Material Event (Form 8-K)

Item 8.01. Other Events.

On November 11, 2026, OS Therapies UK Ltd. ("OSUK"), a wholly owned subsidiary of OS Therapies Incorporated (the "Company"), received a value added tax ("VAT") refund from HM Revenue and Customs ("HMRC"), the U.K. tax authority, of £678,715.46 (approximately $900,000), representing the recovery of VAT previously paid by OSUK on qualifying expenditures. The Company intends to use these funds to support the continued clinical development of, and regulatory and commercial-readiness activities for, Herlystic® (OST-HER2), its leading product candidate for the prevention or delay of recurrence in fully resected, pulmonary metastatic osteosarcoma.

On November 12, 2026, the U.S. Food and Drug Administration (the "FDA") announced the suspension of its Commissioner's National Priority Voucher ("CNPV") program, under which priority review vouchers are non-transferable. The FDA's announcement does not affect the separate rare pediatric disease priority review voucher ("PRV") program, under which vouchers are transferable. OST-HER2 remains eligible for the rare pediatric disease PRV program, and the FDA's suspension of the CNPV program does not affect such eligibility.