldCo common stock, at HoldCo’s sole discretion, upon the achievement of certain regulatory and sales milestones relating to Strongbridge’s products, Keveyis and Recorlev. The minimum payment on the CVR is zero and the maximum payment is $1.00.

Immediately following and conditioned on the concurrent consummation of the Acquisition, MergerSub, a Delaware corporation and wholly owned subsidiary of HoldCo, will merge with and into Xeris, with Xeris continuing as the surviving corporation and wholly owned subsidiary of HoldCo (the “Merger”, and together with the Acquisition, the “Transaction”). At the effective time of the Merger, all existing shares of Xeris common stock (“Xeris common stock”) will be cancelled and will automatically be converted into the right to receive HoldCo common stock on a one-for-one basis.

Upon completion of the Transaction, based on the number of shares of Xeris common stock and Strongbridge ordinary shares outstanding as of July 27, 2021, the former stockholders of Xeris are expected to own approximately 60%, and the former shareholders of Strongbridge are expected to own approximately 40%, of the outstanding HoldCo common stock. The HoldCo common stock is expected to trade on the Nasdaq Global Select Market (the “Nasdaq”) under the ticker “XERS”. Based on the number of shares of Xeris

common stock and Strongbridge ordinary shares outstanding as of the applicable record dates, the total amount of HoldCo common stock that is expected to be issued in connection with the Transaction is approximately 125,329,065.

We urge all Xeris stockholders to read the accompanying joint proxy statement/prospectus, including the Annexes and the documents incorporated by reference therein, carefully and in their entirety. In particular, we urge you to read carefully “Risk Factors” beginning on page 30 of the accompanying joint proxy statement/prospectus.

Xeris is holding a special meeting of stockholders to seek your approval to adopt the Transaction Agreement and approve the Transaction.

Your proxy is being solicited by the board of directors of Xeris (the “Xeris Board”). After careful consideration, the Xeris Board, excluding Dr. Jeffrey W. Sherman, a director on the boards of directors of both Xeris and Strongbridge who recused himself from discussions and consideration of the Transaction and abstained from voting on the Transaction (such Xeris Board without Dr. Sherman, the “Independent Xeris Directors”), have unanimously approved the Transaction Agreement and determined that the entry into the Transaction Agreement and the Transaction are fair and in the best interest of Xeris and its stockholders. The Independent Xeris Directors recommend that you vote “FOR” the proposals to adopt the Transaction Agreement and approve the Transaction and “FOR” the other proposals described in the accompanying joint proxy statement/prospectus.

In considering the recommendation of the Independent Xeris Directors, you should be aware that directors and executive officers of Xeris have interests in the proposed transaction that are in addition to, or different from, any interests they might have as stockholders. See “The Transaction—Interests of Xeris’ Directors and Executive Officers in the Transaction” in the accompanying joint proxy statement/prospectus. Your vote is very important. Please vote as soon as possible whether or not you plan to attend the special meeting by following the instructions in the accompanying joint proxy statement/prospectus.

To be admitted to the special meeting and vote your shares of common stock, you must register in advance at www.proxydocs.com/XERS prior to the deadline of September 13, 2021 at 4:00 p.m. Central Time. Upon completing your registration, you will receive further instructions via email, including unique links to access the special meeting and to vote and submit questions in advance of the special meeting. As part of the registration process, you must enter the control number located on your proxy card or voting instruction form, as applicable. If you are a beneficial owner of shares of common stock registered in the name of a broker, bank or other nominee, you will also need to provide the registered name on your account and the name of your broker, bank or other nominee as part of the registration process. Please see the “Questions and Answers About the Transaction and the Special Meetings” section of the accompanying joint proxy statement/prospectus for more details regarding the logistics of the special meeting, including the ability of Xeris stockholders to submit questions during the special meeting and technical details and support related to accessing the virtual platform.

On behalf of the Xeris board of directors, thank you for your consideration and continued support.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued in connection with the Transaction or determined if the accompanying joint proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

For the avoidance of doubt, the accompanying joint proxy statement/prospectus is not intended to be and is not a prospectus within the meaning of section 1348 of the Act, the Prospectus Regulation (EU) 2017/1129 of 14 June 2017 (as amended), the European Union (Prospectus) Regulations 2019 of Ireland (S.I. No. 380/2019), or the Central Bank (Investment Market Conduct) Rules (S.I. No. 366 of 2019). This document has not been approved or reviewed by or registered with the Central Bank of Ireland.

The accompanying joint proxy statement/prospectus is dated July 29, 2021, and is first being mailed to stockholders of Xeris on or about July 30, 2021.

ADDITIONAL INFORMATION

If you have questions about the Transaction or the special meeting, or if you need to obtain copies of the accompanying joint proxy statement/prospectus, proxy card or any documents incorporated by reference in the joint proxy statement/prospectus, you may contact the contact listed below. You will not be charged for any of the documents you request.

Innisfree M&A Incorporated

501 Madison Avenue, 20^th Floor

New York, NY 10022

Stockholders may call toll free: (877) 750-9499

Banks and Brokers may call collect: (212) 750-5833

If you would like to request documents, please do so by 5:00 p.m. Central Time on September 3, 2021, in order to receive them before the special meeting.

The accompanying joint proxy statement/prospectus incorporates by reference important business and financial information about Xeris from documents that are not included in or delivered with the joint proxy statement/prospectus. For a more detailed description of the information incorporated by reference in the accompanying joint proxy statement/prospectus and how you may obtain it, see “Where You Can Find More Information” beginning on page 205 of the accompanying joint proxy statement/prospectus.

XERIS PHARMACEUTICALS, INC.

180 N. LaSalle Street, Suite 1600

Chicago, Illinois 60601

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS

More information about the transaction and the proposals is contained in the accompanying joint proxy statement/prospectus. We urge all Xeris stockholders to read the accompanying joint proxy statement/prospectus, including the Annexes and the documents incorporated by reference therein, carefully and in their entirety. In particular, we urge you to read carefully “Risk Factors” beginning on page 30 of the accompanying joint proxy statement/prospectus.

The board of directors of Xeris, excluding Dr. Jeffrey W. Sherman, a director on the boards of directors of both Xeris and Strongbridge who recused himself from discussions and consideration of the Transaction and abstained from voting on the Transaction, recommend that Xeris stockholders vote “FOR” the proposal to adopt the Transaction Agreement, “FOR” the proposal to approve the Merger and “FOR” the Xeris adjournment proposal.

By order of the Xeris Board

Paul R. Edick

Chairman and Chief Executive Officer

July 29, 2021

YOUR VOTE IS IMPORTANT

If you are a record holder, you may vote your shares of Xeris common stock by using a toll-free telephone number or electronically over the internet as described on the enclosed proxy card. We encourage you to file your proxy using either of these options if they are available to you. Alternatively, you may mark, sign, date and mail your proxy card in the postage-paid envelope provided. If you hold your shares of Xeris common stock through a bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee in order to instruct them how to vote such shares. The method by which you vote does not limit your right to vote virtually at the special meeting. We strongly encourage you to vote.

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QUESTIONS AND ANSWERS ABOUT THE TRANSACTION AND THE SPECIAL MEETINGS

The following questions and answers are intended to address briefly some commonly asked questions regarding the Transaction, the Xeris Special Meeting and the Strongbridge Special Meetings. These questions and answers only highlight some of the information contained in this joint proxy statement/prospectus. They may not contain all the information that is important to you. You should read carefully this entire joint proxy statement/prospectus, including the Annexes and the documents incorporated by reference into this joint proxy statement/prospectus, to understand fully the proposed Transaction and the voting procedures for the Xeris Special Meeting and the Strongbridge Special Meetings. See “Where You Can Find More Information” beginning on page 205. If you are in any doubt about this Transaction you should consult an independent financial advisor who, if you are taking advice in Ireland, is authorized or exempted by the Investment Intermediaries Act 1995 (as amended), or the European Union (Markets in Financial Instruments) Regulations 2017 (S.I. No. 375 of 2017).

Information for Xeris Stockholders and Strongbridge Shareholders

Xeris is holding the Xeris Special Meeting in order to obtain stockholder approval to adopt the Transaction Agreement and approve the Merger, as described in this joint proxy statement/prospectus.

Strongbridge will request the Irish High Court to convene the Court Meeting in order to obtain shareholder approval of the Scheme of Arrangement. As soon as possible after the conclusion or adjournment of the Court Meeting, Strongbridge will convene the EGM in order to obtain shareholder approval of the resolutions necessary to implement the Scheme of Arrangement and related resolutions.

Strongbridge and Xeris will be unable to complete the Merger and the Acquisition unless the requisite Xeris stockholder and Strongbridge shareholder approvals described above are obtained at the respective special meetings.

We have included in this joint proxy statement/prospectus important information about the Merger, the Acquisition, the Transaction Agreement (a copy of which is attached as Annex A), the Conditions Appendix (a copy of which is attached as Annex B), the Expenses Reimbursement Agreement (a copy of which is attached as Annex C), the form of CVR Agreement (a copy of which is attached as Annex D), the Xeris Special Meeting and the Strongbridge Special Meetings. You should read this information carefully and in its entirety. If you are a record holder, the enclosed voting materials allow you to vote your shares without attending the applicable special meeting by granting a proxy or voting your shares by mail, telephone or over the internet. If you hold your shares through a bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee in order to instruct them how to vote such shares.

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HoldCo will not issue any fractions of shares of HoldCo common stock to Xeris stockholders in the Transaction and instead, all fractional entitlements that would otherwise have been due to Xeris stockholders will be aggregated and sold in the market by the exchange agent, with the net proceeds of any sale distributed pro rata to the Xeris stockholders in accordance with the fractional entitlements to which they would otherwise have been entitled.

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It is expected that the HoldCo common stock will be listed on the Nasdaq under the ticker “XERS”. Following the consummation of the Transaction, Strongbridge ordinary shares will be delisted from the Nasdaq.

HoldCo will not issue any fractions of shares of HoldCo common stock to Strongbridge shareholders in the Transaction and instead, all fractional entitlements that would otherwise have been due to Strongbridge shareholders will be aggregated and sold in the market by the exchange agent, with the net proceeds of any sale distributed pro rata to the Strongbridge shareholders in accordance with the fractional entitlements to which they would otherwise have been entitled.

1. $0.25 per CVR upon the earlier of: (i) any patent with respect to the Keveyis Product (as defined in the CVR Agreement) being listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations (the Orange Book) on or before December 31, 2023 (the “Keveyis Patent Milestone”), and (ii) HoldCo achieving at least $40,000,000 in net sales of the Keveyis Product in the period beginning on January 1, 2023 and ending on December 31, 2023;

2. $0.25 per CVR upon the first achievement of at least $40,000,000 of net sales of the Recorlev Product (as defined in the CVR Agreement) in the period between January 1, 2023 through December 31, 2023 (the “Recorlev 2023 Commercial Milestone”); and

3. $0.50 per CVR upon the first achievement of at least $80,000,000 of net sales of the Recorlev Product in the period between January 1, 2024 through December 31, 2024 (the “Recorlev 2024 Commercial Milestone”).

Milestone Payments will be paid within 15 Business Days following the achievement of the Keveyis Patent Milestone (or within 15 Business Days following the Scheme Effective Date if achieved prior to the Scheme Effective Date) and within 15 Business Days following the date HoldCo files its Annual Report on 10-K for the applicable year in which the Milestone is achieved for all other Milestones. Any payment amounts made in HoldCo common stock will be the product of (a) the applicable Milestone Payment divided by the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date and (b) the number of CVRs held by the holder.

There can be no assurance that the various Milestones set forth in the CVR Agreement will be achieved, and the total amount payable under the CVR Agreement could be zero. There will be no interest conferred by a CVR in the economic activities of the Strongbridge Group generally or the Xeris Group generally.

For a more detailed description of the CVRs, see the section entitled “Contingent Value Rights Agreement” beginning on page 159 of this joint proxy statement/prospectus.

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A vote as a Xeris stockholder to approve the Transaction Agreement and the Merger or any of the other proposals at the Xeris Special Meeting will not constitute a vote as a Strongbridge shareholder on the proposal to approve the Scheme of Arrangement or any of the other proposals at the Court Meeting or EGM, or vice versa.

Therefore, if you are a record holder, please mark, sign, date and return all proxy cards that you receive, whether from Xeris or Strongbridge, or submit a separate proxy as both a Xeris stockholder and a Strongbridge shareholder for each special meeting, over the internet or by telephone. If you hold your shares of Xeris common stock or Strongbridge ordinary shares through a bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee in order to instruct them on how to vote such shares as both a Xeris stockholder and/or a Strongbridge shareholder for each applicable special meeting.

See “About the Xeris Special Meeting” and “About the Strongbridge Special Meeting” below for further information on the Xeris Special Meeting and the Strongbridge Special Meetings, as applicable.

If you hold your shares through a bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee when instructing them how to vote your shares. If you are a shareholder of record, please sign the relevant proxy card(s) exactly as your name appears on the card. In the case of joint holders, the vote of the senior member who tenders a vote, whether in person or by proxy, will be accepted to the exclusion of the vote(s) of the other joint holder(s) and, for this purpose, seniority will be determined by the order in which the names stand in the register of members of Xeris or Strongbridge, as applicable, in respect of the joint holding. If you are a shareholder that is a corporation, limited liability company or partnership, the form of proxy must be either under its common seal or under the hand of an officer or attorney, duly authorized. If the relevant proxy card(s) is signed pursuant to a power of attorney or by an executor, administrator, trustee or guardian, please state the signatory’s full title and provide a certificate or other proof of appointment.

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If you are a Xeris stockholder, you should contact Innisfree M&A Incorporated, the proxy solicitation agent for Xeris, by mail at 501 Madison Avenue, 20th Floor, New York, NY 10022, by telephone at (877) 750-9499 (stockholders may call toll free) or (212) 750-5833 (banks and brokers may call collect).

If you are a Strongbridge shareholder, you should contact MacKenzie Partners, the proxy solicitation agent for Strongbridge, by mail at 1407 Broadway – 27th Floor, New York, NY 10018, by telephone at (800) 322-2885 (toll-free) or (212) 929-5500 (collect), or by email at proxy@mackenziepartners.com.

If your shares are held by a broker, bank or other nominee, you should contact your broker, bank or other nominee for additional information.

About the Xeris Special Meeting

The Transaction Agreement and Merger are not conditioned on approval of proposal 3.

As of the Xeris record date, directors and executive officers of Xeris and their affiliates owned and were entitled to vote 813,233 shares of Xeris common stock, representing approximately 1.22% of the shares of Xeris common stock outstanding on that date. It is expected that the Independent Xeris Directors and executive officers who are stockholders of Xeris will vote “FOR” the proposal to approve the Transaction Agreement, “FOR” the proposal to approve the Merger and “FOR” the Xeris adjournment proposal, although none of them has entered into any agreement requiring them to do so.

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The Independent Xeris Directors recommend that Xeris stockholders vote:

“FOR” the proposal to adopt the Transaction Agreement;

“FOR” the proposal to approve the Merger;

“FOR” the Xeris adjournment proposal.

See “The Transaction—Recommendation of the Independent Xeris Directors and Xeris’ Reasons for the Transaction” beginning on page 68.

In considering the recommendation of the Independent Xeris Directors, you should be aware that directors and executive officers of Xeris have interests in the proposed transaction that are in addition to, or different from, any interests they might have as stockholders. See “The Transaction—Interests of Xeris’ Directors and Executive Officers in the Transaction.”

If a quorum is not present, the only business that can be transacted at the Xeris Special Meeting is the adjournment or postponement of the meeting to another date or time.

As part of the registration process, you must enter the control number that is located on the proxy card. If you are a beneficial owner of shares of common stock registered in the name of a broker, bank or other nominee, you will also need to provide the registered name on your account and the name of your broker, bank or other nominee as part of the registration process.

Further instructions on how to virtually attend, participate in and vote at the Xeris Special Meeting, including how to demonstrate your ownership of our shares of common stock as of the record date, are available at www.proxydocs.com/XERS.

Xeris’ Special Meeting will begin promptly at 8:00 a.m. Central Time in a virtual meeting format on September 14, 2021. We encourage you to access the meeting prior to the start time. Online access will start 15 minutes before the meeting start time, and you should allow ample time to check your audio settings. If your shares of common stock are held in a bank or brokerage account, instructions should also be provided on the voting instruction form provided by your bank or brokerage firm.

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Stockholder of record: If your shares are registered directly in your name with our transfer agent, Computershare Trust Company, N.A., you are the stockholder of record, and these proxy materials are being sent directly to you. As the stockholder of record, you have the right to grant your voting proxy directly to the individuals named on the proxy card and to vote at the Xeris Special Meeting.

Beneficial owner: If your shares are held in a stock brokerage account or by a bank or other nominee, you are the beneficial owner of shares held in “street name,” and these proxy materials are being forwarded to you by your broker or other nominee, who is considered to be the stockholder of record. As the beneficial owner, you have the right to tell your nominee how to vote, and you are also invited to attend the Xeris Special Meeting. However, since you are not the stockholder of record, you may not vote your shares at the Xeris Special Meeting unless you obtain a legal proxy from your nominee authorizing you to do so. Your nominee has sent you instructions on how to direct the nominee’s vote. You may vote by following those instructions and the instructions on the Notice of 2021 Xeris Special Meeting of Stockholders.

If you hold your shares through a bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee in order to instruct them how to vote such shares. If you want to vote in person virtually at the Xeris Special Meeting, you must register in advance at www.proxydocs.com/XERS prior to the deadline of September 13, 2021 at 4:00 p.m. Central Time. You may be instructed to obtain a legal proxy from your broker, bank or other nominee and to submit a copy in advance of the meeting. Further instructions will be provided to you as part of your registration process.

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If a broker, bank, or other nominee holds your shares, you must contact such broker, bank, or nominee in order to find out how to change your vote.

About the Strongbridge Special Meetings

Strongbridge shareholders are being asked to vote on a proposal to approve the Scheme at both the Court Meeting and at the EGM. However, the vote required for such proposal is different at each of the meetings. As set out in full under the section entitled “Part 2—Explanatory Statement—Consents and Meetings—4,” beginning on page 211, in order for the resolution at the Court Meeting to pass, those voting to approve the Scheme must: (a) represent a simple majority (being more than 50%) in number of the Strongbridge shareholders of record as of 5:00 p.m. (Eastern Time in the U.S.) on July 27, 2021 (the “Voting Record Time”), present and voting (in person or by proxy), and (b) also represent 75% or more in value of the Strongbridge ordinary shares held by such holders as of the Voting Record Time, present and voting (in person or by proxy).

Because the vote required to approve the proposal at the Court Meeting is based on votes properly cast at the meeting, and because abstentions and broker non-votes are not considered votes properly cast, abstentions and broker non-votes, along with failures to vote, will have no effect on such proposal.

The Acquisition is conditioned on approval of the Scheme at the Court Meeting.

