Alkermes plc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No. )

Registered in Ireland—No. 498284

Connaught House

1 Burlington Road

Dublin 4, Ireland, D04 C5Y6

NOTICE OF 2026 ANNUAL GENERAL MEETING OF SHAREHOLDERS SCHEDULEDTo be held MAY 20, 2026

To the Shareholders of Alkermes plc:

The 2026 Annual General Meeting of Shareholders (including any adjournments or postponements thereof, the “Annual Meeting”) of Alkermes plc (the “Company” or “Alkermes”), a company incorporated under the laws of Ireland, is scheduled to be held on May 20, 2026 at 2:00 p.m., Irish Standard Time, at the Company’s offices at Connaught House, 1 Burlington Road, Dublin 4, Ireland, D04 C5Y6, for the following purposes:

To elect, by separate resolutions, each of the following director nominees to serve on the Company’s Board of Directors (the “Board”) for a one-year term until the Company’s 2027 annual general meeting of shareholders:

To approve, in a non-binding, advisory vote, the compensation of the Company’s named executive officers.

To ratify, in a non-binding vote, the appointment of PricewaterhouseCoopers LLP as the independent auditor and accounting firm of the Company and to authorize, in a binding vote, the Audit and Risk Committee of the Board to set the independent auditor and accounting firm’s remuneration.

To approve the Alkermes plc 2018 Stock Option and Incentive Plan, as amended.

To renew Board authority to allot and issue shares under Irish law.

To renew Board authority to disapply the statutory pre-emption rights that would otherwise apply under Irish law.

To transact such other business as may properly come before the Annual Meeting.

Proposal 1 relates solely to the election of directors nominated by the Board and does not include any other matters relating to the election of directors. A separate resolution will be presented at the Annual Meeting for each of the director nominees. Proposals 2 through 5 are ordinary resolutions under Irish law, requiring the affirmative vote of a majority of the votes cast (in person or by proxy) on each resolution at the Annual Meeting for approval. Proposal 6 is a special resolution under Irish law, requiring the affirmative vote of the holders of at least 75% of the votes cast (in person or by proxy) at the Annual Meeting for approval. The foregoing items of business are more fully described in the proxy statement accompanying this notice. Shareholders as of March 13, 2026, the record date for the Annual Meeting, are entitled to notice of and to vote at the Annual Meeting.

ALKERMES PLC Notice of 2026 Annual Meeting

During the Annual Meeting, following a review of the Company’s affairs, management will present the Company’s Irish statutory financial statements for the year ended December 31, 2025, and the reports of the directors and the independent auditor and accounting firm thereon. There is no requirement under Irish law that the Irish statutory financial statements be approved by shareholders, and no such approval will be sought at the Annual Meeting.

YOUR VOTE IS VERY IMPORTANT. It is important that your voice be heard and your shares be represented at the Annual Meeting whether or not you are able to attend. We encourage you to cast your vote promptly so that your shares will be represented and voted at the meeting. Any shareholder entitled to attend, speak and vote at the Annual Meeting may appoint one or more proxies, who need not be a shareholder of record of the Company. If you wish to appoint as proxy any person other than the individuals specified on the Company’s proxy card, you may do so by contacting the Company Secretary at Alkermes plc, Connaught House, 1 Burlington Road, Dublin 4, Ireland, D04 C5Y6, Attention: Company Secretary or by delivering to the Company Secretary a proxy card in the form mailed to you or in the form set forth in Section 184 of the Irish Companies Act 2014. Your appointed proxy must attend the Annual Meeting in person in order for your votes to be cast. We recommend that you review the further information on the process for, and deadlines applicable to, voting and appointing a proxy under the section entitled “General Information about the Meeting and Voting” commencing on page 15 of the proxy statement accompanying this notice.

By Order of the Board of Directors.

DAVID J. GAFFIN

Secretary

Dublin, Ireland

April 6, 2026

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF SHAREHOLDERS TO BE HELD ON MAY 20, 2026. This notice, the accompanying proxy statement and the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 (together, the “Proxy Materials”) are available at www.proxydocs.com/ALKS. The Proxy Materials are also available free of charge on the Investors section of our website at www.alkermes.com.

The Company’s Irish statutory financial statements for the year ended December 31, 2025, including the related reports thereon (together, the “Irish Statutory Reports”), are available on the Annual Reports page of the Investors section of our website at www.alkermes.com.

Shareholders may obtain printed copies of the Proxy Materials and the Irish Statutory Reports free of charge by writing to our Company Secretary at Alkermes plc, Connaught House, 1 Burlington Road, Dublin 4, Ireland, D04 C576, Attention: Company Secretary.

ALKERMES PLC Notice of 2026 Annual Meeting

Letter to our Shareholders

Dear Fellow Shareholders,

Alkermes’ mission is to pursue great science with deep compassion to make a real impact on people living with complex psychiatric and neurological disorders.

As a result of our employees’ hard work and dedication, we achieved significant milestones across all aspects of our business in 2025, including:

▪

We recorded revenues of approximately $1.48 billion, driven by sales of FDA-approved products developed by Alkermes scientists and manufactured and commercialized by Alkermes’ teams in the U.S.

▪

We successfully advanced alixorexton, our lead orexin 2 receptor agonist, through phase 2 studies in narcolepsy and obtained FDA Breakthrough Therapy designation in narcolepsy type 1 and, in doing so, further characterized what we expect to be the next major product to emerge from our extensive R&D capabilities.

▪

We announced the acquisition of Avadel Pharmaceuticals plc and closed the transaction earlier this year, adding a new, high potential product to our commercial portfolio and a sales organization experienced in narcolepsy, which serve to accelerate our entry into the sleep medicine market and provides access to and insights from clinicians in this disease state ahead of the potential launch of alixorexton.

▪

We progressed the development of multiple exciting early- and late-stage pipeline candidates, including sodium oxybate for the treatment of idiopathic hypersomnia, alixorexton for the treatment of narcolepsy types 1 and 2 and idiopathic hypersomnia, and additional orexin 2 receptor agonists, ALKS 7290 and ALKS 4510, in first-in-human studies.

The foundation of our success is our vibrant and collaborative culture. Alkermes is comprised of over 2,000 dedicated individuals, animated by the challenge of working together to make important new medicines. We are guided by scientific curiosity and driven by purpose—a commitment to follow the data, act with integrity and make a meaningful difference for patients.

In February, I announced my decision to retire as Chief Executive Officer (CEO) of Alkermes at the end of July, after 35 years leading the company. Blair Jackson, our current Chief Operating Officer and my valued colleague for many years, will become CEO at that time.

I cannot think of a time when Alkermes has been in a stronger position, poised for its next stage of growth. We have a well-established and scalable U.S. commercial infrastructure, proven R&D capabilities and an efficient operating structure and capital allocation strategy.

I am extremely proud of this company, its employees and all that we have accomplished over the years. We have continuously evolved and advanced the business to take advantage of opportunities to meaningfully grow the company and create value for our shareholders. Evidence of our accomplishments can be seen in the thousands of patients receiving our medicines every year and in the remarkable company we have built together.

I have great confidence in Blair's leadership and the progress we expect to make in the years ahead. I will continue to stay engaged in my role as Chairman and advisor.

Thank you for your investment and continued support of Alkermes.

Richard F. Pops Chief Executive Officer and Chairman

ALKERMES PLC Letter to Shareholders

Registered in Ireland—No. 498284

PROXY STATEMENT

2026 ANNUAL GENERAL MEETING OF SHAREHOLDERS SCHEDULED FOR MAY 20, 2026