You are cordially invited to attend a special meeting of stockholders (which, together with any adjournments or postponements thereof, we refer to as the “Special Meeting”) of Amicus Therapeutics, Inc., a Delaware corporation (which we refer to as “Amicus,” “we,” “us” or “our”) to be held virtually via live webcast on March 3, 2026, at 9:00 a.m., Eastern Time (unless the Special Meeting is adjourned or postponed). You may attend the Special Meeting via the Internet by live webcast at www.virtualshareholdermeeting.com/FOLDSM2026, where you will also be able to vote. Please note that you will not be able to attend the Special Meeting physically in person. For purposes of attendance at the Special Meeting, all references in the enclosed proxy statement, which is first being mailed on or about February 2, 2026, to “attendance at the Special Meeting” or “present at the Special Meeting” mean virtually present at the Special Meeting. Formal notice of the Special Meeting, a proxy statement, and a proxy card accompany this letter.

At the Special Meeting, you will be asked to consider and vote on a proposal to adopt the Agreement and Plan of Merger (which we refer to, as it may be amended from time to time, as the “Merger Agreement”), dated December 19, 2025, by and among Amicus, BioMarin Pharmaceutical Inc., a Delaware corporation (which we refer to as “BioMarin”), and Lynx Merger Sub 1, Inc., a Delaware corporation and wholly owned subsidiary of BioMarin (which we refer to as “Merger Sub”) (we refer to such proposal as the “Merger Proposal”). At the Special Meeting, you will also be asked to consider and vote on a non-binding, advisory proposal to approve compensation that may be paid or become payable by Amicus to its named executive officers that is based on or otherwise relates to the Merger (as defined below) (which we refer to as the “Compensation Proposal”) and a proposal to adjourn the Special Meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes in favor of the Merger Proposal at the time of the Special Meeting (which we refer to as the “Adjournment Proposal”).

Pursuant to the terms and subject to the conditions of the Merger Agreement, Merger Sub will merge with and into Amicus (which we refer to as the “Merger”), with Amicus surviving the Merger as a wholly owned subsidiary of BioMarin. If you are an Amicus stockholder and the Merger is completed, each of your Amicus shares of common stock, par value $0.01 (which we refer to as the “common stock”), will be converted into the right to receive $14.50 per share, in cash, without interest (which we refer to as the “Merger Consideration”) and subject to any applicable withholding of taxes (unless you have properly demanded, and not subsequently withdrawn, failed to perfect or otherwise lost your appraisal rights, under Section 262 of the Delaware General Corporation Law (which we refer to as the “DGCL”)).

Amicus’ Board of Directors (the “Board of Directors”), after careful consideration, including considering the various factors more fully described in the enclosed proxy statement, has unanimously (1) determined that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger (which we refer to as the “Transactions”), are advisable and fair to, and in the best interest of, Amicus and its stockholders; (2) declared it advisable for Amicus to enter into the Merger Agreement; (3) approved the execution, delivery and performance by Amicus of the Merger Agreement and the consummation of the Transactions; (4) resolved that the Merger shall be governed by Section 251(c) of the DGCL, upon the terms and subject to the conditions set forth in the Merger Agreement; (5) resolved to recommend that Amicus stockholders adopt the Merger Agreement at the Special Meeting; and (6) directed that the Merger Agreement be submitted to Amicus stockholders for approval at the Special Meeting.

The Board of Directors unanimously recommends that you vote (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

The enclosed proxy statement provides detailed information about the Special Meeting, the Merger Agreement and the Merger. A copy of the Merger Agreement is attached as Annex A to the proxy statement. The proxy statement also describes the actions and determinations of the Board of Directors in connection with its evaluation of the Merger Agreement and the Merger. We encourage you to read the proxy statement and its annexes, including the Merger Agreement, carefully and in their entirety, as they contain important information.

Whether or not you plan to attend the Special Meeting virtually, please sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone by following the instructions on the enclosed proxy card. If you are a stockholder of record and you attend the Special Meeting and vote online during the Special Meeting, your vote will revoke any proxy that you have previously submitted.

If you hold your shares of our common stock in “street name,” you should instruct your bank, broker or other nominee how to vote your shares of our common stock in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the Merger Proposal, without your instructions.

Your vote is very important, regardless of the number of shares of our common stock that you own. We cannot complete the Merger unless the Merger Proposal is approved by the affirmative vote of the holders of a majority of the outstanding shares of our common stock at the close of business January 28, 2026 which is the record date for the Special Meeting.

If you have any questions or need assistance voting your shares of our common stock, please contact our Proxy Solicitor:

On behalf of the Board of Directors, I thank you for your support and appreciate your consideration of this matter.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the Merger, the adoption of the Merger Agreement or any other transaction described in the accompanying proxy statement, or passed upon the adequacy or accuracy of the disclosure in the accompanying proxy statement. Any representation to the contrary is a criminal offense.

The accompanying proxy statement is dated February 2, 2026 and, together with the enclosed form of proxy card, is first being mailed on or about February 2, 2026.

Notice is hereby given that a special meeting of stockholders (including any adjournments or postponements thereof, which we refer to as the “Special Meeting”) of Amicus Therapeutics, Inc., a Delaware corporation (which we refer to as “Amicus,” “we,” “us” or “our”), will be held on March 3, 2026, at 9:00 a.m., Eastern Time (unless the Special Meeting is adjourned or postponed). Amicus stockholders will be able to attend the Special Meeting via the Internet by live webcast at www.virtualshareholdermeeting.com/FOLDSM2026, where you will be also able to vote. Please note that you will not be able to attend the Special Meeting physically in person. For purposes of attendance at the Special Meeting, all references in the enclosed proxy statement to “attendance at the Special Meeting” or “present at the Special Meeting” mean virtually present at the Special Meeting. The Special Meeting is being held for the following purposes:

Only Amicus stockholders of record as of the close of business on January 28, 2026 are entitled to notice of the Special Meeting and to vote at the Special Meeting or any adjournment, postponement or other delay thereof.

Your vote is very important, regardless of the number of shares of our common stock that you own. We cannot complete the Merger unless the Merger Proposal is approved by the affirmative vote of the holders of a majority of the outstanding shares of our common stock at the close of business January 28, 2026 which is the record date for the Special Meeting.

The Board of Directors unanimously recommends that you vote (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

Whether or not you plan to attend the Special Meeting virtually, please sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone by following the instructions on the enclosed proxy card. If you are a stockholder of record and you attend the Special Meeting and vote online during the Special Meeting, your vote will revoke any proxy that you have previously submitted. If you hold your shares of our common stock in “street name,” you should instruct your bank, broker or other nominee how to vote your shares of our common stock in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the Merger Proposal, without your instructions.

WHETHER OR NOT YOU PLAN TO ATTEND THE SPECIAL MEETING VIRTUALLY, WE ENCOURAGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) BY SIGNING AND DATING THE ENCLOSED PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED; (2) VIA THE INTERNET; OR (3) BY TELEPHONE. You may revoke your proxy or change your vote at any time before it is voted at the Special Meeting.

If you hold your shares of our common stock in “street name,” you should instruct your bank, broker or other nominee how to vote your shares of our common stock in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the Merger Proposal, without your instructions.

If you are a stockholder of record, voting online during the Special Meeting will revoke any proxy that you previously submitted. If you hold your shares of our common stock through a bank, broker or other nominee, you must obtain a “legal proxy” in order to vote online at the Special Meeting.

If you fail to (1) return your signed proxy card; (2) grant your proxy electronically over the Internet or by telephone; or (3) attend the Special Meeting and vote online during the meeting, your shares of our common stock will not be counted for purposes of determining whether a quorum is present at the Special Meeting and, if a quorum is present, will have the same effect as a vote “AGAINST” the Merger Proposal, but will have no effect on the Compensation Proposal or the Adjournment Proposal.

We encourage you to read the accompanying proxy statement and its annexes, including all documents incorporated by reference into the accompanying proxy statement, carefully and in their entirety. If you have any questions concerning the Merger, the Special Meeting or the accompanying proxy statement, would like additional copies of the accompanying proxy statement or need help voting your shares of our common stock, please contact our Proxy Solicitor:

The following questions and answers address some commonly asked questions regarding the Merger, the Merger Agreement and the Special Meeting. These questions and answers may not address all questions that are important to you. We encourage you to read carefully the more detailed information contained elsewhere in this proxy statement and the full text of the annexes to this proxy statement and the documents we refer to in this proxy statement because the information in this section does not provide all the information that might be important to you with respect to the Merger, the Merger Agreement and the Special Meeting. You may obtain the information incorporated by reference in this proxy statement without charge by following the instructions in the section of this proxy statement captioned “Where You Can Find More Information.”

This proxy statement contains certain “forward-looking statements” intended to qualify for the “safe harbor” from liability established by the Private Securities Litigation Reform Act of 1995, as amended, including, but not limited to, statements about the anticipated timing of closing of the Transactions in the second quarter of the calendar year 2026. Forward-looking statements include any statements containing the words “anticipate,” “believe,” “estimate,” “expect,” “intend”, “goal,” “may”, “might,” “plan,” “predict,” “project,” “seek,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue” and similar expressions. Forward-looking statements are subject to certain risks, uncertainties, or other factors that are difficult to predict and could cause actual events or results to differ materially from those indicated in any such statements due to a number of risks and uncertainties. Those risks and uncertainties that could cause the actual results to differ from expectations contemplated by forward-looking statements include, among other things: consummating the Transactions and financing in the anticipated timeframe, if at all; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement; uncertainties as to the ability to obtain stockholder approval; the possibility that competing acquisition proposals will be made; the possibility that various closing conditions for the Transactions may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the Transactions (or only grant approval subject to adverse conditions or limitations); the effects of the Transactions on relationships with employees, customers, suppliers, other business partners or governmental entities, including the risk that the Transactions adversely affect employee retention; the difficulty of predicting the timing or outcome of regulatory approvals or actions; the impact of competitive products and pricing; the risk that BioMarin may not realize the potential benefits of the Transactions, including the possibility that the expected benefits from the proposed Transactions will not be realized or will not be realized within the expected time period and that BioMarin and Amicus will not be integrated successfully or that such integration may be more difficult, time-consuming or costly than expected; the risks related to disruption of management’s time from ongoing business operations as a result of the Transactions; risks that the Transactions disrupt current plans and operations; obtaining and maintaining adequate coverage and reimbursement for Amicus’ products; changes in Amicus’ business during the period between announcement and closing of the Transactions; any legal proceedings and/or regulatory actions that may be instituted related to the Transactions; other business effects, including the effects of industry, economic or political conditions outside of the companies’ control; costs and expenses related to the Transactions; actual or contingent liabilities; the effects of the Transactions (or the announcement thereof) on Amicus’ and BioMarin’s stock price and/or operating results; and the other risks and uncertainties discussed in Amicus’ periodic reports filed with the SEC, including Amicus’ quarterly reports on Form 10-Q and annual reports on Form 10-K. The list of factors presented in the foregoing is not complete and you should not place undue reliance on these statements. Actual results could differ materially from those anticipated in these forward-looking statements. All forward-looking statements are based on information currently available to Amicus and BioMarin, and, except as required by applicable law, Amicus and BioMarin disclaim any obligation to update the information contained in this proxy statement as new information becomes available. All forward-looking statements in this proxy statement or made in connection therewith in writing or orally are qualified in their entirety by this cautionary statement.

The enclosed proxy is solicited on behalf of the Board of Directors for use at the Special Meeting.

We will hold the Special Meeting on March 3, 2026, at 9:00 a.m., Eastern time (unless the Special Meeting is adjourned or postponed). You can virtually attend and vote in the Special Meeting by accessing a live webcast using the Internet at www.virtualshareholdermeeting.com/FOLDSM2026. Please note that you will not be able to attend the Special Meeting physically in person. Instructions on how to attend and participate online are provided on the proxy card. We expect check-in to be available starting around 8:45 a.m., Eastern time on the day of the Special Meeting, March 3, 2026, and you should allow ample time for online check-in proceedings. We encourage you to access the meeting prior to the start time to allow ample time to complete the online check-in process. If you encounter any difficulties accessing the virtual meeting during the check-in or meeting time, please call the technical support number that will be provided on the log-in page.

At the Special Meeting, we will ask stockholders to vote to approve (1) the Merger Proposal, (2) the Compensation Proposal and (3) the Adjournment Proposal.

Only stockholders of record as of the Record Date are entitled to notice of the Special Meeting and to vote at the Special Meeting. As of the Record Date, there were 313,918,463 shares of our common stock outstanding and entitled to vote at the Special Meeting. A complete list of registered stockholders as of the close of business on the Record Date will be available for inspection during ordinary business hours by stockholders of record 10 days prior to the Special Meeting at our principal business offices at 47 Hulfish Street, Princeton, New Jersey 08542.

A majority of the issued and outstanding shares of our common stock entitled to vote, present virtually at the Special Meeting or represented by proxy, will constitute a quorum at the Special Meeting. In the event that a quorum is not present at the Special Meeting, it is expected that the meeting will be adjourned to solicit additional proxies.

Each Amicus stockholder will be entitled to one vote for each share of our common stock that such stockholder owns at the close of business on the Record Date on each proposal to be acted upon at the Special Meeting. The affirmative vote of the holders of a majority of the outstanding shares of our common stock entitled to vote as of the close of business on the Record Date is required to approve the Merger Proposal. As of the Record Date, 156,959,232 votes constitute a majority of the outstanding shares of our common stock entitled to vote on the Merger Proposal. Shares deemed not in attendance at the Special Meeting (whether due to a record holder’s failure to vote or a “street name” holder’s failure to provide any voting instructions to such holder’s bank, broker or other nominee), abstentions and broker non-votes will have the same effect as a vote “AGAINST” the Merger Proposal. Approval of the Merger Proposal by our stockholders is a condition to the closing of the Transactions.

The approval of the Compensation Proposal, on a non-binding, advisory basis, requires the affirmative vote of a majority of shares of our common stock present or represented by proxy and entitled to vote thereon. Accordingly, shares deemed not in attendance at the Special Meeting (whether due to a record holder’s failure to vote or a “street name” holder’s failure to provide any voting instructions to such holder’s bank, broker or other nominee) and broker non-votes will have no effect on the outcome of the Compensation Proposal. Abstentions will have the same effect as a vote “AGAINST” the Compensation Proposal. The approval of the Compensation Proposal is advisory and non-binding and is not a condition to the completion of the Merger.

