OS Therapies (OSTX) Registration Filing summary

Company overview and business model

• Clinical-stage biopharmaceutical company focused on developing treatments for osteosarcoma and other solid tumors, with a mission to address unmet needs in pediatric and young adult bone cancers.

• Lead product candidate, OST-HER2, is a cancer immunotherapy targeting HER2, with positive Phase IIb results and orphan drug, rare pediatric disease, and fast track designations.

• Pipeline includes OST-tADC, a tunable antibody-drug conjugate platform in preclinical development, targeting multiple solid tumor indications.

• Growth strategies include potential out-licensing of OST-HER2 for veterinary use and evaluation of OST-HER2 in additional human and animal indications.

Financial performance and metrics

• Recent PIPE financing raised approximately $7.1 million in gross proceeds through the sale of Series A preferred stock and warrants.

• Warrant exercise inducement and exchange offer generated gross proceeds of approximately $4.2 million.

• As of August 7, 2025, 31,624,076 shares of common stock were outstanding, with additional shares issuable upon conversion of preferred stock, warrants, and options.

• Net tangible book value as of March 31, 2025 was $(0.20) per share; after the offering, as adjusted, it would be $0.47 per share, resulting in immediate dilution of $1.28 per share to new investors.

Use of proceeds and capital allocation

• Net proceeds from the offering will fund clinical development activities, including ongoing and planned trials, advance R&D programs, and support potential acquisitions or investments aligned with strategic objectives.

• Remaining proceeds may be used for working capital and general corporate purposes, with investments in short-term, investment-grade, interest-bearing securities pending use.