OS Therapies Initiates Commercial-Ready Manufacturing of OST-HER2 to Support Anticipated Biologics Licensing Application (BLA) Filing
OS Therapies, Inc. (NYSE-A: OSTX), a clinical-stage biotechnology company dedicated to advancing immunotherapies and targeted drug conjugates for the treatment of cancer, has announced a significant milestone in its development efforts. The company has formally entered into agreements to begin commercial-scale manufacturing of OST-HER2, its lead immunotherapeutic candidate. This strategic move positions OS Therapies to accelerate regulatory approval processes and eventual commercialization of OST-HER2, a novel treatment aimed at preventing the recurrence of lung metastatic osteosarcoma.
Advancing Towards Regulatory Approval
In parallel with the initiation of commercial manufacturing, OS Therapies is actively compiling additional clinical data following the completion of the treatment phase of its Phase 2b clinical trial for OST-HER2. The primary focus of this data collection is to support an upcoming meeting with the U.S. Food & Drug Administration (FDA). This engagement, which may take the form of either a Type B or Type C meeting, will provide an opportunity for OS Therapies to present its findings and discuss the pathway for regulatory approval.
The company anticipates that this regulatory dialogue will pave the way for the submission of a Biologics License Application (BLA) to the FDA. If granted, a BLA would allow OS Therapies to seek either accelerated or conditional approval for OST-HER2, expediting its availability to patients in need. Given the severity and rarity of osteosarcoma, regulatory bodies have historically been supportive of innovative therapies that address high unmet medical needs, potentially positioning OST-HER2 as a strong candidate for expedited review programs.
Significance of OST-HER2 in Cancer Treatment
OST-HER2 is an immunotherapy that harnesses the immune-stimulatory effects of Listeria bacteria to elicit a robust immune response against the HER2 protein. The HER2 protein is commonly expressed in various aggressive cancers, including breast cancer and osteosarcoma. By leveraging this mechanism, OST-HER2 aims to improve the body’s ability to recognize and eliminate HER2-expressing tumor cells, reducing the risk of recurrence.
The therapy has already received multiple regulatory designations from the FDA, including Rare Pediatric Disease, Fast Track, and Orphan Drug designations. These designations reflect the FDA’s recognition of OST-HER2’s potential to address a significant medical need in a patient population that has limited treatment options. Furthermore, these regulatory advantages may facilitate a smoother and faster approval process, making OST-HER2 available to patients sooner.
Progress of OST-HER2 Clinical Trials
OS Therapies has successfully completed patient enrollment in a 41-subject Phase 2b clinical trial investigating OST-HER2 in recurrent, fully resected lung metastatic osteosarcoma. The promising results from this study were released in the first quarter of 2025, providing critical evidence of the drug’s efficacy and safety profile. These findings will serve as the foundation for the forthcoming BLA submission.
Beyond osteosarcoma, OST-HER2 has demonstrated encouraging potential in other cancer types. The therapy has completed a Phase 1 clinical study in breast cancer patients, where it exhibited a favorable safety profile and preliminary signs of anti-tumor activity. Preclinical studies have further supported OST-HER2’s effectiveness in multiple breast cancer models, highlighting its broader therapeutic potential.
Additionally, OST-HER2 has received conditional approval from the U.S. Department of Agriculture for the treatment of canines with osteosarcoma. This unique regulatory approval underscores the therapy’s potential utility in veterinary oncology, expanding its impact beyond human medicine.
Commercial Manufacturing Strategy
The decision to initiate commercial-ready manufacturing reflects OS Therapies’ confidence in OST-HER2’s clinical success and regulatory prospects. Establishing a scalable manufacturing process is a critical step in preparing for market launch, ensuring that the company can meet anticipated demand upon regulatory approval.
Manufacturing biological therapeutics, such as OST-HER2, presents unique challenges due to the complexity of the production process. OS Therapies has partnered with leading contract manufacturing organizations (CMOs) to ensure that OST-HER2 is produced under stringent quality control standards that comply with FDA regulations. These partnerships will enable the company to streamline production, optimize costs, and accelerate time-to-market.
Potential Impact of a Biologics Licensing Application (BLA) Approval
If the FDA grants a Biologics License Application (BLA) for OST-HER2, OS Therapies could become eligible to receive a Priority Review Voucher (PRV). The PRV program incentivizes drug development for rare pediatric diseases by allowing companies to receive expedited FDA review for a future drug application or sell the voucher to another company. These vouchers have historically been sold for substantial financial returns, which could provide OS Therapies with additional resources to further advance its oncology pipeline.
Regulatory approval of OST-HER2 would mark a significant advancement in the treatment landscape for osteosarcoma, particularly for patients with recurrent lung metastatic disease. Current treatment options for osteosarcoma are limited, and recurrence presents a major challenge, often leading to poor prognosis. By offering a novel immunotherapy approach, OST-HER2 has the potential to transform treatment outcomes and improve survival rates in affected patients.
OS Therapies’ Broader Oncology Pipeline
Beyond OST-HER2, OS Therapies is actively developing its next-generation Antibody-Drug Conjugate (ADC) platform. This innovative platform, known as tunable ADC (tADC), is designed to enhance the precision and efficacy of targeted cancer therapies. Unlike traditional ADCs, which rely on a fixed linker-payload mechanism, OS Therapies’ tADC technology incorporates proprietary silicone linker technology. This novel approach allows for the delivery of multiple payloads per linker, offering greater flexibility and potency in targeting solid tumors.
The tADC platform represents a promising advancement in cancer therapy, with the potential to improve drug stability, reduce off-target toxicity, and enhance overall therapeutic efficacy. By leveraging this technology, OS Therapies aims to expand its portfolio of targeted therapies and address additional unmet needs in oncology