The approval of the Adjournment Proposal, if necessary or appropriate, requires the affirmative vote of a majority of shares of our common stock present or represented by proxy and entitled to vote thereon. Accordingly, shares deemed not in attendance at the Special Meeting (whether due to a record holder’s failure to vote or a “street name” holder’s failure to provide any voting instructions to such holder’s bank, broker or other nominee) and broker non-votes will have no effect on the outcome of the Adjournment Proposal. Abstentions will have the same effect as a vote “AGAINST” the Adjournment Proposal.

If you fail to (1) return your signed proxy card; (2) grant your proxy electronically over the Internet or by telephone; or (3) attend the Special Meeting and vote online during the meeting, your shares of our common stock will not be counted for purposes of determining whether a quorum is present at the Special Meeting and, if a quorum is present, will have the same effect as a vote “AGAINST” the Merger Proposal, but will have no effect on the Compensation Proposal or the Adjournment Proposal.

Amicus does not expect any broker non-votes at the Special Meeting because the rules applicable to banks, brokers and other nominees only provide them with discretionary authority to vote on proposals that are considered routine, whereas each of the proposals to be presented at the Special Meeting is considered non-routine. As a result, no bank, broker or other nominee will be permitted to vote your shares of our common stock at the Special Meeting without receiving instructions. Failure to instruct your bank, broker or other nominee on how to vote your shares of our common stock will have the same effect as a vote “AGAINST” the Merger Proposal, but assuming a quorum is present at the Special Meeting, not have any effect on the Compensation Proposal or the Adjournment Proposal.

As of the Record Date, our directors and executive officers beneficially owned and were entitled to vote, in the aggregate, 2,153,328 shares of our common stock, representing approximately 0.69% of the shares of our common stock outstanding on the Record Date.

We currently expect that our directors and executive officers will vote all of their respective shares of our common stock: (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

If you are a stockholder of record (that is, if your shares of our common stock are registered in your name with Equiniti Trust Company, LLC, our transfer agent), there are four ways to vote:

You must have the enclosed proxy card available, and follow the instructions on the proxy card, in order to grant a proxy electronically over the Internet or by telephone. Based on your proxy cards or Internet and telephone proxies, the proxy holders will vote your shares of our common stock according to your directions.

Voting instructions are included on your proxy card. All shares of our common stock represented by properly signed and dated proxies received in time for the Special Meeting will be voted at the Special Meeting in accordance with the instructions of the stockholder. Properly signed and dated proxies that do not contain voting instructions will be voted (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

If your shares of our common stock are held in “street name” through a bank, broker or other nominee, you may vote:

If you do not return your bank’s, broker’s or other nominee’s voting form, do not vote via the Internet or telephone through your bank, broker or other nominee, if possible, or do not attend the Special Meeting and vote online with a “legal proxy” from your bank, broker or other nominee, it will have the same effect as if you voted “AGAINST” the Merger Proposal but, assuming a quorum is present at the Special Meeting, will not have any effect on the Compensation Proposal or the Adjournment Proposal.

Even if you plan to attend the Special Meeting virtually, you are strongly encouraged to vote your shares of our common stock by proxy. If you are a record holder or if you obtain a “legal proxy” to vote your shares of our common stock that you beneficially own, you may still vote your shares of our common stock online at the Special Meeting even if you have previously voted by proxy. If you are present at the Special Meeting virtually and vote online during the Special Meeting, your previous vote by proxy will not be counted.

If you are a stockholder of record, you may change your vote or revoke your proxy at any time before it is voted at the Special Meeting by:

If you have submitted a proxy, your appearance at the Special Meeting virtually, in the absence of voting online during the Special Meeting or submitting an additional proxy or revocation, will not have the effect of revoking your prior proxy.

If you hold your shares of our common stock in “street name,” you should contact your bank, broker or other nominee for instructions regarding how to change your vote. You may also vote online at the Special Meeting if you obtain a “legal proxy” from your bank, broker or other nominee.

Any adjournment, postponement or other delay of the Special Meeting, including for the purpose of soliciting additional proxies, will allow stockholders who have already sent in their proxies to revoke them at any time prior to their use at the Special Meeting as adjourned, postponed or delayed.

The Board of Directors, after careful consideration, including considering various factors described in the section of this proxy statement captioned “The Merger — Recommendation of the Board of Directors and Reasons for the Merger,” has unanimously (1) determined that the Merger Agreement and the Transactions, are advisable and fair to, and in the best interest of, Amicus and its stockholders; (2) declared it advisable for Amicus to enter into the

Merger Agreement; (3) approved the execution, delivery and performance by Amicus of the Merger Agreement and the consummation of the Transactions; (4) resolved that the Merger shall be governed by Section 251(c) of the DGCL, upon the terms and subject to the conditions set forth in the Merger Agreement; (5) resolved to recommend that Amicus stockholders adopt the Merger Agreement at the Special Meeting; and (6) directed that the Merger Agreement be submitted to Amicus stockholders for approval at the Special Meeting.

The Board of Directors unanimously recommends that you vote (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

The expense of soliciting proxies will be borne by Amicus. We have retained Innisfree M&A Incorporated, a proxy solicitation firm, as the Proxy Solicitor to solicit proxies in connection with the Special Meeting at a cost of approximately $60,000, plus a success fee of $30,000 and expenses, as well as additional fees, as agreed between the Proxy Solicitor and Amicus, in certain circumstances. We will also indemnify the Proxy Solicitor against losses arising out of its provisions of these services on our behalf. In addition, we may reimburse banks, brokers and other nominees representing beneficial owners of shares of our common stock for their expenses in forwarding soliciting materials to such beneficial owners. Proxies may also be solicited by our directors, officers and employees, personally or by telephone, email, fax, over the Internet or other means of communication. No additional compensation will be paid for such services.

Assuming timely satisfaction of necessary closing conditions, including the approval by our stockholders of the Merger Proposal, we anticipate, but cannot guarantee, that the Merger will be consummated in the second quarter of the calendar year 2026.

If the Merger is completed, stockholders who do not vote in favor of the adoption of the Merger Agreement and who properly demand appraisal of their shares of our common stock will be entitled to appraisal rights in connection with the Merger so long as they comply fully with Section 262. This means that stockholders are entitled to have their shares of our common stock appraised by the Delaware Court of Chancery and to receive in lieu of the Merger Consideration payment in cash of the amount determined by the Delaware Court of Chancery to be the “fair value” of their shares of our common stock, exclusive of any elements of value arising from the accomplishment or expectation of the Merger, together with interest to be paid on the amount determined to be fair value, if any, as determined by the court, so long as they comply fully with the procedures established by Section 262. Due to the complexity of the appraisal process, stockholders who wish to seek appraisal of their shares of our common stock are encouraged to seek the advice of legal counsel with respect to the exercise of appraisal rights.

Stockholders considering seeking appraisal should be aware that the fair value of their shares of our common stock as determined pursuant to Section 262 could be more than, the same as or less than the value of the Merger Consideration.

Stockholders wishing to exercise the right to seek an appraisal of their shares of our common stock must do ALL of the following:

Your failure to follow exactly the procedures specified under the DGCL will result in the loss of your appraisal rights. The DGCL requirements for exercising appraisal rights are described in further detail in the section of this proxy statement captioned “The Merger — Appraisal Rights,” and Section 262, the relevant section of the DGCL regarding appraisal rights, may be accessed without subscription or cost at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262. If you hold your shares of our common stock through a bank, broker or other nominee and you wish to exercise appraisal rights, you should consult with your bank, broker or other nominee to determine the appropriate procedures.

The SEC has adopted rules that permit companies and intermediaries, such as brokers, to satisfy the delivery requirements for proxy materials with respect to two or more stockholders sharing the same address by delivering a single set of proxy materials addressed to those stockholders. This process, which is commonly referred to as “householding,” potentially provides extra convenience for stockholders and cost savings for companies. A single set of proxy materials will be delivered to multiple stockholders sharing an address unless contrary instructions have been received from the affected stockholders.

We will promptly deliver a separate copy of this proxy statement to any stockholder upon request submitted in writing to us at our principal offices at 47 Hulfish Street, Princeton, New Jersey 08542 Attn: Chief Legal Officer and Corporate Secretary, c/o Amicus Therapeutics, Inc., or by email at ir@amicusrx.com. You may also orally submit your request by calling (609) 662-2000.

If two or more stockholders sharing the same address are currently receiving multiple copies of this proxy statement and would like to receive only one copy for their household, the stockholders should contact their bank, broker or other nominee record holder, or contact us as instructed above.

If you have any questions concerning the Merger, the Special Meeting or this proxy statement, would like additional copies of this proxy statement or need help voting your shares of our common stock, please contact our Proxy Solicitor:

We are asking you to adopt the Merger Agreement pursuant to which Merger Sub will merge with and into Amicus, and Amicus will become a wholly owned subsidiary of BioMarin.

For a summary of and detailed information regarding this proposal, see the information about the Merger Agreement and the Merger throughout this proxy statement, including the information set forth in the sections of this proxy statement captioned “The Merger” and “The Merger Agreement.” This summary does not purport to be complete and may not contain all of the information about the Merger that is important to you. A copy of the Merger Agreement is attached to this proxy statement as Annex A. You are urged to read the Merger Agreement carefully and in its entirety.

Under applicable law, we cannot complete the Merger without the affirmative vote by holders of a majority of the outstanding shares of our common stock as of the Record Date in favor of this Merger Proposal. If you abstain from voting, fail to cast your vote (online during the Special Meeting or by proxy) or fail to give voting instructions to your brokerage firm, bank, trust or other nominee, it will have the same effect as a vote against the Merger Proposal.

Section 14A of the Exchange Act, which was enacted as part of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, and Rule 14a-21(c) thereunder, requires that we provide stockholders with the opportunity to vote to approve, on a non-binding, advisory basis, the payment of certain compensation that may be paid or become payable to our named executive officers that is based on or otherwise relates to the Merger, as disclosed in the section of this proxy statement captioned “The Merger - Interests of Amicus’ Directors and Executive Officers in the Merger” on page 67.

We are asking stockholders to indicate their approval of the various items of compensation that may be paid or become payable to our named executive officers that is based on or otherwise relates to the Merger. These payments are set forth in the section of this proxy statement captioned “The Merger - Interests of Amicus’ Directors and Executive Officers in the Merger - Golden Parachute Compensation,” and the accompanying footnotes. In general, the various plans and arrangements pursuant to which these compensation payments may be made have previously formed part of Amicus’ overall compensation program for our named executive officers.

Accordingly, we are seeking approval of the following resolution at the Special Meeting, on an advisory, non-binding basis:

“RESOLVED, that the stockholders of Amicus Therapeutics, Inc. hereby approve, on a nonbinding, advisory basis, the compensation that may be paid or become payable to Amicus’ named executive officers that is based on or otherwise relates to the Merger as disclosed pursuant to Item 402(t) of Regulation S-K in the section of the proxy statement captioned ‘The Merger - Interests of Amicus’ Directors and Executive Officers in the Merger - Golden Parachute Compensation,’ including the associated narrative discussion, and the agreements, plans, arrangements or understandings pursuant to which such compensation may be paid or become payable.”

The vote on the Compensation Proposal is a vote separate and apart from the vote on the Merger Proposal to approve the Merger. Accordingly, if you are a stockholder, you may vote to approve the Merger Proposal, and vote not to approve the Compensation Proposal, and vice versa. Stockholders should note that the approval of this proposal is not a condition to completion of the Merger, and as an advisory vote, the result will not be binding on Amicus, the Board of Directors, BioMarin or the named executive officers. Further, certain payments under the underlying plans and arrangements are contractual in nature and not, by their terms, subject to stockholder approval. Accordingly, regardless of the outcome of the advisory vote, if the Merger is consummated, our named executive officers will be eligible to receive the compensation that is based on or otherwise relates to the Merger in accordance with the terms and conditions of the underlying plans and agreements and the Merger Agreement.

We are asking you to approve a proposal to adjourn the Special Meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes in favor of the adoption of the Merger Agreement at the time of the Special Meeting. If stockholders approve this Adjournment Proposal, we could adjourn the Special Meeting and any adjourned session of the Special Meeting and use the additional time to solicit additional proxies, including proxies from stockholders that have previously returned properly executed proxies voting against approval of the Merger Proposal. Among other things, approval of the Adjournment Proposal could mean that, even if we had received proxies representing a sufficient number of votes against approval of the Merger Proposal such that the proposal to adopt the Merger Agreement would be defeated, we could adjourn the Special Meeting without a vote on the approval of the Merger Proposal and seek to convince the stockholders of those shares of our common stock to change their votes to votes in favor of approval of the Merger Proposal. Additionally, we may seek to adjourn the Special Meeting if a quorum is not present or otherwise at the discretion of the chairman of the Special Meeting.

We do not anticipate calling a vote on this proposal if the Merger Proposal is approved by at least a majority of the outstanding shares of our common stock as of the Record Date.

This discussion of the Merger Agreement and the Merger in this proxy statement is qualified in its entirety by reference to the Merger Agreement, which is attached to this proxy statement as Annex A and incorporated into this proxy statement by reference. You should read and consider the Merger Agreement, which is the legal document that governs the Merger, carefully and in its entirety.

Amicus is a leading, global biotechnology company with a clear and compelling mission: to develop and deliver transformative medicines for people living with rare diseases. With extraordinary patient focus, Amicus strives to redefine expectations in rare disease.

Amicus maintains a website at www.amicusrx.com. Amicus’ common stock, par value $0.01, is listed on Nasdaq under the symbol “FOLD.”

BioMarin is a leading, global rare disease biotechnology company focused on delivering medicines for people living with genetically defined conditions. Founded in 1997, the San Rafael, California-based company has a proven track record of innovation, with eight commercial therapies and a strong clinical and preclinical pipeline. Using a distinctive approach to drug discovery and development, BioMarin seeks to unleash the full potential of genetic science by pursuing category-defining medicines that have a profound impact on patients.

