Other Events. ​ As previously disclosed, on July 25, 2024, Fortress Biotech, Inc. (the “ Company ”), as borrower, entered into a $50.0 million senior secured credit agreement (as amended on December 12, 2025 and February 22, 2026, the “ Oaktree Agreement ”) with Oaktree Fund Administration, LLC and the lenders from time-to-time party thereto. On September 30, 2026, the Company repaid in full the remaining $15.0 million in outstanding principal under the facility, together with approximately $…

Results of Operations and Financial Condition . ​ On August 13, 2026, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the quarter ended June 30, 2026. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or other…

Results of Operations and Financial Condition . ​ On May 14, 2026, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the quarter ended March 31, 2026. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwi…

Results of Operations and Financial Condition . ​ On March 31, 2026, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the year ended December 31, 2025. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or other…

Other Events. ​ On March 30, 2026, Fortress Biotech, Inc. (the “ Company ”) issued a press release announcing the closing of the sale by Cyprium Therapeutics, Inc. (“ Cyprium ”), a majority-owned subsidiary of the Company, of its Rare Pediatric Disease Priority Review Voucher (“ PRV ”) for $205 million in gross proceeds pursuant to the previously disclosed definitive asset purchase agreement (the “ PRV APA ”). ​ In connection with the sale of the PRV, Cyprium redeemed all outstanding shares o…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information provided in

Other Events. ​ On February 23, 2026, the Company issued a press release announcing that Cyprium entered into the PRV APA to sell the PRV for $205 million. The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference. ​ The Company currently owns 80.4% of Cyprium’s outstanding common stock, on an as-converted basis, and expects to receive its pro rata share of future dividends from Cyprium following the closing of the P…

Entry into a Material Definitive Agreement . ​ Priority Review Voucher Asset Purchase Agreement ​ On February 22, 2026, Cyprium Therapeutics, Inc. (“Cyprium”), a majority-owned subsidiary of Fortress Biotech, Inc. (the “ Company ”), entered into a definitive asset purchase agreement (the “ PRV APA ”) pursuant to which Cyprium agreed to sell a Rare Pediatric Disease Priority Review Voucher (“ PRV ”). As previously disclosed, the PRV was originally issued in connection with the FDA’s approval o…

Other Events . ​ On January 13, 2026, Fortress Biotech, Inc. (the “ Company ”) issued a press release announcing that the U.S. Food and Drug Administration (“FDA”) approved ZYCUBO® (copper histidinate, formerly known as CUTX-101) for the treatment of Menkes disease in pediatric patients . A Rare Pediatric Disease Priority Review Voucher (“PRV”) was issued in connection with the FDA approval and will be transferred to Cyprium Therapeutics, Inc. (“Cyprium”), a majority-owned subsidiary of the C…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information provided in

Entry into a Material Definitive Agreement . ​ On December 12, 2025, Fortress Biotech, Inc. (the “ Company ”), as borrower, entered into the First Amendment to Credit Agreement (the “ Amendment ”), which amends that certain Credit Agreement dated July 25, 2024 (the “ Agreement ”) with Oaktree Fund Administration, LLC, as the administrative agent (in such capacity, the “ Agent ”), and the lenders from time to time party thereto. The Company initially borrowed $35.0 million under the Agreement…

The Warrants are being issued in a transaction that is exempt from registration under Section 4(a)(2) of the Securities Act of 1933. ​ ​ SIGNATURES ​ Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ​ Fortress Biotech, Inc. ​ (Registrant) ​ ​ Date: December 15, 2025 ​ ​ ​ By: /s/ David Jin David Jin Chief Financial Officer ​ ​ ​ ​ ​

Other Events . As previously disclosed, on October 1, 2025, Fortress Biotech, Inc. (the “ Company ”) and its majority-owned subsidiary, Cyprium Therapeutics, Inc. (“ Cyprium ”), announced that the U.S. Food and Drug Administration (the “ FDA ”) had issued a Complete Response Letter relating to the New Drug Application (“ NDA ”) for CUTX-101 (copper histidinate), intended to treat Menkes disease in pediatric patients. In December 2023, Sentynl Therapeutics, Inc. (“ Sentynl ”), a U.S.-based bio…

