Pharmaceutical subsidiary plans to become a public animal health company

OS Animal Health may soon stand on its own. A subsidiary of OS Therapeutics—a company known for Listeria-based oncology immunotherapies for humans—OS Animal Health intends to become a public company on the national stock exchange in 2026.¹

OS Animal Health is currently developing OST-HER2 for canine osteosarcoma. It uses the immune-stimulatory effects of Listeria to initiate a strong immune response targeting the HER2 protein.²

Initially developed by OS Therapies for treatment of osteosarcoma in humans, the drug has received conditional approval from the USDA canine use.^1,3 “The trials that we've done, both in humans and in canines, are very safe and seem to extend life and control the disease,” Paul Romness, MPH, chairman and CEO of OS Therapies, said in a dvm360 interview.² “The genetic makeup of osteosarcoma in canines and humans is like 99% exact.”

Relying on OST-HER2, Romness noted that OS Animal Health has worked to create a critical mass of industry leaders, regulatory experts, management candidates, potential investors and potential commercial manufacturers needed for the company to be successful as a standalone venture. "With a path forward for OST-HER2 in human osteosarcoma based upon the FDA's August 18, 2025, Draft Regulatory Guidance that outlines the importance of increasing overall survival as the overarching efficacy endpoint in oncology clinical trials, we believe it is now prudent to have a separately financed entity bringing the canine version of this product forward," he said in a news release.¹ “We have a high degree of confidence that USDA will allow OST-HER2 back on the market.”

According to Romness, osteosarcoma is very rare in humans but much more prevalent—and deadly—in canines. “In dogs, it's approaching 100% fatality within 12 months. In humans, 10% of the kids [with osteosarcoma] pass away. Of the 90% [of children] that survive the 9 months of chemotherapy, half of them go on to live their life with the side effects of chemotherapy and the surgery” he said.²

“There is significant interest and significant demand in the canine osteosarcoma market,” Gerald Commissiong, chief business officer for OS Therapies, said in a dvm360 interview. “OST-HER2 is a molecularly targeted therapy. So while it does have applications in osteosarcoma, because many osteosarcoma cases are HER2- positive, the reality is that many cancers beyond osteosarcoma are also HER2-positive. And so, as we think about how OST-HER2 could be used to treat osteosarcoma, but other canine cancers separately as well, there's an opportunity, once it's on the market, for veterinarians to explore the potential use of this and other indications….Additional research can be done to expand the potential uses.”

Logistics is also a consideration in transitioning OS Animal Health into a standalone company. The move will help OS Therapeutics focus on its primary mission developing human therapies, Romness said, while also responding to the needs of the veterinary market.

Commissiong noted that there is “a big distinction” between the regulatory processes for human and canine osteosarcoma products. “So, when we're producing a product for human osteosarcoma, it's got to be manufactured in an FDA certified facility, and those products cannot be used to treat animals. The animal biologic product must be manufactured in a USDA sanctioned facility. So that kind of product distinction is really at the core, because we can't manufacture in one facility and then service the other species,” he added.

Meanwhile, the science and research behind OST-HER2 was featured in the Emmy-nominated documentary Shelter Me: The Cancer Pioneers. The film shows veterinarians and other health experts from multiple academic and government institutions as they investigated comparative oncology.²

The documentary recently won an Anthem Award under the awareness category for health.^1,4 The Anthem Awards credited the impact of “highly engaged media and social media campaign” that supported the documentary’s broadcast, streaming, public screenings and panel discussions for building awareness about clinical trials and their importance for new cancer treatments.⁴

References

1. OS Therapies to spinoff OS Animal Health into standalone public company. News release. OS Therapies. November 20, 2025. Accessed November 20, 2025. https://ir.ostherapies.com/news-events/press-releases/detail/89/os-therapies-to-spinoff-os-animal-health-into-standalone
2. Crossley KC. Canine oncology drug featured in Emmy-nominated documentary. dvm360. October 20, 2025. Accessed November 20, 2025. https://www.dvm360.com/view/canine-oncology-drug-featured-in-emmy-nominated-documentary
3. Bautista-Alejandre A. New immunotherapy treatment may delay metastasis in dogs with osteosarcoma. dvm360. April 14, 2025. Accessed November 20, 2025. https://www.dvm360.com/view/new-immunotherapy-treatment-may-delay-metastasis-in-dogs-with-osteosarcoma#:~:text=2%20(HER2).-,1,2
4. Shelter Me: The Cancer Pioneers. Anthem Awards. Accessed November 20, 2025. https://www.anthemawards.com/winners/list/entry/#!health/documentary-or-film/shelter-me-the-cancer-pioneers/0/shelter/609668