BioMarin maintains a website at www.biomarin.com. BioMarin’s common stock, par value $0.001, is listed on Nasdaq under the symbol “BMRN.”

Merger Sub is a wholly owned subsidiary of BioMarin and was formed on December 8, 2025, solely for the purpose of engaging in the Transactions and has not engaged in any business activities other than in connection with the Transactions.

Upon the terms and subject to the conditions of the Merger Agreement, if the Merger is completed, at the Effective Time, Merger Sub will merge with and into Amicus, and Amicus will continue as the Surviving Corporation and a wholly owned subsidiary of BioMarin. As a result of the Merger, our common stock will no longer be publicly traded, will be delisted from Nasdaq and will be deregistered under the Exchange Act, and Amicus will no longer file periodic reports with the SEC. If the Merger is completed, you will not own any shares of the capital stock of the Surviving Corporation.

The Effective Time will occur upon the filing of a certificate of merger with the Secretary of State of the State of Delaware (or at such later time as we, BioMarin and Merger Sub may agree and specify in the certificate of merger).

If the Merger Agreement is not adopted by our stockholders or if the Merger is not completed for any other reason, stockholders will not receive any payment for their shares in connection with the Merger. Instead, Amicus will remain an independent public company, our common stock will continue to be listed and traded on Nasdaq and

registered under the Exchange Act and we will continue to file periodic reports with the SEC. In addition, if the Merger is not completed, we expect that stockholders will continue to be subject to the same risks and opportunities to which they are currently subject, including, without limitation, risks related to the highly competitive industry in which Amicus operates and risks related to adverse economic conditions.

Upon termination of the Merger Agreement under specified circumstances, Amicus will be required to pay BioMarin a termination fee of $175,000,000 in cash. For more information, please see the section of this proxy statement captioned “The Merger Agreement — Expenses; Termination Fee.”

Furthermore, if the Merger is not completed, and depending on the circumstances that caused the Merger not to be completed, it is likely that the price of our common stock will decline significantly. If that were to occur, it is uncertain when, if ever, the price of our common stock would return to the price at which it trades as of the date of this proxy statement.

Accordingly, if the Merger is not completed, there can be no assurance as to the effect of these risks and opportunities on the future value of your shares of our common stock. If the Merger is not completed, the Board of Directors will continue to evaluate and review Amicus’ business operations, strategic direction and capitalization, among other things, and will make such changes as are deemed appropriate and continue to seek to identify strategic alternatives to enhance shareholder value. If the Merger Agreement is not adopted by our stockholders or if the Merger is not completed for any other reason, there can be no assurance that any other transaction acceptable to the Board of Directors will be offered or that Amicus’ business, prospects or results of operation will not be adversely impacted.

At the Effective Time, each outstanding share of our common stock (other than the Excluded Shares and the Dissenting Shares) will be converted into the right to receive the Merger Consideration.

After the Merger is completed, you will have the right to receive the Merger Consideration, but you will no longer have any rights as a stockholder (except that stockholders who properly exercise and perfect, and do not subsequently withdraw, their appraisal rights will have the right to receive a payment for the “fair value” of their shares of our common stock as determined pursuant to an appraisal proceeding as contemplated by Section 262, as described in the section of this proxy statement captioned “— Appraisal Rights”).

The following chronology summarizes the key meetings and events that led to the signing of the Merger Agreement. This chronology does not purport to catalogue every conversation of or among members of the Board of Directors, Amicus’ representatives, BioMarin’s representatives and other parties.

At the direction of the Board of Directors, Amicus’ management regularly meets with other biotechnology and pharmaceutical companies regarding a variety of potential partnerships, licensing arrangements, collaborations and other strategic transactions. The Board of Directors also periodically evaluates Amicus’ historical performance, future growth prospects and long-term strategic plan and considers various strategic opportunities available to Amicus as well as ways to enhance shareholder value, including in light of the business, competitive, regulatory, financing and economic environment and developments in the biopharmaceutical industry. These reviews have included discussions as to whether Amicus should continue to execute on its strategy as a standalone company, pursue various partnerships, collaborations or licensing arrangements, seek to raise additional capital, and/or pursue a sale of Amicus.

In August 2013, Amicus executed an engagement letter with Goldman Sachs for Goldman Sachs to serve as a financial advisor to the Board of Directors in connection with its exploration and evaluation of strategic alternatives, including a potential sale of Amicus. This engagement letter has been periodically renewed or amended in subsequent years to, among other things, extend its term. The most recent renewed engagement letter was executed on March 20, 2025.

In the fourth quarter of 2022, Amicus received Paragraph IV Certification Notice Letters from Teva Pharmaceuticals USA, Inc. (which we refer to as “Teva”), Aurobindo Pharma Limited (which we refer to as “Aurobindo”), and Lupin Limited (which we refer to as “Lupin”) in connection with their Abbreviated New Drug Applications filed with the FDA requesting approval to market generic Galafold. In November 2022, Amicus filed

lawsuits against Teva, Lupin, and Aurobindo in the U.S. District Court for the District of Delaware (which we refer to as the “Court”) for infringement of Amicus’ Orange Book-listed patents (which we refer to as the “Teva Litigation,” the “Lupin Litigation,” and the “Aurobindo Litigation,” respectively and, collectively, the “Hatch Waxman Litigation”).

In the fourth quarter of 2023, Amicus and Lupin entered a stipulation to stay the Lupin Litigation.

On March 6, 2024, the Board of Directors formed a Transactions Committee comprised of the Chair of the Board of Directors and members of the Audit and Compliance Committee. The Transactions Committee was formed for convenience to permit the Board of Directors to exercise efficient oversight of Amicus’ management and to review and evaluate a potential licensing transaction then under consideration by Amicus and other potential business development opportunities. Amicus ultimately discontinued evaluation of this potential licensing transaction in May 2024; however, the Board of Directors retained the Transactions Committee to continue to meet from time to time to review and evaluate other potential business development activities.

In October 2024, Amicus entered into a non-exclusive, non-transferable, royalty-free, fully paid-up license with Teva which permits Teva to market its generic version of Galafold in the United States beginning on January 30, 2037, or earlier in certain circumstances. In accordance with the license agreement, Amicus and Teva terminated the Teva Litigation pursuant to a consent judgment and permanent injunction that was entered with the Court.

In March 2025, representatives of Amicus met with representatives of Party A, a commercial stage biopharmaceutical company, to discuss a potential in-licensing transaction involving one of Party A’s product candidates. In connection with these discussions, on March 31, 2025, Amicus entered into a confidentiality agreement with Party A that did not contain a standstill provision. Pursuant to this confidentiality agreement, Party A shared non-public due diligence information with Amicus related to Party A’s product candidate. Amicus did not share any of its own non-public information with Party A in connection with these discussions.

On May 12, 2025, the chief executive officer of Party A contacted Bradley Campbell, President and Chief Executive Officer of Amicus, about a potential strategic transaction with Amicus. No specific terms were proposed or discussed.

On May 16, 2025, the Transactions Committee held a meeting, which was also attended by representatives of Amicus’ management, Centerview, which had previously served as a financial advisor to Amicus and Board of Directors on unrelated matters, and Skadden, Arps, Slate, Meagher & Flom LLP (which we refer to as “Skadden”), which then served as Amicus’ outside M&A counsel. Mr. Campbell updated the Transactions Committee on his recent interactions with the chief executive officer of Party A and the Transactions Committee discussed a potential strategic transaction with Party A, including the likelihood that Party A would propose an all-stock strategic combination. Mr. Campbell confirmed that Amicus’ management was preparing a preliminary financial model to be used for valuation of Amicus in the event of an offer from Party A. A representative of Skadden discussed legal considerations for the Transactions Committee and the Board of Directors in evaluating an acquisition offer, including the directors’ fiduciary duties. Representatives of Centerview reviewed macroeconomic factors affecting the M&A market, the biopharmaceutical industry and Amicus and discussed the value and risks of an all-stock strategic combination. Following discussion, the Transactions Committee determined that Amicus should continue discussions with Party A if Party A made a sufficient offer.

On May 19, 2025, Mr. Campbell and the chief executive officer of Party A had a call to discuss a potential strategic transaction between Party A and Amicus. Consistent with instruction from the Transactions Committee, Mr. Campbell conveyed that the Transactions Committee was open to engaging with Party A if Party A made a sufficient offer and his perspectives on Amicus’ opportunities as a standalone company.

On May 27, 2025, Mr. Campbell and the chief executive officer of Party A met for dinner. The chief executive officer of Party A reiterated Party A’s interest in a strategic transaction with Amicus, and Mr. Campbell reiterated that the Transactions Committee was open to engaging with Party A if Party A made a sufficient offer.

On June 5, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland & Ellis LLP (which we refer to as “Kirkland”) (which was engaged by Amicus as its outside M&A counsel following the transition of the lead transactional partners from Skadden to Kirkland in May 2025). Representatives of Centerview and Goldman Sachs reviewed perspectives on the biopharmaceutical industry, Wall Street analyst perspectives on Amicus, and strategic considerations for Amicus.

On June 11, 2025, Amicus executed an engagement letter with Centerview for Centerview to serve as a co-financial advisor to assist the Board of Directors with its exploration and evaluation of strategic alternatives, including a potential sale of Amicus. In determining that Amicus should engage Centerview as co-advisor, the Board of Directors considered that Centerview had extensive relationships throughout, and experience and expertise in, the biopharmaceutical industry. The Board of Directors decided to have two financial advisors given the expertise and knowledge of each of the advisors.

On June 12, 2025, the chief executive officer of Party A submitted to Mr. Campbell a written non-binding expression of interest to acquire all of the outstanding common stock of Amicus in an all-stock transaction for $8.50 per share of Amicus’ common stock, with such consideration to be paid in newly-issued Party A shares (which we refer to as the “June 12 Proposal”).

On June 13, 2025, the Transactions Committee held a meeting, which was also attended by all of the other members of the Board of Directors and representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Representatives of Centerview and Goldman Sachs reviewed the June 12 Proposal, including the timing of a potential transaction and events in that timeframe that could affect the stock price of both Amicus and Party A. The Transactions Committee and the members of the Board of Directors discussed the June 12 Proposal with the advisors. Following discussion, the Transactions Committee and the members of the Board of Directors determined that the price offered in the June 12 Proposal was insufficient and directed Mr. Campbell to reject the June 12 Proposal and decline to offer any counterproposal.

Later on June 13, 2025, consistent with the Board of Directors’ instructions, Mr. Campbell informed Party A’s chief executive officer that Amicus was rejecting the June 12 Proposal. Subsequently, in August 2025, Amicus also discontinued discussions with Party A regarding a potential in-licensing transaction involving one of Party A’s product candidates.

On June 23, 2025, Mr. Campbell and Alexander Hardy, President and Chief Executive Officer of BioMarin, had an introductory conversation and briefly discussed their respective backgrounds, the history of each of Amicus and BioMarin and macroeconomic factors affecting the biopharmaceutical industry.

On July 25, 2025, Mr. Hardy contacted Mr. Campbell to arrange a dinner.

On July 27, 2025, Mr. Campbell and Mr. Hardy met over dinner. During the meeting, Mr. Hardy expressed BioMarin’s interest in a potential strategic transaction with Amicus. Mr. Campbell conveyed his confidence in Amicus’ current strategy and his focus on the interests of Amicus’ patients, stockholders and employees.

On July 28 and 29, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Mr. Campbell updated the Board of Directors on his conversation with Mr. Hardy. Representatives of Amicus’ management then discussed with the Board of Directors a preliminary financial model prepared by Amicus’ management and the underlying assumptions used to prepare the model (which we refer to as the “July Projections”). For more information about the July Projections presented at the July 28 and 29 Board of Directors meeting, see the section of this proxy statement captioned “— Certain Financial Projections.” Representatives of Centerview and Goldman Sachs also provided their perspectives on the biopharmaceutical market, strategic considerations for Amicus, and their respective preliminary financial analyses of Amicus prepared based on the July Projections.

On August 1, 2025, Mr. Hardy called Mr. Campbell to discuss BioMarin’s continued interest in a potential strategic transaction with Amicus.

From September 29, 2025 to October 1, 2025, the Court held a three-day trial in the Aurobindo Litigation (which we refer to as the “Aurobindo Trial”) to hear evidence and argument as to the disputed patent issues between Aurobindo and Amicus. Following the conclusion of the Aurobindo Trial, the Court established a post-trial briefing schedule, with Amicus and Aurobindo to submit final briefings by December 16, 2025.

On September 29, 2025, Mr. Hardy and Mr. Campbell met over dinner. During the meeting, Mr. Hardy reiterated BioMarin’s interest in a potential strategic transaction with Amicus. Mr. Campbell explained that Amicus would need a definitive indication of BioMarin’s interest, together with a preliminary proposal on the consideration to be offered, before Amicus would be able to consider engaging further. Mr. Hardy inquired whether any other

parties were pursuing a potential strategic transaction with Amicus, and Mr. Campbell explained that Amicus had received an indication of value from another interested party that fell short of the Board of Directors’ view of Amicus’ value and that Amicus had therefore declined to engage further with that party.

Following the Aurobindo Trial, beginning in October 2025 and continuing until the execution of the Lupin License Agreement (as defined below), Amicus and Lupin discussed a potential settlement of the Lupin Litigation.

On October 6, 2025, Mr. Hardy called Mr. Campbell and verbally communicated that BioMarin would be making an offer to acquire Amicus for $12.50 per share in cash. Mr. Hardy emphasized the value of a strategic combination of Amicus and BioMarin. Mr. Hardy indicated that BioMarin’s offer evidenced BioMarin’s confidence in achieving a final offer in the “teens”, subject to BioMarin’s receipt of confidential due diligence materials to confirm BioMarin’s view of value. Mr. Hardy noted that a transaction between BioMarin and Amicus would be predicated on prior resolution of the remaining Hatch Waxman Litigation. Mr. Campbell confirmed that he would discuss the offer with the Transactions Committee.