Extraordinary General Meeting

Set forth below is a table summarizing certain information with respect to the resolutions to be voted on at the EGM:

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At the EGM, the requisite approval of each of the resolutions depends on whether it is an “ordinary resolution” (resolutions 1, 3, 5 and 6), which requires the approval of the holders of at least a majority of the votes cast by the holders of Strongbridge ordinary shares present and voting, either in person or by proxy, or a “special resolution” (resolutions 2 and 4), which requires the approval of the holders of at least 75% of the votes cast by the holders of Strongbridge ordinary shares present and voting, either in person or by proxy.

For all the resolutions, because the votes required to approve such resolutions are based on votes properly cast at the EGM, and because abstentions and broker non-votes are not considered votes properly cast, abstentions and broker non-votes, along with failures to vote, will have no effect on the EGM resolutions.

As of the Voting Record Time, the Strongbridge directors and executive officers had the right to vote less than 1% of the Strongbridge ordinary shares then outstanding and entitled to vote at the Court Meeting and the EGM. It is expected that Strongbridge’s directors and executive officers will vote “FOR” each of the proposals at the Court Meeting and at the EGM, and in addition, certain Strongbridge directors, executive officers, CAM Capital and HealthCap, representing, in aggregate, approximately 17% of Strongbridge’s outstanding ordinary shares, have entered into irrevocable undertakings to vote in favor of the Transaction. For more detail on these matters, see “Irrevocable Undertakings” beginning on page 161.

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At the Court Meeting, Strongbridge shareholders (excluding Xeris and its affiliates to the extent they hold Strongbridge ordinary shares) will be asked to approve the Scheme for the purposes of satisfying the requirements of the Irish legislation upon which the Scheme is based.

At the EGM, Strongbridge shareholders (including Xeris and its affiliates to the extent they hold Strongbridge ordinary shares) will also be asked to approve the Scheme, authorize Strongbridge’s directors to take whatever actions they deem necessary or appropriate for carrying the Scheme into effect and approve the cancellation of certain ordinary shares and issuance of new ordinary shares as part of the Scheme and other related matters. For more detail on these matters, see “The Special Meetings of Strongbridge’s Shareholders” beginning on page 52.

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See “The Transaction—Recommendation of the Independent Strongbridge Directors and Strongbridge’s Reasons for the Transaction” beginning on page 72 of this joint proxy statement/prospectus. In considering the recommendation of the Independent Strongbridge Directors, you should be aware that certain directors and executive officers of Strongbridge have interests in the proposed transaction that are in addition to, or different from, any interests they might have as shareholders. See “The Transaction—Interests of Strongbridge’s Executive Officers and Directors.”

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If you are a Strongbridge shareholder of record, the shares listed on your proxy cards will include, if applicable, shares held in a book-entry account at Computershare Trust Company, N.A., Strongbridge’s transfer agent.

If you hold your shares through a bank, broker or other nominee, you should follow the instructions provided by your bank, broker or other nominee in order to instruct them how to vote such shares.

In the case of joint holders, the vote of the senior member who tenders a vote, whether in person or by proxy, will be accepted to the exclusion of the votes of the other joint holders of record and, for this purpose, seniority will be determined by the order in which the names appear in the Strongbridge register of members in respect of the joint holding.

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If you have instructed a bank, broker or other nominee to vote your shares, you must follow directions received from your bank, broker or other nominee to change your vote or revoke your proxy.

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RISK FACTORS

In addition to the other information contained in or incorporated by reference into this joint proxy statement/prospectus, you should consider carefully the following risk factors, including the matters addressed under the caption “Cautionary Statement Regarding Forward-Looking Statements.” You should also read and consider the risks associated with the business of Xeris and the risks associated with the business of Strongbridge because these risks will also affect HoldCo. Descriptions of these risks can be found in each of Xeris’ and Strongbridge’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, each of which is filed with the SEC and incorporated by reference into this joint proxy statement/prospectus and any subsequent reports filed with the SEC. You should also read and consider the other information in this joint proxy statement/prospectus and the other documents incorporated by reference into this joint proxy statement/prospectus. See the section entitled “Where You Can Find More Information” beginning on page 205 of this joint proxy statement/prospectus.

Xeris stockholders and Strongbridge shareholders cannot be sure of the value of the consideration they will receive in the Transaction.

Xeris stockholders and Strongbridge shareholders will receive a fixed number of shares of HoldCo common stock in the Merger and the Acquisition, respectively, rather than a number of shares of HoldCo common stock with a particular fixed market value. The market values of Xeris common stock and Strongbridge ordinary shares at the completion of the Transaction may vary significantly from their prices on the date prior to the date the Transaction Agreement was executed, the date of this joint proxy statement/prospectus or the date on which Xeris stockholders and Strongbridge shareholders vote on the Merger proposal and the Acquisition proposal, respectively. Because the respective Xeris and Strongbridge exchange ratios are fixed and will not be adjusted to reflect any changes in the market prices of Xeris common stock or Strongbridge ordinary shares, the market value of the HoldCo common stock issued in the Merger or the Acquisition, as applicable, and the Xeris common stock and Strongbridge ordinary shares surrendered in the Merger and the Acquisition, respectively, may be higher or lower than the market values of these shares on earlier dates. All of the consideration to be received by Xeris stockholders and Strongbridge shareholders pursuant to the Transaction will be HoldCo common stock, with the exception of cash in lieu of fractional shares and, in the case of Strongbridge shareholders, CVRs, each worth up to a maximum of $1.00 per Strongbridge ordinary share settleable in cash, additional shares of HoldCo common stock or a combination of cash and additional shares of HoldCo’s common stock, at HoldCo’s sole discretion. At the time of the special meetings, Xeris stockholders and Strongbridge shareholders will not know or be able to determine the value of the HoldCo common stock they may receive upon completion of the Transaction. Changes in the market prices of Xeris common stock and Strongbridge ordinary shares may result from a variety of factors that are beyond the control of Xeris or Strongbridge, including changes in their respective businesses, operations and prospects, regulatory considerations, governmental actions, and legal proceedings and other developments. Market assessments of the benefits of the Transaction, the likelihood that the Transaction will be completed and general and industry-specific market and economic conditions may also have an effect on the market price of Xeris common stock and Strongbridge ordinary shares.

Changes in market prices of Xeris common stock and Strongbridge ordinary shares may also be caused by fluctuations and developments affecting industry specific and general economic and market conditions and may have an adverse effect on Xeris common stock and Strongbridge ordinary shares prior to the consummation of the Transaction.

Neither Xeris nor Strongbridge is permitted to terminate the Transaction Agreement solely because of changes in the market prices of Xeris common stock and/or Strongbridge ordinary shares. In addition, the market values of Xeris common stock and Strongbridge ordinary shares may vary significantly from the date of the special meetings to the date of the completion of the Transaction. You are urged to obtain up-to-date prices for Xeris common stock and Strongbridge ordinary shares. There is no assurance that the Transaction will be completed, that there will not be a delay in the completion of the Transaction, or that all or any of the anticipated benefits of the Transaction will be obtained.

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The market price for HoldCo common stock may be affected by factors different from those that historically have affected Xeris common stock and Strongbridge ordinary shares.

Upon completion of the Transaction, holders of shares of Xeris common stock and holders of Strongbridge ordinary shares will become holders of shares of HoldCo common stock. Xeris and Strongbridge each have businesses that differ from each other. Accordingly, the results of operations of HoldCo will be affected by some factors that are different from those currently affecting the results of operations of each of Xeris and Strongbridge. For a discussion of the businesses of Xeris and Strongbridge and of some important factors to consider in connection with those businesses, see the documents incorporated by reference in this joint proxy statement/prospectus and referred to under “Where You Can Find More Information” beginning on page 205 of this joint proxy statement/prospectus.

Regulatory approvals may not be received, may take longer than expected or may impose conditions that are not presently anticipated or that cannot be met.

Completion of the Transaction is conditioned upon, among other things, the expiration or termination of the waiting period (and any extensions thereof) applicable to the Transaction under the HSR Act. While Xeris and Strongbridge have determined that a filing is not required under the HSR Act, at any time before or after the Transaction is consummated, any of the DOJ, the FTC or U.S. state attorneys general or foreign governmental authorities could take action under the antitrust laws in opposition to the Transaction, including seeking to enjoin completion of the Transaction, condition completion of the Transaction upon the divestiture of assets of Xeris, Strongbridge or their subsidiaries or impose restrictions on HoldCo’s post-Transaction operations. These could negatively affect the results of operations and financial condition of the combined company following completion of the Transaction. Any such requirements or restrictions may prevent or delay completion of the Transaction or may reduce the anticipated benefits of the Transaction, which could also have a material adverse effect on the combined company’s business and cash flows, financial condition and results of operations.

The Transaction Agreement may be terminated in accordance with its terms and the Transaction may not be completed.

The completion of the Transaction is subject to the satisfaction or waiver of a number of conditions. Those conditions include: (i) the approval by the Strongbridge shareholders; (ii) the approval of the Transaction Agreement by the Xeris stockholders; (iii) certain of the EGM resolutions being duly passed by the Strongbridge shareholders at the EGM; (iv) the Irish High Court’s sanction of the Scheme (without material modification) and confirmation of the reduction of the share premium account and registration of the Court Order and minutes by the Registrar; (v) the Nasdaq having authorized, and not withdrawn such approval, the listing of all of the HoldCo common stock to be issued in the Scheme, subject only to official notice of issuance; (vi) all applicable waiting periods under the HSR Act in connection with the Acquisition and/or the Merger, if any, having expired or having been terminated; (vii) the European Commission deciding that it will allow closing of the Acquisition, to the extent it constitutes a concentration within the scope of the EC Merger Regulation or otherwise constitutes a concentration subject to the EC Merger Regulation, or, to the extent that all or part of the Acquisition is referred to a competent authority of an EEA member state, such authority or authorities having issued a final decision or decisions constituting such decision; (viii) the effectiveness of the registration statement of which this joint proxy statement/prospectus forms a part and the absence of any stop order or proceedings by the SEC; (ix) all required clearances having been obtained and remaining in full force and effect and applicable waiting periods having expired, lapsed or been terminated (as appropriate), in each case in connection with the Acquisition and/or the Merger, under the antitrust, competition or foreign investment laws of any jurisdiction in which Xeris, Strongbridge or any of their affiliates operate their respective businesses or own any assets; (x) no law, order, writ, decree, judgment, injunction, restraint or prohibition by any court of competent jurisdiction or order, writ, decree, judgment, injunction, restraint or prohibition under any antitrust order by any relevant authority which restrains, enjoins, makes illegal or otherwise prohibits consummation of the Acquisition or the Merger having been issued, made, enacted or entered and continuing to be in effect; (xi) the Transaction

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Agreement not having been terminated in accordance with its terms; (xii) the accuracy of the other party’s representations and warranties, subject to specified materiality standards; (xiii) the performance by the other party of its obligations, covenants and agreements under the Transaction Agreement in all material respects; and (xiv) the delivery by the other party of an officer’s certificate certifying such accuracy of its representations and warranties and such performance of its obligations and covenants.

These conditions to the closing may not be fulfilled and, accordingly, the Transaction may not be completed. In addition, if the Transaction is not completed by February 24, 2022, either Xeris or Strongbridge may choose not to proceed with the Transaction, and the parties can mutually decide to terminate the Transaction Agreement at any time prior to the consummation of the Merger and the Scheme. In addition, Xeris or Strongbridge may elect to terminate the Transaction Agreement in certain other circumstances. If the Transaction Agreement is terminated, Xeris and Strongbridge may incur substantial fees in connection with termination of the Transaction Agreement and will not recognize the anticipated benefits of the Transaction. See “The Transaction Agreement—Expenses” and “Expenses Reimbursement Agreement” beginning on pages 156 and 157 respectively of this joint proxy statement/prospectus.

Termination of the Transaction Agreement could negatively impact Xeris and/or Strongbridge.

If the Transaction Agreement is terminated in accordance with its terms and the Transaction is not consummated, the ongoing businesses of Xeris and Strongbridge may be adversely affected by a variety of factors. Xeris and Strongbridge’s respective businesses may be adversely impacted by the failure to pursue other beneficial opportunities during the pendency of the Transaction, by the failure to obtain the anticipated benefits of completing the Transaction, by payment of certain costs relating to the Transaction, and by the focus of their respective managements on the Transaction for an extended period of time rather than on management opportunities or other issues. The market price of Xeris common stock and/or Strongbridge ordinary shares might decline as a result of any such failures to the extent that the current market prices reflect a market assumption that the Transaction will be completed.

Xeris or Strongbridge may also be negatively impacted if the Transaction Agreement is terminated and their respective boards seek but are unable to find another business combination or strategic transaction offering equivalent or more attractive consideration than the consideration to be provided in the Transaction, or if the respective companies become subject to litigation related to entering into or failing to consummate the Transaction, including direct actions by Xeris stockholders or Strongbridge shareholders, as applicable, against the directors and/or officers of Xeris or Strongbridge for breaches of fiduciary duty, or derivative actions brought by Xeris stockholders or Strongbridge shareholders in the name of the respective companies.

Xeris and Strongbridge will be subject to business uncertainties while the Transaction, including the Scheme, are pending.

Uncertainty about the completion or effect of the Transaction may affect the relationship between Xeris and Strongbridge and their respective suppliers, customers, distributors, licensors and licensees and may have an adverse effect on Xeris and/or Strongbridge, and consequently on the combined company. These uncertainties may cause suppliers, customers, distributors, licensors and others that deal with the parties to seek to change existing business relationships with Xeris or Strongbridge, as applicable, and to delay or defer decisions concerning Xeris or Strongbridge. Changes to existing business relationships, including termination or modification, could negatively affect each of Xeris’ and Strongbridge’s revenues, earnings and cash flow, as well as the market price of Xeris’ common stock and Strongbridge’s ordinary shares.

Xeris and Strongbridge will be subject to certain contractual restrictions while the Transaction is pending.

The Transaction Agreement restricts each of Xeris and Strongbridge, and each of their subsidiaries, from making certain acquisitions and divestitures, entering into certain contracts, incurring certain indebtedness and

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expenditures, paying dividends, repurchasing or issuing securities outside of existing share repurchase and equity award programs, and taking other specified actions until the earlier of the completion of the Transaction or the termination of the Transaction Agreement without the consent of the other party. These restrictions may prevent Xeris and/or Strongbridge from pursuing attractive business opportunities that may arise prior to the completion of the Transaction and could have the effect of delaying or preventing other strategic transactions. Adverse effects arising from the pendency of the Transaction could be exacerbated by any delays in consummation of the Transaction or the termination of the Transaction Agreement. See “The Transaction Agreement—Covenants and Agreements” beginning on page 143 of this joint proxy statement/prospectus.

Third parties may terminate or alter existing contracts or relationships with Xeris or Strongbridge.

Each of Xeris and Strongbridge has contracts with customers, suppliers, vendors, distributors, landlords, licensors, joint venture partners, and other business partners which may require Xeris or Strongbridge, as applicable, to obtain consent from these other parties in connection with the Transaction. If these consents cannot be obtained, the counterparties to these contracts and other third parties with which Xeris and/or Strongbridge currently have relationships may have the ability to terminate, reduce the scope of or otherwise materially adversely alter their relationships with either or both of the parties in anticipation of the Transaction, or with the combined company following the Transaction. The pursuit of such rights may result in Xeris, Strongbridge or the combined company suffering a loss of potential future revenue or incurring liabilities in connection with a breach of such agreements and may lose rights that are material to its business. Any such disruptions could limit the combined company’s ability to achieve the anticipated benefits of the Transaction. The adverse effect of such disruptions could also be exacerbated by a delay in the completion of the Transaction or the termination of the Transaction Agreement.

Xeris and Strongbridge will incur significant transaction costs in connection with the Acquisition.

Xeris and Strongbridge have incurred and expect to incur a number of non-recurring costs associated with the Transaction. These costs and expenses include financial advisory, legal, accounting, consulting and other advisory fees and expenses, reorganization and restructuring costs, severance/employee benefit-related expenses, public company filing fees and other regulatory expenses, printing expenses and other related charges. Some of these costs are payable by Xeris and Strongbridge regardless of whether the Transaction is completed. Moreover, under specified circumstances, Xeris or Strongbridge may be required to pay an expense reimbursement amount of up to $1,950,000. See “The Transaction Agreement—Expenses” and “Expenses Reimbursement Agreement” beginning on pages 156 and 157 respectively of this joint proxy statement/prospectus.

The combined company will also incur restructuring and integration costs in connection with the Transaction. The costs related to restructuring and integration will be expensed as a cost of the ongoing results of operations of the combined company. There are a large number of processes, policies, procedures, operations, technologies and systems that must be integrated in connection with the Merger and the integration of the two companies’ businesses. Although Xeris and Strongbridge expect that the elimination of duplicative costs, strategic benefits, additional income as well as the realization of other efficiencies related to the integration of the businesses may offset incremental transaction-related and restructuring and integration costs over time, any net benefit may not be achieved in the near term or at all. While both Xeris and Strongbridge have assumed that certain expenses would be incurred in connection with the Transaction and other transactions contemplated by the Transaction Agreement, there are many factors beyond their control that could affect the total amount or the timing of the restructuring, integration and implementation expenses.

Xeris directors and executive officers may have interests in the Merger different from the interests of Xeris stockholders generally, and Strongbridge directors and executive officers may have interests in the Acquisition different from the interests of Strongbridge shareholders generally.

Certain of the directors and executive officers of each of Xeris and Strongbridge negotiated the terms of the Transaction Agreement, the Independent Xeris Directors recommended that Xeris stockholders vote in favor of

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adopting the Transaction Agreement and approving the Merger, and the Independent Strongbridge Directors recommended that Strongbridge shareholders vote in favor of the Scheme proposal at the Court Meeting and the other Strongbridge proposals to be proposed at the EGM. These directors and executive officers may have interests in the Transaction which are different from, or in addition to, or in conflict with, those of Xeris stockholders and Strongbridge shareholders, generally. These interests include the continued employment of certain executive officers of Xeris and Strongbridge by the combined company, the continued positions of a number of directors of Xeris and Strongbridge as directors of HoldCo, the payment of cash retention awards to certain Strongbridge executive officers, the treatment in the Merger and the Acquisition of stock options and restricted stock units held by Xeris directors and executive officers or Strongbridge directors and executive officers, as applicable, the effect of the Transaction on any employment, severance or change in control arrangements entered into with Xeris directors and executive officers or Strongbridge directors and executive officers, as applicable, and the indemnification of former Xeris and Strongbridge directors and officers by HoldCo. Xeris stockholders and Strongbridge shareholders should be aware of these interests when they consider recommendations of the respective Independent Xeris Directors and Independent Strongbridge Directors that they vote in favor of the Transaction and the proposals. The Independent Xeris Directors were aware of these interests when they determined that the Transaction Agreement and the Transaction contemplated thereby were advisable and fair to, and in the best interests of, the Xeris stockholders and recommended that the Xeris stockholders adopt the Transaction Agreement. The interests of Xeris directors and executive officers are described in more detail in the section of this joint proxy statement/prospectus entitled “The Transaction—Interests of Xeris’ Directors and Executive Officers in the Transaction” beginning on page 108 of this joint proxy statement/prospectus. Likewise, the Independent Strongbridge Directors were aware of these interests when they determined that the Transaction Agreement and the Transaction contemplated thereby were advisable and fair to, and in the best interests of, the Strongbridge shareholders and recommended that the Strongbridge shareholders approve the Transaction Agreement and the Scheme. The interests of Strongbridge directors and executive officers are described in more detail in the section of this joint proxy statement/prospectus entitled “The Transaction—Interests of Strongbridge’s Executive Officers and Directors” beginning on page 108 of this joint proxy statement/prospectus.

