Alkermes plc

To the Board of Directors and Shareholders of Alkermes plc

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheets of Alkermes plc and its subsidiaries (the “Company”) as of December 31, 2023 and 2022, and the related consolidated statements of operations and comprehensive income (loss), of shareholders' equity and of cash flows for each of the three years in the period ended December 31, 2023, including the related notes (collectively referred to as the “consolidated financial statements”). We also have audited the Company's internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.

Basis for Opinions

The Company's management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in Management’s Annual Report on Internal Control over Financial Reporting appearing under Item 9A. Our responsibility is to express opinions on the Company’s consolidated financial statements and on the Company's internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the consolidated financial statements that were communicated or required to be communicated to the audit committee and that (i) relate to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Tax-Free Determination of the Separation of the Oncology Business

As described in Notes 1 and 3 to the consolidated financial statements, the Company completed the separation of its oncology business into a new, independent, publicly-traded company on November 15, 2023. The separation was effected by means of a distribution of shares to the Company’s shareholders. Management determined that the separation and related distribution qualified as tax-free for U.S. federal income tax purposes, which required significant judgment by management. In making such determinations, management applied U.S. federal tax law to relevant facts and circumstances and obtained: (i) a favorable private letter ruling from the IRS; (ii) a tax opinion; and (iii) other external tax advice related to the concluded tax treatment. If the separation and distribution were to fail to qualify for tax-free treatment for U.S. federal income tax purposes, the Company and/or its shareholders could be subject to significant liabilities, which could have material adverse impacts on the Company’s business, financial condition, results of operations and cash flows in future reporting periods.

The principal considerations for our determination that performing procedures relating to the tax-free determination of the separation of the oncology business is a critical audit matter are (i) the significant judgment by management with regards to interpretation of the facts and the application of tax laws and regulations in order to conclude the divestiture would qualify as a tax-free transaction, (ii) a high degree of auditor judgment, subjectivity, and effort in performing procedures and evaluating audit evidence in connection with management’s tax-free determination, and (iii) the audit effort involved the use of professionals with specialized skill and knowledge.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the key judgments in management’s evaluation of the tax treatment of the transaction. These procedures also included, among others (i) testing management’s process for determining the tax-free treatment of the transaction, (ii) evaluating the information used in management’s determination, such as tax rulings from relevant taxing authorities and supporting information, tax opinion, and relevant tax laws, and (iii) evaluating the reasonableness of management’s position that the transaction qualifies for tax-free status. Professionals with specialized skill and knowledge were used to assist in evaluating the transaction, the application of tax laws and regulations, the private letter ruling and tax opinion, and certain representations from management

Rebate Accruals – Medicaid Drug Rebate Program

As described in Notes 2 and 11 to the consolidated financial statements, the Company’s revenue from product sales are recorded net of reserves established for applicable discounts and allowances that are offered within contracts with the Company’s customers, health care providers or payers. The Company records accruals for rebates to U.S. states under the Medicaid Drug Rebate Program as a reduction of sales when the product is shipped into the distribution channel using the expected value method. As of December 31, 2023, accrued Medicaid rebates were $213.8 million, of which a significant amount related to the Medicaid Drug Rebate Program. The Company rebates individual U.S. states for all eligible units purchased under the Medicaid program based on a rebate per unit calculation, which is based on the Company’s average manufacturer prices. The Company estimates expected unit sales to individuals covered by Medicaid and rebates per unit under the Medicaid program and adjusts its rebate accrual based on actual unit sales and rebates per unit and changes in trends in Medicaid utilization.

The principal considerations for our determination that performing procedures relating to rebate accruals for the Medicaid Drug Rebate Program is a critical audit matter are (i) the significant judgment by management due to significant measurement uncertainty involved in developing the reserves, as the reserves are based on assumptions developed using historical experience, current contractual requirements, specific known market events and payment patterns and (ii) a high degree of auditor judgment, subjectivity and effort in applying procedures and evaluating evidence related to these assumptions.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to rebate accruals for the Medicaid Drug Rebate Program, including controls over the assumptions used to estimate the rebate accruals. These procedures also included, among others, (i) developing an independent estimate of the rebate accruals by utilizing third-party data related to product sales, the historical trend of actual rebate claims paid and consideration of contractual requirement changes and market events; (ii) comparing the independent estimate to management’s estimate; and (iii) testing rebate claims processed by the Company.

/s/PricewaterhouseCoopers LLP

Boston, Massachusetts

February 21, 2024

We have served as the Company’s auditor since 2007.