Shortly thereafter, BioMarin submitted a written, preliminary non-binding indication of interest to acquire all of the fully diluted equity securities of Amicus for $12.50 per share in cash (which we refer to as the “October 6 Proposal”). The October 6 Proposal indicated that BioMarin would finance the transaction through a combination of existing cash and accessing new debt. BioMarin indicated that it could work quickly towards a definitive agreement and proposed a four-week timeline for due diligence. The October 6 Proposal included a letter from Morgan Stanley & Co. LLC (which we refer to as “Morgan Stanley”), financial advisor to BioMarin, confirming that Morgan Stanley was highly confident that it could arrange a debt financing in connection with an acquisition of Amicus by BioMarin. Following receipt, Mr. Campbell shared the October 6 Proposal and the letter from Morgan Stanley with the Board of Directors.

On October 8, 2025, the Transactions Committee held a meeting, which was also attended by all but one of the other members of the Board of Directors and representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. A representative of Kirkland discussed legal considerations for the Transactions Committee and the Board of Directors in evaluating an acquisition offer, including the directors’ fiduciary duties. Representatives of Centerview, Goldman Sachs and Kirkland reviewed the October 6 Proposal and potential next steps for Amicus. Mr. Campbell discussed concerns that BioMarin had expressed, including resolution of the remaining Hatch Waxman Litigation. Following discussion, the Transactions Committee and other members of the Board of Directors determined that the per share price in the October 6 Proposal was insufficient but that Amicus should allow BioMarin to conduct limited due diligence with the expectation that BioMarin would return with a significantly improved offer. The Transactions Committee and other members of the Board of Directors discussed the possibility of reaching out to other potential counterparties to gauge their interest in a potential strategic transaction but determined not to conduct such outreach at that time to mitigate the risk of a potential leak and to reduce distraction to Amicus’ management.

On October 10, 2025, Mr. Campbell and Mr. Hardy had a call to discuss the October 6 Proposal. Consistent with the determination of the Transactions Committee and the Board of Directors, Mr. Campbell conveyed that the Board of Directors had determined that the per share price in the October 6 Proposal was insufficient but explained that Amicus would allow limited due diligence with the expectation that BioMarin would return with a significantly improved offer. Mr. Campbell and Mr. Hardy discussed the topics of BioMarin’s proposed initial due diligence.

On October 15, 2025, Amicus entered into a confidentiality agreement with BioMarin and subsequently shared limited non-public due diligence information with BioMarin. The confidentiality agreement included a standstill provision. Thereafter, this confidentiality agreement was amended from time to time to allow BioMarin to share certain non-public information of Amicus with its third-party advisors and potential financing sources.

On October 22, 2025, Amicus provided representatives of BioMarin, representatives of Jones Day, BioMarin’s legal counsel, and representatives of Morgan Stanley with access to an electronic due diligence data room. Thereafter, Amicus provided updates and materials to BioMarin in response to BioMarin’s requests for additional information.

On October 23, 2025, representatives of Amicus gave a management presentation to representatives of BioMarin.

On October 24, 2025, Amicus and its advisors participated in a due diligence call with BioMarin and representatives of Jones Day to discuss questions regarding intellectual property matters, including the remaining Hatch Waxman Litigation.

On October 27, 2025, Mr. Campbell and Mr. Hardy had a call to discuss the due diligence process. Mr. Hardy conveyed that he would meet with BioMarin’s board of directors to discuss a revised offer to acquire Amicus. Mr. Hardy expressed that the remaining Hatch Waxman Litigation continued to be the central question for BioMarin. Mr. Campbell reported that Amicus expected to have an update on the status of settlement discussions with Lupin by the end of the week and explained that Amicus was not in active discussions with Aurobindo regarding a potential settlement.

On October 28, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Representatives of Centerview and Goldman Sachs reviewed the biopharmaceutical market, strategic considerations for Amicus, and potential next steps if BioMarin were to submit a revised offer. Mr. Campbell provided an update on discussions with BioMarin. The Board of Directors then discussed the remaining Hatch Waxman Litigation and BioMarin’s position that a transaction between BioMarin and Amicus would be predicated on prior resolution of the remaining Hatch Waxman Litigation.

On October 29, 2025, Mr. Hardy called Mr. Campbell and verbally communicated a revised offer to acquire Amicus for $13.50 per share in cash. Mr. Hardy reiterated that the remaining Hatch Waxman Litigation remained one of BioMarin’s concerns and stated that the revised offer would be contingent on resolution of the remaining Hatch Waxman Litigation, which BioMarin hoped would be negotiated in parallel with finalizing a transaction with BioMarin.

Following this call, BioMarin submitted a written, preliminary non-binding indication of interest to acquire all of the fully diluted equity securities of Amicus for $13.50 per share in cash (which we refer to as the “October 29 Proposal”). The October 29 Proposal indicated that BioMarin would finance the transaction through a combination of existing cash and new debt. BioMarin indicated that it could work quickly towards a definitive agreement and proposed a four-week timeline for the remaining due diligence.

Later on October 29, 2025, Mr. Campbell shared the October 29 Proposal with the Board of Directors, and the Board of Directors determined that Mr. Campbell should communicate to BioMarin that Amicus did not believe the October 29 Proposal was sufficient for Amicus to enter into a transaction with BioMarin.

On November 3, 2025, Amicus and its advisors participated in another due diligence call with BioMarin and its advisors to discuss the remaining Hatch Waxman Litigation.

On November 6, 2025, Mr. Campbell and Mr. Hardy had a call to discuss the October 29 Proposal. Mr. Campbell conveyed that the per share price in the October 29 Proposal was insufficient but explained that Amicus would allow continued diligence with the expectation that BioMarin would return with a further improved offer. Mr. Campbell and Mr. Hardy discussed the topics of BioMarin’s remaining due diligence.

On November 7, 2025, representatives of Centerview and Goldman Sachs had a call with representatives of Morgan Stanley to discuss next steps for BioMarin’s due diligence.

On November 9, 2025, the Transactions Committee held a meeting, which was also attended by two other members of the Board of Directors, representatives of Amicus’ management, Groombridge Wu, Amicus’ outside intellectual property counsel, and Kirkland. A representative of Groombridge Wu provided an update on the status of the remaining Hatch Waxman Litigation. The Transactions Committee and other members of the Board of Directors discussed BioMarin’s position that BioMarin would not enter into a transaction with Amicus until the remaining Hatch Waxman Litigation was resolved and considered potential strategies for reaching a settlement with each of Aurobindo and Lupin.

On November 14, 2025, James Sabry, Chief Business Officer of BioMarin, contacted Sébastien Martel, Chief Business Officer of Amicus, to discuss the status of BioMarin’s due diligence. During this conversation, Mr. Sabry indicated that the October 29 Proposal would not be BioMarin’s final offer. Mr. Sabry also reiterated that Amicus resolving the remaining Hatch Waxman litigation was critical for BioMarin.

Also on November 14, 2025, Amicus updated BioMarin on the status of the settlement discussions with Lupin.

Between November 18, 2025, and November 25, 2025, Amicus participated in multiple diligence calls with BioMarin and its advisors to discuss BioMarin’s due diligence questions.

On November 19, 2025, Mr. Hardy and Mr. Campbell met in person at a conference in Europe they were both attending. Mr. Hardy reiterated BioMarin’s interest in acquiring Amicus and expressed a desire to enter into an agreement to acquire Amicus before the J.P. Morgan Healthcare Conference in January 2026, with a preference to enter into an agreement to acquire Amicus by December 15, 2025. Mr. Campbell responded that Amicus was prepared to move expeditiously towards an announcement of a transaction once BioMarin made an offer with sufficient value that the Board of Directors would support.

Later on November 19, 2025, Mr. Campbell had dinner with a representative of Party B, a global biopharmaceutical company that had historically expressed strategic interest in Amicus. During dinner, among other topics, Mr. Campbell inquired as to whether Amicus should reach out to Party B if Amicus were ever in serious discussions to be acquired. The representative from Party B confirmed that Amicus should reach out in that circumstance.

Between November 19, 2025 and December 10, 2025, Mr. Sabry and Mr. Martel held calls to discuss key remaining due diligence items and the remaining Hatch Waxman Litigation.

On November 20, 2025, Mr. Hardy and Mr. Campbell had a phone conversation. Mr. Hardy noted that BioMarin was speaking with financing parties to support the transaction.

On November 21, 2025, Mr. Hardy and Mr. Campbell spoke by phone again and Mr. Hardy indicated that BioMarin was prepared to offer $14.00 per share. Mr. Hardy emphasized that BioMarin was interested in entering into an agreement to acquire Amicus by December 15, 2025. Mr. Hardy also emphasized the importance to BioMarin of Amicus reaching a resolution on the remaining Hatch Waxman Litigation prior to BioMarin signing the agreement to acquire Amicus. Mr. Hardy explained that BioMarin was very interested in acquiring Amicus, but that BioMarin was also evaluating other potential acquisitions. Mr. Hardy expressed his hope that the Board of Directors would quickly meet to discuss and allow BioMarin to move forward with confirmatory diligence. Mr. Hardy requested a call with Mr. Campbell on November 22, 2025 to further discuss.

Later on November 21, 2025, BioMarin submitted a written, preliminary non-binding indication of interest to acquire all of the fully diluted equity securities of Amicus for $14.00 per share in cash (which we refer to as the “November 21 Proposal”). The November 21 Proposal indicated that BioMarin would finance the transaction through a combination of existing cash and new debt. BioMarin indicated it would need 2−3 weeks to complete the remaining due diligence and expressed a commitment to sign a definitive transaction agreement on or before December 15, 2025.

On November 22, 2025, the Transactions Committee held a meeting, which was also attended by all of the other members of the Board of Directors and representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Mr. Campbell summarized the recent communications from BioMarin, including the November 21 Proposal. The Transactions Committee and other members of the Board of Directors discussed the November 21 Proposal, including potential strategies to further increase the per share price offered and timing of next steps. Representatives of Centerview and Goldman Sachs reviewed public market perspectives and analyst views of Amicus, as well as the current M&A market sentiment. Representatives of Amicus’ management then discussed with the Transactions Committee and other members of the Board of Directors an updated preliminary financial model prepared by Amicus’ management and the underlying assumptions used to prepare the updated model (which we refer to as the “November 22 Projections”). For more information about the November 22 Projections presented at the November 22, 2025 Transactions Committee meeting, see the section of this proxy statement captioned “— Certain Financial Projections.” Representatives of Centerview and Goldman Sachs then reviewed their respective preliminary financial analyses of Amicus and a potential transaction prepared based on the November 22 Projections. The Transactions Committee and other members of the Board of Directors then discussed the current status of the remaining Hatch Waxman Litigation and BioMarin’s position that the remaining Hatch Waxman Litigation must be settled prior to entering into a definitive transaction agreement. The Transactions Committee and other members of the Board of Directors discussed strategies for reaching a settlement with each of Aurobindo and Lupin and the possibility that these settlements may be completed when the transaction with BioMarin may remain uncertain. Following discussion, the Transactions Committee and other members of the Board of Directors determined that settling the remaining Hatch Waxman Litigation would be in the best interests of Amicus whether or not Amicus completed a transaction with BioMarin. The Transactions Committee and other members of the Board of Directors then instructed Amicus to continue to work towards settling the Aurobindo Litigation and the Lupin

Litigation in advance of a potential transaction date and authorized Amicus’ management to enter into a settlement agreement with Aurobindo on the terms discussed at this meeting. The Transactions Committee and other members of the Board of Directors next discussed with Amicus’ advisors potentially conducting outreach to other counterparties to gauge interest in a potential strategic transaction with Amicus. The Transactions Committee and other members of the Board of Directors considered the advantages and disadvantages of conducting this outreach, including timing considerations and the risk of leaks. Mr. Campbell provided his recommendation to move forward with the outreach. Following discussion, the Transactions Committee and other members of the Board of Directors determined that Amicus, Centerview and Goldman Sachs should conduct outreach to five parties that the Board of Directors determined were most likely to be interested in a potential strategic transaction with Amicus, including Party A and Party B. The Transactions Committee and other members of the Board of Directors next discussed how to respond to the November 21 Proposal. Following discussion, the Transactions Committee and other members of the Board of Directors determined that Mr. Campbell should reject the November 21 Proposal but inform BioMarin that Amicus would continue to advance due diligence with BioMarin. The Transactions Committee and other members of the Board of Directors authorized Mr. Campbell to propose a counteroffer of $15.00 per share of Amicus’ common stock in cash.

Later on November 22, 2025, consistent with the Transactions Committee’s and the Board of Directors’ direction, Mr. Campbell called Mr. Hardy. Mr. Campbell informed Mr. Hardy that Amicus would provide additional due diligence information to BioMarin and explained that Amicus was working towards a resolution of the remaining Hatch Waxman Litigation. Mr. Campbell emphasized that the per share price in the November 21 Proposal was not sufficient for Amicus to enter into a definitive agreement with BioMarin and proposed that BioMarin agree to pay $15.00 per share of Amicus’ common stock in cash to acquire Amicus.

On November 24, 2025, at the direction of the Transactions Committee and the Board of Directors, representatives of Amicus, Goldman Sachs or Centerview reached out to representatives of each of the five parties that the Board of Directors had identified at the November 22, 2025 Transactions Committee meeting, including Party A and Party B, to determine each party’s interest in a potential strategic transaction with Amicus. Subsequently, each of these parties ultimately declined to engage in further discussions regarding a potential strategic transaction at that time.

Also on November 24, 2025, Jones Day shared a draft merger agreement with Kirkland. Between November 24, 2025, and the announcement of the Transactions on December 19, 2025, representatives of Kirkland and Jones Day exchanged drafts of the merger agreement and various other ancillary transaction documents. The key issues negotiated and resolved in the draft merger agreement included the size of the termination fee payable by Amicus, the scope of Amicus’ obligations to deliver financial information to BioMarin to support BioMarin’s acquisition financing, the parties’ obligations to seek regulatory approvals for the transaction, the circumstances under which the parties could terminate the merger agreement, and Amicus’ ability to implement various executive and employee compensation matters, such as filling vacant positions and paying increases in base salaries and bonuses to all employees in the ordinary course of business consistent with Amicus’ past practice (for a summary of these matters affecting executive officers, please see the section of this proxy statement captioned “— Interests of Amicus’ Directors and Executive Officers in the Merger”; for more information about the Merger Agreement, please see the section of this proxy statement captioned “The Merger Agreement.”).

