Meet OS Therapies: Fly exclusive interview with CEO Paul Romness

In an exclusive interview, OS Therapies’ (OSTX) CEO Paul Romness met with The Fly to discuss the company, its pipeline, next-generation cancer treatments, and much more.

COMMERCIAL BIOTECH SOON: OS Therapies is a clinical stage cancer immunotherapy company developing new treatments for Osteosarcoma and other solid tumors. “We hope to be a commercial biotech company at some point in early 2026 with the approval of our first drug, which would be OST-HER2. We do not have a brand name for it yet, but we will soon,” CEO Paul Romness explained to The Fly.

“I think the technology was once very much loved and cherished by Wall Street, but it got a little lost,” OS Therapies told The Fly. The focus of the company was not picked randomly. CEO Paul Romness has a personal connection to it through his daughter’s best friend. “By going towards a pediatric disease, you can get through the clinical trials faster. FDA is looking for new treatments, especially in osteosarcoma because nothing new in 40 years. The current treatment is extremely toxic, with 10% of the kids passing away from the chemotherapy alone. So going after a rare disease, getting the priority review voucher and then our ability to pivot to other solid tumors has a huge upside potential.”

OSTEOSARCOMA: Late last month, OS Therapies announced that it received written feedback from the United States Food and Drug Administration Type D Meeting that occurred in mid-June 2025 regarding endpoints required to support an accelerated approval program marketing application for its Phase 2b trial of OST-HER2 in the prevention or delay of recurrence in fully resected, pediatric lung metastatic osteosarcoma. “Osteosarcoma is a very deadly bone cancer, and this would be the first new treatment in over four years, and the FDA is very supportive of rare and pediatric diseases, with significant numbers of approval–I think 60 approvals last year of single arm Phase 1/Phase 2 trials. The current FDA has shown a great deal of interest in supporting pediatric cancer but if we do get approval, we will receive what’s called a priority review voucher, or PRV, and those have a market of at least $160M,” the executive said.

A few days later, OS Therapies OS Therapies announced it was granted an End of Phase 2 Meeting by the FDA to review the OST-HER2 program in the prevention or delay of recurrent, fully resected, pulmonary metastatic osteosarcoma. The company expects the meeting to occur in the third quarter of 2025. The End of Phase 2 Meeting marks a pivotal point in the drug development process, and a significant milestone towards market access, the company said. OS Therapies intends to seek alignment with FDA to begin a Rolling Review process for the forthcoming Biologics Licensing Application submission for OST-HER2.

NEXT-GEN CANCER TREATMENTS: OS Therapies is not just addressing Osteosarcoma. “With the other uses of our HER2 target cancer immunotherapy and the addition of our OST-tADC tunable Antibody Drug Conjugate silicone linker platform, we are paving the way for the next-generation of cancer treatments,” the company said.

“There are two really hot subjects in biotech right now. One is ADCs (antibody drug conjugates) and we do have an early stage or antibody drug conjugate platform. But much more on the forefront is immunotherapy and there are some immunotherapy products out there right now. We still have a lot of challenges in solid tumor. We believe that if our OST works in Osteosarcoma, which is considered one of the toughest cancers out there– that and Glioblastoma, we can pivot then to other solid tumors like breast cancer and colorectal cancer,” Romness told The Fly.

UPCOMING EVENTS: Discussing near- and medium-term milestones, OS Therapies CEO said, “There will be milestones between now and a potential FDA approval, but obviously FDA approval and then that priority review voucher–which we intend to sell immediately—are really the key to the stock in the short term.”

Meet the Company” is The Fly’s recurring series of exclusive short interviews with Executive Officers to offer a deeper look inside the company.