Existing Xeris stockholders and Strongbridge shareholders will have a reduced ownership and voting interest in, and will exercise less influence over management of, HoldCo after the Transaction than they did with respect to Xeris and Strongbridge prior to the Transaction.

Xeris stockholders and Strongbridge shareholders currently have the right to vote in the election of the Xeris Board and the Strongbridge Board, respectively, and on other matters affecting the respective companies. Upon the completion of the Transaction, each Xeris stockholder and each Strongbridge shareholder who receives shares of HoldCo common stock in the Transaction will become a stockholder of HoldCo with a percentage ownership of, and voting interest in, HoldCo that is smaller than such stockholder’s or shareholder’s percentage ownership of, and voting interest in, Xeris or Strongbridge, as applicable, immediately prior to the Transaction. Immediately following the completion of the Transaction, the former Xeris stockholders, as a group, will own approximately 60% of HoldCo and the former Strongbridge shareholders, as a group, will own approximately 40% of HoldCo. In particular, Strongbridge shareholders, as a group, will have less than a majority of the ownership and voting power of HoldCo and, therefore, will be able to exercise less collective influence over the management and policies of HoldCo than they currently exercise over the management and policies of Strongbridge. In addition, former directors of Xeris will constitute a majority of the HoldCo board and former directors of Strongbridge will constitute a minority. Accordingly, Xeris stockholders and Strongbridge shareholders will have less influence on the management and policies of the combined company than they now have on the management and policies of Xeris or Strongbridge, as applicable.

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Shares of HoldCo common stock to be received by Xeris stockholders in the Merger and Strongbridge shareholders in the Acquisition will have rights different from the shares of Xeris common stock and Strongbridge ordinary shares, respectively.

Upon completion of the Transaction, Xeris stockholders and Strongbridge shareholders will no longer be stockholders/shareholders of Xeris and/or Strongbridge, as applicable, but will instead be stockholders of HoldCo. The rights of former Xeris stockholders and Strongbridge shareholders who become HoldCo stockholders will be governed by the HoldCo charter and the HoldCo bylaws, each of which will be adopted, prior to the completion of the Transaction, in substantially the form attached as Annex G and Annex H, respectively. The rights associated with shares of HoldCo common stock are different from the rights associated with shares of Xeris common stock or Strongbridge ordinary shares. See “Comparison of Stockholders’ Rights” beginning on page 191 of this joint proxy statement/prospectus.

Declaration, payment and amounts of dividends, if any, to holders of shares of HoldCo common stock will be uncertain.

The amounts of dividends, if any, that are declared or paid to HoldCo stockholders cannot yet be determined and depends on a number of factors. The HoldCo board will have sole discretion to determine whether any dividends will be declared, when dividends, if any, are declared, and the amounts of such dividends. We expect that such determination would be based on a number of considerations, including HoldCo’s results of operations and capital management plans and the market price of HoldCo common stock, the combined company’s access to capital markets, as well as industry practice and other factors deemed relevant by the HoldCo board. In addition, HoldCo’s ability to pay dividends and the amounts of any dividends ultimately paid in respect of the HoldCo common stock will, in each case, be subject to HoldCo receiving funds, directly or indirectly, from its operating subsidiaries, including Xeris and Strongbridge. Further, the ability of Xeris and Strongbridge to make distributions to HoldCo will depend on satisfying Delaware and Irish law respectively with respect to such distributions, and the ability of Xeris and Strongbridge to receive distributions from their own respective subsidiaries will continue to depend on the laws of the jurisdictions in which such subsidiaries are organized. In addition, such distributions may be limited or prohibited by contractual agreements of either Xeris or Strongbridge. There can be no guarantee that HoldCo stockholders will receive or be entitled to dividends commensurate with the historical dividends of Xeris or Strongbridge. Finally, distributions may be further restricted by current or future debt or other financing agreements.

The Transaction Agreement contains provisions that may discourage other companies from trying to enter into a strategic transaction with either Xeris or Strongbridge for greater consideration.

The Transaction Agreement contains provisions that may discourage a third party from submitting a business combination proposal to Xeris or Strongbridge or both during the pendency of the proposed combination transaction as well as afterward, should the Transaction not be consummated, that might result in greater value to Xeris stockholders or Strongbridge shareholders, as applicable, than the Transaction. These Transaction Agreement provisions include a general prohibition on each company from soliciting, or, subject to certain exceptions, entering into discussions with any third party regarding any Acquisition or combination proposal or offers for competing transactions, subject to limited exceptions. Further, if either the Independent Xeris Directors or the Independent Strongbridge Directors (i) withdraws, qualifies or modifies, or proposes publicly to withdraw, qualify or modify, or fails to make, in each case in any manner adverse to the other party, its approval or recommendation of adopting the Transaction Agreement and approving the Merger or the Scheme, as applicable, or (ii) approves or recommends, or proposes publicly to approve or recommend, any alternative acquisition proposal, Xeris or Strongbridge, as applicable, will still be required to submit the Merger and the Acquisition, respectively, to a vote of its stockholders or shareholders (as applicable) at their respective special meeting(s) unless the Transaction Agreement is earlier terminated in accordance with its terms. For further information, please see the section entitled “The Transaction Agreement” beginning on page 138 of this joint proxy statement/prospectus.

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Moreover, under specified circumstances, either Xeris or Strongbridge may be required to pay an expense reimbursement amount of up to $1,950,000. For further information, please see the sections entitled “The Transaction Agreement—Expenses” and “Expenses Reimbursement Agreement” beginning on pages 156 and 157 respectively of this joint proxy statement/prospectus.

If the Transaction Agreement is terminated and either Xeris or Strongbridge determines to seek another strategic transaction, Xeris or Strongbridge, as applicable, may not be able to negotiate a transaction on terms comparable to, or better than, the terms of this Transaction.

The market price of the combined company’s common stock may be volatile, and holders of the combined company’s common stock could lose a significant portion of their investment due to drops in the market price of the combined company’s common stock following completion of the Transaction.

The market price of the combined company’s common stock may be volatile, and following completion of the Transaction, stockholders may not be able to resell their HoldCo common stock at or above the value at which they acquired the common stock pursuant to the Transaction Agreement or otherwise due to fluctuations in its market price, including changes in price caused by factors unrelated to the combined company’s operating performance or prospects.

Specific factors that may have a significant effect on the market price for the combined company’s common stock include, among others, the following:

The fairness opinion of SVB Leerink delivered prior to the entry into the Transaction Agreement does not reflect changes in circumstances that may have occurred since the date of the opinion.

The Xeris Board have not obtained an updated opinion from its financial advisor either as of the date of this joint proxy statement/prospectus or as of any other date subsequent to the date of the opinion, and Xeris does not anticipate asking its financial advisor to update its opinion. Changes in circumstances, including the operations and prospects of Xeris or Strongbridge, stock prices, general market and economic conditions and other factors, some or all of which may be beyond the control of Xeris or Strongbridge, including the recent coronavirus pandemic (COVID-19) that has caused higher than normal volatility in the financial markets generally, are not reflected in such opinion.

The Independent Xeris Directors’ recommendation that Xeris stockholders vote “FOR” the Xeris transaction proposal, however, is made as of the date of this joint proxy statement/prospectus. For a description of the opinion that the Independent Xeris Directors received from its financial advisor, please refer to “The Transaction—Opinion of Xeris’ Financial Advisor” beginning on page 88 of this joint proxy statement/prospectus.

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The fairness opinion of MTS Securities delivered prior to Strongbridge’s entry into the Transaction Agreement does not reflect changes in circumstances that may have occurred since the date of the opinion.

The Strongbridge Board has not obtained an updated fairness opinion either as of the date of this joint proxy statement/prospectus or as of any other date subsequent to the date of the MTS Opinion from MTS Securities, an affiliate of MTS Health Partners, Strongbridge’s financial advisor. Changes in circumstances, including in the operations and prospects of Strongbridge or Xeris, stock prices, general market and economic conditions and other factors, some or all of which may be beyond the control of Strongbridge and Xeris, including the recent COVID-19 pandemic that has caused higher than normal volatility in the financial markets generally, are not reflected in such opinion. The MTS Opinion does not speak as of any date other than the date of the opinion. For a description of the MTS Opinion, please refer to “The Transaction—Opinion of Strongbridge’s Financial Advisor” beginning on page 98 of this joint proxy statement/ prospectus.

The Independent Strongbridge Directors’ recommendation that Strongbridge shareholders vote “FOR” the resolutions to approve the Scheme of Arrangement at the Strongbridge Special Meetings, however, is made as of the date of this joint proxy statement/prospectus.

Xeris and Strongbridge shareholders will not be entitled to appraisal rights in the Transaction.

Appraisal rights are statutory rights that, if applicable under law, enable stockholders to dissent from an extraordinary transaction, such as a merger, and to demand that the corporation pay the fair value for their shares as determined by a court in a judicial proceeding instead of receiving the consideration offered to stockholders in connection with the extraordinary transaction. Under the DGCL, stockholders do not have appraisal rights if the shares of stock they hold, as of the record date for determination of stockholders entitled to vote at the meeting of stockholders to act upon a merger, are either (i) listed on a national securities exchange or (ii) held of record by more than 2,000 holders. Notwithstanding the foregoing, appraisal rights are available if stockholders are required by the terms of the Transaction Agreement to accept for their shares anything other than (a) shares of stock of the surviving corporation, (b) shares of stock of another corporation that will either be listed on a national securities exchange or held of record by more than 2,000 holders, (c) cash instead of fractional shares or (d) any combination of clauses (a)-(c).

Because Xeris common stock is listed on the Nasdaq, a national securities exchange, and is expected to continue to be so listed on the record date for the Xeris Special Meeting, and because Xeris stockholders will receive shares of HoldCo common stock in the Merger, which is expected to be listed on the Nasdaq upon the effective time of the Transaction, Xeris stockholders will not be entitled to appraisal rights in the Merger with respect to their shares of Xeris common stock.

If Strongbridge shareholders approve the Scheme and the Irish High Court sanctions the Scheme, no Strongbridge shareholder will have “dissenters’ or “appraisal” rights under Irish law or otherwise have any right to seek a court appraisal of the value of the Strongbridge ordinary shares. If the Scheme becomes effective, all Strongbridge shareholders who hold Strongbridge ordinary shares will receive the same Scheme Consideration per Strongbridge ordinary share.

Risks Related to the CVRs

You may not receive any payment pursuant to the CVRs

Your right to receive any future payment on the CVRs will be contingent upon the achievement of certain agreed upon regulatory and sales milestones within the time periods specified in the CVR Agreement. If any of the milestones are not achieved for any reason within the applicable time periods, no payment will be made under the CVRs, and the CVRs will expire and become valueless. Accordingly, the value, if any, of the CVRs is speculative, and the CVRs may ultimately have no value. See “Contingent Value Rights Agreement” beginning on page 159 of this joint proxy statement/prospectus.

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Any payment on the CVRs may be, at HoldCo’s sole discretion, made in a number of shares of HoldCo common stock based on the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date, which means you may receive shares of HoldCo common stock with a value less than the cash value of the corresponding Milestone Payment if the value of HoldCo common stock at the time of such Milestone Payment is less than the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date.

If a Milestone is achieved, the payment on such CVR will be made in cash, additional shares of HoldCo common stock or a combination of cash and additional shares of HoldCo common stock, at HoldCo’s sole discretion. Any payment amounts made in HoldCo common stock will be based on the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date. The market price of Xeris common stock has fluctuated and will continue to fluctuate over time, and no guarantee can be made that HoldCo common stock will trade above the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date at or around the time of any CVR payment if such payment is made in HoldCo common stock in whole or in part. Therefore, you may receive shares of HoldCo common stock with a value less than the cash value of the corresponding Milestone Payment if the value of HoldCo common stock at the time of such Milestone Payment is less than the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date. See “Contingent Value Rights Agreement” beginning on page 159 of this joint proxy statement/prospectus.

The CVRs are non-transferable and non-tradeable, and the value of the CVRs is only realizable to the extent that the Milestones are achieved.

Holders of the CVRs are not permitted to sell, assign, transfer, pledge, encumber, or in any other manner dispose of the CVRs, in whole or in part, other than in certain highly limited circumstances specified in the CVR Agreement, and holders of the CVRs will receive payments on the CVR in whole or in part only if one or more Milestones are achieved. The CVRs will not be listed on any quotation system or traded on any securities exchange. As a result, holders of the CVRs may not realize full or any value from the CVRs for several years, if ever. See “Contingent Value Rights Agreement” beginning on page 159 of this joint proxy statement/prospectus.

The U.S. federal income tax treatment of the CVRs is unclear.

The U.S. federal income tax treatment of the CVRs is uncertain. There is no clear legal authority directly addressing the U.S. federal income tax treatment of the receipt of, and payments on, the CVRs. Whether the receipt of CVR is treated as an “open transaction” or a “closed transaction” for U.S. federal income tax purposes, and whether the CVR is paid in cash, additional shares of HoldCo common stock or a combination of cash and additional shares of HoldCo common stock, will affect the amount, timing, and character of any gain or loss recognized by a U.S. Holder (as defined in “Tax Consequences of the Scheme—U.S. Federal Income Tax Consequences of the Scheme to Holders of Strongbridge Ordinary Shares”) in the Scheme and upon the receipt of payments under a CVR. See “Tax Consequences of the Scheme—U.S. Federal Income Tax Consequences of the Scheme to Holders of Strongbridge Ordinary Shares—Potential Treatments of the CVR Consideration” beginning on page 121 of this joint proxy statement/prospectus.

Risks Related to the Combined Company

Failure to successfully integrate the businesses of Xeris and Strongbridge in the expected timeframe may adversely affect the combined company’s future results.

Xeris and Strongbridge entered into the Transaction Agreement with the expectation that the Transaction will result in various benefits, including certain cost savings and operational efficiencies or synergies. To realize these anticipated benefits, the businesses of Xeris and Strongbridge must be successfully integrated. Historically, Xeris and Strongbridge have been independent companies, and they will continue to be operated as such until the completion of the Transaction. The integration may be complex and time consuming and may require substantial

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resources and effort. The management of the combined company may face significant challenges in consolidating the operations of Xeris and Strongbridge, integrating the two companies’ technologies, procedures, and policies, as well as addressing the different corporate cultures of the two companies. If the companies are not successfully integrated, the anticipated benefits of the Transaction may not be realized fully (or at all) or may take longer to realize than expected.

The combined company must successfully combine the businesses of Xeris and Strongbridge in a manner that permits these cost savings and synergies to be realized. In addition, the combined company must achieve the anticipated savings and synergies in a timely manner and without adversely affecting current revenues and investments in future growth. If the combined company is not able to successfully achieve these objectives, the anticipated benefits of the Transaction may not be realized fully or at all or may take longer to realize than expected. A variety of factors may adversely affect the combined company’s ability to realize the currently expected operating synergies, savings and other benefits of the Transaction, including the failure to identify and eliminate duplicative programs and the failure to otherwise integrate Xeris’ and Strongbridge’s respective businesses.

HoldCo has no operating or financial history and the unaudited pro forma condensed combined financial statements included in this joint proxy statement/prospectus are preliminary. Therefore, the actual financial condition and results of operations of HoldCo after the Transaction may differ materially.

HoldCo has been recently incorporated in connection with the proposed transaction and has no operating history or revenues. This joint proxy statement/prospectus includes unaudited pro forma condensed combined financial information for HoldCo, which we refer to as the pro forma financial statements, that combine the audited historical consolidated statement of operations of Xeris for the year ended December 31, 2020 with the audited historical consolidated statement of operations of Strongbridge for the year ended December 31, 2020, and the unaudited historical consolidated statement of operations of Xeris for the three months ended March 31, 2021 with the unaudited historical consolidated statement of operations of Strongbridge for the three months ended March 31, 2021, in each case adjusted to give effect to the Transaction as if it had been consummated on January 1, 2020, and should be read in conjunction with such financial statements and accompanying notes which are incorporated by reference in this joint proxy statement/prospectus. The unaudited pro forma condensed combined balance sheet of HoldCo as of March 31, 2021, combines the audited historical balance sheets of Xeris and Strongbridge as of March 31, 2021, and gives pro forma effect to the Transaction as if it been consummated on March 31, 2021. The pro forma financial statements are presented for illustrative purposes only, are based on certain assumptions, address a hypothetical situation and reflect limited historical financial data. The pro forma condensed combined financial information reflects adjustments that were developed using preliminary estimates based on available information and various assumptions and may be revised as additional information becomes available. The pro forma financial statements do not include, among other things, estimated cost or growth synergies, adjustments related to restructuring or integration activities, future acquisitions or disposals not yet known or probable, including those that may be required by regulatory or governmental authorities in connection with the Transaction, or impacts of transaction-related change in control provisions that are currently not factually supportable and/or probable of occurring. Therefore, the pro forma financial statements are presented for informational purposes only and are not necessarily indicative of what the combined company’s actual financial condition or results of operations would have been had the Transaction been completed on the dates indicated. The final transaction accounting adjustments may differ materially from the pro forma adjustments reflected in this joint proxy statement/prospectus. Accordingly, HoldCo’s business, assets, results of operations and financial condition may differ significantly from those indicated by the pro forma financial statements included in this joint proxy statement/prospectus. For more information, see “Unaudited Pro Forma Condensed Combined Financial Information” beginning on page 167 of this joint proxy statement/prospectus.

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The financial analyses and forecasts considered by Xeris and Strongbridge and their respective financial advisors may not be realized, which may adversely affect the market price of HoldCo common stock following the completion of the Transaction.

In performing their financial analyses and rendering their opinions regarding the fairness, from a financial point of view, of the Xeris exchange ratio and Strongbridge exchange ratio, as applicable, the respective financial advisor to Xeris and Strongbridge relied on, among other things, internal stand-alone financial analyses and forecasts as separately provided to each respective financial advisor by Xeris and Strongbridge. See “Xeris Unaudited Prospective Financial Information” and “Strongbridge Unaudited Prospective Financial Information.” These analyses and forecasts were prepared by, or as directed by, the managements of Xeris or Strongbridge, as applicable. None of these analyses or forecasts were prepared with a view towards public disclosure or compliance with the published guidelines of the SEC or U.S. GAAP, or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of financial forecasts. These projections are inherently based on various estimates and assumptions that are subject to the judgment of those preparing them. These projections are also subject to significant economic, competitive, industry and other uncertainties and contingencies, all of which are difficult or impossible to predict and many of which are beyond the control of Xeris and Strongbridge. As a result of these contingencies, there can be no assurance that the prospective financial forecasts of Xeris or Strongbridge will be realized or that actual results will not be significantly higher or lower than projected. In view of these uncertainties, the inclusion of the prospective financial forecasts of Xeris and Strongbridge in this joint proxy statement/prospectus should not be regarded as an indication that the Xeris board, the Strongbridge board, Xeris, Strongbridge, HoldCo, or any other recipient of this information considered, or now considers, it to be an assurance of the achievement of future results.

