OS Therapies Gets EMA Rolling Review for OST-HER2, Forecasts $300M Peak Sales
EMA has initiated rolling review of OS Therapies’ OST-HER2 CMA to prevent recurrence in resected metastatic osteosarcoma, with ATGA aligning on 3-year overall survival as primary endpoint. The therapy received UK MHRA ATMP designation and forecasts peak European sales above $300 million, with Phase 3 confirmatory trial starting Q3 2026.
1. Rolling Review Initiation
EMA’s Committee for Advanced Therapy has begun a rolling review of the OST-HER2 conditional marketing authorization application for preventing recurrence in resected metastatic osteosarcoma.
2. Efficacy Endpoint Alignments
OS Therapies and regulators have agreed on 3-year overall survival as the primary efficacy endpoint and accepted seroconversion biomarker data as a surrogate to support early CMA decisions.
3. Regulatory Designations
OST-HER2 received Advanced Therapy Medicinal Product designation from the UK MHRA and was selected for EMA’s Raw Data Pilot programme, while Australia’s TGA has agreed to a provisional CMA pathway.
4. Commercial Outlook and Next Steps
OS Therapies forecasts peak European OST-HER2 sales exceeding $300 million, including over $50 million in 2027, and plans to launch its global confirmatory Phase 3 trial in Q3 2026 ahead of FDA and MHRA meetings in Q2.