OS Therapies (OSTX) investor relations material

Executive summary

• Focused on developing treatments for Osteosarcoma and other solid tumors, with OST-HER2 as the lead candidate showing positive Phase IIb results and ongoing regulatory submissions in the US, UK, EU, and Australia.

• Achieved significant clinical milestones, including strong two-year survival data, positive immune biomarker findings, and regulatory alignment with EMA and ATGA for OST-HER2.

• Submitted key clinical and biomarker data to FDA, advancing BLA preparations for OST-HER2, and initiated rolling review of conditional MAA with EMA.

• Engaged in multiple financing activities, including warrant inducement offerings, bridge financing, and registered direct offerings, raising over $11.2 million in Q1 and April 2026.

• Appointed Dr. Craig Eagle as Chief Medical Advisor and Dr. Robert Langer as strategic advisor.

Financial highlights

• Net loss for Q1 2026 was $10.4 million, compared to $3.9 million in Q1 2025, driven by increased R&D and regulatory expenses.

• Research and development expenses rose to $7.4 million from $1.3 million year-over-year, mainly due to regulatory and clinical trial costs.

• General and administrative expenses decreased to $2.8 million from $3.7 million year-over-year.

• Cash and cash equivalents as of March 31, 2026 were $0.9 million, up from $0.3 million at year-end 2025, with accrued $4.5 million in VAT refunds and R&D tax credits from the U.K. subsidiary.

• Financing activities provided $5.2 million in Q1 2026, primarily from warrant exercises and bridge financing.

Outlook and guidance

• Expects continued high expenses as regulatory submissions and confirmatory clinical studies progress, with cash runway now expected to extend into 2027 due to financings and U.K. tax credits.

• Anticipates BLA submission and potential FDA approval for OST-HER2 in 2026, with conditional marketing authorizations in Europe, U.K., and Australia.

• Upcoming milestones include release of 2.5- and 3-year overall survival data and initiation of Phase 3 trials.

• Management is actively seeking additional capital through equity or debt offerings.