Combining the businesses of Xeris and Strongbridge may be more difficult, costly or time consuming than expected, which may adversely affect the combined company’s results and negatively affect the value of HoldCo common stock following the Transaction.

Xeris and Strongbridge have entered into the Transaction Agreement because each believes that the Transaction will be beneficial to its respective company and stockholders, as applicable, and that combining the businesses of Xeris and Strongbridge will produce benefits and cost savings. Xeris and Strongbridge have historically operated as independent companies and will continue to do so until the completion of the Transaction. Following the completion of the Transaction, HoldCo’s management will need to integrate Xeris’ and Strongbridge’s respective business. The combination of two independent businesses is a complex, costly and time-consuming process and the management of the combined company may face significant challenges in implementing such integration, many of which may be beyond the control of management, including, without limitation:

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Some of these factors will be outside of the control of Xeris and Strongbridge, and any one of them could result in increased costs and diversion of management’s time and energy as well as decreases in the amount of expected revenue which could materially impact Xeris’ and/or Strongbridge’s business, financial conditions and results of operations. The integration process and other disruptions resulting from the Transaction may also adversely affect the combined company’s relationships with employees, suppliers, customers, distributors, licensors and others with whom Xeris and Strongbridge have business or other dealings, and difficulties in integrating the businesses or regulatory functions of Xeris and Strongbridge could harm the reputation of the combined company. If the combined company is not able to successfully combine the businesses of Xeris and Strongbridge in an efficient, cost-effective and timely manner, the anticipated benefits and cost savings of the Transaction may not be realized fully, or at all, or may take longer to realize than expected, and the value of HoldCo common stock, the revenue, levels of expenses and results of operations may be affected adversely. If the combined company is not able to adequately address integration challenges, the combined company may be unable to successfully integrate Xeris’ and Strongbridge’s operations or realize the anticipated benefits of the Transaction.

Whether or not the Transaction is completed, the announcement and pendency of the Transaction will divert significant management resources to complete the Transaction, which could have an adverse effect on their respective businesses, financial results, and/or market prices.

Whether or not the Transaction is completed, the announcement and pendency of the Transaction could cause disruptions in the businesses of Xeris and Strongbridge by directing the attention of management of each of Xeris and Strongbridge toward the completion of the Transaction. Xeris and Strongbridge have each diverted significant management resources in an effort to complete the Transaction and are each subject to restrictions contained in the Transaction Agreement on the conduct of their respective businesses. If the efforts and actions required of Xeris and Strongbridge in order to consummate the Transaction and other transactions contemplated by the Transaction Agreement are more difficult, costly or time consuming than expected, such efforts and actions could result in the additional diversion of each company’s management’s attention and resources or the disruption or interruption of, or the loss of momentum in, each company’s ongoing businesses, which could adversely affect the business and financial results of Xeris or Strongbridge, as applicable. If the Transaction is not completed, Xeris and Strongbridge will have incurred significant costs, including the diversion of management resources, for which they will have received little or no benefit.

HoldCo’s future results will suffer if it does not effectively manage its expanded operations following the Transaction.

Following the Transaction, the size of the business of HoldCo will increase significantly beyond the current size of both Xeris’ and Strongbridge’s current businesses. HoldCo’s future success depends, in part, upon its ability to manage this expanded business, which may pose substantial challenges for management, including challenges related to the management and monitoring of new operations and associated increased costs and complexity. There can be no assurance that the combined company will be successful or that it will realize the expected operating efficiencies, cost savings, revenue enhancements and other benefits currently anticipated from the Transaction.

HoldCo will incur significant costs in connection with the integration of the combined company.

There are a large number of processes, policies, procedures, operations, technologies and systems that must be integrated in connection with the Transaction. While both Xeris and Strongbridge have assumed that a certain level of expenses would be incurred in connection with the Transaction, there are many factors beyond their control that could affect the total amount of, or the timing of, anticipated expenses with respect to the integration and implementation of the combined businesses.

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There may also be additional unanticipated significant costs in connection with the Transaction that the combined company may not recoup. These costs and expenses could reduce the benefits and additional income HoldCo expects to achieve from the Transaction. Although HoldCo expects that these benefits will offset the Transaction expenses and implementation costs over time, this net benefit may not be achieved in the near term or at all.

The combined company will be exposed to the risks related to international operations.

Strongbridge is headquartered in Dublin, Ireland, from which it conducts a portion of its operations. The combined company may also pursue growth opportunities in sales outside the U.S. for any approved products, which could expose it to risks associated with international sales and operations. Therefore, the combined company will have exposure to risks of operating in many foreign countries, including:

Any one or more of the above factors could adversely affect the international operations of the combined company and could significantly affect the combined company’s results of operations, financial condition and cash flows.

The results of operations of the combined company will be dependent to a large extent upon the global economy. Geopolitical factors such as terrorist activities, armed conflict or global health conditions that adversely affect the global economy may adversely affect the operating results and financial condition of the combined company.

Changes in tax laws or regulations that are applied adversely to the combined company or our customers may have a material adverse effect on our business, cash flow, financial condition or results of operations.

New income, sales, use or other tax laws, statutes, rules, regulations or ordinances could be enacted at any time, which could adversely affect the combined company’s business operations and financial performance. Further, existing tax laws, statutes, rules, regulations or ordinances could be interpreted, changed, modified or

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applied adversely to the combined company. In recent years, many such changes have been made and changes are likely to continue to occur in the future. On May 28, 2021, the Treasury Department released the General Explanations of the Administration’s Fiscal Year 2022 Revenue Proposals (commonly referred to as the “Green Book”), which includes an increase in the U.S. corporate income tax rate from 21% to 28%, doubling the rate of tax on certain earnings of foreign subsidiaries, and a 15% minimum tax on worldwide book income. If any or all of these (or similar) proposals are ultimately enacted into law, in whole or in part, they could have a negative impact on the combined company’s effective tax rate. Future guidance from the IRS and other tax authorities or future changes in tax legislation and changes in corporate tax rates, the taxation of foreign earnings, and the deductibility of expenses under current law or future reform legislation could have a material impact on Xeris, Strongbridge or the combined company.

Our ability to use net operating losses and credits to offset future taxable income may be subject to limitations.

As of December 31, 2020, Xeris had U.S. federal and state net operating losses of approximately $284.8 million and $220.6 million, respectively. As of December 31, 2020, Strongbridge had U.S. federal and state net operating losses of approximately $26.3 million and $26.5 million, respectively. A portion of Strongbridge’s state net operating loss carryforwards will begin to expire, if not utilized, in 2031. A portion of Xeris’ federal and state net operating loss carryforwards will begin to expire, if not utilized, in 2025. Net operating losses that expire unused will be unavailable to offset future income tax liabilities. Federal net operating losses incurred in 2018 and in future years may be carried forward indefinitely, but the deductibility of such federal net operating losses is limited. In addition, as of December 31, 2020, Xeris had $5.8 million of U.S. federal research and development tax credit carryforwards which begin to expire in 2025, $2.2 million of U.S. federal orphan drug tax credit carryforwards which begin to expire in 2025, and $1.7 million of state income tax credits, to reduce future tax liabilities. As of December 31, 2020, Strongbridge had $0.2 million of U.S. federal research and development tax credit carryforwards which begin to expire in 2031 and $16.6 million of U.S. federal orphan drug tax credit carryforwards which begin to expire in 2032, to reduce future tax liabilities. Under Sections 382 and 383 of the Code and corresponding provisions of state law, if a corporation undergoes an “ownership change,” which is generally defined as a greater than 50% change, by value, in its equity ownership over a three (3)-year period, the corporation’s ability to use its pre-change net operating loss carryforwards and other pre-change tax attributes to offset its post-change income or taxes may be limited. Xeris or Strongbridge may have experienced an ownership change in the past. It is expected that Strongbridge will, and Xeris may, experience an ownership change as a result of the Transaction. Further, HoldCo may experience ownership changes in the future as a result of subsequent shifts in HoldCo’s stock ownership, some of which may be outside of HoldCo’s control. If an ownership change occurs and Xeris’, Strongbridge’s or HoldCo’s ability to utilize their net operating loss or tax credit carryforwards is materially limited, it could harm HoldCo’s future operating results by effectively increasing HoldCo’s future tax obligations. In addition, at the state level, there may be periods during which the use of net operating loss carryforwards is suspended or otherwise limited, which could accelerate or permanently increase state taxes owed by HoldCo.

Use of HoldCo stock for future acquisitions may be limited.

HoldCo’s ability to use HoldCo stock for future acquisitions without triggering an ownership change for the purposes of Sections 382 and 383 of the Code may be limited for three (3) years following the Transaction, depending on whether one or more ownership changes results from the Transaction.

The combined company may be exposed to increased litigation, which could have an adverse effect on the combined company’s business and operations.

The combined company may be exposed to increased litigation from stockholders, customers, suppliers, consumers and other third parties due to the combination of Xeris’ business and Strongbridge’s business following the Transaction. Such litigation may have an adverse impact on the combined company’s business and results of operations or may cause disruptions to the combined company’s operations.

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The HoldCo bylaws will provide that the Court of Chancery of the State of Delaware or the federal district courts of the United States shall be the exclusive forum for certain disputes between HoldCo and its shareholders, which could limit shareholders’ ability to obtain a favorable judicial forum for disputes with HoldCo. If this exclusive forum provision is found to be inapplicable or unenforceable, HoldCo may not achieve the intended benefits of such provision.

The HoldCo bylaws will provide that unless HoldCo consents in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall be the sole and exclusive forum for any state law claims for (i) any derivative action or proceeding brought on behalf of HoldCo, (ii) any action asserting a claim of, or a claim based on, a breach of a fiduciary duty owed by any HoldCo director, officer or other employee to HoldCo or HoldCo’s stockholders, (iii) any action asserting a claim arising pursuant to any provision of the DGCL, or (iv) any action asserting a claim governed by the internal affairs doctrine, in each case subject to the Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein. This provision will not apply to any causes of action arising under the Securities Act or the Exchange Act. In addition, the bylaws will further provide that the federal district courts of the United States shall be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act.

This forum selection provision may limit a shareholder’s ability to bring a claim in a judicial forum that it finds favorable or cost-efficient for disputes with HoldCo or any director, officer, employee or agent of HoldCo, which may discourage such lawsuits, or increase the costs to a shareholder of bringing such lawsuits, against HoldCo and such persons.

The enforceability of forum selection provisions in other companies’ articles of incorporation, bylaws or similar governing documents has been challenged in legal proceedings, and it is possible that in connection with any action a court could find the forum selection provision contained in HoldCo’s bylaws to be inapplicable or unenforceable in such action. If a court were to find this forum selection provision inapplicable or unenforceable, HoldCo may incur additional costs associated with resolving such matters in other jurisdictions, which could adversely impact HoldCo’s operating or financial condition or performance.

Risks Related to Xeris’ Business

You should read and consider risk factors specific to Xeris’ businesses that will also affect the combined company after the completion of the Transaction. These risks are described in Part I, Item 1A of Xeris’ Annual Report on Form 10-K for the fiscal year ended December 31, 2020, and in other documents that are incorporated by reference into this document. See “Where You Can Find More Information” beginning on page 205 of this joint proxy statement/prospectus for the location of information incorporated by reference in this joint proxy statement/prospectus.

Risks Related to Strongbridge’s Business

You should read and consider risk factors specific to Strongbridge’s businesses that will also affect the combined company after the completion of the Transaction. These risks are described in Part I, Item 1A of Strongbridge’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, and in other documents that are incorporated by reference into this document. See “Where You Can Find More Information” beginning on page 205 of this joint proxy statement/prospectus for the location of information incorporated by reference in this joint proxy statement/prospectus.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This joint proxy statement/prospectus and the documents incorporated into it by reference contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 concerning Xeris, Strongbridge, HoldCo, the Transaction and other transactions contemplated by the Transaction Agreement that involve risks and uncertainties. All statements, trend analyses and other information contained herein about the markets for the services and products of HoldCo, Xeris and Strongbridge and future trends, plans, events, results of operations or financial condition, as well as other statements identified by the use of forward-looking terminology, including “anticipate,” “believe,” “plan,” “could,” “estimate,” “expect,” “goal,” “forecast,” “guidance,” “predict,” “project,” “intend,” “may,” “possible,” “potential” or the negative of these terms or other similar words, phrases or expressions, constitute forward-looking statements. In particular, statements, express or implied, concerning future actions, conditions or events, future operating results, the ability to generate sales, income or cash flow, to realize cost savings or other benefits associated with the Transaction or to pay dividends or repurchase shares are forward-looking statements. These forward-looking statements are not historical facts but instead represent only HoldCo’s, Xeris’ and Strongbridge’s expectations, estimates and projections regarding future events, based on current beliefs of management as well as assumptions made by, and information currently available to, management. These statements are not guarantees of future performance and involve certain risks and uncertainties that are difficult to predict, many of which are outside the control of HoldCo, Xeris and Strongbridge, which may include the risk factors set forth below and other market, business, legal and operational uncertainties discussed elsewhere in this joint proxy statement/prospectus and the documents which are incorporated herein by reference. Those uncertainties include, but are not limited to:

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The foregoing list of factors is not exhaustive. You should carefully consider the foregoing factors and the other risks and uncertainties that affect our businesses described herein and in Xeris’ and Strongbridge’s most recent Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K and other documents filed from time to time with the SEC or incorporated herein by reference.

Actual results might differ materially from those expressed or implied by these forward-looking statements because these forward-looking statements are subject to assumptions and uncertainties. You are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date of this joint proxy statement/prospectus or the date of any document incorporated by reference. All subsequent written and oral forward-looking statements concerning the Merger, the Acquisition or the other matters addressed in this joint proxy statement/prospectus and attributable to HoldCo, Xeris or Strongbridge or any person acting on their behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section. Except as required by applicable law or regulation, none of HoldCo, Xeris or Strongbridge undertakes any obligation to update publicly or revise any forward-looking statements, whether as a result of new information, future events or otherwise. In light of these risks, uncertainties and assumptions, the forward-looking events discussed in this joint proxy statement/prospectus or any document incorporated by reference might not occur.

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PART 1—THE TRANSACTION AND THE SPECIAL MEETINGS

THE SPECIAL MEETING OF XERIS’ SHAREHOLDERS

Overview

This joint proxy statement/prospectus is being provided to Xeris stockholders as part of a solicitation of proxies by the Independent Xeris Directors for use at the Xeris Special Meeting and at any adjournments or postponements of such meeting. This joint proxy statement/prospectus is being furnished to Xeris stockholders on or about July 30, 2021. In addition, this joint proxy statement/prospectus constitutes a prospectus for HoldCo in connection with the issuance by HoldCo of shares of common stock to be delivered to Xeris stockholders in connection with the Transaction. This joint proxy statement/prospectus provides Xeris stockholders with information they need to be able to vote or instruct their vote to be cast at the Special Meeting.

Date, Time and Place of the Xeris Special Meeting

Xeris will hold the Special Meeting on September 14, 2021 at 8:00 a.m. Central Time. The Special Meeting will be a virtual meeting due to the public health impact of the COVID-19 pandemic. Xeris stockholders will be able to attend and participate in the Special Meeting online (see below for details regarding admission), where Xeris stockholders will be able to listen to the Special Meeting live, vote electronically and submit questions.

Attendance and Admission

The Special Meeting will be held in a virtual-only meeting format. Only stockholders of record and beneficial owners of shares of our common stock as of the close of business on July 21, 2021, the record date, may attend and participate in the Special Meeting, including voting and asking questions during the Special Meeting. You will not be able to attend the Special Meeting physically in person.

In order to attend the Special Meeting, you must register in advance at www.proxydocs.com/XERS prior to the deadline of September 13, 2021 at 4:00 p.m. Central Time and use the 16-digit control number included on your proxy card or voting instruction form, as applicable. Upon completing your registration, you will receive further instructions via email, including a unique link that will allow you to access the Special Meeting and to vote and submit questions during the Special Meeting.

As part of the registration process, you must enter the control number that is located on the proxy card. If you are a beneficial owner of shares of our common stock registered in the name of a broker, bank or other nominee, you will also need to provide the registered name on your account and the name of your broker, bank or other nominee as part of the registration process.

On the day of the Special Meeting, September 14, 2021, stockholders may begin to log in to the virtual-only Special Meeting 15 minutes prior to the Special Meeting. The Special Meeting will begin promptly at 8:00 a.m. Central Time.

We will have technicians ready to assist you with any technical difficulties you may have accessing the Special Meeting. If you encounter any difficulties accessing the virtual-only Special Meeting platform, including any difficulties voting or submitting questions, you may call the technical support number that will be posted in your instructional email.

Further instructions on how to attend, participate in and vote at the Special Meeting, including how to demonstrate your ownership of our stock as of the record date, are available at www.proxydocs.com/XERS.

Proposals

At the Special Meeting, Xeris stockholders will vote upon proposals to:

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Record Date; Outstanding Stock; Stock Entitled to Vote

Only holders of shares of Xeris common stock at the close of business (Eastern Time in the U.S.) on July 21, 2021, the record date for the Special Meeting, will be entitled to notice of, and to vote at, the Special Meeting or any adjournments or postponements thereof. On the Xeris record date, there were 66,497,370 shares of Xeris common stock outstanding, held by 42 holders of record. Each outstanding Xeris share of common stock is entitled to one vote on each proposal and any other matter properly coming before the Special Meeting.

Quorum

Our Amended and Restated Bylaws, or bylaws, provide that a majority of the outstanding shares entitled to vote, present in person or represented by proxy, will constitute a quorum for the transaction of business at the Special Meeting.

Under the General Corporation Law of the State of Delaware, shares that are voted “abstain” or “withheld” and broker “non-votes” are counted as present for purposes of determining whether a quorum is present at the Special Meeting. If a quorum is not present, the meeting may be adjourned until a quorum is obtained.

Vote Required; Recommendation of the Independent Xeris Directors

Proposal to adopt the Transaction Agreement, dated as of May 24, 2021, among Xeris, Strongbridge, HoldCo and MergerSub

Xeris stockholders are considering and voting on a proposal to adopt the Transaction Agreement. You should carefully read this joint proxy statement/prospectus in its entirety for more detailed information concerning the Transaction. In particular, you are directed to the Transaction Agreement and the Conditions Appendix, which are attached as Annex A and Annex B, respectively to this joint proxy statement/prospectus.