Results of Operations and Financial Condition . ​ On November 14, 2025, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the quarter ended September 30, 2025. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, o…

Other Events. ​ On October 1, 2025, Fortress Biotech, Inc. issued a press release announcing that the U.S. Food and Drug Administration issued a complete response letter for CUTX-101 (copper histidinate). The full text of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference. ​

Results of Operations and Financial Condition . ​ On August 14, 2025, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the quarter ended June 30, 2025. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or other…

Other Events . ​ As previously disclosed, on October 6, 2021, AstraZeneca’s Alexion Therapeutics, Inc. (“ AstraZeneca ”) purchased 100% of the equity securities (the “ Caelum Acquisition ”) of Caelum Biosciences, Inc. (“ Caelum ”), a privately held biopharmaceutical company founded by Fortress Biotech, Inc. (“ Fortress ”). As part of the Caelum Acquisition, AstraZeneca obtained all of Caelum’s right and interest to CAEL-101, its proprietary product candidate for the treatment of light chain (…

Results of Operations and Financial Condition . ​ On May 15, 2025, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the quarter ended March 31, 2025. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwi…

Chief Strategy Officer — Lucy Lu, M.D.: Dr. Lucy Lu resigned from the Board of Directors to join the Company as Chief Strategy Officer.

Results of Operations and Financial Condition . ​ On March 31, 2025, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the year ended December 31, 2024. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or other…

Entry into a Material Definitive Agreement. ​ Merger Agreement On March 9 , 2025, Checkpoint Therapeutics, Inc., a Delaware corporation (“ Checkpoint ”) and majority-controlled subsidiary of Fortress Biotech, Inc. (“ Fortress ”), entered into an Agreement and Plan of Merger (the “ Merger Agreement ”) with Sun Pharmaceutical Industries, Inc., a Delaware corporation (“ Sun Pharma ” or “ Parent ”), and Snoopy Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“ Mer…

Other Events . ​ On December 13, 2024, Checkpoint Therapeutics (“ Checkpoint ”), a majority-controlled subsidiary of Fortress Biotech, Inc. (the “ Company ” or “ Fortress ”), announced that the U.S. Food and Drug Administration (the “ FDA ”) approved UNLOXCYT™ (cosibelimab-ipdl) for the treatment of adults with metastatic or locally advanced cutaneous squamous cell carcinoma (“ cSCC ”) who are not candidates for curative surgery or curative radiation. UNLOXCYT is the first and only programmed…

Results of Operations and Financial Condition . ​ On November 14, 2024, Fortress Biotech, Inc. issued a press release to provide a corporate update and to announce its financial results for the quarter ended September 30, 2024. A copy of such press release is being furnished as Exhibit 99.1 to this report. The information, including Exhibit 99.1, in this Form 8-K is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, o…

Other Events . ​ On November 4, 2024, Journey Medical Corporation (“ Journey Medical ”), a majority-controlled subsidiary of Fortress Biotech, Inc. (the “ Company ” or “ Fortress ”), announced that the U.S. Food and Drug Administration (the “ FDA ”) approved Emrosi™ (Minocycline Hydrochloride Extended Release Capsules, 40mg) for the treatment of inflammatory lesions of rosacea in adults. Emrosi (also known as DFD-29) was developed by Journey Medical in collaboration with Dr. Reddy’s Laborator…

Based in part upon the representations of the purchasers in the Purchase Agreements, the offering and sale of the PIPE Warrants and the shares of Common Stock sold in the Chairman Private Placement were exempt from registration under Section 4(a)(2) of the Securities Act of 1933, as amended (the “ Securities Act ”), and corresponding provisions of state securities or “blue sky” laws. The sale of the PIPE Warrants, the shares of Common Stock issuable upon exercise of the PIPE Warrants and the…