SUPERNUS PHARMACEUTICALS, INC.

false 0001356576 0001356576 2026-08-03 2026-08-03 iso4217:USD xbrli:shares iso4217:USD xbrli:shares 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): August 3, 2026 Supernus Pharmaceuticals, Inc. (Exact name of registrant as specified in its charter) Delaware 001-35518 20-2590184 (State or other jurisdiction of incorporation or organization) (Commission File Number) (I.R.S. Employer Identification No.) 9715 Key West Ave Rockville MD 20850 (Address of Principal Executive Offices) (Zip Code) Registrant’s telephone number, including area code: ( 301 ) 838-2500 Not Applicable (Former name or former address, if changed since last report.) Securities registered pursuant to Section 12(b) of the Exchange Act Title of each class Trading Symbol Name of each exchange on which registered Common Stock, $0.001 par value per share SUPN The Nasdaq Stock Market LLC 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): x Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) x 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)) 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). ¨ 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 8.01 Other Events. On August 3, 2026, Supernus Pharmaceuticals, Inc. (the “Company”) published a post relating to the proposed merger of equals of the Company and Indivior Pharmaceuticals Inc. (“Indivior”) on the Company’s LinkedIn account. In addition, on August 3, 2026, the Company distributed to its employees communications relating to the proposed merger, consisting of an email to Company employees from Jack A. Khattar, the Company’s President and Chief Executive Officer, and a presentation used at a Company employee meeting. Copies of the LinkedIn post, the employee email and the employee presentation are filed as Exhibit 99.1, Exhibit 99.2 and Exhibit 99.3 hereto, respectively, and are incorporated herein by reference. Important Additional Information and Where to Find It In connection with the proposed transaction, Indivior intends to file with the SEC a registration statement on Form S-4, which will include a document that serves as a prospectus of Indivior and a joint proxy statement of Indivior and Supernus (the “joint proxy statement/prospectus”). Each party also plans to file other relevant documents with the SEC regarding the proposed transaction. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND OTHER RELEVANT DOCUMENTS FILED WITH THE SEC WHEN THEY BECOME AVAILABLE, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION. A definitive joint proxy statement/prospectus will be sent to Indivior’s stockholders and Supernus’ stockholders. Investors and securityholders may obtain a free copy of the joint proxy statement/prospectus (if and when it becomes available) and other relevant documents filed by Indivior and Supernus with the SEC at the SEC’s website at www.sec.gov. Copies of the documents filed by Indivior with the SEC will be available free of charge on Indivior’s website at www.indivior.com or by contacting Indivior’s Investor Relations at InvestorRelations@indivior.com. Copies of the documents filed by Supernus with the SEC will be available free of charge on Supernus’ website at www.supernus.com. No Offer or Solicitation This report and the information contained herein is for informational purposes only and does not constitute an offer to sell or the solicitation of an offer to buy or exchange any securities, or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. This report does not constitute a prospectus or prospectus equivalent document. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended. Participants in the Solicitation Indivior and Supernus and their respective directors, executive officers and other members of management and employees may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information about directors and executive officers of Indivior is available in the Indivior proxy statement for its 2026 Annual Meeting, which was filed with the SEC on March 27, 2026. Information about directors and executive officers of Supernus is available in the Supernus proxy statement for its 2026 Annual Meeting, which was filed with the SEC on April 30, 2026. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint proxy statement/prospectus and other relevant materials filed with the SEC regarding the proposed transaction when they become available. Investors should read the joint proxy statement/prospectus carefully when it becomes available before making any voting or investment decisions. Investors may obtain free copies of these documents from Indivior and Supernus as indicated above. 2 Forward-Looking Statements This report contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and other federal securities laws. From time to time, oral or written forward-looking statements may also be included in other information released to the public. These forward-looking statements are intended to provide Supernus’s and Indivior’s respective management’s current expectations or plans for our future operating and financial performance, based on assumptions currently believed to be valid. Words such as “anticipate,” “believe,” “estimate,” “expect,” “intend,” “plan,” “project,” “may,” “will,” “would,” “could,” “should,” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these words. All forward-looking statements involve risks, uncertainties and other factors that may cause actual results to differ materially from those expressed or implied in the forward-looking statements. These statements, including statements regarding the proposed merger of equals of Supernus and Indivior, the expected timing of the closing, and the anticipated benefits and prospects of the combined company, are based on management’s current expectations and are subject to risks and uncertainties that could cause actual results to differ materially, including, among others: the risk that the proposed merger may not be completed in a timely manner or at all; the failure to obtain the required approvals of Supernus' or Indivior’s stockholders; the failure or delay in obtaining required regulatory approvals, or the imposition of conditions in connection therewith; the failure to satisfy the other conditions to closing; the possibility that a competing or superior acquisition proposal is made; the fact that the e