The adoption of the Transaction Agreement requires the affirmative vote of holders of a majority of the shares of Xeris common stock outstanding and entitled to vote on this proposal. Because the vote required to approve this proposal is based upon the total number of shares of outstanding Xeris common stock, abstentions, failures to vote and broker non-votes will have the same effect as a vote against the proposal to adopt the Transaction Agreement.

The Independent Xeris Directors recommend that you vote “FOR” the proposal to adopt the Transaction Agreement.

In considering the recommendation of the Independent Xeris Directors, Xeris stockholders should be aware that directors and executive officers of Xeris have interests in the proposed transaction that are in addition to, or different from, any interests they might have as stockholders. See “The Transaction—Interests of Xeris’ Directors and Executive Officers in the Transaction”.

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Proposal to approve, immediately after and conditioned on the consummation of the Acquisition contemplated by the Transaction Agreement, the Merger

Xeris stockholders are considering and voting on a proposal to approve the Merger. You should carefully read this joint proxy statement/prospectus in its entirety for more detailed information concerning the Merger. In particular, you are directed to the Transaction Agreement and the Conditions Appendix, which are attached as Annex A and Annex B, respectively to this joint proxy statement/prospectus.

The approval of the Merger requires the affirmative vote of holders of a majority of the shares of Xeris common stock outstanding and entitled to vote on this proposal. Because the vote required to approve this proposal is based upon the total number of shares of outstanding Xeris common stock, abstentions, failures to vote and broker non-votes will have the same effect as a vote against the proposal to approve the Merger.

The Independent Xeris Directors recommend that you vote “FOR” the proposal to approve the Merger.

In considering the recommendation of the Independent Xeris Directors, Xeris stockholders should be aware that directors and executive officers of Xeris have interests in the proposed transaction that are in addition to, or different from, any interests they might have as stockholders. See “The Transaction—Interests of Xeris’ Directors and Executive Officers in the Transaction” beginning on page 108.

Proposal to adjourn the Special Meeting

Xeris stockholders may be asked to vote on a proposal to approve adjournments or postponements of the Special Meeting to another time or place if necessary or appropriate in order (i) to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to adopt the Transaction Agreement and approve the Merger, (ii) to provide to Xeris stockholders in advance of the Special Meeting any supplement or amendment to the joint proxy statement/prospectus or (iii) to disseminate any other information which is material to the Xeris stockholders voting at the Special Meeting.

Approval of the Xeris adjournment proposal requires the affirmative vote of a majority of the votes properly cast for or against such proposal at the Special Meeting. Abstentions, failures to vote and broker non-votes will have no effect on the outcome of proposal. Approval of this proposal is not a condition to the completion of the Transaction and whether or not this proposal is approved will have no impact on the completion of the Transaction.

The Independent Xeris Directors recommend that you vote “FOR” the Xeris adjournment proposal.

Stock Ownership and Voting by Xeris’ Officers and Directors

As of the Xeris record date, the Xeris directors and executive officers had the right to vote approximately 813,233 shares of Xeris common stock, representing approximately 1.22% of the shares of Xeris common stock then outstanding and entitled to vote at the meeting. It is expected that the Independent Xeris Directors and executive officers who are stockholders of Xeris will vote “FOR” the proposal to adopt the Transaction Agreement, “FOR” the proposal to approve the Merger, and “FOR” the Xeris adjournment proposal, although none of them has entered into any agreement requiring them to do so.

Voting Your Shares of Common Stock

Xeris stockholders may vote online while attending the Special Meeting or by proxy. Xeris recommends that you submit your proxy even if you plan to virtually attend the Special Meeting. If you vote by proxy, you may change your vote, among other ways, if you virtually attend and vote at the Special Meeting.

If you do not wish to vote online during the Special Meeting, you may vote by proxy. You can vote by proxy over the internet by following the instructions provided on your proxy card as described in the proxy

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materials. In order to be counted, proxies submitted by internet must be received by the cutoff time of 7:59 a.m. Central Time on September 14, 2021. Proxies submitted by mail must be received before the start of the Special Meeting.

If you complete and submit your proxy before the Special Meeting, the persons named as proxies will vote the shares of common stock represented by your proxy in accordance with your instructions. If you submit a proxy without giving voting instructions, your shares of common stock will be voted in the manner recommended by the Independent Xeris Directors on all matters presented in this joint proxy statement/prospectus. You may also authorize another person or persons to act for you as proxy in a writing, signed by you or your authorized representative, specifying the details of those proxies’ authority. The original writing must be given to each of the named proxies, although it may be sent to them by electronic transmission if, from that transmission, it can be determined that the transmission was authorized by you.

If any other matters are properly presented for consideration at the Special Meeting, including, among other things, consideration of a motion to adjourn the Special Meeting to another time or place (including, without limitation, for the purpose of soliciting additional proxies), the persons named in your proxy and acting thereunder will have discretion to vote on those matters in accordance with their best judgment. We do not currently anticipate that any other matters will be raised at the Special Meeting.

Xeris stockholders should not send in their stock certificates with their proxy cards. As described on page 49 of this joint proxy statement/prospectus, Xeris stockholders will be sent materials for exchanging shares of Xeris common stock shortly after the completion of the Transaction.

Voting Shares Held in Street Name

If your shares of common stock are held in an account through a broker, bank or other nominee, you must instruct the broker, bank or other nominee how to vote your shares of common stock by following the instructions that the broker, bank or other nominee provides you along with this joint proxy statement/prospectus. Your broker, bank or other nominee may have an earlier deadline by which you must provide instructions to it as to how to vote your shares of common stock, so you should read carefully the materials provided to you by your broker, bank or other nominee.

If you do not provide a signed voting instruction form to your bank, broker or other nominee, your shares of common stock will not be voted on any proposal on which the bank, broker or other nominee does not have discretionary authority to vote. This is referred to in this joint proxy statement/prospectus and in general as a broker non-vote. In these cases, the bank, broker or other nominee will not be able to vote your shares of common stock on those matters for which specific authorization is required. Shares of common stock constituting broker non-votes on proposal 1 and proposal 2 are the same as voting against such proposals, and broker non-votes for proposal 3 will have no outcome on proposal 3.

Accordingly, if you fail to provide a signed voting instruction form to your bank, broker or other nominee, your shares of common stock held through such bank, broker or other nominee will not be voted.

Revoking Your Proxy

You may revoke your proxy by (1) following the instructions on the proxy card and entering a new vote by mail that we receive before the start of the Special Meeting or over the internet by the cutoff time of 7:59 a.m. Central Time on September 14, 2021, (2) attending and voting online at the Special Meeting (although attendance at the Special Meeting will not in and of itself revoke a proxy), or (3) filing an instrument in writing revoking the proxy or another duly executed proxy bearing a later date with our corporate secretary. Any written notice of revocation or subsequent proxy card must be received by our corporate secretary prior to the taking of the vote at the Special Meeting. Such written notice of revocation or subsequent proxy card should be hand delivered to our corporate secretary or sent to our principal executive offices at Xeris Pharmaceuticals, Inc., 180 N. LaSalle Street, Suite 1600, Chicago, Illinois 60601, Attention: Corporate Secretary.

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If a broker, bank, or other nominee holds your shares of common stock, you must contact such broker, bank, or nominee in order to find out how to change your vote.

Costs of Solicitation

Xeris will solicit proxies by mail. In addition, the directors, officers and employees of Xeris may solicit proxies from its stockholders by telephone, electronic communication, or in person, but will not receive any additional compensation for their services. Xeris will make arrangements with brokerage houses and other custodians, nominees, and fiduciaries for forwarding proxy solicitation material to the beneficial owners of shares of Xeris common stock held of record by those persons and will reimburse them for their reasonable out-of-pocket expenses incurred in forwarding such proxy solicitation materials.

Xeris has engaged a professional proxy solicitation firm, Innisfree M&A Incorporated (referred to as Innisfree), to assist in soliciting proxies. As compensation for its services, Xeris has agreed to pay Innisfree a solicitation fee of $20,000 plus reasonable out-of-pocket expenses.

Other Business

Xeris is not aware of any other business to be acted upon at the Special Meeting. If, however, other matters are properly brought before the Special Meeting, including an adjournment of the meeting for any reason other than the ones specified in the adjournment proposal, the proxies will have discretion to vote or act on those matters according to their best judgment and they intend to vote the shares of common stock as the Independent Xeris Directors may recommend.

Assistance

If you need assistance in completing your proxy card or have questions regarding the Special Meeting, please contact Innisfree toll-free at (877) 750-9499.

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THE SPECIAL MEETINGS OF STRONGBRIDGE’S SHAREHOLDERS

Overview

This joint proxy statement/prospectus is being provided to Strongbridge shareholders as part of a solicitation of proxies by the Strongbridge Board, excluding Dr. Jeffrey W. Sherman, a director on the boards of directors of both Xeris and Strongbridge who recused himself from all board meetings, discussions and consideration of the Transaction and abstained from voting on the Transaction (such Strongbridge Board without Dr. Sherman, the “Independent Strongbridge Directors”) for use at the Strongbridge Special Meetings of Strongbridge shareholders referred to below and at any adjournments of such meetings. This joint proxy statement/prospectus is being furnished to Strongbridge shareholders on or about July 30, 2021. This joint proxy statement/prospectus provides Strongbridge shareholders with information they need to be able to vote or instruct their vote to be cast at the Strongbridge Special Meetings.

Date, Time and Place of the Strongbridge Special Meetings

The Court Meeting will be held on September 8, 2021, at 12:00 p.m. local time (5:00 p.m. Irish Time), at 900 Northbrook Drive, Suite 200, Trevose, Pennsylvania 19053, United States of America. The EGM will be held on September 8, 2021 at 12:30 p.m. local time (5:30 p.m. Irish Time), at 900 Northbrook Drive, Suite 200, Trevose, Pennsylvania 19053, United States of America, or, if the Court Meeting has not concluded by 12:30 p.m. local time (5:30 p.m. Irish Time), as soon as possible after the conclusion or adjournment of the Court Meeting. Strongbridge shareholders in Ireland, or their proxies, may participate in the Court Meeting and EGM by audio link at the offices of Arthur Cox LLP, located at Ten Earlsfort Terrace, Dublin 2, D02 T380, Ireland.

Attendance

Attendance at the Court Meeting and the EGM is limited to Strongbridge shareholders or their proxies at 5:00 p.m. (Eastern Time in the U.S.) on July 27, 2021 (the “Voting Record Time”). Please indicate on the relevant proxy card if you plan to attend the Strongbridge Special Meetings. If your shares are held through a bank, broker or other nominee, and you would like to attend, please write to Strongbridge Biopharma plc, Corporate Secretary, 900 Northbrook Drive, Suite 200, Trevose, PA 19053, or bring to the applicable meeting a statement or a letter from the bank, broker or other nominee confirming beneficial ownership of Strongbridge ordinary shares as of the Voting Record Time. Any beneficial holder who plans to vote at either Strongbridge Special Meeting must obtain a legal proxy from his or her bank, broker or other nominee and should contact such bank, broker or other nominee for instructions on how to obtain a legal proxy. Each Strongbridge shareholder may be asked to provide a valid picture identification, such as a driver’s license or passport, and proof of ownership as of the Voting Record Time. The use of cell phones, smartphones, pagers and recording and photographic equipment will not be permitted in the meeting rooms.

In light of the ongoing COVID-19 pandemic, we encourage Strongbridge shareholders to vote their proxy by telephone and internet prior to 12:30 p.m. (Eastern Time) (5:30 p.m. Irish Time) on September 6, 2021 as described in the accompanying joint proxy statement/prospectus for the Strongbridge Special Meetings. Strongbridge asks that, in considering whether to attend such meetings in person, Strongbridge shareholders follow public health and travel guidelines with respect to COVID-19, including as applicable to Ireland and the United States. Those guidelines may restrict or prevent any Strongbridge shareholder from attending such meetings in person.

Strongbridge therefore strongly encourages shareholders not to attend such meetings in person if they are experiencing any of the described COVID-19 symptoms. Strongbridge shareholders attending the Strongbridge Special Meetings in person are also requested to follow the hygiene instructions consistent with applicable public health guidelines, including social distancing, washing or disinfecting hands upon arrival at such meetings and wearing a face mask. Strongbridge may take additional precautionary measures in relation to the Strongbridge Special Meetings in response to further developments in the COVID-19 pandemic. Strongbridge will be obliged

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to comply with any legal restrictions that are imposed as a consequence of COVID-19 and that affect such meetings, which may include preventing or restricting access to such meetings. Strongbridge also intends to comply with any applicable public health and travel guidelines, which may affect the Strongbridge Special Meetings.

Depending on concerns about and developments relating to the COVID-19 pandemic, the Strongbridge Board could determine to change the date, time, location or format of the Strongbridge Special Meetings, subject to Irish legal requirements. In the event Strongbridge determines it is necessary or appropriate to take additional steps regarding how the Strongbridge Special Meetings will be conducted, Strongbridge will announce such determinations in advance in accordance with applicable legal requirements, and details will be posted on Strongbridge’s website and filed with the U.S. Securities and Exchange Commission.

Proposals

Court Meeting: Strongbridge shareholders (excluding Xeris, HoldCo or any of their affiliates, to the extent they hold Strongbridge ordinary shares) are being asked to consider and vote on a proposal at the Court Meeting to approve the Scheme of Arrangement.

EGM: Strongbridge shareholders (including Xeris, HoldCo or any of their affiliates, to the extent they hold Strongbridge ordinary shares) are also being asked to consider and vote on a proposal at the EGM to approve the Scheme of Arrangement, in addition to certain other proposals as set forth in the resolutions described below.

The first three resolutions relate to the approval of the Scheme of Arrangement and of actions required to be taken in connection with the Scheme — specifically, the cancellation of the existing Strongbridge ordinary shares that are not already owned by Xeris, HoldCo or their affiliates and the subsequent use of the reserve created as a result of the cancellation of such shares to allot and issue new Strongbridge ordinary shares to HoldCo and/or its nominee(s) in exchange for the Scheme Consideration. The fourth resolution also relates to the Scheme of Arrangement and would ensure that the holders of any new Strongbridge ordinary shares issued on or after the Voting Record Time to persons other than HoldCo and/or its nominee(s) are acquired by HoldCo and/or its nominee(s) for the Scheme Consideration. The Acquisition is conditioned on the approval of resolutions 1 through 4.

1. Resolution #1: To approve the Scheme of Arrangement and authorize the directors of Strongbridge to take all such actions as they consider necessary or appropriate for carrying the Scheme of Arrangement into effect.

2. Resolution #2: To approve the cancellation of any Strongbridge ordinary shares in issue at 10.00 p.m., Irish time, on the day before the Irish High Court hearing to sanction the Scheme (excluding, in any case, any Strongbridge ordinary shares which are held from time to time by Xeris, HoldCo or any other subsidiary of Xeris, if any).

3. Resolution #3: To authorize the directors of Strongbridge to use the reserve created as a result of the cancellation of the Strongbridge ordinary shares to allot and issue new Strongbridge ordinary shares to HoldCo and/or its nominee(s) in exchange for the Scheme Consideration.

4. Resolution #4: To amend the articles of association of Strongbridge so that any ordinary shares of Strongbridge that are issued on or after the Voting Record Time to persons other than HoldCo and/or its nominee(s) will either be subject to the terms of the Scheme or will be immediately and automatically acquired by HoldCo and/or its nominee(s) for the Scheme Consideration.

The Acquisition is not conditioned on the approval of the remaining resolutions.

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5. Resolution #5: To approve, on a non-binding, advisory basis, specified compensatory arrangements between Strongbridge and its named executive officers relating to the Transaction.

6. Resolution #6: To approve any motion by the chairman of the meeting to adjourn the EGM, or any adjournments thereof, to another time and place if necessary or appropriate to solicit additional proxies if there are insufficient votes at the time of the EGM to approve resolutions 1 through 4 set out above.

Record Date; Outstanding Ordinary Shares; Ordinary Shares Entitled to Vote

Only holders of Strongbridge ordinary shares as of the Voting Record Time will be entitled to notice of, and to vote at the Strongbridge Special Meetings or any adjournments thereof. At the Voting Record Time, there were 67,828,952 Strongbridge ordinary shares outstanding, held by 15 holders of record. Each outstanding Strongbridge ordinary share (other than those held by Xeris, HoldCo or any of their affiliates in respect of the Court Meeting only) is entitled to one vote on each proposal and any other matter properly coming before the special meetings.

Quorum

The presence, in person or by proxy, of holders of Strongbridge ordinary shares outstanding which entitle the holders to a majority of the voting power of Strongbridge at the Voting Record Time will constitute a quorum for each of the special meetings. While Strongbridge does not currently hold any ordinary shares in treasury, any such shares held as at the Voting Record Time would not be included in the calculation of the number of ordinary shares present at the special meetings for the purposes of determining a quorum. Strongbridge’s inspector of election intends to treat as “present” for these purposes shareholders who have submitted properly executed or transmitted proxies that are marked “abstain”. The inspector will also treat as “present” shares held in “street name” by brokers that are voted on at least one proposal to come before the meeting.

Ordinary Share Ownership and Voting by Strongbridge’s Directors and Officers

As of the Voting Record Time, the Strongbridge Board and executive officers had the right to vote approximately 505,516 of the then-outstanding Strongbridge ordinary shares at the special meetings, representing less than 1% of the Strongbridge ordinary shares then outstanding and entitled to vote at the Court Meeting and less than 1% of the Strongbridge ordinary shares then outstanding and entitled to vote at the EGM. To the knowledge of Strongbridge, as of the date of this joint proxy statement/prospectus, the Strongbridge directors and executive officers who are shareholders of Strongbridge intend to vote “FOR” each of the proposals at the Court Meeting and “FOR” each of the proposals at the EGM. Pursuant to irrevocable undertakings, certain Strongbridge directors and executive officers have agreed to vote their Strongbridge ordinary shares “FOR” the proposals at the Court Meeting and the EGM, subject to certain exceptions. See the section entitled “Irrevocable Undertakings” beginning on page 161 of this joint proxy statement/prospectus.

Vote Required; Recommendation of the Independent Strongbridge Directors

Court Meeting

Proposal to approve the Scheme of Arrangement: Strongbridge shareholders are being asked to vote on a proposal to approve the Scheme at both the Court Meeting and the EGM. The vote required for such proposal is different at each of the special meetings, however. As set out in full under the section entitled “Part 2—Explanatory Statement—Consents and Meetings—4” beginning on page 208 of this joint proxy statement/prospectus in order for the resolution at the Court Meeting to pass, those voting to approve the Scheme must: (a) represent a simple majority (being more than 50%) in number of the Strongbridge shareholders of record as of the Voting Record Time, present and voting (in person or by proxy), and (b) represent 75% or more in value of the Strongbridge ordinary shares held by such holders, as of the Voting Record Time, present and voting (in person or by proxy).

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Because the vote required to approve the proposal at the Court Meeting is based on votes properly cast at the meeting, and because abstentions and broker non-votes are not considered votes properly cast, abstentions and broker non-votes, along with failures to vote, will have no effect on such proposal.

