OS Therapies Reports First Quarter 2026 Financials and Provides Business Update

$5.5 million financing that closed on April 2, 2026 together with $5.7 million in capital raised in Q1-2026, expected to provide Company with cash runway into 2027 $4.5 million of accrued VAT refunds and R&D refundable tax credits from UK subsidiary begin maturing, including $1.9 million VAT cash refund expected in June 2026 Successful EMA and Australia TGA (ATGA) meetings aligned around use of existing biomarker and pending release of 3-year overall survival data to support Conditional Marketing Authorisations (CMAs) for OST-HER2 in prevention or delay of recurrence in fully-resected, pulmonary metastatic osteosarcoma ("Metastatic Osteosarcoma") 2.5-year overall survival data expected to be released during ASCO 2026 EMA and ATGA have aligned on key design aspects of confirmatory Phase 3 Metastatic Osteosarcoma protocol required to have commenced prior to grant of CMAs or FDA BLA, including alignment on 3-year overall survival as a primary clinical efficacy endpoint Upcoming U.S. FDA Type C meeting and U.K. MHRA SAM meeting to align with EMA & ATGA prior to Australia Clinical Trial Notification submission for Phase 3, including alignment on 3-year overall survival as a primary clinical efficacy endpoint. U.S. FDA ("FDA") Pre-BLA meeting to confirm alignment on surrogate and primary clinical efficacy endpoints with EMA/ATGA, including alignment on 3-year overall survival as a primary clinical efficacy endpoint, and seek decisions on rolling review acceptance and RMAT designation following the EMA and U.K. MHRA granting ATMP designation (EMA/MHRA RMAT equivalent) for OST-HER2 in Metastatic Osteosarcoma OS Animal Health S-1 filing for proposed 'Go-Public' transaction and receipt of SEC comments New York, New York and Rockville, Maryland--(Newsfile Corp. - May 18, 2026) - OS Therapies, Inc. (NYSE American: OSTX) ("OS Therapies" or "the Company"), the world leader in gene-edited, listeria-based cancer immunotherapies, reported first quarter 2026 financial results and provided a business update centered on the Company's lead program for OST-HER2 in the prevention or delay of recurrence in fully-resected, pulmonary metastatic osteosarcoma ("Metastatic Osteosarcoma").