On November 26, 2025, Centerview provided a customary material relationships disclosure letter to Amicus.

On December 1, 2025, Mr. Hardy contacted Mr. Campbell and informed him that BioMarin intended to submit a revised offer to acquire Amicus. Mr. Hardy also indicated that BioMarin was prepared to sign definitive transaction documents in the coming weeks.

On December 2, 2025, Mr. Hardy and Mr. Campbell had a call to discuss key remaining due diligence items and the timing of a potential revised offer from BioMarin.

On December 4, 2025, Mr. Hardy and Mr. Campbell spoke on the phone. Mr. Hardy verbally communicated a revised offer to acquire Amicus for $14.25 per share in cash (which we refer to as the “December 4 Proposal”) and BioMarin’s rationale for the increased offer. Mr. Hardy noted that BioMarin worked hard to improve their offer to $14.25 per share in cash.

On December 5, 2025, Amicus sent Lupin a proposed execution version of a non-exclusive, non-transferable, royalty-free, fully paid-up license with Lupin which would allow Lupin to market its generic version of Galafold in the United States beginning on January 30, 2037, or earlier in certain circumstances (which we refer to as the “Lupin License Agreement”) that would resolve the Lupin Litigation. The Lupin License Agreement required two Lupin signatories to fully execute the document.

On December 6, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Mr. Campbell summarized recent interactions with BioMarin, including receipt of the December 4 Proposal. Representatives of Centerview and Goldman Sachs reviewed the December 4 Proposal and feedback from other outreach parties. The Board of Directors discussed how to best position a potential counterproposal. A representative of Amicus’ management reviewed various executive and employee compensation matters in connection with a proposed transaction with BioMarin. Following discussion, the Board of Directors authorized Mr. Campbell to respond to the December 4 Proposal with a counterproposal of $14.50 per share in cash.

Later on December 6, 2025, Mr. Campbell and Mr. Hardy had a call to discuss the December 4 Proposal. Following discussion, Mr. Hardy responded to the December 4 Proposal with a new proposal of $14.50 per share in cash and indicated that BioMarin would not be willing to increase the offer beyond $14.50 per share in cash (which we refer to as the “December 6 Proposal”). Consistent with the Board of Directors’ instruction, Mr. Campbell agreed in principle with Mr. Hardy that Amicus would be willing to enter into a definitive transaction agreement at the price included in the December 6 Proposal.

Later on December 6, 2025, representatives of Centerview and Goldman Sachs had a call with representatives of Morgan Stanley to discuss next steps in the process.

On December 8, 2025, Amicus entered into a non-exclusive, non-transferable, royalty-free, fully paid-up license with Aurobindo which will allow Aurobindo to market its generic version of Galafold in the United States beginning on January 30, 2037, or earlier in certain circumstances (which we refer to as the “Aurobindo License Agreement”) and Amicus and Aurobindo agreed to resolve the Aurobindo Litigation. Subsequently, Amicus informed BioMarin that Amicus had entered into the Aurobindo License Agreement that would resolve the Aurobindo Litigation.

Between December 9, 2025 and December 18, 2025, consistent with the guidance from the Board of Directors to explore a potential transaction with BioMarin at $14.50 per share in cash, Mr. Hardy and Mr. Campbell spoke daily to discuss topics including the status of BioMarin’s due diligence, the status and timing of a potential settlement of the Lupin Litigation and the potential timing of entering into and announcing a transaction between BioMarin and Amicus. Prior to the execution of the Merger Agreement, Mr. Hardy and Mr. Campbell did not discuss, and BioMarin did not make any proposals or enter into any agreements with employees of Amicus relating to, the post-closing employment, retention or compensation of Amicus’ employees, except for BioMarin’s customary commitments included in the Merger Agreement to maintain certain aspects of Amicus’ existing arrangements (or BioMarin’s arrangements for similarly situated employees) for a period of 12 months following the completion of the Merger.

On December 10, 2025, representatives of Centerview and Goldman Sachs had a call with representatives of Morgan Stanley to discuss the potential timing of entering into and announcing a transaction between BioMarin and Amicus. Representatives of Morgan Stanley reiterated that BioMarin was unwilling to enter into a transaction with Amicus until the remaining Hatch Waxman Litigation was resolved.

On December 12, 2025, Amicus and Aurobindo advised the Court that the parties had resolved the Aurobindo Litigation. Later in the day, an entry on the Court docket indicated that the Court had stayed the Aurobindo Litigation. Amicus’ stock price increased approximately 7% in after-market trading to approximately $10.55 per share.

On December 14, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Mr. Campbell updated the Board of Directors on the current status of the remaining Hatch Waxman Litigation, including executing a settlement agreement with Aurobindo and the most recent discussions with Lupin. Mr. Campbell then updated the Board of Directors on his recent conversations with Mr. Hardy. The Board of Directors discussed strategies for reaching a settlement with Lupin, the potential to sign a definitive agreement with BioMarin before securing a settlement with Lupin, and the recent increase in Amicus’ stock price following the updated Court docket for the Aurobindo Litigation.

On December 17, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Mr. Campbell updated the Board of Directors on his recent conversations with Mr. Hardy. Mr. Campbell expressed concern that BioMarin might lose interest in a potential transaction with Amicus in light of the recent increase in Amicus’ stock price and the lack of resolution of the Lupin Litigation. Representatives of Centerview and Goldman Sachs reviewed Amicus’ recent stock prices and trading patterns. The Board of Directors discussed whether Amicus’ increased stock price could affect BioMarin’s offer and Mr. Hardy’s indications that BioMarin would be unwilling to increase its offer beyond the December 6 Proposal. The Board of Directors then discussed strategies for quickly reaching a settlement with Lupin. Following discussion, the Board of Directors determined that Amicus should continue to work towards and agree to a settlement with Lupin.

On December 18, 2025, Goldman Sachs provided a customary material relationships disclosure letter to Amicus.

Also on December 18, 2025, Mr. Campbell, on behalf of Amicus, and one of the two required Lupin signatories each executed the Lupin License Agreement.

Later on December 18, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. Mr. Campbell updated the Board of Directors on Amicus’ expectation that the Lupin License Agreement would be fully executed by early the next morning. Representatives of Kirkland provided an overview of the directors’ fiduciary duties and reviewed with the Board of Directors the relationship disclosures that had been provided to the Board of Directors by Centerview and Goldman Sachs. The Board of Directors discussed such disclosures and determined that none of these relationships presented conflicts that interfered with Amicus’ engagement of either of Centerview or Goldman Sachs in connection with an M&A transaction involving BioMarin. Representatives of Centerview and Goldman Sachs reviewed the updates to the preliminary financial model prepared by Amicus’ management and the underlying assumptions used to prepare the updated model (which we refer to as the “December 18 Projections”). For more information about the December 18 Projections presented at the December 18 Board of Directors meeting, see the section of this proxy statement captioned “— Certain Financial Projections.” Following discussion, the Board of Directors approved the December 18 Projections. Representatives of Centerview and Goldman Sachs then reviewed their respective financial analyses of Amicus and the proposed transaction, prepared based on the December 18 Projections. The Board of Directors then discussed the material terms of the Merger Agreement and related documentation and the changes that had occurred in the documents since prior meetings of the Board of Directors. After further discussion, including a discussion regarding the various reasons described in the section of this proxy statement captioned “— Recommendation of the Board of Directors and Reasons for the Merger,” the Board of Directors determined to meet again on the morning of December 19, 2025, if the Lupin License Agreement had been executed, in order to determine whether Amicus should enter into the Merger Agreement.

In the morning on December 19, 2025, the second required Lupin signatory executed the Lupin License Agreement. As a result, the Lupin License Agreement was fully executed.

Shortly thereafter on December 19, 2025, the Board of Directors held a meeting, which was also attended by representatives of Amicus’ management, Centerview, Goldman Sachs and Kirkland. A representative of Centerview delivered to the Board of Directors an oral opinion, which was subsequently confirmed in writing, that, as of such date and based upon and subject to the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, the Merger Consideration to be received by the holders of shares of Company common stock (other than “Excluded Shares” as defined in Centerview’s written opinion (which we refer to as “Centerview Fairness Opinion Excluded Shares”)) pursuant to the Merger Agreement was fair, from a financial point of view, to such holders. A representative of Goldman Sachs then delivered to the Board of Directors an oral opinion, which was subsequently confirmed in writing, that, as of such date and based upon and subject to the factors and assumptions set forth therein, the Merger Consideration to be paid to the holders (other than BioMarin and its affiliates) of shares of Company common stock pursuant to the Merger Agreement was fair from a financial point of view to such holders. For a discussion of the opinions of each of Centerview and Goldman Sachs, please see the sections of this proxy statement captioned “— Opinion of Amicus’ Financial Advisor — Centerview Partners LLC” and “— Opinion of Amicus’ Financial Advisor — Goldman Sachs & Co LLC.” For a discussion of the non-public, unaudited risk-adjusted financial projections prepared by Amicus’ management and authorized by the Board of Directors for use by Centerview and Goldman Sachs in their respective financial analyses in connection with their respective opinions, please see the section of this

proxy statement captioned “— Certain Financial Projections.” After further discussion, including a discussion regarding the various reasons described in the section of this proxy statement captioned “— Recommendation of the Board of Directors and Reasons for the Merger,” the Board of Directors unanimously (1) determined that the Merger Agreement and the Transactions are advisable, fair to, and in the best interests of, Amicus and its stockholders; (2) declared it advisable for Amicus to enter into the Merger Agreement; (3) approved the execution, delivery and performance by Amicus of the Merger Agreement and the consummation of the Transactions; (4) resolved that the Merger should be governed by Section 251(c) of the DGCL, upon the terms and subject to the conditions set forth in the Merger Agreement; (5) resolved to recommend that Amicus’ stockholders adopt the Merger Agreement at the Special Meeting; and (6) directed that the Merger Agreement be submitted to Amicus’ stockholders for approval at the Special Meeting.

On December 19, 2025, Amicus and BioMarin entered into the Merger Agreement and Amicus and BioMarin issued a joint press release announcing the execution of the Merger Agreement.

The Board of Directors has unanimously (1) determined that the Merger Agreement and the Transactions are advisable and fair to, and in the best interest of, Amicus and its stockholders; (2) declared it advisable for Amicus to enter into the Merger Agreement; (3) approved the execution, delivery and performance by Amicus of the Merger Agreement and the consummation of the Transactions; (4) resolved that the Merger shall be governed by Section 251(c) of the DGCL, upon the terms and subject to the conditions set forth in the Merger Agreement; (5) resolved to recommend that Amicus stockholders adopt the Merger Agreement at the Special Meeting; and (6) directed that the Merger Agreement be submitted to Amicus stockholders for approval at the Special Meeting.

The Board of Directors unanimously recommends that you vote (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

In evaluating the Merger Agreement and the Transactions, including the Merger, the Board of Directors consulted with outside legal counsel, its financial advisors and Amicus’ senior management. In reaching their decision to approve the Merger Agreement, and in recommending that Amicus’ stockholders vote in favor of the adoption of the Merger Agreement, the Board of Directors considered numerous positive reasons relating to the Merger Agreement, the Merger and the other Transactions, including the following material reasons (which reasons are not necessarily presented in order of relative importance):

In the course of reaching the determinations and decisions and making the recommendation described above, the Board of Directors, in consultation with Amicus’ senior management, outside legal counsel and financial advisors, also considered the risks and potential reasons to not proceed with the Merger and the other Transactions, including the following material reasons (which reasons are not necessarily presented in order of relative importance):

The Board of Directors concluded that, overall, the potential benefits of the Merger to Amicus’ stockholders outweighed the risks and uncertainties of the Merger.

The foregoing discussion of reasons considered by the Board of Directors contains the material reasons considered by the Board of Directors, but is not in any way intended to be exhaustive. In light of the variety of reasons considered in connection with its evaluation of the Merger, the Board of Directors did not find it practicable to, and did not, quantify or otherwise assign relative weights to the specific reasons considered in reaching its determinations and recommendations. Each member of the Board of Directors applied his or her own individual business judgment to the process and may have given different weight to different reasons. The Board of Directors did not undertake to make any specific determination as to whether any reason or any particular aspect of a reason supported or did not support its ultimate determination. Rather, the Board of Directors based its recommendation on the totality of the information presented.

On December 19, 2025, Centerview rendered to the Board of Directors its oral opinion, subsequently confirmed by delivery of a written opinion dated such date, that, as of such date and based upon and subject to various assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, the Merger Consideration to be paid to the holders of shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) pursuant to the Merger Agreement was fair, from a financial point of view, to such holders.

The full text of Centerview’s written opinion, dated December 19, 2025, which describes the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, is attached as Annex B and is incorporated herein by reference. The summary of the written opinion of Centerview set forth below is qualified in its entirety to the full text of Centerview’s written opinion attached as Annex B. Centerview’s financial advisory services and opinion were provided for the information and assistance of the Board of Directors (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transactions and Centerview’s opinion only addressed the fairness, from a financial point of view, as of the date thereof, to the holders of

outstanding shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) of the Merger Consideration to be paid to such holders pursuant to the Merger Agreement. Centerview’s opinion did not address any other term or aspect of the Merger Agreement or the Transactions and does not constitute a recommendation to any Amicus stockholder or any other person as to how such stockholder or other person should vote with respect to the Merger or otherwise act with respect to the Transactions or any other matter.

The full text of Centerview’s written opinion should be read carefully in its entirety for a description of the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion.

In connection with rendering the opinion described above and performing its related financial analyses, Centerview reviewed, among other things:

Centerview also participated in discussions with members of the senior management and representatives of Amicus regarding their assessment of the Internal Data. In addition, Centerview reviewed publicly available financial and stock market data, including valuation multiples, for Amicus and compared that data with similar data for certain other companies, the securities of which are publicly traded, in lines of business that Centerview deemed relevant. Centerview also compared certain of the proposed financial terms of the Transactions with the financial terms, to the extent publicly available, of certain other transactions that Centerview deemed relevant, and conducted such other financial studies and analyses and took into account such other information as Centerview deemed appropriate.