The Merger and the Acquisition are conditional on approval of the Scheme at the Court Meeting.

The Independent Strongbridge Directors recommend that Strongbridge shareholders vote “FOR” the proposal to approve the Scheme of Arrangement at the Court Meeting.

In considering the recommendation of the Independent Strongbridge Directors, Strongbridge shareholders should be aware that directors and executive officers of Strongbridge have interests in the proposed transaction that are in addition to, or different from, any interests they might have as shareholders. See “The Transaction—Interests of Strongbridge’s Executive Officers and Directors” beginning on page 108 of this joint proxy statement/prospectus. In particular, Dr. Jeffrey W. Sherman is not participating in the recommendation of the Independent Strongbridge Directors due to Dr. Sherman’s directorship of, and shareholding in, Xeris.

EGM

Set forth below is a table summarizing certain information with respect to the resolutions:

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At the EGM, the requisite approval of each of the resolutions depends on whether it is an “ordinary resolution” (resolutions 1, 3, 5 and 6), which requires the approval of the holders of at least a majority of the votes cast by the holders of Strongbridge ordinary shares present and voting, either in person or by proxy, or a “special resolution” (resolutions 2 and 4), which requires the approval of the holders of at least 75% of the votes cast by the holders of Strongbridge ordinary shares present and voting, either in person or by proxy.

For all the resolutions, because the votes required to approve such resolutions are based on votes properly cast at the EGM, and because abstentions and broker non-votes are not considered to be votes properly cast, abstentions and broker non-votes, along with failures to vote, will have no effect on the resolutions.

The Independent Strongbridge Directors recommend that Strongbridge shareholders vote “FOR” the proposals to approve each of the resolutions.

In considering the recommendations of the Independent Strongbridge Directors described above, Strongbridge shareholders should be aware that directors and executive officers of Strongbridge have interests in the proposed transaction that are in addition to, or different from, any interests they might have as shareholders. See “The Transaction—Interests of Strongbridge’s Executive Officers and Directors” beginning on page 108 of this joint proxy statement/prospectus. In particular, Dr. Jeffrey W. Sherman is not participating in the recommendation of the Independent Strongbridge Directors due to Dr.  Sherman’s directorship of, and shareholding in, Xeris.

Voting Your Ordinary Shares

Strongbridge shareholders may vote by proxy or in person at each Strongbridge Special Meeting. Strongbridge recommends that you submit your proxy even if you plan to attend either or both of the Strongbridge Special Meetings. If you vote by proxy, you may change your vote, among other ways, if you attend and vote at either or both of the Strongbridge Special Meetings.

If you own shares in your own name, you are considered, with respect to those shares, the “shareholder of record” and you will receive two forms of proxy (one for each special meeting). If your shares are held in a stock brokerage account or by a bank or other nominee, you are considered the beneficial owner of shares held in “street name.”

If you are a Strongbridge shareholder of record, you may use the enclosed forms of proxy to tell the persons named as proxies how to vote your shares. If you are a Strongbridge shareholder of record, the shares listed on your forms of proxy will include, if applicable, shares held in a book-entry account at Computershare Trust Company, N.A., Strongbridge’s transfer agent.

If you properly complete, sign and date your forms of proxy, your shares will be voted in accordance with your instructions. Giving a proxy means that a Strongbridge shareholder of record authorizes the persons named in the enclosed form of proxy to vote its shares at the applicable Strongbridge Special Meeting in the manner it directs. The named proxies will vote all shares at the Strongbridge Special Meetings for which forms of proxy have been properly submitted and not revoked. If you sign and return a form of proxy appointing the chairman as your proxy but do not mark your card to tell the proxy how to vote on a voting item, your shares will be voted with respect to such item in accordance with the recommendations of the Independent Strongbridge Directors.

Strongbridge shareholders may also vote over the internet at the internet site indicated on the enclosed proxy card or by telephone at the toll-free telephone number indicated on the enclosed proxy card anytime up to 12:30 p.m. (Eastern Time in the U.S.) (5:30 p.m. Irish Time) on September 6, 2021. Voting instructions are printed on the form of proxy you received. Either method of submitting a proxy will enable your shares to be represented and voted at the special meetings. You may also hand your applicable completed and signed form of proxy to the chairman of the Court Meeting before the start of the Court Meeting.

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Voting Ordinary Shares Held in Street Name

If your shares are held in an account through a bank, broker or other nominee, you must likewise instruct the bank, broker or other nominee how to vote your shares by following the instructions that the bank, broker or other nominee provides you along with this joint proxy statement/prospectus. Your bank, broker or other nominee, as applicable, may have an earlier deadline by which you must provide instructions to it as to how to vote your shares, so you should read carefully the materials provided to you by your bank, broker or other nominee.

If you do not provide a signed voting instruction form to your bank, broker or other nominee, your shares will not be voted on any proposal on which the bank, broker or other nominee does not have discretionary authority to vote. This is referred to in this joint proxy statement/prospectus and in general as a broker non-vote. In these cases, the bank, broker or other nominee will not be able to vote your shares on those matters for which specific authorization is required. Brokers do not have discretionary authority to vote on any of the proposals at either of the Strongbridge Special Meetings.

Accordingly, if you fail to provide a signed voting instruction form to your bank, broker or other nominee, your shares held through such bank, broker or other nominee will not be voted at either of the Strongbridge Special Meetings.

Revoking Your Proxy

If you are a Strongbridge shareholder of record, you may revoke your proxy at any time before it is voted at the applicable Strongbridge Special Meeting by:

Attendance at either Strongbridge Special Meeting will not, in and of itself, revoke a proxy or change your voting instructions; you must vote by ballot at the applicable meeting to change your vote.

If your shares are held in “street name” by a bank, broker or other nominee, you should follow the instructions of your bank, broker or other nominee regarding the revocation of proxies.

Costs of Solicitation

Strongbridge will bear the cost of soliciting proxies from its shareholders.

Strongbridge will solicit proxies by mail. In addition, the directors, officers and employees of Strongbridge may solicit proxies from its shareholders by telephone, electronic communication, or in person, but will not receive any additional compensation for their services. Strongbridge will make arrangements with brokerage houses and other custodians, nominees, and fiduciaries for forwarding proxy solicitation material to the beneficial owners of Strongbridge ordinary shares held of record by those persons and will reimburse them for their reasonable out-of-pocket expenses incurred in forwarding such proxy solicitation materials.

Strongbridge has engaged a professional proxy solicitation firm, MacKenzie Partners, Inc., to assist in soliciting proxies. As compensation for its services, Strongbridge has agreed to pay MacKenzie Partners, Inc. a solicitation fee of $12,500, plus reimbursement for its reasonable and customary documented expenses in connection with the solicitation.

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Other Business

Strongbridge is not aware of any other business to be acted upon at the Strongbridge Special Meetings. If, however, other matters are properly brought before the Strongbridge Special Meetings, the proxies will have discretion to vote or act on those matters according to their best judgment and they intend to vote the shares as the Strongbridge Board or the Independent Strongbridge Directors, as applicable, may recommend.

Adjournment; Postponement

Any adjournment or postponement of the Court Meeting will result in an adjournment or postponement, as applicable, of the EGM.

Assistance

If you need assistance in completing your proxy card or have questions regarding Strongbridge’s Special Meetings, please contact MacKenzie Partners, Inc., the proxy solicitation agent for Strongbridge, by mail at 1407 Broadway, 27th Floor, New York, NY 10018, by telephone at 1-800-322-2885 (toll free) or 1-212-929-5500 (call collect), or by email at proxy@mackenziepartners.com.

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THE TRANSACTION

The Acquisition and the Merger

At the effective time of the Scheme (the Scheme Effective Time), HoldCo will acquire the entire issued and to be issued ordinary share capital of Strongbridge by means of a scheme of arrangement under Chapter 1 of Part 9 of the Act (the Scheme of Arrangement or the Scheme).

Subject to the terms and conditions set forth in the Transaction Agreement, Strongbridge shareholders will have the right to receive, with respect to each share of Strongbridge ordinary share they hold at the Scheme Effective Time: (a) 0.7840 of a newly issued share of HoldCo common stock, and (b) one non-tradeable CVR, worth up to a maximum of $1.00 per CVR, settleable in cash or additional HoldCo common stock, or a combination of cash and additional HoldCo common stock, at HoldCo’s sole discretion. If any payment pursuant to the CVR is settled in HoldCo common stock, the number of shares of HoldCo common stock payable thereunder will be calculated based on the volume weighted average price of Xeris common stock in the 10 trading days immediately prior to the Scheme Effective Date, as more fully described in “—Contingent Value Rights Agreement” beginning on page 159 of this joint proxy statement/prospectus.

At the effective time of the Merger (the Merger Effective Time), MergerSub will be merged with and into Xeris, with Xeris being the surviving corporation and becoming a wholly owned subsidiary of HoldCo (the Merger). Xeris stockholders will have the right to receive, with respect to each share of Xeris common stock they hold at the Merger Effective Time, one share of HoldCo common stock.

Background of the Transaction

The Strongbridge Board and management have, on an ongoing basis, considered the long-term strategy of Strongbridge and strategic opportunities that might be available to it to enhance shareholder value, including investments in new growth opportunities, potential acquisitions, the possible sale of Strongbridge or other strategic transactions. In accordance with the Strongbridge Board’s discussion and review of such strategic opportunities, Strongbridge management had been engaged in preliminary discussions with various potentially interested third parties from time to time, and has kept the Strongbridge Board updated regarding its interactions with third parties.

Strongbridge began such preliminary discussions with two parties in late 2019, including Party A. Discussions with Party A ended in December 2020, while discussions with the other party ended in early 2020, neither of which resulted in an indication of interest in a strategic transaction involving Strongbridge.

In March 2020, in connection with the discussions with the two parties mentioned above, the Strongbridge Board authorized the engagement with MTS Health Partners to act as its financial advisor in connection with Strongbridge’s consideration of certain potential merger and acquisition transactions or similar transactions, and MTS Health Partners continued to act as Strongbridge’s financial advisor in connection with Strongbridge’s exploration of opportunities of potential strategic transactions. See “Opinion of Strongbridge’s Financial Advisor—Miscellaneous” for a discussion of the qualifications of MTS Health Partners, the Strongbridge Board’s method of selecting MTS Health Partners as its financial advisor and the relationship between Strongbridge and MTS Health Partners in the past two years.

As a part of the ongoing review of Xeris’ long-term strategy, the Xeris Board has, from time to time, considered strategic opportunities that might be available to it to enhance stockholder value, including additional investments in new growth opportunities and potential acquisitions, taking into account global healthcare, industry and transaction trends as well as economic and other conditions generally. In this context, Xeris management identified that expanding Xeris’ product offerings to include a broader product portfolio would be a way to better position Xeris to execute on its economic value strategies.

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On September 8, 2020, Strongbridge announced positive top-line results of its phase 3 clinical study evaluating Recorlev for the treatment of endogenous Cushing’s syndrome.

From September 2020 through the first half of April 2021, as part of the continuing process of exploring potential strategic transactions involving Strongbridge, Strongbridge management entered into confidentiality agreements with five parties, Party B, Party C, Party D, Party E and Xeris, and continued discussions with Party A, Party F and Party G under existing confidentiality agreements. All of these confidentiality agreements either did not contain standstill provisions or had standstill provisions that became ineffective prior to or at the time of the public announcement of the Transaction, except for the confidentiality agreement with Party B which contains a standstill provision that is effective until January 2022. Strongbridge provided non-public due diligence information to five of these parties, including Xeris. Out of the five parties receiving non-public diligence information, Party B, Party C, Party E and Xeris requested and received access to Strongbridge’s virtual data room. In addition to Xeris and Parties A through G, Strongbridge also identified seven additional parties as potentially interested in a strategic transaction with Strongbridge, with which Strongbridge did not enter into any confidentiality agreement or exchange any non-public information (the “Other Parties”). Strongbridge management and MTS Health Partners considered Parties A through G and the Other Parties to be potentially interested in a strategic transaction with Strongbridge because they were all biopharmaceutical companies with commercialized products that were complementary to Strongbridge’s products and as such could be interested in adding Strongbridge’s products into their product portfolios.

On January 19, 2021, members of Xeris management met with representatives of MTS Health Partners and had a general discussion regarding potential strategic transaction partners that may be of interest to Xeris. During the discussion, representatives of MTS Health Partners indicated that Strongbridge could be interested in a potential strategic transaction. Over the last several years, representatives of MTS Health Partners have periodically discussed with Xeris management industry and capital markets trends and developments and have also, from time to time, had informal discussions with strategic and financial sponsor parties that could be interested in a potential transaction with Xeris. None of these discussions progressed beyond preliminary phases except for the discussions with Strongbridge described below. In the past two years, neither MTS Health Partners nor MTS Securities provided investment banking or financial advisory services to Xeris for which it has received compensation.

On January 20, 2021, Mr. Paul Edick, Chief Executive Officer of Xeris, contacted Mr. John H. Johnson, Chief Executive Officer of Strongbridge, requesting a discussion regarding Xeris’ potential interest in Strongbridge.

On January 27, 2021, a member of Xeris management informed a representative of MTS Health Partners that Xeris was interested in learning more about Strongbridge and requested that Xeris be connected directly with Strongbridge.

On February 2, 2021, Strongbridge and Xeris entered into a confidentiality agreement to provide for the exchange of information in furtherance of discussions regarding a potential strategic transaction between the parties.

Also on February 2, 2021, Strongbridge provided Xeris with access to Strongbridge’s due diligence virtual data room containing non-public diligence information regarding Strongbridge.

Between February 2 and March 12, 2021, various members of Strongbridge senior management, including Mr. Johnson and Mr. Richard Kollender, President and Chief Financial Officer of Strongbridge, held several meetings through video conference and telephone conversations with members of Xeris senior management, including Mr. Edick and Mr. John Shannon, President and Chief Operating Officer of Xeris, regarding Xeris’ ongoing diligence of Strongbridge. During such discussions, Mr. Edick informed Mr. Johnson that any proposal with respect to a strategic transaction would be in the form of a stock-for-stock deal with a contingent value rights component.

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On February 25, 2021, the Xeris Board held a regularly scheduled meeting with members of Xeris management present. During a portion of the meeting, Xeris management provided an update on business development activities, including a potential transaction with Strongbridge. Dr. Jeffrey W. Sherman, a director on the boards of both Xeris and Strongbridge, was not present for this portion of the meeting and recused himself from the relevant portions of all Xeris Board meetings and other discussions regarding a potential transaction between Xeris and Strongbridge and abstained from voting on any transaction-related items. At the meeting, Xeris management provided an overview of Strongbridge, including its organizational and operating structure, product profile, historical financial performance and growth prospects, and reviewed the strategic and financial rationale for a potential transaction with Strongbridge, including a preliminary assessment of potential synergies and a discussion of benefits of a transaction with Strongbridge to Xeris and its stockholders. Following discussion, the Independent Xeris Directors authorized Xeris management to explore a possible transaction with Strongbridge and authorized John Schmid, an independent nonexecutive director, and Mr. Edick as an ad hoc working group available to provide Xeris management with prompt guidance and advice from time to time, in connection with a potential transaction with Strongbridge. The Independent Xeris Directors also considered the qualifications and engagement of SVB Leerink to act as Xeris’ financial advisor in connection with a potential transaction with Strongbridge. The Independent Xeris Directors considered SVB Leerink as a potential financial advisor to assist and advise Xeris given, among other things, SVB Leerink’s qualifications, reputation, experience and expertise in the biopharmaceutical industry, its knowledge of and involvement in recent transactions in the biopharmaceutical industry and its relationship and familiarity with Xeris and its business. Following discussions, the Independent Xeris Directors authorized the engagement of SVB Leerink and directed management to negotiate an appropriate engagement letter with SVB Leerink consistent with terms discussed with the Independent Xeris Directors. The engagement letter was executed by Xeris and SVB Leerink on February 26, 2021.

On March 4, 2021, Xeris provided Strongbridge with access to Xeris’ due diligence virtual data room containing non-public diligence information regarding Xeris.

On March 11, 2021, the ad hoc working group of the Independent Xeris Directors, with the assistance of Xeris management and its advisors, reviewed the submission to Strongbridge of a non-binding offer letter providing for a stock-for-stock acquisition of Strongbridge by Xeris, which proposal would serve as a basis for obtaining additional information regarding Strongbridge to assess the Transaction and its potential benefits and other due diligence response to assess the potential for a transaction.

On March 12, 2021, Xeris submitted a non-binding proposal to acquire Strongbridge (the “March 12 Proposal”) where Strongbridge shareholders would receive newly-issued shares of Xeris common stock equal to approximately 34% of the combined company on a fully diluted basis, plus contingent value rights to receive additional consideration, in cash or in Xeris common stock at Xeris’ exclusive option, of up to $1.00 per Strongbridge ordinary share in the aggregate upon achievement of the following milestones: (i) the FDA approval of Recorlev in the United States before the end of 2022, (ii) listing of at least one issued patent in the FDA’s Orange Book (the “Orange Book”) for Keveyis, (iii) $50 million in Recorlev annual net sales in 2023, and (iv) $80 million in Recorlev annual net sales in 2024. The March 12 Proposal did not specify the portion of the aggregate payment allocated to each milestone.

In the March 12 Proposal, Xeris indicated that it had conducted a significant amount of the operational, clinical, regulatory and financial due diligence on Strongbridge and the proposal was subject to the completion of further confirmatory due diligence, which Xeris was prepared to commence immediately. Xeris also requested that the parties enter into an exclusivity agreement through April 30, 2021. Xeris also expressed its expectation that certain of Strongbridge’s significant shareholders would provide irrevocable undertakings to vote in favor of the proposed transaction concurrently with the parties’ entry into the definitive transaction agreement.

After receipt of the March 12 Proposal, Strongbridge management and MTS Health Partners informed Parties A through G and the Other Parties that Strongbridge had received an acquisition proposal from a publicly

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listed pharmaceutical company and inquired whether they would be interested in submitting a competing proposal.

On or about March 15, 2021, Mr. Johnson informed Mr. Edick that Strongbridge would get back to them with a reaction to the proposal and would begin an outreach process to gauge whether other parties may be interested in a strategic transaction with Strongbridge.

On March 15, 2021, Mr. Kollender met with Mr. John Shannon, President and Chief Operating Officer of Xeris, Mr. Kevin McCulloch, Senior Vice President, Global Operations and Business Development of Xeris, and other representatives from Xeris senior management to discuss Gvoke, Xeris’ commercial product, including certain due diligence information relating thereto.

On March 16, 2021, the chief executive officer of Party D informed Mr. Johnson that it would not submit an acquisition proposal to acquire Strongbridge.

On March 17, 2021, Strongbridge received a non-binding proposal from Party E to acquire Strongbridge for $3.50 per Strongbridge ordinary share in cash plus a contingent value right to receive $0.50 in cash payable upon Recorlev receiving FDA approval in the United States. The proposal was subject to further confirmatory due diligence, among other conditions. The closing price for Strongbridge’s ordinary shares on March 17, 2021 was $3.34.

