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 2024 ANNUAL GENERAL MEETING OF SHAREHOLDERS SCHEDULEDTo be held MAY 31, 2024

To the Shareholders of Alkermes plc:

The 2024 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 31, 2024 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 2025 annual general meeting of shareholders:

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

To approve, in a non-binding, advisory vote, the frequency of future advisory votes on 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.

ALKERMES PLC Notice of 2024 Annual Meeting

Proposal 1 relates solely to the election of 11 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 6 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 7 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 18, 2024, the record date for the Annual Meeting, are entitled to notice of and to vote at the 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, 2023, 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 15, 2024

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF SHAREHOLDERS TO BE HELD ON MAY 31, 2024. This notice, the accompanying proxy statement and the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 (together, the “Proxy Materials”) are available at http://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, 2023, 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 2024 Annual Meeting

Letters to our Shareholders

Dear Fellow Shareholders,

Alkermes entered 2024 as a stand-alone neuroscience company in a position of strength, having redefined the business through a series of commercial and scientific successes, and transformational activities, in 2023. At the same time, we continued our focus on strong corporate governance, dedication to patients and employees, diversity education and awareness, and commitment to operating ethically and responsibly.

From a commercial perspective, we made exciting progress in growing our proprietary products and improving access to patients in need of these important treatments. We achieved revenues in excess of $1 billion, primarily driven by our three proprietary products, LYBALVI®, VIVITROL® and ARISTADA® which, together, were used to treat more than 200,000 people in the U.S. in 2023.

From a scientific perspective, we significantly advanced our development program for ALKS 2680, our orexin 2 receptor agonist, presenting initial data from the first cohort of patients with narcolepsy type 1 and advancing clinical trial readiness activities in preparation for the commencement of the phase 2 clinical study. We also continued to progress a number of earlier-stage neuroscience development programs.

From a transactional perspective, we executed on activities to transform and strengthen the profile of the business. We completed the separation of our oncology business into a new, independent, publicly-traded company, thereby enabling us to further focus our efforts, and capital, on developing and strengthening our portfolio of neuroscience commercial products and pipeline opportunities. We prevailed in arbitration with Janssen Pharmaceutica N.V., resulting in resumption of royalties and approximately $486 million in revenue in 2023, and settled favorably our VIVITROL patent litigation, delaying generic entry by Teva until 2027. And we announced an agreement to sell our manufacturing facility in Athlone, Ireland, which we expect to drive operational efficiencies and enhance profitability over the long term.

Underpinning these accomplishments is our continued operation of the business in an ethical and responsible manner. In 2023, we published our sixth annual Corporate Responsibility Report, highlighting our diversity, inclusion and belonging-related initiatives, employee wellness and career development programs, key environmental performance data and site-specific conservation and sustainability efforts.

We continued to cultivate a diverse and inclusive workforce, leveraging our five employee resource groups, which represent various dimensions of diversity at our company and which serve to support and enhance the inclusiveness of our culture and provide opportunities for professional development, networking, learning and building deeper connections within Alkermes.

We continue to engage regularly with our shareholders throughout the year on topics related to the business. In 2023, as in prior years, our management team and Board engaged with shareholders and collected, and considered, their feedback. We look forward to continued engagement in the future.

Today, our business consists of a strong and scalable commercial infrastructure focused in serious mental illness and addiction, proven development capabilities with an advancing neuroscience pipeline, an efficient operating structure and capital allocation strategy that positions the business for sustained profitability, cash generation and growth, and a dedicated and skilled employee base committed to excellence in their work.

As we look ahead, we remain committed to the pursuit of great science that can make a real impact for patients and their families. We firmly believe that doing so is best for our business, our employees, for patients, for the communities where we live and work, and for the shareholders that have entrusted us with their investment.

We thank you for your support of Alkermes.

Richard F. PopsCEO and Chairman

ALKERMES PLC Letters to our Shareholders

Dear Fellow Shareholders,

On behalf of the Board and the Company, thank you for your investment in Alkermes. I am privileged to serve as Lead Independent Director, working closely with the Chairman & Chief Executive Officer and my fellow Board members in executing our fiduciary responsibilities to you, our shareholders. 2023 was a remarkably productive year for the Company and a busy year for the Board. I am pleased to highlight a few oversight activities the Board undertook over the past year.

Board Oversight of Strategy

Alkermes’ business performance is critically important to the Board. The Board takes an active and integrated approach to oversight of the Company’s strategic priorities, which are designed to facilitate growth of the Company into the future. During 2023, the Board and its committees met regularly with management to discuss strategic initiatives and their execution, including separation of the Company’s oncology business and sale of the Company’s Ireland-based manufacturing facility, as well as capital allocation priorities and a strategic approach to research and development.

Board and Management Succession Planning

To ensure our ability to support and oversee management’s execution of strategic priorities and a strong management team for the future, we have continued to focus on succession planning for the Board and the senior leadership team. For the Board, we have focused on maintaining a relevant mix of skills and perspectives aligned with the Company’s strategic direction. We have added eight new, independent directors to our Board in the last five years, the last four of whom have been diverse both in terms of their experience and skill sets and also gender or race/ethnicity. Most recently, we welcomed Nancy S. Lurker, an experienced public company director with significant biopharmaceutical executive experience and deep commercial expertise, and we look forward to her insights and contributions. To ensure continuity of strong Company leadership in the future, the Board also continues to actively engage in ongoing assessment, development and succession planning efforts for the senior leadership team.

Our commitment to ensuring that the Board remains well-positioned to govern extends to our own efforts to continuously improve the Board’s operations through our annual Board and Board committee assessments. In 2023, in order to gain additional insights from our annual self-evaluation process on how we might improve overall effectiveness, the Board further enhanced its assessment approach by using an external third-party facilitator and also collected input from Company management.

Strong Commitment to Shareholder Engagement

We would like to thank you, our shareholders, and other stakeholders for again engaging in productive dialogues with the Board and Company management which, last year, took place against the backdrop of a contested director election. This extensive engagement and the feedback you shared provided us with a better appreciation of your perspectives. The Board considers this input essential in its ongoing commitment to excellence in the execution of its strategic oversight and corporate governance responsibilities and is committed to continuing such engagement in the future.

As we look to the future, the Company and the Board remain committed to, and guided by, the opportunity to impact the lives of people who may benefit from Alkermes’ medicines.

Thank you for your investment in Alkermes and the trust that it implies. We remain committed to serving your interests in 2024 and beyond.

Frank A. WilsonLead Independent DirectorChair, Audit and Risk Committee

ALKERMES PLC Letters to our Shareholders