OS Therapies Inc. (AMEX:OSTX) reported a larger third-quarter loss on Monday as the biotech moves into a heavier phase of regulatory preparation for its osteosarcoma therapy OST-HER2. The company posted a net loss of $0.21 per share for the period, widening from the $0.18 loss recorded a year earlier.
Shares fell 5.56% in pre-market trading following the update, as operating expenses accelerated sharply. The company reported an operating loss of $6.879 million, compared with $2.875 million in last year’s third quarter, largely reflecting upfront spending tied to regulatory and early commercialization work for OST-HER2. OS Therapies ended the quarter with $1.9 million in cash and later received an additional $1.5 million after quarter-end.
The company spotlighted new clinical data showing strong performance for OST-HER2. In patients with recurrent, fully resected pulmonary metastatic osteosarcoma, the treatment delivered a 2-year overall survival rate of 75%, compared with 40% for historical controls (p<0.0001). With pivotal regulatory milestones approaching, OS Therapies has set meetings with the FDA on December 11 and the UK’s MHRA on December 8, ahead of BLA and MAA submissions planned for January 2026.
Calling the coming period critical for the company, Chairman and CEO Paul Romness said, “The next six to twelve months will be transformative for OS Therapies. We expect to align on the expectations for our pending BLA for OST-HER2 under the Accelerated Approval Program at our December 11, 2025 FDA Type C Meeting.”
OS Therapies also recently completed a $7.8 million warrant exercise, which it says extends its cash runway into late 2026 by shifting the anticipated product launch into 2027. If its therapy is approved by September 30, 2026, the company would remain eligible for a Priority Review Voucher thanks to its Rare Pediatric Disease Designation.