OS Therapies will meet with the U.S. FDA, U.K. MHRA, European Medicines Agency and Australian TGA in Q2 2026 to review the design of its global confirmatory Phase 3 OST-HER2 trial for metastatic osteosarcoma. These meetings will cover trial endpoints, patient eligibility criteria and data package requirements ahead of initiation.

Enrollment for the Phase 3 study is slated to begin in Australia in Q3 2026. Initiating this trial is required for a Biologics License Application under the U.S. Accelerated Approval Program and Conditional Marketing Authorisations in the U.K. and Europe, both targeted for H2 2026.

OST-HER2 holds Orphan Drug, Fast Track and Rare Pediatric Disease designations from the FDA and ATMP status from the EMA. If approved, the U.S. BLA could earn a Priority Review Voucher valued around $205 million based on recent market transactions.