OS Therapies shares rise 10.45% premarket after providing H1 2026 corporate outlook with OST-HER2 regulatory submissions and biomarker data release.

OS Therapies Inc. (OSTX) surged 10.45% in premarket trading following the announcement of its first-half 2026 corporate outlook, highlighting regulatory milestones for its lead candidate OST-HER2. The company outlined plans to submit a U.S. FDA Biologics License Application by late January 2026, UK and EU Marketing Authorisation Applications by late February and March 2026, and the release of Phase 2b biomarker data during the J.P. Morgan Healthcare Conference. These developments position OST-HER2 for potential accelerated approvals under the FDA’s Accelerated Approval Program and eligibility for a $160 million Priority Review Voucher if approved before September 30, 2026. Additionally, the company emphasized progress in its pipeline, including End of Phase 2 meetings for OST-503 and OST-504 programs, reinforcing investor confidence in its oncology platform. The positive momentum was overshadowed by a concurrent shareholder investigation, but the regulatory advancements and near-term catalysts drove the significant premarket rise.