Centerview assumed, without independent verification or any responsibility therefore, the accuracy and completeness of the financial, legal, regulatory, tax, accounting and other information supplied to, discussed with, or reviewed by Centerview for purposes of its opinion and, with Amicus’ consent, Centerview relied upon such information as being complete and accurate. In that regard, Centerview assumed, at Amicus’ direction, that the Internal Data (including, without limitation, the Forecasts) were reasonably prepared on bases reflecting the best currently available estimates and judgments of the management of Amicus as to the matters covered thereby and Centerview relied, at Amicus’ direction, on the Internal Data for purposes of Centerview’s analysis and opinion. Centerview expressed no view or opinion as to the Internal Data or the assumptions on which it was based. In addition, at Amicus’ direction, Centerview did not make any independent evaluation or appraisal of any of the assets or liabilities (contingent, derivative, off-balance-sheet or otherwise) of Amicus, nor was Centerview furnished with any such evaluation or appraisal, and was not asked to conduct, and did not conduct, a physical inspection of the properties or assets of Amicus. Centerview assumed, at Amicus’ direction, that the final executed Merger Agreement would not differ in any respect material to Centerview’s analysis or opinion from the Draft Merger Agreement reviewed by Centerview. Centerview also assumed, at Amicus’ direction, that the Transactions will be consummated on the terms set forth in the Merger Agreement and in accordance with all applicable laws and other relevant documents or requirements, without delay or the waiver, modification or amendment of any term, condition or agreement, the effect of which would be material to Centerview’s analysis or Centerview’s opinion and that, in the course of obtaining the necessary governmental, regulatory and other approvals, consents, releases and waivers for the Transactions, no delay, limitation, restriction, condition or other change will be imposed, the effect of which

would be material to Centerview’s analysis or Centerview’s opinion. Centerview did not evaluate and did not express any opinion as to the solvency or fair value of Amicus, or the ability of Amicus to pay its obligations when they come due, or as to the impact of the Transactions on such matters, under any state, federal or other laws relating to bankruptcy, insolvency or similar matters. Centerview is not a legal, regulatory, tax or accounting advisor, and Centerview expressed no opinion as to any legal, regulatory, tax or accounting matters.

Centerview’s opinion expressed no view as to, and did not address, Amicus’ underlying business decision to proceed with or effect the Transactions, or the relative merits of the Transactions as compared to any alternative business strategies or transactions that might be available to Amicus or in which Amicus might engage. Centerview’s opinion was limited to and addressed only the fairness, from a financial point of view, as of the date of Centerview’s written opinion, to the holders of the outstanding shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) of the Merger Consideration to be paid to such holders pursuant to the Merger Agreement. For purposes of its opinion, Centerview was not asked to, and Centerview did not, express any view on, and its opinion did not address, any other term or aspect of the Merger Agreement or the Transactions, including, without limitation, the structure or form of the transactions contemplated by the Merger Agreement, or any other agreements or arrangements contemplated by the Merger Agreement or entered into in connection with or otherwise contemplated by the Transactions, including, without limitation, the fairness of the Transactions or any other term or aspect of the Transactions to, or any consideration to be received in connection therewith by, or the impact of the Transactions on, the holders of any other class of securities, creditors or other constituencies of Amicus or any other party. In addition, Centerview expressed no view or opinion as to the fairness (financial or otherwise) of the amount, nature or any other aspect of any compensation to be paid or payable to any of the officers, directors or employees of Amicus or any party, or class of such persons in connection with the Transactions, whether relative to the Merger Consideration to be paid to the holders of the shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) pursuant to the Merger Agreement or otherwise. Centerview’s opinion was necessarily based on financial, economic, monetary, currency, market and other conditions and circumstances as in effect on, and the information made available to Centerview as of, the date of Centerview’s written opinion, and Centerview does not have any obligation or responsibility to update, revise or reaffirm its opinion based on circumstances, developments or events occurring after the date of Centerview’s written opinion. Centerview’s opinion does not constitute a recommendation to any Amicus stockholder or any other person as to how such stockholder or other person should vote with respect to the Merger or otherwise act with respect to the Transactions or any other matter. Centerview’s financial advisory services and its written opinion were provided for the information and assistance of the Board of Directors (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transactions. The issuance of Centerview’s opinion was approved by the Centerview Partners LLC Fairness Opinion Committee.

The following is a summary of the material financial analyses prepared and reviewed with the Board of Directors in connection with Centerview’s opinion, dated December 19, 2025. The order of the financial analyses described does not represent the relative importance or weight given to those financial analyses by Centerview. Centerview may have deemed various assumptions more or less probable than other assumptions, so the reference ranges resulting from any particular portion of the analyses summarized below should not be taken to be Centerview’s view of the actual value of Amicus. Some of the summaries of the financial analyses set forth below include information presented in tabular format. In order to fully understand the financial analyses, the tables must be read together with the text of each summary, as the tables alone do not constitute a complete description of the financial analyses performed by Centerview. Considering the data in the tables below without considering all financial analyses or factors or the full narrative description of such analyses or factors, including the methodologies and assumptions underlying such analyses or factors, could create a misleading or incomplete view of the processes underlying Centerview’s financial analyses and its opinion. In performing its analyses, Centerview made numerous assumptions with respect to industry performance, general business and economic conditions and other matters, many of which are beyond the control of Amicus or any other parties to Transactions. None of Amicus, BioMarin, Merger Sub or Centerview or any other person assumes responsibility if future results are materially different from those discussed. Any estimates contained in these analyses are not necessarily indicative of actual values or predictive of future results or values, which may be significantly more or less favorable than as set forth below. In addition, analyses relating to the value of Amicus do not purport to be appraisals or reflect the prices at which Amicus may actually be sold. Accordingly, the assumptions and estimates used in, and the results derived from, the

financial analyses are inherently subject to substantial uncertainty. Except as otherwise noted, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before December 18, 2025 (the last trading day before the public announcement of the Merger) and is not necessarily indicative of current market conditions.

Centerview reviewed and compared certain financial information of Amicus to corresponding financial information of certain publicly traded commercial-stage biopharmaceutical companies listed below that Centerview deemed comparable, based on its experience and professional judgment, to Amicus (which companies are referred to as the “selected companies” in this summary of Centerview’s opinion).

Using publicly available information obtained from SEC filings and other data sources as of December 18, 2025, Centerview calculated, for each selected company, such selected company’s implied enterprise value (calculated as the equity value, determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units, performance stock units and other convertible securities plus the book value of debt and certain liabilities less cash and cash equivalents) as a multiple of Wall Street research analyst consensus estimated four-year forward revenue (based on 25% of estimated revenue for calendar year 2028 and 75% of estimated revenue for calendar year 2029) (“EV/4-Year Forward Revenue Multiple”).

The selected companies reviewed and the EV/4-Year Forward Revenue Multiples of the selected companies were as follows:

Although none of the selected companies is directly comparable to Amicus, the selected companies were chosen by Centerview, among other reasons, because they are publicly traded biopharma companies with certain operational, business and/or financial characteristics that, for purposes of Centerview’s analysis, may be considered similar to those of Amicus.

However, because none of the selected companies is exactly the same as Amicus, Centerview believed that it was inappropriate to, and therefore did not, rely solely on the quantitative results of the selected public company analysis. Accordingly, Centerview also made qualitative judgments, based on its experience and professional judgment, concerning differences between the operational, business and/or financial characteristics of Amicus and the selected companies that could affect the public trading values of each in order to provide a context in which to consider the results of the quantitative analysis. Based on this analysis and other considerations that Centerview deemed relevant in its experience and professional judgment, Centerview selected a reference range of EV/4-Year Forward Revenue Multiples of 2.00x to 3.25x to apply to Amicus’ estimated four-year forward revenue (which we refer to as “4-Year Forward Revenue”) (based on 25% of Amicus’ estimated risk-adjusted revenue for calendar year 2028 and 75% of Amicus’ estimated risk-adjusted revenue for calendar year 2029), as set forth in the Internal Data. In selecting this reference range of EV/4-Year Forward Revenue Multiples, Centerview made qualitative judgments based on its experience and professional judgment concerning differences between the business, operational, and/or financial characteristics of Amicus and the selected companies that could affect their public trading values in order to provide a context in which to consider the results of the quantitative analysis.

Applying this range of EV/4-Year Forward Revenue Multiples to Amicus’ estimated 4-Year Forward Revenue, as set forth in the Internal Data, and subtracting from the result Amicus’ net debt of as of September 30, 2025, as set forth in the Internal Data, and dividing the result of the foregoing by the number of fully-diluted outstanding shares of our common stock (determined using the treasury stock method and taking into account outstanding in-the-money

options, restricted stock units and performance stock units (including assumptions regarding the vesting of such performance stock units)) as of December 17, 2025, as set forth in the Internal Data, resulted in an implied per share equity value range for shares of our common stock of approximately $7.25 to $11.95, rounded to the nearest $0.05. Centerview then compared this range to the Merger Consideration of $14.50 per share of our common stock to be paid, without interest, to the holders of shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) pursuant to the Merger Agreement.

Centerview reviewed and analyzed certain information relating to the following selected transactions involving biopharma companies (which transactions are referred to as the “selected transactions” in this summary of Centerview’s opinion) that Centerview, based on its experience and professional judgment, deemed relevant to consider in relation to Amicus and the Transactions.

Using publicly available information obtained from SEC filings and other data sources as of the time of the public announcement of the selected transactions, Centerview calculated, for each selected transaction, the transaction value (which we refer to as “TV”), defined as the offer value (determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units, performance stock units and other convertible securities) plus the book value of debt and certain liabilities less cash and cash equivalents implied for each target company based on the consideration payable in the applicable selected transaction, as a multiple of such target company’s management’s risk-adjusted projected four-year forward revenue as of the time of the public announcement of the relevant transaction, per such target company’s schedule 14D-9 or proxy (which we refer to as “TV/4-Year Forward Revenue Multiple”).

The selected transactions and the TV/4-Year Forward Revenue Multiples of the selected transactions considered in this analysis are summarized below:

Although none of the selected transactions is directly comparable to the Transactions, these transactions were selected by Centerview, among other reasons, because they have certain business, operational and/or financial characteristics that, for purposes of Centerview’s analysis, may be considered similar to the Transactions. The reasons for and the circumstances surrounding each of the selected precedent transactions analyzed were diverse and there are inherent differences in the business, operational and/or financial conditions and prospects of Amicus and

the companies included in the selected precedent transactions analysis. However, because none of the selected transactions used in this analysis is identical or directly comparable to the Transactions, Centerview believed that it was inappropriate to, and therefore did not, rely solely on the quantitative results of the selected precedent transaction analysis. Accordingly, Centerview also made qualitative judgments, based on its experience and professional judgment, concerning differences in business, operational and/or financial characteristics and other factors that could affect the transaction values of each in order to provide a context in which to consider the results of the quantitative analysis.

Based on this analysis and other considerations that Centerview deemed relevant in its experience and professional judgment, related to, among other things, differences in the business, operational and/or financial conditions and prospects of Amicus and the companies included in the selected precedent transactions analysis, Centerview selected a reference range of TV/4-Year Forward Revenue Multiples of 2.50x to 4.50x derived from the selected precedent transactions. Applying this reference range of TV/4-Year Forward Revenue Multiples to Amicus’ 4-Year Forward Revenue (based on 25% of Amicus’ estimated risk-adjusted revenue for calendar year 2028 and 75% of Amicus’ estimated risk-adjusted revenue for calendar year 2029), as set forth in the Internal Data, and subtracting from it Amicus’ net debt (including the book value of equity investments and debt prepayment costs) as of September 30, 2025, as set forth in the Internal Data, and dividing the result of the foregoing by the number of fully-diluted outstanding shares of our common stock (determined using the treasury stock method and taking into account outstanding in-the-money options, restricted stock units and performance stock units (including assumptions regarding the vesting of such performance stock units)) as of December 17, 2025, as set forth in the Internal Data, resulted in an implied equity value per share of our common stock of $9.00 to $16.25, rounded to the nearest $0.05. Centerview then compared this range to the Merger Consideration of $14.50 per share of our common stock to be paid, without interest, to the holders of shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) pursuant to the Merger Agreement.

Centerview performed a discounted cash flow analysis of Amicus based on the Forecasts. A discounted cash flow analysis is a traditional valuation methodology used to derive a valuation of an asset or set of assets by calculating the “present value” of estimated future cash flows of the asset or set of assets. “Present value” refers to the current value of future cash flows or amounts and is obtained by discounting those future cash flows or amounts by a discount rate that takes into account macroeconomic assumptions and estimates of risk, the opportunity cost of capital, expected returns and other appropriate factors.

In performing this analysis, Centerview calculated a range of equity values for shares of our common stock by (a) discounting to present value as of September 30, 2025, using discount rates ranging from 10.25% to 12.00% (based on Centerview’s analysis of Amicus’ weighted average cost of capital determined using the capital asset pricing model and using a mid-year convention and based on considerations that Centerview deemed relevant in its professional judgment and experience): (i) the forecasted, risk-adjusted unlevered free cash flows of Amicus over the period beginning on October 1, 2025, and ending on December 31, 2045, utilized by Centerview based on the Forecasts, (ii) a range of implied terminal values of Amicus at the end of the forecast period shown in the Forecasts, estimated by Centerview applying a range of perpetuity growth rates of negative 15.0% to negative 5.0%, as directed by Amicus and (iii) the forecasted tax savings from usage of Amicus’ federal net operating losses as of December 31, 2024, and (b) subtracting Amicus’ net debt as of September 30, 2025, as set forth in the Internal Data, from the foregoing results.

Centerview divided the result of the foregoing calculations by the number of fully diluted outstanding shares of our common stock (determined using the treasury stock method and taking into account outstanding in-the-money options, restricted stock units and performance stock units (including assumptions regarding the vesting of such performance stock units)) as of December 17, 2025, as set forth in the Internal Data, resulting in a range of implied equity values per share of our common stock of $11.75 to $14.35, rounded to the nearest $0.05. Centerview then compared this range to the Merger Consideration of $14.50 per share of our common stock to be paid to the holders of shares of our common stock (other than Centerview Fairness Opinion Excluded Shares) pursuant to the Merger Agreement.