Also on March 17, 2021, following discussion with Strongbridge management, representatives from MTS Health Partners held a call with Party B’s senior management and financial advisor to discuss the process thus far and timetable going forward.

On March 19, 2021, the chief executive officer of Party A informed Mr. Johnson that it would not submit an acquisition proposal to acquire Strongbridge.

On March 26, 2021, as directed by Strongbridge management, MTS Health Partners sent a bid process letter (the “Bid Process Letter”) to Xeris and Party B, Party C and Party E. The Bid Process Letter requested the recipients to submit a written indication of interest no later than April 16, 2021 if they were interested in a strategic transaction with Strongbridge.

Also on March 26, 2021, Xeris management and Strongbridge management held a conference call, during which Xeris management presented Xeris’ portfolio of existing commercial products and its product pipeline.

By March 30, 2021, Parties A, D and G and all the Other Parties either did not respond or declined to move forward with any discussion of a strategic transaction with Strongbridge.

On April 5, 2021, the Independent Xeris Directors held a meeting with members of Xeris management and representatives of Goodwin Procter L.L.P., U.S. counsel to Xeris (“Goodwin”), present. Xeris management presented its business development model, which included management’s projections for the fiscal years ended December 31, 2021 through December 31, 2025, and the assumptions on which the projections were based. In the context of reviewing the projections, the Independent Xeris Directors discussed the risks, challenges, and strategic opportunities facing Xeris. Following discussion and questions of management regarding various matters relating to the projections, including the assumptions on which the projections were based, the Independent Xeris Directors approved the projections for disclosure to prospective acquisition targets and for use by SVB Leerink in conducting its financial analyses of Xeris. See the Unadjusted Xeris Projections as defined in “—Xeris Unaudited Prospective Financial Information” for further information regarding these financial projections. These projections were provided to Strongbridge.

On April 8, 2021, the Strongbridge board of directors (other than Dr. Sherman) held a meeting through videoconference, also attended by senior management of Strongbridge and representatives from MTS Health

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Partners and Skadden, Arps, Slate, Meagher & Flom LLP, U.S. counsel to Strongbridge (“Skadden”). Dr. Sherman, a director on the boards of both Xeris and Strongbridge, recused himself from the relevant portions of all board meetings and other discussions regarding a potential transaction between Xeris and Strongbridge and abstained from voting on the Transaction (such board without Dr. Sherman, the “Independent Strongbridge Directors”).

At the April 8 meeting of the Independent Strongbridge Directors, Strongbridge management and representatives from MTS Health Partners discussed with the Independent Strongbridge Directors the status of discussions with the potentially interested third parties. Representatives from MTS Health Partners also discussed with the Independent Strongbridge Directors the terms of Party E’s March 17 acquisition proposal and preliminary financial information regarding the contingent value right component in such proposal and Xeris’ March 12 Proposal. Strongbridge management also presented to the Independent Strongbridge Directors a set of projections for Strongbridge as more fully described in “—Strongbridge Unaudited Prospective Financial Information.”

On April 15, 2021, the ad hoc working group of the Independent Xeris Directors, with the assistance of Xeris management and its advisors, reviewed the submission to Strongbridge of a revised non-binding offer letter.

Throughout January, February, March and the first half of April 2021, Strongbridge management held discussions with representatives from the management of each of Party B, Party C and Party E regarding their diligence of Strongbridge. Strongbridge senior management also held discussions with Party E’s financial advisor and financing source, in addition to Party E’s senior management. Party E indicated that it would be interested in a strategic transaction with Strongbridge, but it would need to see further regulatory developments of the New Drug Application for Recorlev for the treatment of endogenous Cushing’s syndrome that Strongbridge submitted to the FDA on March 1, 2021, which developments would not occur under the timeline requested in the Bid Process Letter.

By April 16, 2021, representatives from the senior management of each of Party B, Party C, Party E and Party F informed Strongbridge, through Mr. Kollender, that they would not submit an indication of interest in response to the Bid Process Letter.

On April 16, 2021, Xeris submitted a revised non-binding proposal to acquire Strongbridge (the “April 16 Proposal”) where Strongbridge shareholders would receive 0.70 newly-issued shares of Xeris common stock for each Strongbridge ordinary share, noted as equivalent to approximately $2.70 per Strongbridge ordinary share, plus contingent value rights to receive additional consideration, in cash or in Xeris common stock at Xeris’ exclusive option, of up to $0.75 per Strongbridge ordinary share in the aggregate upon achievement of the following milestones: (i) listing of at least one issued patent in the Orange Book for Keveyis ($0.25 per Strongbridge ordinary share), (ii) $50 million in Recorlev annual net sales in 2023 ($0.25 per Strongbridge ordinary share), and (iii) $80 million in Recorlev annual net sales in 2024 ($0.25 per Strongbridge ordinary share). The April 16 Proposal would result in the Strongbridge shareholders owning approximately 37.3% of the combined company on a fully diluted basis prior to receiving any CVR payment. If all of the CVR milestones were achieved and all of the CVR payments were made in Xeris common stock, the April 16 Proposal would result in the Strongbridge shareholders owning approximately 43.1% of the combined company on a fully diluted basis. The closing price for Strongbridge’s ordinary shares on April 16, 2021 was $2.43.

In the April 16 Proposal, Xeris requested that Xeris and Strongbridge enter into an exclusivity agreement providing for exclusive discussions through May 17, 2021. Xeris reiterated its expectation to receive irrevocable undertakings from certain of Strongbridge’s significant shareholders to vote in favor of the proposed transaction. The April 16 Proposal also indicated that the combined company would be led by Xeris’ executive management team and proposed that Mr. Johnson would join the board of directors of the combined company as an independent director, while the common director of Strongbridge and Xeris, Dr. Sherman, would continue to serve on the board of the combined company.

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On April 21, 2021, the Independent Strongbridge Directors held a meeting through videoconference, also attended by Strongbridge senior management, representatives from MTS Health Partners and Skadden. Representatives from MTS Health Partners discussed with the Independent Strongbridge Directors preliminary financial information regarding the April 16 Proposal. After discussion, the Independent Strongbridge Directors authorized Strongbridge management to, at its discretion, grant Xeris exclusivity for a limited period of time as requested in the April 16 Proposal.

Following the April 21 Independent Strongbridge Directors meeting, consistent with the discussion of the Independent Strongbridge Directors, Mr. Johnson told Mr. Edick that Xeris needed to improve the April 16 Proposal as follows: (i) the upfront portion of the proposal should result in the Strongbridge shareholders owning approximately 40% of the combined company on a fully diluted basis prior to receiving any CVR payment, rather than approximately 37.3%; (ii) the Keveyis CVR milestone should be triggered on either at least one issued patent in the Orange Book for Keveyis or 2023 annual net sales of $40 million for Keveyis; and (iii) the milestone threshold for Recorlev annual net sales in 2023 should be reduced to $40 million instead of $50 million. Mr. Johnson also requested an additional board seat in the combined company. Mr. Johnson indicated that Strongbridge would agree to negotiate exclusively with Xeris if Xeris made these improvements to its proposal.

On April 23, 2021, Strongbridge received a notice of allowance from the U.S. Patent and Trademark Office relating to a patent application for Recorlev, potentially providing Recorlev with additional patent protection until 2040. On the same day, Mr. Johnson informed Mr. Edick of this development and Mr. Edick indicated that Xeris would revise its April 16 Proposal in light of this development and requested that Xeris have a few days to prepare a revised proposal.

Also on April 23, 2021, the ad hoc working group of the Independent Xeris Directors, with the assistance of Xeris management and SVB Leerink, discussed revisions to the April 16 Proposal in light of the recent development regarding the patent application for Recorlev.

Also on April 23, 2021, Strongbridge management decided to revise the Strongbridge projections in light of the notice of allowance, as more fully described in “—Strongbridge Unaudited Prospective Financial Information”.

On April 26, 2021, Xeris submitted a revised non-binding proposal to acquire Strongbridge (the “April 26 Proposal”) where Strongbridge shareholders would receive newly-issued shares of Xeris common stock equal to approximately 40.0% of the combined company on a fully diluted basis, noted as equivalent to approximately $3.10 per Strongbridge ordinary share, plus contingent value rights to receive additional consideration, in cash or in Xeris common stock at Xeris’ exclusive option, of up to $0.75 per Strongbridge ordinary share in the aggregate upon achievement of the following milestones: (i) listing of at least one issued patent in the Orange Book for Keveyis or $40 million in Keveyis annual net sales in 2023 ($0.25 per Strongbridge ordinary share), (ii) $40 million in Recorlev annual net sales in 2023 ($0.25 per Strongbridge ordinary share), and (iii) $80 million in Recorlev annual net sales in 2024 ($0.25 per Strongbridge ordinary share). The closing price for Strongbridge’s ordinary shares on April 26, 2021 was $2.58.

In the April 26 Proposal, Xeris requested that Xeris and Strongbridge enter into an exclusivity agreement providing for exclusive discussions through May 18, 2021, which would be a few days after the anticipated date of the FDA’s decision of whether to accept for filing Strongbridge’s new drug application for Recorlev submitted on March 1, 2021. Xeris also reiterated its expectation to receive irrevocable undertakings from certain of Strongbridge’s significant shareholders to vote in favor of the proposed transaction. The April 26 Proposal also indicated that the combined company would be led by Xeris’ executive management team and proposed that Mr. Johnson and an additional mutually-agreed-upon member of the Strongbridge board of directors join the board of directors of the combined company as independent directors, while the common director of Strongbridge and Xeris, Dr. Sherman, would continue to serve on the board of the combined company.

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In addition to the April 26 Proposal, Xeris provided a draft of the proposed exclusivity agreement.

On April 28, 2021, in furtherance of the plan reviewed with the Independent Strongbridge Directors, Mr. Johnson contacted Mr. Edick and requested an aggregate CVR consideration of $1.00 per CVR. Mr. Johnson also requested that, if any CVR were to be paid in stock of the combined company, the stock price used to calculate the number of shares of stock receivable by CVR holders be based on the price of Xeris stock at the time of the closing of the Transaction instead of based on the stock price at the time the relevant milestone is achieved.

On April 29, 2021, the Independent Strongbridge Directors held a meeting through videoconference, also attended by Strongbridge senior management, representatives from MTS Health Partners and Skadden. Representatives from MTS Health Partners discussed with the Independent Strongbridge Directors the preliminary financial information regarding the April 26 Proposal. After discussion, the Independent Strongbridge Directors reaffirmed its authorization that Strongbridge management could, at its discretion, grant Xeris exclusivity for a limited period of time as requested in the April 26 Proposal.

Later on April 29, 2021, Xeris submitted a revised non-binding proposal to acquire Strongbridge (the “April 29 Proposal”) where Strongbridge shareholders would receive newly-issued shares of Xeris common stock equal to approximately 40.0% of the combined company on a fully diluted basis, noted as equivalent to approximately $3.12 per Strongbridge ordinary share, plus contingent value rights to receive additional consideration, in cash or in Xeris common stock at Xeris’ sole discretion, of up to $1.00 per Strongbridge ordinary share in the aggregate upon achievement of the following milestones: (i) listing of at least one issued patent in the Orange Book for Keveyis or $40 million in Keveyis annual net sales in 2023 ($0.25 per Strongbridge ordinary share), (ii) $40 million in Recorlev annual net sales in 2023 ($0.25 per Strongbridge ordinary share), and (iii) $80 million in Recorlev annual net sales in 2024 ($0.50 per Strongbridge ordinary share). The closing price for Strongbridge ordinary shares on April 29, 2021 was $2.65.

On the same day, after receipt of the April 29 Proposal, Xeris and Strongbridge entered into an exclusivity agreement, which provided for an exclusivity period through the end of day on May 18, 2021, provided that the exclusivity period would automatically be extended for an additional 14 days if neither party gave written notice to the other party of its intent to terminate the exclusivity period at the end of the initial period.

On May 11, 2021, the Xeris Board held a regularly scheduled meeting with members of Xeris management present to discuss, among other things, the discussions with Strongbridge. Representatives of SVB Leerink, Goodwin and A&L Goodbody LLP, Irish counsel to Xeris (“A&L Goodbody”), were present for a portion of the meeting. Xeris management discussed the status of the discussions with Strongbridge, including the status of ongoing due diligence, the strategic rationale for the Transaction and the proposed structure and timing. Representatives of A&L Goodbody discussed the directors’ obligations under Irish law. Representatives of Goodwin discussed the directors’ fiduciary duties. Representatives of Goodwin and A&L Goodbody discussed the legal structure of the proposed transaction and approach to the transaction documentation as well as a summary of the timeline, required shareholder approvals and tax treatment of the Transaction, the proposed deal protection provisions and the conditionality of the Transaction. Representatives of SVB Leerink discussed preliminary financial information regarding the proposed transaction. Xeris management discussed its assessment of the probability of technical and regulatory success applied to the Xeris business development model previously approved by Independent Xeris Directors on April 5, 2021 and to certain projected financial information for Strongbridge provided by Strongbridge management. In the context of reviewing the projections, the Independent Xeris Directors discussed the risks, challenges and strategic opportunities facing Xeris. Following discussion, the Independent Xeris Directors approved the financial projections provided by Xeris management, including the methodology and assumptions, for use by SVB Leerink in their financial analyses. See “—Xeris Unaudited Prospective Financial Information” for further information regarding these financial projections. SVB Leerink relied upon these financial projections for its financial analysis and fairness opinion.

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On May 12, 2021, Goodwin and A&L Goodbody provided Skadden and Arthur Cox LLP, Irish counsel to Strongbridge (“Arthur Cox”), with an initial draft of the Transaction Agreement, the Expenses Reimbursement Agreement and the conditions appendix, which contained the conditions to the consummation of the Transaction. The draft documents contemplated mostly reciprocal representations, warranties, covenants, closing conditions, termination rights and rights of the parties to engage in discussions for alternative transactions.

On May 13, 2021, Skadden and Arthur Cox provided Goodwin and A&L Goodbody with an initial draft of the CVR Agreement.

Between May 13 and May 21, 2021, Skadden and Arthur Cox with input from the Independent Strongbridge Directors and management, on the one hand, and Goodwin and A&L Goodbody with input from the Independent Xeris Directors and management, on the other hand, exchanged drafts of the Transaction Agreement, the Expenses Reimbursement Agreement, the conditions appendix, the Rule 2.5 Announcement, the CVR Agreement and other transaction documents, including both parties’ confidential disclosure schedules. Among other items, the parties negotiated the conditions to the consummation of the Transaction, the termination provisions of the Transaction Agreement, the circumstances in which expense reimbursement would be payable by either party, the parties’ respective non-solicitation obligations, the ability of both Xeris and Strongbridge boards of directors to change their recommendations and to engage with potential third parties interested in pursuing an alternative proposal to acquire their respective companies, the structuring of the CVRs and the definition of net sales for purposes of determining the achievement of applicable milestones, and the treatment of outstanding Strongbridge equity awards.

On May 13, 2021, the Independent Strongbridge Directors held their regular quarterly meeting through videoconference, also attended by Strongbridge senior management. Strongbridge management provided the Independent Strongbridge Directors with an update of its due diligence review of Xeris. Representatives of MTS Health Partners, Skadden and Arthur Cox attended relevant portions of this meeting. Representatives from MTS Health Partners discussed with the Independent Strongbridge Directors the anticipated implied premium of the proposed transaction, including as compared with prior comparable transactions. Skadden and Arthur Cox provided the Independent Strongbridge Directors with an update of the status of the discussion with Xeris and its advisors regarding the proposed transaction, including the status of draft transaction agreements.

On May 14, 2021, the compensation committee of the Strongbridge Board held a meeting through video conference, also attended by representatives from Holland & Knight LLP (“Holland & Knight”), Strongbridge’s counsel for compensation matters. Representatives from Holland & Knight discussed with the compensation committee potential changes in Strongbridge’s equity compensation plans and programs for the purpose of aligning the interests of Strongbridge’s employees with the interests of Strongbridge’s shareholders in the contemplation of the proposed transaction with Xeris. At the direction of the compensation committee, Strongbridge management conveyed such proposals to Xeris management. Between May 14 and May 23, 2021, Strongbridge’s and Xeris’ respective representatives and legal counsel engaged in discussions as to the proposals authorized by the compensation committee of the Strongbridge Board, ultimately resulting in the extension of exercisability of certain Strongbridge Options described in “—Interests of Strongbridge’s Executive Officers and Directors—Treatment of Strongbridge Options in the Transaction” and the Retention Bonus Pool described in “—Interests of Strongbridge’s Executive Officers and Directors—Retention Bonus Pool.”

At the end of day on May 18, 2021, the initial exclusivity period under the exclusivity agreement expired and neither Xeris nor Strongbridge provided written notice of its intent to terminate the exclusivity period. Therefore, pursuant to the terms of the exclusivity agreement, the exclusivity period was automatically extended for another 14 days.

As of the close of trading on the Nasdaq on May 21, 2021, Strongbridge and Xeris had resolved all outstanding material issues under the proposed Transaction Agreement and the other transaction documents.

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On May 21, 2021, the Independent Strongbridge Directors held a meeting by videoconference, also attended by Strongbridge senior management and representatives from MTS Health Partners, Arthur Cox and Skadden. Representatives from Skadden and Arthur Cox discussed with the Independent Strongbridge Directors the material terms of the Transaction Agreement, including the conditions to the consummation of the Transaction set forth in the conditions appendix, the CVR Agreement, and the Expenses Reimbursement Agreement. Representatives from MTS Health Partners discussed with the Independent Strongbridge Directors the financial analyses of MTS Securities regarding the Scheme Consideration to be considered in connection with the delivery of the MTS Opinion. See “—Opinion of Strongbridge’s Financial Advisor” for a summary of the financial analyses of MTS Securities; see “—Strongbridge Unaudited Prospective Financial Information” for a discussion of the management projections with respect to Strongbridge and Xeris used by MTS Securities in its financial analyses.

Also at the May 21 meeting, members of Strongbridge management discussed with the Independent Strongbridge Directors the proposed compensation arrangements, as described in “—Interests of Strongbridge Executive Officers and Directors—Executive Employment Agreements,” that had been agreed upon by Strongbridge and Xeris.

After discussion, the Independent Strongbridge Directors (i) determined that it was advisable and in the best interests of Strongbridge and its shareholders to create, and authorized the creation of, an ad hoc committee of the Independent Strongbridge Directors consisting of Messrs. John H. Johnson and David Gill and Dr. Marten Steen (the “Strongbridge Committee”) to act on behalf of the Independent Strongbridge Directors to take any and all actions which the Independent Strongbridge Directors could take with respect to the Transaction, including to approve the final exchange ratio; (ii) determined that the terms of the Scheme were fair and reasonable and it was advisable and in the best interests of Strongbridge and its shareholders to enter into the Transaction Agreement, consummate the Transaction, enter into the Expenses Reimbursement Agreement and approve the contents and release of the Rule 2.5 Announcement; (iii) approved the execution and delivery of the Transaction Agreement, and the Expenses Reimbursement Agreement in substantially the form presented to the Independent Strongbridge Directors, with such changes the Strongbridge Committee might approve; (iv) resolved to recommend Strongbridge shareholders that they vote in favor of the Transaction; (v) approved the content and release of the Rule 2.5 Announcement in substantially the form presented to the Independent Strongbridge Directors, with such changes the Strongbridge Committee might approve; and (vi) approved the compensation arrangements as described in “—Interests of Strongbridge’s Executive Officers and Directors”.

