alex Alkermes Contacts: For Investors: Sandy Coombs +1 781 609 6377 For Media: Katie Joyce +1 781 249 8927 Alkermes plc Reports First Quarter 2022 Financial Results - First Quarter Revenues of $278.5 Million Reflect Stro

Alkermes plc Reports First Quarter 2022 Financial Results

- First Quarter Revenues of $278.5 Million Reflect Strong Performance of LYBALVI , ARISTADA and VIVITROL -

- GAAP Loss per Share of $0.22 and Basic and Diluted Non-GAAP Earnings per Share of $0.12 -

- Financial Expectations for 2022 Reiterated -

DUBLIN, April 27, 2022 - Alkermes plc (Nasdaq: ALKS) (Nasdaq: ALKS) today reported financial results for the first quarter of 2022.

"Our strong first quarter results reflect continued momentum across the business, and a sharp operational focus that provides a solid foundation to drive further growth of our proprietary products and advance our pipeline of development programs in 2022. As we execute on our launch strategy for LYBALVI , we are particularly encouraged by early utilization trends and feedback from healthcare providers that underscore LYBALVI's value proposition in the oral antipsychotic market," said Richard Pops, Chief Executive Officer of Alkermes. "With our focus on disciplined allocation of capital, strong corporate governance, and our commitment to long-term profitability targets, we are delivering on our commitment to efficiently drive growth and are actively managing the business to create value for our shareholders in 2022 and beyond."

Quarter Ended March 31, 2022 Financial Results

"Our first quarter results demonstrate the strength of our proprietary commercial product portfolio and our continued focus on efficient management of our cost structure. We are in a strong financial position to execute on our strategic priorities and work toward achievement of our long-term profitability targets," commented Iain Brown, Chief Financial Officer of Alkermes. "Today, we are reiterating our financial expectations for 2022, as we focus on efficiently driving growth of LYBALVI, ARISTADA and VIVITROL, and advancing our development pipeline."

Financial Expectations for 2022

Alkermes reiterates its financial expectations for 2022, and the assumptions underlying such expectations, as set forth in its press release dated Feb. 16, 2022.

Alkermes will host a conference call and webcast presentation with accompanying slides at 8:00 a.m. ET (1:00 p.m. BST) on Wednesday, April 27, 2022, to discuss these financial results and provide an update on the company. The webcast may be accessed on the Investors section of Alkermes' website at www.alkermes.com. The conference call may be accessed by dialing +1 877 407 2988 for U.S. callers and +1 201 389 0923 for international callers. In addition, a replay of the conference call will be available from 11:00 a.m. ET (4:00 p.m. BST) on Wednesday, April 27, 2022, through Wednesday, May 4, 2022, and may be accessed by visiting Alkermes' website or by dialing +1 877 660 6853 for U.S. callers and +1 201 612 7415 for international callers. The replay conference ID is 13727838.

Alkermes plc is a fully-integrated, global biopharmaceutical company developing innovative medicines in the fields of neuroscience and oncology. The company has a portfolio of proprietary commercial products focused on alcohol dependence, opioid dependence, schizophrenia and bipolar I disorder, and a pipeline of product candidates in development for neurodegenerative disorders and cancer. Headquartered in Dublin, Ireland, Alkermes has an R&D center in Waltham, Massachusetts; a research and

manufacturing facility in Athlone, Ireland; and a manufacturing facility in Wilmington, Ohio. For more information, please visit Alkermes' website at www.alkermes.com.

Non-GAAP Financial Measures

This press release includes information about certain financial measures that are not prepared in accordance with GAAP, including non-GAAP net income (loss) and non-GAAP basic and diluted earnings (loss) per share. These non-GAAP measures are not based on any standardized methodology prescribed by GAAP and are not necessarily comparable to similar measures presented by other companies.

Non-GAAP net income (loss) adjusts for certain one-time and non-cash charges by excluding from GAAP results: share-based compensation expense; amortization; depreciation; non-cash net interest expense; change in the fair value of contingent consideration; certain other one-time or non-cash items; and the income tax effect of these reconciling items.

The company's management and board of directors utilize these non-GAAP financial measures to evaluate the company's performance. The company provides these non-GAAP financial measures of the company's performance to investors because management believes that these non-GAAP financial measures, when viewed with the company's results under GAAP and the accompanying reconciliations, are useful in identifying underlying trends in ongoing operations. However, non-GAAP net income (loss) and non-GAAP basic and diluted earnings (loss) per share are not measures of financial performance under GAAP and, accordingly, should not be considered as alternatives to GAAP measures as indicators of operating performance. Further, non-GAAP net income (loss) and non-GAAP basic and diluted earnings (loss) per share should not be considered measures of the company's liquidity.

A reconciliation of GAAP to non-GAAP financial measures has been provided in the tables included in this press release.

Note Regarding Forward-Looking Statements

Certain statements set forth in this press release constitute "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, but not limited to, statements concerning: the company's expectations concerning its future financial and operating performance, business plans or prospects, including its commitment and plans to drive, and ability to achieve, growth, long-term profitability and shareholder value creation, and its ability to execute on its strategic priorities; and the potential therapeutic and commercial value of the company's products. The company cautions that forward-looking statements are inherently uncertain. The forward-looking statements are neither promises nor guarantees and they are necessarily subject to a high degree of uncertainty and risk. Actual performance and results may differ materially from those expressed or implied in the forward-looking statements due to various risks and uncertainties. These risks and uncertainties include, among others: the company's efforts to manage its cost structure may not yield the intended results; the company may not be able to achieve long-term profitability or its profitability targets in a timely manner or at all; the impacts of the ongoing COVID-19 pandemic on the company's business, results of operations or financial condition, including impacts on healthcare systems and on patient and healthcare provider access to the company's marketed products; the unfavorable outcome of arbitration or litigation, including so-called "Paragraph IV" litigation and other patent litigation, or other disputes related to the company's products or products using the company's proprietary technologies, including the arbitration proceedings with Janssen; clinical development activities may not be completed on time or at all; the results of the company's development activities may not be positive, or predictive of final results from such activities, results of future development activities or real-world results; the U.S. Food and Drug Administration (FDA) may not agree with the company's regulatory approval strategies or components of the company's marketing applications; the FDA or regulatory authorities outside the U.S. may make adverse decisions regarding the company's products; the company and its licensees may not be able to continue to successfully commercialize their products; there may be a reduction in payment rate or

reimbursement for the company's products or an increase in the company's financial obligations to government payers; the company's products may prove difficult to manufacture, be precluded from commercialization by the proprietary rights of third parties, or have unintended side effects, adverse reactions or incidents of misuse; and those risks and uncertainties described under the heading "Risk Factors" in the company's Annual Report on Form 10-K for the year ended Dec. 31, 2021 and in subsequent filings made by the company with the U.S. Securities and Exchange Commission (SEC), which are available on the SEC's website at www.sec.gov. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. Except as required by law, the company disclaims any intention or responsibility for updating or revising any forward-looking statements contained in this press release.

VIVITROL is a registered trademark of Alkermes, Inc.; ARISTADA , ARISTADA INITIO , LYBALVI and NanoCrystal are registered trademarks of Alkermes Pharma Ireland Limited, used by Alkermes, Inc. under license; INVEGA , INVEGA HAFYERA , INVEGA SUSTENNA , INVEGA TRINZA , RISPERDAL CONSTA , TREVICTA and XEPLION are registered trademarks of Johnson & Johnson Corporation; CABENUVA is a registered trademark of ViiV Healthcare UK (No.3) Limited; and VUMERITY is a registered trademark of Biogen Inc., used by Alkermes under license.