Centerview noted for the Board of Directors certain additional factors solely for reference and informational purposes only, including, among other things, the following:

The preparation of a financial opinion is a complex analytical process involving various determinations as to the most appropriate and relevant methods of financial analysis and the application of those methods to the particular circumstances and, therefore, a financial opinion is not readily susceptible to summary description. In arriving at its opinion, Centerview did not draw, in isolation, conclusions from or with regard to any factor or analysis that it considered. Rather, Centerview made its determination as to fairness on the basis of its experience and professional judgment after considering the results of all of the analyses.

Centerview’s financial analyses and opinion were only one of many factors taken into consideration by the Board of Directors in its evaluation of the Transactions. Consequently, the analyses described above should not be viewed as determinative of the views of the Board of Directors or management of Amicus with respect to the Merger Consideration or as to whether the Board of Directors would have been willing to determine that a different consideration was fair. The consideration for the transaction was determined through arm’s-length negotiations between Amicus and BioMarin and was approved by the Board of Directors. Centerview provided advice to Amicus during these negotiations. Centerview did not, however recommend any specific amount of consideration to Amicus or the Board of Directors or that any specific amount of consideration constituted the only appropriate consideration for the transaction.

Centerview is a securities firm engaged directly and through affiliates and related persons in a number of investment banking, financial advisory and merchant banking activities. In the two years prior to the date of its written opinion, except for Centerview’s engagement by the Board of Directors in connection with the Transactions, Centerview had not been engaged to provide financial advisory or other services to Amicus, and Centerview did not receive any compensation from Amicus during such period. In the two years prior to the date of its written opinion, Centerview had not been engaged to provide financial advisory or other services to BioMarin or Merger Sub, and Centerview did not receive any compensation from BioMarin or Merger Sub during such period. Centerview may provide financial advisory and other services to or with respect to Amicus or BioMarin or their respective affiliates in the future, for which Centerview may receive compensation. Certain (i) of Centerview’s and Centerview’s affiliates’ directors, officers, members and employees, or family members of such persons, (ii) of Centerview’s affiliates or related investment funds and (iii) investment funds or other persons in which any of the foregoing may

have financial interests or with which they may co-invest, may at any time acquire, hold, sell or trade, in debt, equity and other securities or financial instruments (including derivatives, bank loans or other obligations) of, or investments in, Amicus, BioMarin, or any of their respective affiliates, or any other party that may be involved in the Transactions.

The Board of Directors selected Centerview as a financial advisor in connection with the Transactions based on Centerview’s extensive relationships throughout, and experience and expertise in, the pharmaceutical industry. Centerview is an internationally recognized investment banking firm that has substantial experience in transactions similar to the Transactions.

In connection with Centerview’s services as a financial advisor to the Board of Directors, Amicus has agreed to pay Centerview an aggregate fee of approximately $52.7 million, $2.0 million of which was payable upon the rendering of Centerview’s opinion and $50.7 million of which is payable contingent upon consummation of the Transactions. In addition, Amicus has agreed to reimburse certain of Centerview’s expenses arising, and to indemnify Centerview against certain liabilities that may arise, out of Centerview’s engagement. 

Goldman Sachs rendered its opinion to the Board of Directors that, as of December 19, 2025, and based upon and subject to the factors and assumptions set forth therein, the $14.50 in cash per share of our common stock to be paid to holders (other than BioMarin and its affiliates) of shares of our common stock pursuant to the Merger Agreement was fair from a financial point of view to such holders.

The full text of the written opinion of Goldman Sachs, dated December 19, 2025, which sets forth assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with the opinion, is attached as Annex C. Goldman Sachs provided advisory services and its opinion for the information and assistance of the Board of Directors in connection with its consideration of the Transactions. Goldman Sachs’ opinion is not a recommendation as to how any holder of shares of our common stock should vote with respect to the Transactions or any other matter.

In connection with rendering the opinion described above and performing its related financial analyses, Goldman Sachs reviewed, among other things:

Goldman Sachs also held discussions with members of senior management of Amicus regarding their assessment of the past and current business operations, financial condition, and future prospects of Amicus; reviewed the reported price and trading activity for the Shares; compared certain financial and stock market information for Amicus with similar information for certain other companies the securities of which are publicly traded; reviewed the financial terms of certain recent business combinations in the biopharmaceutical industry; and performed such other studies and analyses, and considered such other factors, as it deemed appropriate.

For purposes of rendering its opinion, Goldman Sachs, with our consent, relied upon and assumed the accuracy and completeness of all of the financial, legal, regulatory, tax, accounting and other information provided to, discussed with or reviewed by Goldman Sachs, without assuming any responsibility for independent verification

thereof. In that regard, Goldman Sachs assumed with our consent that the Forecasts and the NOL Forecasts have been reasonably prepared on a basis reflecting the best then available estimates and judgments of our management. Goldman Sachs did not make an independent evaluation or appraisal of the assets and liabilities (including any contingent, derivative or other off-balance-sheet assets and liabilities) of Amicus or any of its subsidiaries and Goldman Sachs was not furnished with any such evaluation or appraisal. Goldman Sachs assumed that all governmental, regulatory or other consents and approvals necessary for the consummation of the Transactions will be obtained without any adverse effect on the expected benefits of such transactions in any way meaningful to its analysis and assumed that such transactions will be consummated on the terms set forth in the Merger Agreement, without the waiver or modification of any term or condition the effect of which would be in any way meaningful to its analysis.

Goldman Sachs’ opinion does not address our underlying business decision to engage in the Transactions, or the relative merits of such transactions as compared to any strategic alternatives that may be available to us; nor does it address any legal, regulatory, tax or accounting matters. Goldman Sachs’ opinion addresses only the fairness from a financial point of view, as of the date of the opinion, of the $14.50 in cash per share of our common stock to be paid to the holders (other than BioMarin and its affiliates) of shares of our common stock pursuant to the Merger Agreement. Goldman Sachs’ opinion does not express any view on, and does not address, any other term or aspect of the Merger Agreement or the Transactions or any term or aspect of any other agreement or instrument contemplated by the Merger Agreement or entered into or amended in connection with the Transactions, including the fairness of the Transactions to, or any consideration received in connection therewith by, the holders of any other class of our securities, our creditors, or other constituencies of Amicus; nor as to the fairness of the amount or nature of any compensation to be paid or payable to any of our officers, directors or employees, or class of such persons in connection with the Transactions, whether relative to the $14.50 in cash per share of our common stock to be paid to the holders (other than BioMarin and its affiliates) of shares of our common stock pursuant to the Merger Agreement or otherwise. Goldman Sachs’ opinion is necessarily based on economic, monetary, market and other conditions as in effect on, and the information made available to Goldman Sachs as of, the date of its opinion and Goldman Sachs assumes no responsibility for updating, revising or reaffirming its opinion based on circumstances, developments or events occurring after the date of its opinion. In addition, Goldman Sachs does not express any opinion as to the prices at which shares of our common stock will trade at any time, as to the potential effects of volatility in the credit, financial and stock markets on us, BioMarin or the Transactions, or as to the impact of the Transactions on the solvency or viability of Amicus or BioMarin or the ability of Amicus or BioMarin to pay their respective obligations when they come due. Goldman Sachs’ opinion was approved by a fairness committee of Goldman Sachs.

The following is a summary of the material financial analyses delivered by Goldman Sachs to the Board of Directors in connection with rendering the opinion described above. The following summary, however, does not purport to be a complete description of the financial analyses performed by Goldman Sachs, nor does the order of analyses described represent relative importance or weight given to those analyses by Goldman Sachs. Some of the summaries of the financial analyses include information presented in tabular format. The tables must be read together with the full text of each summary and are alone not a complete description of Goldman Sachs’ financial analyses. Except as otherwise noted, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before December 18, 2025, the last trading day before the public announcement of the Merger and is not necessarily indicative of current market conditions.

Historical Stock Trading Analysis. Goldman Sachs analyzed the $14.50 in cash per share of our common stock to be paid to holders of shares of our common stock pursuant to the Merger Agreement in relation to the closing price per share of our common stock as of December 18, 2025 (which we refer to as the “Last Close”), the last trading day before the Board of Directors approved the Transactions, the 52-week high closing trading price per share as of December 18, 2025 (which we refer to as the “52-Week High”), and the volume weighted average price (which we refer to as the “VWAP”) of the shares for the preceding 30-trading day (which we refer to as the “30-Day VWAP”), 60-trading day (which we refer to as the “60-Day VWAP”) and 90-trading day (which we refer to as the “90-Day VWAP”) periods ending December 18, 2025.

The following table presents the results of this analysis:

Illustrative Discounted Cash Flow Analysis. Using the Forecasts and NOL Forecasts, Goldman Sachs performed an illustrative discounted cash flow analysis on Amicus to derive a range of illustrative present values per share of our common stock. Using the mid-year convention for discounting cash flows and discount rates ranging from 10% to 12%, reflecting estimates of Amicus’ weighted average cost of capital, Goldman Sachs discounted to present value as of September 30, 2025, (i) estimates of unlevered free cash flow for Amicus for the period beginning on October 1, 2025, and ending on December 31, 2025, and for fiscal years 2026 through 2045 as reflected in the Forecasts and NOL Forecasts and (ii) a range of illustrative terminal values for Amicus, which were calculated by applying perpetuity growth rates ranging from negative 15% to negative 5% to a terminal year estimate of the unlevered free cash flow to be generated by Amicus, as reflected in the Forecasts. The range of perpetuity growth rates was estimated by Goldman Sachs utilizing its professional judgment and experience, taking into account the Forecasts and market expectations regarding long-term real growth of gross domestic product and inflation. Goldman Sachs derived such discount rates by application of the Capital Asset Pricing Model, which requires certain company-specific inputs, including Amicus’ target capital structure weightings, the cost of long-term debt, after-tax yield on permanent excess cash, if any, future applicable marginal cash tax rate and a beta for Amicus, as well as certain financial metrics for the United States financial markets generally.

Goldman Sachs derived ranges of illustrative enterprise values for Amicus by adding the ranges of present values it derived above. Goldman Sachs then subtracted from the range of illustrative enterprise values it derived for Amicus the amount of Amicus’ debt and debt like items and added the amount of Amicus’ cash and cash equivalents, in each case, as provided by and approved for Goldman Sachs’ use by our management, to derive a range of illustrative equity values for Amicus. Goldman Sachs then divided the range of illustrative equity values it derived by the number of fully diluted outstanding shares of Amicus, as provided by and approved for Goldman Sachs’ use by our management, using the treasury stock method, to derive a range of illustrative present values per share ranging from $11.77 to $14.70.

Premia Paid Analysis. Goldman Sachs reviewed and analyzed, using publicly available information, the acquisition premia for the following selected transactions completed since 2020 and involving public commercial stage companies in the biopharmaceutical industry as the target where the disclosed enterprise values for the transactions were between $2 billion and $10 billion. While none of the companies that participated in the selected transactions are directly comparable to Amicus, the companies that participated in the selected transactions are companies with operations that, for the purposes of analysis, may be considered similar to certain of Amicus’ results, market sizes and product profile. For each of the selected biopharmaceutical transactions, Goldman Sachs calculated the implied acquisition premia based on the applicable target company’s last undisturbed closing price prior to announcement based on information in public filings. Goldman Sachs calculated the median, 25th percentile, and 75th percentile premia of the price paid in biopharmaceutical transactions relative to the target’s last undisturbed closing stock price prior to announcement of the transaction. Based on the target companies’ last undisturbed closing prices, this analysis indicated a median premium of 50.3%, a 25th percentile premium of 30.1%, and a 75th percentile premium of 57.7% across the period. Using this analysis, Goldman Sachs applied a reference range of illustrative premia of 30.1% to 57.7% to the closing price per Share of $10.89 as of December 18, 2025, and calculated a range of implied equity values per Share of $14.17 to $17.17.

The following table presents the results of this analysis:

The preparation of a fairness opinion is a complex process and is not necessarily susceptible to partial analysis or summary description. Selecting portions of the analyses or of the summary set forth above, without considering the analyses as a whole, could create an incomplete view of the processes underlying Goldman Sachs’ opinion. In arriving at its fairness determination, Goldman Sachs considered the results of all of its analyses and did not attribute any particular weight to any factor or analysis considered by it. Rather, Goldman Sachs made its determination as to fairness on the basis of its experience and professional judgment after considering the results of all of its analyses. No company or transaction used in the above analyses as a comparison is directly comparable to Amicus or BioMarin or the Transactions.

Goldman Sachs prepared these analyses for purposes of Goldman Sachs’ providing its opinion to the Board of Directors as to the fairness from a financial point of view of the $14.50 in cash per share of our common stock to be paid to the holders (other than BioMarin and its affiliates) of shares of our common stock pursuant to the Merger Agreement. These analyses do not purport to be appraisals nor do they necessarily reflect the prices at which businesses or securities actually may be sold. Analyses based upon forecasts of future results are not necessarily indicative of actual future results, which may be significantly more or less favorable than suggested by these analyses. Because these analyses are inherently subject to uncertainty, being based upon numerous factors or events beyond the control of the parties or their respective advisors, none of Amicus, BioMarin, Goldman Sachs or any other person assumes responsibility if future results are materially different from those forecasts.

The Merger Consideration was determined through arm’s-length negotiations between Amicus and BioMarin and was approved by the Board of Directors.  Goldman Sachs provided advice to Amicus during these negotiations.  Goldman Sachs did not, however, recommend any specific amount of consideration to Amicus or its Board of Directors or that any specific amount of consideration constituted the only appropriate consideration for the Transactions.

As described below in the section of this proxy statement captioned “— Recommendation of the Board of Directors and Reasons for the Merger,” Goldman Sachs’ opinion to the Board of Directors was one of many factors taken into consideration by the Board of Directors in making its determination to approve the Merger Agreement. The foregoing summary does not purport to be a complete description of the analyses performed by Goldman Sachs in connection with the fairness opinion and is qualified in its entirety by reference to the written opinion of Goldman Sachs attached as Annex C.

