False 0001520262 Alkermes plc.0001520262 2025-09-08 2025-09-08

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT
PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): September 8, 2025

ALKERMES PUBLIC LIMITED COMPANY

(Exact name of registrant as specified in its charter)

Ireland |  | 001-35299 |  | 98-1007018
(State or other jurisdiction |  | (Commission |  | (IRS Employer
of incorporation) |  | File Number) |  | Identification No.)
Connaught House, 1 Burlington Road
Dublin 4, Ireland D04 C5Y6
(Address of principal executive offices)

Registrant's telephone number, including area code: + 353-1-772-8000

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ |  | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐ |  | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐ |  | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐ |  | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class |  | Trading Symbol(s) |  | Name of each exchange on which registered
Ordinary shares, $0.01 par value |  | ALKS |  | Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

|  | Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 7.01 Regulation FD Disclosure.

On September 8, 2025, in connection with its participation at the World Sleep Congress taking place September 5-10, 2025, Alkermes plc (the “Company”) issued a press release announcing detailed safety and efficacy results from Vibrance-1, the Company’s phase 2 study evaluating the safety and efficacy of alixorexton (formerly referred to as ALKS 2680) compared to placebo in patients with narcolepsy type 1. Copies of the Company’s press release and related investor presentation and scientific presentations are furnished herewith as Exhibit 99.1, Exhibit 99.2 and Exhibit 99.3, respectively, and are incorporated herein by reference.

The information in this Item 7.01, and in Exhibit 99.1, Exhibit 99.2 and Exhibit 99.3 furnished herewith, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.

Item 9.01 Financial Sta tements and Exhibits.

(d) Exhibits

EXHIBIT INDEX

Exhibit No. |  | Description
99.1 |  | Press release issued by Alkermes plc dated September 8, 2025.
99.2 |  | Investor presentation of Alkermes plc displayed on September 8, 2025.
99.3 |  | Scientific presentations of Alkermes plc displayed on September 8, 2025.
104 |  | Cover page interactive data file (embedded within the Inline XBRL document).

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SIGNA TURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

| ALKERMES PLC
Date: September 8, 2025 | By: |  | /s/ David J. Gaffin
|  |  | David J. Gaffin
|  |  | Secretary

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