OS Therapies (NYSE:OSTX) announced on Tuesday, March 31, 2026, that it has reached a pivotal regulatory milestone by submitting its Phase 2b clinical and biomarker data to the U.S. Food and Drug Administration (FDA) for a formal Pre-BLA (Biologics License Application) meeting.
The submission marks a critical step toward the company's goal of seeking Accelerated Approval in the United States and Conditional Marketing Authorizations (CMAs) in Europe and the United Kingdom during the second half of 2026.
The data package includes positive results for both Event-Free Survival (EFS) and Overall Survival (OS) from the company's Phase 2b study in osteosarcoma, a rare and aggressive bone cancer primarily affecting children and young adults.
Management indicated that the strength of the clinical signals and supporting biomarkers provides a robust foundation for the upcoming regulatory discussions.
Financially, OS Therapies reported a net operating loss of $28.75 million for the full year 2025.
The results reflect the significant investment required to advance its lead programs and the strategic acquisition of a listeria-based immunotherapy platform.
This platform acquisition is expected to provide a sustainable pipeline of candidates targeting various HER2-expressing solid tumors beyond the initial osteosarcoma indication.
In preparation for potential commercialization, the company has successfully extended its core patent protections through 2040, providing long-term exclusivity for its therapeutic approach.
Additionally, OS Therapies is finalizing plans to initiate a confirmatory Phase 3 clinical trial in Australia during the third quarter of 2026.
This trial is intended to serve as the post-marketing commitment required under the Accelerated Approval pathway.
Operationally, the company has focused on scaling its manufacturing and supply chain capabilities to support a potential global launch.