Goldman Sachs and its affiliates (collectively, “Goldman Sachs Affiliated Entities”) are engaged in advisory, underwriting, lending and financing, principal investing, sales and trading, research, investment management and other financial and non-financial activities and services for various persons and entities. Goldman Sachs and its affiliates and employees, and funds or other entities they manage or in which they invest or have other economic interests or with which they co-invest, may at any time purchase, sell, hold or vote long or short positions and investments in securities, derivatives, loans, commodities, currencies, credit default swaps and other financial instruments of Amicus, BioMarin, any of their respective affiliates and third parties (collectively, “Relevant Entities”) or any currency or commodity that may be involved in the Transactions. Goldman Sachs Investment Banking has an existing lending relationship with BioMarin. Goldman Sachs acted as a financial advisor to Amicus in connection with, and participated in certain of the negotiations leading to, the Transactions. Goldman Sachs has provided certain financial advisory and/or underwriting services to us and our affiliates from time to time for which Goldman Sachs Investment Banking has received, and may receive, compensation, including having acted as sole bookrunner with respect to a public offering of shares of our common stock in September 2025. During the two-year period ended December 19, 2025, Goldman Sachs has recognized compensation for financial advisory and/or underwriting services provided by Goldman Sachs Investment Banking to Amicus and/or its affiliates of approximately $1 million. Goldman Sachs also has provided certain financial advisory and/or underwriting services to BioMarin and its affiliates from time to time for which Goldman Sachs Investment Banking has received, and may receive, compensation, including having acted as financial advisor to BioMarin with respect to its acquisition of Inozyme Pharma, Inc. in July 2025. During the two-year period ended December 19, 2025, Goldman Sachs has recognized compensation for financial advisory and/or underwriting services provided by Goldman Sachs Investment Banking to BioMarin and/or its affiliates of approximately $7.5 million. As of December 19, 2025, Goldman Sachs Investment Banking was mandated by BioMarin and/or its Related Entities (as defined below) to provide financial advisory and/or underwriting services unrelated to the Transactions with respect to one or more matters and, if all such matters were to be consummated, Goldman Sachs Investment Banking expected, as of December 19, 2025, that it would recognize compensation in an aggregate amount less than the transaction fee to be paid to Goldman Sachs by Amicus in connection with the Transactions. As of December 19, 2025, Goldman Sachs Investment Banking was not soliciting BioMarin and/or its Related Entities (as defined below) to work on financial advisory and/or underwriting matters for any such persons on which it has not been mandated. Goldman Sachs may also in the future provide financial advisory and/or underwriting services to Amicus, BioMarin and their Related Entities for which Goldman Sachs Investment Banking may receive compensation.

As of December 19, 2025, Goldman Sachs Affiliated Entities had (i) no direct GS Principal Investment (as defined below) in Amicus and/or its affiliates and (ii) no direct GS Principal Investment in BioMarin and/or its Related Entities (as defined below).

On the public side of Goldman Sachs’ informational wall (the “Public Side”) and in the ordinary course of its various business activities, Goldman Sachs Affiliated Entities may also own equity securities in the Relevant Entities and/or their respective affiliates arising from engaging in market making, trade execution, clearing, custody, margin lending and other similar financing transactions, securities lending, and related activities (including by acting as agent for third parties executing their transactions or as principal supplying liquidity to market participants, and any related hedging, other risk management or inventory management) (collectively, “Market Making Activities”), which positions change frequently. Regulatory, informational and operational barriers separate the Public Side from Goldman Sachs Investment Banking.

For purposes of this section of the proxy, (x) Goldman Sachs relied on its books and records to (i) unless otherwise indicated, calculate all amounts and (ii) determine whether an entity is an affiliate, portfolio company, subsidiary or majority-owned subsidiary of another entity, and (y) the following terms have the definitions set forth below:

“GS Principal Investments” (including any associated commitments) are (i) direct balance sheet investments in equity interests or equity securities held by Goldman Sachs Affiliated Entities for its own account or (ii) direct investments in equity interests held by a fund managed by a Goldman Sachs Affiliated Entity which fund is primarily for the benefit of Goldman Sachs Affiliated Entities and/or its current and former employees and not third party clients. GS Principal Investments do not include equity interests arising from Market Making Activities, equity derivatives, convertible debt instruments, or warrants or equity kickers received in connection with senior secured loans, mezzanine loans, warehouse loans, preferred equity with a fixed rate of return or other similar types of financing transactions (which may also be subject to hedging or other risk-mitigating instruments). GS Principal

Investments also do not include investments by funds managed by Goldman Sachs Affiliated Entities which funds are almost entirely for the benefit of third party clients (“GS Client Funds”), which funds can co-invest alongside, and/or make investments in, the Relevant Entities or their respective Related Entities. As investment managers for GS Client Funds, Goldman Sachs Affiliated Entities are required to fulfill a fiduciary responsibility to GS Client Funds in making decisions to purchase, sell, hold or vote on, or take any other action with respect to, any financial instrument.  

“Related Entities” are, as applicable, a person or entity’s subsidiaries, affiliates, portfolio companies and/or funds managed thereby.

The Board of Directors selected Goldman Sachs as its financial advisor because it is an internationally recognized investment banking firm that has substantial experience in transactions similar to the Transactions. Pursuant to a letter agreement dated March 20, 2025, Amicus engaged Goldman Sachs to act as its financial advisor in connection with the contemplated transaction. The engagement letter between Amicus and Goldman Sachs provides for a transaction fee that is estimated, based on the information available as of the date of announcement of the Transactions, at approximately $52.7 million, all of which is contingent upon consummation of the Transactions. In addition, Amicus has agreed to reimburse Goldman Sachs for certain of its expenses, including attorneys’ fees and disbursements, and to indemnify Goldman Sachs and related persons against various liabilities, including certain liabilities under the federal securities laws. 

Amicus does not, as a matter of course, publicly disclose forecasts or internal projections as to future performance, results of operations, earnings or other results, due to, among other things, the inherent difficulty of predicting financial performance for future periods and the likelihood that the underlying assumptions and estimates may not be realized.

In July 2025, Amicus’ senior management, at the direction of the Board of Directors, prepared non-public, unaudited risk-adjusted financial projections for fiscal years 2025 through 2045 (the “July Projections”) to assist the Board of Directors’ strategic review and evaluation of Amicus’ intrinsic value as a standalone company. The July Projections included three cases (Cases 1, 2 and 3) as more fully described below.

In November 2025, in connection with the evaluation of the proposed transaction with BioMarin considered by the Board of Directors and the Transaction Committee, Amicus’ senior management updated the July Projections to prepare revised non-public, unaudited risk-adjusted financial projections for fiscal years 2025 through 2045 (which we refer to as the “November Projections”). The November Projections included three cases (Cases 1, 2 and 3) consistent with the July Projections, with certain updates as described below.

In December 2025, Amicus’ senior management further updated certain near-term assumptions in Case 2 of the November Projections to reflect more current operating results, resulting in updated projections for Case 2 compared to the November Projections (which we refer to as the “December Projections,” and together with the July Projections and November Projections, the “Projections”). The December Projections, which reflect the Case 2 assumptions, were used by Centerview and Goldman Sachs in connection with their respective financial analyses and fairness opinions delivered to the Board of Directors.

The Projections forecast revenues and associated costs for Amicus’ three commercial and pipeline products: (i) Galafold (migalastat), a treatment for Fabry disease, (ii) Pombiliti + Opfolda (cipaglucosidase alfa and miglustat), a treatment for late-onset Pompe disease, and (iii) DMX-200, a pipeline product in development for focal segmental glomerulosclerosis (FSGS). The November 2025 Case 3 Projections also included potential revenues from an additional indication for DMX-200 in membranous lupus nephritis (MLN). The Projections were prepared assuming Amicus’ continued operation as a standalone company and do not take into account the Merger, including the effect of any business or strategic decision or action that has been or will be taken as a result of the execution of the Merger Agreement.

Amicus is summarizing the Projections in this proxy statement in order to provide stockholders with access to certain non-public, unaudited, and risk-adjusted prospective financial information that was prepared for and used by the Board of Directors and representatives of Amicus’ co-financial advisors, Centerview and Goldman Sachs, to evaluate the Merger.

The Projections, while necessarily presented with numerical specificity, were based on assumptions regarding numerous financial, operating and commercial variables. Such assumptions were developed solely using the information available to Amicus’ management at the time of their development, are inherently uncertain and are, in many cases, beyond Amicus’ control. Important factors that may affect actual results and cause the Projections not to be realized include: the timing of regulatory approvals for DMX-200; the effectiveness of Amicus’ commercial execution for its products; the market acceptance of Galafold, Pombiliti + Opfolda and DMX-200; success of clinical testing; availability of third-party reimbursement; the impact of competitive products and pricing, including the entry of generic competition for Galafold; the availability and use of net operating losses; the effect of regulatory actions, actual or potential litigation, general economic conditions, financial market conditions, and fluctuations in foreign currency exchange rates; the accuracy of certain accounting assumptions; changes in actual or projected cash flows; the cost and effect of changes in tax laws and other legislation; and other risk factors described in Amicus’ Annual Report on Form 10-K for the fiscal year ended December 31, 2024, and its subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. There can be no assurance of the market for, approval of, or the timing of such approval of, DMX-200, and it is possible that other products will be better received by the market. The Projections also reflect assumptions as to certain business decisions that are subject to change. In addition, the Projections do not take into account any circumstances or events occurring after the date on which they were prepared, do not give effect to the Merger (including the announcement thereof), and may be affected by Amicus’ ability to achieve strategic goals and targets over the applicable period. As a result, there can be no assurance that the Projections will be realized, and actual results may be materially better or worse than those contained in the Projections. The Projections cover multiple years, and such information by its nature becomes less reliable with each successive year.

In light of the foregoing factors and the uncertainties inherent in the Projections, stockholders are cautioned not to place undue reliance on the Projections. The Projections were not prepared with a view toward public disclosure, nor were they developed to provide any guidance to stockholders regarding future performance. The inclusion of the Projections in this proxy statement should not be regarded as an indication that Amicus or any of its affiliates, advisors or representatives considered or consider the Projections to be predictive of actual future events, and the Projections should not be relied upon as such or construed as financial guidance. Further, the inclusion of the Projections in this proxy statement does not constitute an admission or representation by Amicus or any of its affiliates that the information presented is material. Neither Amicus nor any of its affiliates assumes any responsibility for the accuracy of this information. Amicus does not intend to make publicly available any update or other revision to the Projections, except as otherwise required by law.

AMICUS DOES NOT INTEND TO UPDATE OR OTHERWISE REVISE THE PROJECTIONS 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 THE PROJECTIONS ARE NO LONGER APPROPRIATE.

Neither Amicus nor any of its affiliates, advisors, officers, directors or representatives has made or makes any representation or warranty to any stockholders or other person regarding the ultimate performance of Amicus compared to the information contained in the Projections or that the Projections will be achieved. Amicus makes and has made no representation to BioMarin or Merger Sub, in the Merger Agreement or otherwise, concerning any projected financial information, including the Projections. The Projections are subjective in many respects and are thus subject to interpretation. Please also refer to the section of this proxy statement captioned “Forward-Looking Statements.”

The Projections were not prepared with a view toward compliance with published guidelines of the SEC, the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of financial forecasts, or U.S. generally accepted accounting principles (“GAAP”). 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 Amicus may not be comparable to similarly titled metrics used by other companies. The financial measures included in the Projections 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 provided to or relied upon by the Board of Directors, Centerview or Goldman Sachs. In addition, the Projections were not prepared with the assistance of, or reviewed, compiled or examined by, independent accountants. The

Projections are not being included in this proxy statement to influence any stockholder’s decision on how to vote with respect to the Merger Proposal. Amicus did not provide the Projections to BioMarin at any time during the course of the parties’ discussions concerning the Merger. The Projections may differ from publicly available analyst estimates.

The Projections were each based on assumptions about Amicus’ continued operation as a standalone, publicly traded company, including with respect to the commercialization of Galafold and Pombiliti + Opfolda and the development and commercialization of DMX-200, which account for risk and probability adjustments reflecting Amicus’ senior management’s good faith assessment as to the probability of success of such products as of the time such Projections were prepared. Such assumptions include internal assumptions about the probability of success associated with regulatory approvals (with respect to DMX-200 only), launch timing, epidemiology, pricing, sales ramp, market share, patent exclusivity, research and development expenses, sales and marketing expenses, general and administrative expenses, effective tax rate and utilization of net operating losses, and other relevant factors related to Amicus’ long-range operating plan. The foregoing is a summary of certain key assumptions and does not purport to be a comprehensive or exhaustive overview of all metrics and assumptions included or reflected in the Projections.

On July 28 and 29, 2025, the July Projections were provided to the Board of Directors, in connection with the Board of Directors’ review of potential strategic alternatives and to assist the Board of Directors’ strategic review and evaluation of Amicus’ intrinsic value as a standalone company, as described in the section of this proxy statement captioned “— Background of the Merger.” The July Projections were also provided to Centerview and Goldman Sachs for use in their respective preliminary financial analyses presented to the Board of Directors during its meetings on July 28 and 29, 2025.

The July Projections included three cases (Case 1, Case 2 and Case 3) reflecting illustrative scenarios regarding assumptions for probability of success associated with regulatory approvals, launch timing and patent exclusivity for DMX-200 as well as certain commercial assumptions for Galafold and Pombiliti + Opfolda. The differences in assumptions underlying each of these cases are presented below.

Case 1: Assumes DMX-200 fails to achieve regulatory approval, more modest growth for Galafold sales internationally, and lower patient uptake for Pombiliti + Opfolda relative to Case 2.

Case 2: Includes revenues and costs associated with the ongoing commercialization of Galafold and Pombiliti + Opfolda as well as potential risk-adjusted revenues and costs associated with the development and commercialization for DMX-200 in FSGS indication with a traditional approval pathway.

Case 3: Includes potential risk-adjusted revenues and costs associated with the development and commercialization for DMX-200 in Focal Segmental Glomerulosclerosis (FSGS) indication with an accelerated approval pathway and a longer patent exclusivity period; assumes higher Galafold peak sales with an expanded Fabry disease market and higher patient uptake for Pombiliti + Opfolda relative to Case 2.