After the close of trading on the Nasdaq on May 21, 2021, at the direction of Strongbridge and Xeris, respectively, MTS Health Partners and SVB Leerink, subject to the approval of Strongbridge and Xeris, calculated the final exchange ratio for the Transaction based on the previously discussed methods for determining the final exchange ratio and the closing prices of Strongbridge ordinary shares and Xeris stock on that day.

The final exchange ratio resulted in no change of the exchange ratio used for purposes of the preliminary financial analyses of MTS Securities presented at the meeting of the Independent Strongbridge Directors on May 21, 2021.

On May 23, 2021, MTS Securities delivered to the Strongbridge Board (i) its written opinion that, as of that date and subject to the various assumptions made, procedures followed, matters considered and qualifications and limitations set forth in such written opinion, the Scheme Consideration to be received by holders of shares of Strongbridge ordinary shares in the Scheme was fair, from a financial point of view, to such holders (solely in their capacity as such, and excluding the Strongbridge Supporting Shareholders and their affiliates); and (ii) its presentation of financial analyses undertaken in connection with the MTS Opinion. Dr. Jeffrey W. Sherman did not receive the distribution of the MTS Opinion because he recused himself from discussions and consideration of the Transaction and abstained from voting on the Transaction. See “—Opinion of Strongbridge’s Financial Advisor” for a summary of the MTS Opinion.

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After receipt of the MTS Opinion, the Strongbridge Committee held a meeting by videoconference, also attended by Strongbridge senior management and representatives from Skadden. After discussion, the Strongbridge Committee approved the final exchange ratio and the content and release of the Rule 2.5 Announcement, which, among other things, included the unanimous recommendation of the Independent Strongbridge Directors that Strongbridge shareholders vote in favor of the Transaction.

Also on May 23, 2021, the Xeris Board held a meeting to consider the proposed transaction with Strongbridge. Members of Xeris management and representatives of SVB Leerink, Goodwin and A&L Goodbody were present. Representatives of KPMG LLP, independent accountant to Xeris (“KPMG”), were present for a portion of the meeting. Members of Xeris management summarized for the Independent Xeris Directors the economic terms of the proposed transaction negotiated by the companies’ management teams, the strategic and financial benefits of the Transaction, the potential timeline to closing, the results of the due diligence performed with respect to Strongbridge, and the communications plan following an announcement, assuming board approval. Representatives of KPMG discussed the report from KPMG in respect of certain merger benefit statements made in the Rule 2.5 Announcement. Representatives of Goodwin discussed the directors’ fiduciary duties in connection with considering the Transaction. Representatives of Goodwin and A&L Goodbody discussed process and anticipated timing, summarized the transaction structure and the terms of the proposed Transaction Agreement, the Expenses Reimbursement Agreement, the conditions appendix, the irrevocable undertakings of certain directors, officers and shareholders of Strongbridge, the CVR Agreement and the Rule 2.5 Announcement. Representatives of SVB Leerink reviewed its financial analysis of the proposed transaction and then rendered SVB Leerink’s oral opinion, confirmed by delivery of a written opinion dated May 23, 2021, to the effect that as of that date and based upon and subject to the various assumptions, and qualifications and limitations upon the review undertaken by SVB Leerink in preparing its opinion, the consideration of one share of HoldCo common stock, without interest, to be received by holders of Xeris common stock in the Merger pursuant to the Transaction Agreement was fair, from a financial point of view, to such holders. For a detailed discussion of SVB Leerink’s opinion, please see “ – Opinion of Xeris’ Financial Advisor.” Following discussion, the Independent Xeris Directors determined that entering into the Transaction Agreement and related documents and consummating the transaction contemplated thereby, including the Merger, was advisable and fair to and in the best interests of Xeris and its stockholders, authorized and approved the execution, delivery and performance of the Transaction Agreement and related documents by Xeris and approved the Merger and recommended the adoption of the Transaction Agreement by the Xeris stockholders and directed that the Transaction Agreement be submitted for consideration by the Xeris stockholders at the Xeris Special Meeting. On a motion duly made and seconded, the Independent Xeris Directors approved the resolutions by unanimous vote of those directors in attendance. Dr. Sherman abstained from this vote because, as aforementioned, Dr. Sherman may be considered as having a conflict of interest due to his directorship of and shareholdings in Strongbridge.

On May 24, 2021, Xeris, Strongbridge, HoldCo and MergerSub executed and delivered the Transaction Agreement and the Expenses Reimbursement Agreement.

On May 24, 2021, prior to the start of trading on the Nasdaq, Xeris and Strongbridge jointly issued the Rule 2.5 Announcement pursuant to the Irish Takeover Rules and a press release announcing the execution of the Transaction Agreement.

Recommendation of the Independent Xeris Directors and Xeris’ Reasons for the Transaction

At its meeting on May 23, 2021, the Independent Xeris Directors unanimously approved the plan of merger contained in the Transaction Agreement and found that the Merger is fair to and in the best interests of Xeris and its stockholders. The Independent Xeris Directors unanimously recommend that the stockholders of Xeris vote for the adoption of the Transaction Agreement and the approval of the plan of merger contained in the Transaction Agreement and for the other resolutions at the Xeris Special Meeting.

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The Independent Xeris Directors considered many factors in making its determination that the entry into the Transaction Agreement and the Merger are fair to and in the best interests of Xeris and its stockholders and recommending approval of the plan of merger contained in the Transaction Agreement and the other resolutions by the Xeris stockholders at the Xeris Special Meeting. In arriving at its determination, the Independent Xeris Directors consulted with Xeris’ management, legal advisors and financial advisor, reviewed a significant amount of information, considered a number of factors in its deliberations and concluded that the Transaction is likely to result in significant strategic and financial benefits to Xeris and its stockholders, including:

These beliefs are based in part on the following factors that the Independent Xeris Directors considered:

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The Independent Xeris Directors weighed these factors against a number of uncertainties, risks and potentially negative factors relevant to the Transaction, including the following:

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In considering the recommendation of the Independent Xeris Directors, Xeris stockholders should be aware that directors and executive officers of Xeris have interests in the proposed transaction that are different from, or in addition to, any interests they might have as shareholders. See “Interests of Xeris’ Directors and Executive Officers in the Transaction”.

The Independent Xeris Directors concluded that the uncertainties, risks and potentially negative factors relevant to the Transaction were outweighed by the potential benefits that it expected Xeris and the Xeris stockholders would achieve as a result of the Transaction.

This discussion of the information and factors considered by the Independent Xeris Directors includes the principal positive and negative factors considered by the Independent Xeris Directors, but is not intended to be exhaustive and may not include all of the factors considered by the Independent Xeris Directors. In view of the wide variety of factors considered in connection with its evaluation of the Transaction, and the complexity of these matters, the Independent Xeris Directors did not find it useful and did not attempt to quantify or assign any relative or specific weights to the various factors that it considered in reaching its determination to approve the Transaction and to make its recommendations to the Xeris stockholders.

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Rather, the Independent Xeris Directors viewed its decisions as being based on the totality of the information presented to them and the factors they considered. In addition, individual members of the Independent Xeris Directors may have given differing weights to different factors.

Recommendation of the Independent Strongbridge Directors and Strongbridge’s Reasons for the Transaction

At its meeting on May 21, 2021, the Independent Strongbridge Directors unanimously determined that the Transaction Agreement and the transactions contemplated thereby, including the Scheme, were advisable for, fair to and in the best interests of Strongbridge and the Strongbridge shareholders, and that the terms of the Scheme were fair and reasonable, subject to receipt of the final exchange ratio and the MTS Opinion. The Independent Strongbridge Directors also delegated to a transaction committee of their members the full power and authority to act on their behalf to take any and all actions with respect to the Transaction, including to approve the final exchange ratio. On May 23, 2021, the Transaction committee met and approved the final exchange ratio. The Independent Strongbridge Directors unanimously recommend that the shareholders of Strongbridge vote in favor of the Scheme at the Court Meeting and in favor of the Scheme and other resolutions at the EGM.

In evaluating the Transaction Agreement and the Transaction, the Independent Strongbridge Directors consulted with management, as well as Strongbridge’s internal and outside legal counsel and its financial advisor, and considered a number of factors, weighing both perceived benefits of the Transaction as well as potential risks of the Transaction.

The Independent Strongbridge Directors considered the following factors that it believes support its determinations and recommendations:

Aggregate Value and Composition of the Scheme Consideration

Synergies and Strategic Considerations

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Opinion of Financial Advisor

Likelihood of Completion of the Transaction

Favorable Terms of the Transaction Agreement and Expenses Reimbursement Agreement

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Tax Treatment

The Independent Strongbridge Directors also considered a variety of risks and other countervailing factors, including:

Fluctuations in Share Price

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Risks that the CVR Milestones may not be Achieved

Limitations on Strongbridge’s Business Pending Completion of the Transaction

Possible Disruption of Strongbridge’s Business

Risks of Delays or Non-Completion

Uncertainties Following Completion

Other Risks

The Independent Strongbridge Directors concluded that the uncertainties, risks and potentially negative factors relevant to the Transaction were outweighed by the potential benefits that it expected Strongbridge and its shareholders would achieve as a result of the Transaction.

In considering the recommendation of the Independent Strongbridge Directors, you should be aware that directors and executive officers of Strongbridge have interests in the proposed transaction that are in addition to, or different from, any interests they might have as shareholders. See “ —Interests of Strongbridge’s Executive Officers and Directors” beginning on page 108.

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This discussion of the information and factors considered by the Independent Strongbridge Directors includes the principal positive and negative factors considered by the Independent Strongbridge Directors, but is not intended to be exhaustive and may not include all of the factors considered by the Independent Strongbridge Directors. In view of the wide variety of factors considered in connection with their evaluation of the Transaction, and the complexity of these matters, the Independent Strongbridge Directors did not find it useful and did not attempt to quantify or assign any relative or specific weights to the various factors that they considered in reaching its determination to approve the Transaction and to make their recommendations to the Strongbridge shareholders. Rather, the Independent Strongbridge Directors viewed their decisions as being based on the totality of the information presented to them and the factors they considered. In addition, different members of the Independent Strongbridge Directors may have given differing weights to different factors.

Xeris Unaudited Prospective Financial Information

As a matter of course, Xeris does not publicly disclose long-term projections as to future revenues, earnings or other results due to, among other reasons, the uncertainty of the underlying assumptions and estimates. However, in connection with Xeris’ and Strongbridge’s evaluation of the Transaction, Xeris made available certain unaudited prospective financial information relating to Xeris on a stand-alone, pre-transaction basis to Xeris’ financial advisor, SVB Leerink, Strongbridge and Strongbridge’s financial advisor. In addition, Xeris made available to Xeris’ financial advisor certain unaudited prospective financial information relating to Strongbridge as adjusted by Xeris. The unaudited prospective financial information was not prepared with a view toward public disclosure, and the inclusion of this information should not be regarded as an indication that any of Xeris, Strongbridge or any other recipient of this information considered, or now considers, it to be necessarily predictive of actual future results.

The unaudited prospective financial information included in this joint proxy statement/prospectus was not prepared with a view toward complying with the published guidelines of the SEC regarding projections or the guidelines established by the American Institute of Certified Public Accountants or the Financial Accounting Standards Board for preparation and presentation of prospective financial information, but, in the view of Xeris management, was prepared on a reasonable basis, reflected, at the time the prospective financial information was prepared, the best currently available estimates and judgments, and presented, to the best of Xeris management’s knowledge and belief at that time, the expected course of action and the expected future financial performance of Xeris. However, this information is not fact and should not be relied upon as being necessarily indicative of future results, and readers of this joint proxy statement/prospectus are cautioned not to place undue reliance, if any, on the prospective financial information. Neither Xeris’ independent registered public accounting firm, nor any other independent accountants, have compiled, examined, or performed any procedures with respect to the prospective financial information contained herein, nor have they expressed any opinion or any other form of assurance on such information or its achievability, and assume no responsibility for, and disclaim any association with, the prospective financial information. Xeris stockholders and Strongbridge shareholders are urged to review Xeris’ most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q for a description of risk factors with respect to Xeris’ business and see Strongbridge’s most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q for a description of risk factors relating to Strongbridge’s business. See “Cautionary Statement Regarding Forward-Looking Statements” and “Where You Can Find More Information” beginning on page 205 of this joint proxy statement/prospectus.

The summary below is included solely to give Xeris stockholders access to certain long-term financial analyses and forecasts that were made available to the Independent Xeris Directors and SVB Leerink for purposes of performing analyses underlying SVB Leerink’s fairness opinion, and is not included in this joint proxy statement/prospectus to influence a Xeris stockholder’s decision whether to vote for the merger proposal or for any other purpose. The inclusion of a summary of the financial projections in this document does not constitute an admission or representation that the information is material. The inclusion of a summary of the financial projections set forth below should not be regarded as an indication that Xeris and/or its affiliates, officers, directors, advisors or other representatives consider the financial projections set forth below to be

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necessarily predictive of actual future events, and this information should not be relied upon as such. None of Xeris, Strongbridge, HoldCo and/or their respective affiliates, officers, directors, advisors or other representatives gives any stockholder of Xeris or any other person any assurance that actual results will not differ materially from the financial projections set forth below.

Readers of this joint proxy statement/prospectus are cautioned not to unduly rely on the unaudited prospective financial information. Some or all of the assumptions which have been made regarding, among other things, the timing of certain occurrences or impacts, may have changed since the date such information was prepared. The financial projections set forth below do not take into account any circumstances, transactions or events occurring after the date on which they were prepared. Xeris has not updated and does not intend to update or otherwise revise the unaudited prospective financial information to reflect circumstances existing after the date when such information was prepared or to reflect the occurrence of future events, except to the extent required by applicable law. Xeris has made no representation to Strongbridge or any other person in the Transaction Agreement or otherwise concerning the unaudited prospective financial information.

NEITHER XERIS NOR STRONGBRIDGE HAS UPDATED, AND NEITHER XERIS NOR STRONGBRIDGE INTENDS TO UPDATE OR OTHERWISE REVISE, THE UNAUDITED FORECASTED FINANCIAL INFORMATION TO REFLECT CIRCUMSTANCES EXISTING AFTER THE DATE WHEN MADE OR TO REFLECT THE OCCURRENCE OF FUTURE EVENTS, EVEN IN THE EVENT THAT ANY OR ALL OF THE ASSUMPTIONS UNDERLYING SUCH PROSPECTIVE FINANCIAL INFORMATION ARE NO LONGER APPROPRIATE.

Certain of the measures included in the financial projections set forth below may be considered non-GAAP financial measures, including operating income. Non-GAAP financial measures should not be considered in isolation from, or as a substitute for, financial information presented in compliance with GAAP, and non-GAAP financial measures as used by Xeris may not be comparable to similarly titled amounts used by other companies.

Financial measures provided to a financial advisor are excluded from the definition of non-GAAP financial measures and therefore, are not subject to SEC rules regarding disclosures of non-GAAP financial measures, which would otherwise require a reconciliation of a non-GAAP financial measure to a GAAP financial measure. Reconciliations of non-GAAP financial measures were not relied upon by SVB Leerink for purposes of its financial analysis as described in “—Opinion of Xeris’ Financial Advisor” or by the Independent Xeris Directors in connection with its consideration of the Transaction. Accordingly, neither Xeris nor Strongbridge has provided a reconciliation of the non-GAAP financial measures included in the financial projections set forth below.

For the foregoing and other reasons, readers of this joint proxy statement/prospectus are cautioned that the inclusion of a summary of the financial projections in this joint proxy statement/prospectus should not be regarded as a representation or guarantee that the targets will be achieved nor that they should place undue reliance, if any, on the financial projections set forth below. The financial projections set forth below constitute forward-looking statements and are subject to risks and uncertainties that could cause actual results to differ materially from the projected results. See also “Cautionary Statement Regarding Forward-Looking Statements.”

The unaudited prospective financial information set forth below does not give effect to the Transaction. Xeris stockholders and Strongbridge shareholders are urged to review Xeris’ most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q for a description of Xeris’ reported results of operations, financial condition and capital resources during 2020. See “Cautionary Statement Regarding Forward-Looking Statements” and “Where You Can Find More Information” beginning on page 205 of this joint proxy statement/prospectus.

Summary of the Unadjusted Xeris Projections

Set forth below is a summary of selected projected financial information for Xeris for the quarter ended December 31, 2021 and the fiscal years 2022 through 2025 based on information as prepared by Xeris

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management in connection with Xeris’ evaluation of the Merger (the “Unadjusted Xeris Projections”). The Unadjusted Xeris Projections were presented to the Independent Xeris Directors for the purposes of considering and evaluating the Merger and were approved to be provided to Strongbridge and for use by SVB Leerink for purposes of its financial analysis and fairness opinion.

Summary of the Adjusted Xeris Projections

Set forth in the table below is a summary of the adjusted set of Xeris projections (the “Adjusted Xeris Projections”). The Adjusted Xeris Projections reflect Xeris management’s assessment of the probability of technical and regulatory success (“PTRS”) of the Gvoke Diagnostic, which Xeris attributed a probability of 90%, and the Exercise-Induced Hypoglycemia (“EIH”) indication, which Xeris attributed a probability of 50%. These PTRS probabilities were applied to the forecasted revenue and expense amounts for Gvoke Diagnostic and EIH, with the exception of development costs in 2021 and 2022 and EIH clinical costs in 2023. The Adjusted Xeris Projections were presented to the Independent Xeris Directors for the purposes of considering and evaluating the Merger and for use by SVB Leerink for purposes of its financial analysis and fairness opinion. The Adjusted Xeris Projections included in this joint proxy statement/prospectus have been prepared by, and are the responsibility of, Xeris management.

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Summary of the Xeris Adjusted Strongbridge Management Base Plan Projections

Set forth below is a summary of the base plan projected financial information for Strongbridge for the quarter ended December 31, 2021 and the fiscal years 2022 through 2034 based on information provided by Strongbridge management to Xeris management and SVB Leerink and then adjusted by Xeris management (the “Xeris Adjusted Strongbridge Management Base Plan Projections”). The Xeris Adjusted Strongbridge Management Base Plan Projections reflect Xeris management’s assessment of the PTRS of Recorlev, which Xeris attributed a probability of 90% to the forecasted revenue and gross profits for Recorlev. The Xeris Adjusted Strongbridge Management Base Plan Projections were based upon certain financial, operating and commercial assumptions developed solely using the information available to Xeris management at the time the Xeris Adjusted Strongbridge Management Base Plan Projections were approved for use by SVB Leerink for purposes of its financial analysis and fairness opinion.