Weekly Vet Report: Feline OA stem cell therapy, PFAS in dolphin milk, & more

In this week’s Vet Report, we cover a new regenerative treatment option for cats with osteoarthritis, a new mastitis vaccine launching on the European veterinary market, and a new study that detected PFAS in dolphin milk.

A new approach to feline osteoarthritis

A stem cell therapy for feline osteoarthritis (OA) has reached a key regulatory milestone, and unlike most existing treatments, the treatment works by modulating the immune response.

Gallant, an animal health biotechnology company, has received eligibility for the FDA's expanded conditional approval pathway for its intravenous stem cell therapy for feline OA.¹ The pathway offers a faster route to market for products addressing a significant unmet medical need.

In a pilot study across six US clinics, 76.2% of treated cats showed meaningful improvement in quality of life at 90 days, compared to 36.4% in the placebo group. Unlike most existing treatments, which work by blocking pain signals, this therapy works by addressing the immune response. In an earlier interview with dvm360, Rebecca Windsor, DVM, DACVIM (Neurology), vice president of veterinary affairs at Gallant, described it this way: "Stem cells...start working immediately to reduce that systemic inflammation...and release cytokines, growth factors, exosomes — all things that can help rebalance the immune system to make it less inflammatory."

That mechanism may be particularly relevant here, as research suggests feline OA has an immune-mediated component to its onset and progression.

The cells are donor-derived, sourced from uterine tissue collected from healthy animals already scheduled to be spayed, and designed to be off-the-shelf, meaning it would be available on demand, with no tissue harvested from the patient. OA affects an estimated 45% of all cats, and up to 90% of cats over the age of 12.

A mastitis vaccine launches in Europe

A new mastitis vaccine is entering the European market. Boehringer Ingelheim's Lenzelta targets two of the most common mastitis-causing pathogens — Staph aureus and E. coli — and is administered in two doses during the dry-off period, covering the window when cows are most vulnerable.² It offers up to six months of protection and is designed to integrate into existing herd health routines. No US approval has been announced.

"Forever chemicals" found in dolphin milk

A new study is raising questions about PFAS, commonly known as "forever chemicals,” in marine mammals. Researchers from the University of North Carolina at Chapel Hill, Texas A&M, and the Smithsonian's National Zoo and Conservation Biology Institute detected PFAS in archived dolphin milk samples at concentrations considered potentially concerning based on human health data.³

Weihsueh Chiu, PhD, MA, AB, a professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences, noted that in humans, PFAS exposure poses an immunotoxicity concern, with the potential to suppress the immune system.³ PFAS are widely used in household and industrial applications, including nonstick cookware, stain-resistant fabrics, food packaging, and firefighting foams, and resist natural degradation. Emerging research suggests similar effects may occur in animals, though the clinical significance in companion animals is still being defined.

The findings add to a growing body of evidence that these persistent chemicals move through biological systems, from mothers to nursing offspring, across species, and may offer insight into widespread environmental contamination. A full article on this study and its implications in animal health is coming next week on dvm360.

References

1. Bautista-Alejandre A. Ready-to-use feline OA stem cell therapy gains entry to FDA’s faster conditional approval pathway. dvm360. April 15, 2026. Accessed April 17, 2026. https://www.dvm360.com/view/ready-to-use-feline-oa-stem-cell-therapy-gains-entry-to-fda-s-faster-conditional-approval-pathway
2. Coppock Crossley K. Vaccine for mastitis prevention is launching in the EU. dvm360. April 13, 2026. Accessed April 17, 2026. https://www.dvm360.com/view/vaccine-for-mastitis-prevention-is-launching-in-the-eu
3. Haines C. ‘Forever Chemicals’ Detected In Dolphin Milk, Study By Texas A&M Superfund Center Shows. Texas A&M University. April 14, 2026. Accessed April 17, 2026. https://vetmed.tamu.edu/news/press-releases/pfas-dolphin-milk-texas-am-study/