OS Therapies Granted Patent for OST-HER2 Commercial Manufacturing
OS Therapies, Inc. (NYSE-A: OSTX), a clinical-stage biotechnology company focused on immunotherapies and targeted drug conjugates for cancer treatment, announced today that it has received a Notice of Allowance from the United States Patent & Trademark Office (USPTO) for a patent covering the manufacturing methods of its OST-HER2 commercial product. The patent includes a 572-day Patent Term Adjustment, ensuring market exclusivity for OST-HER2 until 2040.
The company is preparing to engage with the United States Food & Drug Administration (FDA) following the successful treatment phase of its Phase 2b clinical trial, which focuses on preventing recurrent, resected, lung metastatic osteosarcoma. OS Therapies aims to submit a Biologics Licensing Application (BLA) and seeks conditional or accelerated FDA approval by 2025. Additionally, OS Therapies recently completed a $7.1 million financing round in January 2025, providing sufficient capital through mid-2026.
OST-HER2 has received several important designations from the U.S. FDA, including Rare Pediatric Disease (RPDD), Fast-Track (FTD), and Orphan Drug (ODD) for the treatment of osteosarcoma. OS Therapies plans to focus on the following goals for the OST-HER2 program: (1) securing FDA BLA approval for OST-HER2 in osteosarcoma by late 2025, (2) selling the Priority Review Voucher (PRV) it will receive from the FDA approval before the September 30, 2026 deadline, likely to a larger pharmaceutical company at market prices (the most recent PRV sale was valued at $150 million), (3) commercializing OST-HER2 for osteosarcoma, and (4) expanding its clinical development into breast cancer and other solid tumor indications, offering additional revenue potential.
OST-HER2 has successfully completed a Phase 1 trial in adult patients with HER2-overexpressing cancers, including breast cancer. Preclinical studies in breast cancer showed promising results:
- A 78% reduction in tumor size in the FVB/N HER2 transgenic mouse model (3mm for OST-HER2-treated mice vs. 14mm for controls) at day 75
- A 33% prevention of breast cancer in OST-HER2-treated mice vs. 0% prevention in controls at week 50
- A 20% reduction in tumor size for OST-HER2 plus a HER2-targeted antibody, compared to the HER2-targeted antibody alone in a Tg tumor regression model at day 42
- A 65% reduction in metastatic cell concentration in the brain metastasis model of primary breast cancer
The osteosarcoma treatment market was valued at $1.2 billion in 2022 (Data Bridge Market Research), and OS Therapies estimates the market opportunity for OST-HER2 in preventing lung metastases in osteosarcoma to exceed $500 million. For breast cancer, the market was estimated at $29.2 billion in 2023 and is expected to grow to $53.7 billion by 2030 (Grandview Research). The company believes OST-HER2’s market potential in breast cancer treatment exceeds $1 billion.
About OS Therapies
OS Therapies is a clinical-stage oncology company dedicated to the development of treatments for osteosarcoma (OS) and other solid tumors. Its lead asset, OST-HER2, is an immunotherapy designed to leverage the immune-stimulatory effects of Listeria bacteria to initiate a strong immune response targeting the HER2 protein. OST-HER2 has received RPDD, FTD, and ODD designations from the U.S. FDA.
The company has completed enrollment in a 41-patient Phase 2b clinical trial of OST-HER2 for recurrent, fully resected, lung metastatic osteosarcoma, with positive results expected to be released in the first quarter of 2025. OS Therapies plans to submit a Biologics Licensing Application (BLA) to the U.S. FDA in 2025, with approval potentially granting eligibility for a Priority Review Voucher. OST-HER2 has also completed a Phase 1 clinical trial, primarily in breast cancer patients, and has shown strong preclinical efficacy data in various breast cancer models. Additionally, OST-HER2 has been conditionally approved by the U.S. Department of Agriculture for treating canines with osteosarcoma.
OS Therapies is also advancing its next-generation Antibody-Drug Conjugate (ADC) platform, known as tunable ADC (tADC). This platform utilizes proprietary silicone linker technology, allowing for the delivery of multiple payloads per linker and offering tailored, tunable antibody-linker-payload candidates for further cancer treatment opportunities.
