Pilot study supports IV MSC therapy for canine osteoarthritis

Gallant reported new pilot data for an intravenous mesenchymal stromal cell therapy in dogs with osteoarthritis and said the program is now eligible for the FDA Center for Veterinary Medicine’s expanded conditional approval pathway, with a target of conditional approval in 2028.

The company announced the update alongside results from a randomized, blinded, placebo-controlled pilot study in 88 client-owned dogs with naturally occurring osteoarthritis. According to the company, the trial enrolled dogs with radiographically confirmed osteoarthritis and observable lameness or pain in at least 1 affected peripheral joint.

Dogs were randomly assigned to receive 2 intravenous injections, given 14 days apart, of either uterine-derived mesenchymal stromal cells (UMSCs) or saline placebo. Dogs were evaluated by both pet owners and veterinarians through day 90, which served as the primary efficacy endpoint.

Gallant stated that dogs treated with UMSCs showed statistically significant improvement vs placebo on validated pet parent-reported outcome measures at days 60 and 90. The company also reported that both owner and veterinarian assessments of mobility, quality of life, and pain consistently favored the treated group. The release did not provide effect sizes, confidence intervals, or detailed outcome data.

"In this pilot study, we're pleased to see that repeat IV dosing was well tolerated, with positive signals across key outcomes in dogs with osteoarthritis," said Rebecca Windsor, DVM, DACVIM, vice president of Veterinary Affairs at Gallant, in a news release. "By targeting the systemic and local immune dysregulation that precedes the progressive, degenerative changes of OA, MSC therapy has the potential to not only control clinical signs but also impact the course of disease."

For veterinarians, the most practice-relevant aspect of the program may be the delivery route. Gallant emphasized that its product is being developed as an off-the-shelf intravenous therapy, rather than an intra-articular treatment. According to the company, that approach could avoid the sedation or anesthesia, procedural training, and referral requirements often associated with joint injection–based cell therapies.

The company also reported no treatment-related serious adverse events in the pilot study, adding that the early findings support the safety of repeated dosing with donor-derived UMSCs.

Gallant said the FDA-CVM granted expanded conditional approval eligibility for both its canine and feline osteoarthritis programs. If the therapy advances through the pathway, it could reach market earlier than through a traditional full approval route, although the product remains investigational.

Osteoarthritis remains one of the most common chronic conditions in dogs. In the company’s release, Gallant cited prevalence estimates suggesting osteoarthritis affects more than 20% of dogs older than 1 year, 40% of dogs aged 4 years, and up to 80% of dogs older than 8 years.

Reference

Gallant advances canine osteoarthritis IV-delivered stem cell therapy with promising pilot data and expanded FDA conditional approval pathway eligibility. PR Newswire. May 6, 2026. Accessed May 7, 2026. https://www.prnewswire.com/news-releases/gallant-advances-canine-osteoarthritis-iv-delivered-stem-cell-therapy-with-promising-pilot-data-and-expanded-fda-conditional-approval-pathway-eligibility-302763756.html