Indivior Pharmaceuticals, Inc.

Item 7.01 Regulation FD Disclosure. On September 17, 2026, Indivior Pharmaceuticals, Inc., a Delaware corporation (“Indivior”), issued a press release announcing the declaration of a special cash dividend (as further discussed in Item 8.01 of this Current Report on Form 8-K). A copy of the press release is being furnished as Exhibit 99.1 to this Current Report on Form 8-K. The information under Item 7.01 of this Current Report on Form 8-K (including Exhibit 99.1) is intended to be furnished and 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 shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 8.01 Other Events. As previously disclosed, on August 1, 2026, Indivior and Artemis Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of Indivior (“Merger Sub”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Supernus Pharmaceuticals, Inc., a Delaware corporation (“Supernus”). The Merger Agreement provides that, upon the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub will merge with and into Supernus (the “Merger”), with Supernus continuing as the surviving company and a wholly owned subsidiary of Indivior following the transaction. On September 16, 2026, Indivior’s board of directors declared a special cash dividend (the “Special Dividend”) in the amount of (i) $8.13 per share of Indivior common stock payable to holders of record of the issued and outstanding Indivior common stock as of October 30, 2026 (the “Special Dividend Record Date”) (such holders, the “Special Dividend Record Holders”) and (ii) $8.13 per share of Indivior common stock underlying Indivior equity awards on the Special Dividend Record Date payable, upon vesting of such equity awards, to holders of certain Indivior equity awards outstanding as of the Special Dividend Record Date (the “Special Dividend Award Holders”)The payment of the Special Dividend is subject to and contingent upon the closing of the Merger (the “Closing”) and will be made following the Closing. As of the date of this Current Report on Form 8-K, Indivior expects at least a majority of the Special Dividend to exceed Indivior’s current and accumulated earnings and profits, although no assurance can be made in this regard. Such amounts shall be treated by U.S. holders first as a return of capital to the extent of such U.S. holder’s basis in its Indivior common stock and then as capital gain. For additional information regarding tax considerations of the Special Dividend, please see the section entitled “The Merger - Certain U.S. Federal Income Tax Considerations of the Special Dividend to Holders of Indivior Shares” of the joint proxy statement/prospectus filed by Indivior with the U.S. Securities and Exchange Commission (the “SEC”) on September 11, 2026. Payment of the Special Dividend is conditioned upon the Closing which is expected to occur on or about November 2, 2026, subject to, among other things, the approval by Indivior stockholders of the issuance of Indivior common stock in connection with the Merger, the adoption of the Merger Agreement by Supernus stockholders and the satisfaction or waiver of all conditions under the Merger Agreement. Assuming the Merger is consummated on November 2, 2026, payment of the Special Dividend to Special Dividend Record Holders is anticipated to be made on or about November 6, 2026. Supernus stockholders will not be entitled to receive the Special Dividend with respect to any Indivior common stock received as consideration in the Merger.