OS Therapies Targets September Approval for Osteosarcoma Drug with FDA Filing
Rockville, Tuesday, 3 February 2026.
The company initiated its regulatory filing for OST-HER2. Approval by September would secure a Priority Review Voucher, recently valued at $200 million, adding significant financial upside.
Race Against the Calendar
OS Therapies (OSTX) has formally commenced the regulatory review process for its lead immunotherapy candidate, OST-HER2, marking a critical operational pivot for the biopharmaceutical company. On February 2, 2026, the company announced the initiation of its Biologics License Application (BLA) submission to the U.S. Food and Drug Administration (FDA) [1]. While the announcement was made on Tuesday, the company officially submitted the Non-Clinical and Chemistry, Manufacturing, and Controls (CMC) modules on January 30, 2026, alongside a request for a Rolling Review [2]. This submission strategy is designed to expedite the evaluation of OST-HER2, a treatment aimed at preventing or delaying recurrent pulmonary metastatic osteosarcoma [1][2].
Strategic Timeline and Regulatory Milestones
The company has established a tight regulatory schedule to meet specific deadlines later this year. Following the initial filing of non-clinical components, OS Therapies plans to submit the final clinical module of the BLA by the end of March 2026 [1]. This submission is contingent upon an upcoming Type D Meeting with the FDA, also scheduled for March 2026, where the company will review Comparative Oncology biomarker data derived from both the OST-HER2 Phase 2b human clinical trial and canine studies [2]. To further support this expedited pathway, the company submitted an update to its Regenerative Medicine Advanced Therapy (RMAT) designation request on February 2, 2026, incorporating recent biomarker data to bolster the application [1].
The Multi-Million Dollar Incentive
Beyond the clinical imperative, a significant financial catalyst underpins the company’s aggressive timeline. OS Therapies is targeting a potential approval date by September 30, 2026 [2]. Meeting this deadline is crucial, as it would preserve the company’s eligibility for a Priority Review Voucher (PRV) under its Rare Pediatric Disease Designation (RPDD) [1]. These vouchers represent a transferable asset of considerable market value; in January 2026, a PRV was sold for $200 million [2]. For a company whose shares were trading at $1.36—approximately -24.862 percent below their 200-day moving average of $1.81—monetizing such an asset could provide a substantial non-dilutive capital infusion [2].
Addressing a Critical Unmet Need
The clinical urgency for OST-HER2 is driven by the lack of effective therapies for recurrent osteosarcoma, a bone cancer that often metastasizes to the lungs. Paul Romness, CEO of OS Therapies, emphasized the strong demand for compassionate use from the patient community, noting that this pressure underscores the “urgent need for new therapies in Human Metastatic Osteosarcoma” [1]. The drug has already received multiple regulatory nods, including Orphan Disease Designation and Fast Track Designation from the FDA, highlighting the agency’s recognition of the condition’s severity [2]. As the company moves toward the finalization of its biomarker data package for the Type D meeting, the focus remains on securing approval under the Accelerated Approval Program to bring the treatment to market efficiently [1].
Summary
OS Therapies has initiated a rolling BLA submission for OST-HER2, aiming for an FDA decision by September 30, 2026. This timeline is strategically aligned to secure a Priority Review Voucher, an asset recently valued at $200 million, which would offer significant financial leverage for the company. With the initial non-clinical modules filed and a critical meeting regarding clinical data set for March, the coming months will be pivotal in determining both the regulatory and financial future of the program.