OS Therapies, Inc. (NYSE-A: OSTX) has announced a $6 million private placement to advance its lead therapeutic candidate, OST-HER2, for the treatment of recurrent, resected metastatic osteosarcoma. The financing, expected to close around December 27, 2024, will provide the company with sufficient capital to reach key clinical and regulatory milestones into 2026.
The private placement involves the sale of 1.5 million units at $4.00 per unit. Each unit comprises one share of Series A Senior Convertible Preferred Stock, convertible into one share of common stock, and one warrant to purchase one share of common stock. The conversion price for the preferred stock is $4.00, while the warrants are exercisable at $4.40 per share.
Funding Allocation and Clinical Milestones
OS Therapies intends to allocate the proceeds primarily towards working capital, focusing on the clinical and regulatory milestones necessary to support the commercialization of OST-HER2 in the United States by 2025. A significant near-term event is the anticipated announcement of Phase 2b data for OST-HER2 during the JP Morgan Healthcare Conference in January 2025.
Regulatory Designations and Market Opportunity
OST-HER2 has received rare pediatric disease, fast track, and orphan drug designations from the FDA. These designations can expedite the development and review process, potentially leading to faster approval and market exclusivity. Osteosarcoma, particularly in the recurrent setting, represents a high unmet medical need, with approximately 800-900 new patients diagnosed annually in the US.
OST-HER2: An Immunotherapeutic Approach
OST-HER2 is an immunotherapy that leverages Listeria bacteria to stimulate a strong immune response targeting the HER2 protein. The company has completed enrollment for a 41-patient Phase 2b clinical trial of OST-HER2 in resected, recurrent osteosarcoma, with results expected in the fourth quarter of 2024. OST-HER2 has completed a Phase 1 clinical study primarily in breast cancer patients, in addition to showing strong preclinical efficacy data in various models of breast cancer. OST-HER2 has been conditionally approved by the U.S. Department of Agriculture for the treatment of canines with osteosarcoma.
Tunable ADC Platform
OS Therapies is also advancing its next-generation Antibody Drug Conjugate (ADC) platform, known as tunable ADC (tADC), which features tunable, tailored antibody-linker-payload candidates. This platform leverages the Company’s proprietary silicone linker technology, enabling the delivery of multiple payloads per linker.
