OS Therapies (OSTX) investor relations material

Company overview and strategy

• Developing a Listeria-based oncology immunotherapy platform, primarily targeting HER2-expressing cancers.

• Lead program, OST-HER2, focuses on pediatric recurrent metastatic pulmonary osteosarcoma, an area with no approved therapies.

• Pipeline includes additional indications such as breast cancer and a tunable antibody-drug conjugate platform.

• Animal health spinout leverages the same technology, with conditional USDA approval for canine osteosarcoma.

• Strong management team with experience in major pharmaceutical companies and successful drug development.

Clinical and regulatory milestones

• Phase II-B data for OST-HER2 showed 36% event-free survival at 12 months and 75% overall survival at two years, both statistically significant improvements over historical controls.

• Achieved regulatory alignment with EMA and UK MHRA on endpoints; ongoing Type C meeting with FDA for further alignment.

• Plans to file for UK MHRA approval in January and for US BLA in Q1 2026, with potential approval within 3–6 months of filing.

• Eligible for a Priority Review Voucher upon US approval, which could be sold for upwards of $150 million.

Market opportunity and financial outlook

• HER2 platform targets multiple cancer types, with initial focus on rare pediatric osteosarcoma for expedited regulatory pathways.

• Canine osteosarcoma market is a billion-dollar industry, with prior licensing to Eli Lilly's animal health subsidiary.

• Company is funded through mid-to-late 2026; expects significant capital infusion from potential Priority Review Voucher sale.

• Recent increase in institutional investor participation, including Millennium, State Street, BlackRock, and Vanguard.

• OSTX shareholders will participate in equity of the animal health spinout, which plans to go public.