Gallant’s Off-the-Shelf Stem Cell Therapy Demonstrates Safety and Efficacy in Clinical Field Study
In a pivotal trial for refractory feline chronic gingivostomatitis, 79% of treated cats showed improved quality of life, with nearly half demonstrating measurable improvement in oral lesions and no treatment-related serious adverse events reported.
Feline chronic gingivostomatitis (FCGS) remains one of the most painful and challenging oral conditions to treat in small animal practice. Affecting an estimated 10% of cats worldwide1, this inflammatory disease with an immune-mediated component leads to severe ulcerative and proliferative lesions throughout the oral cavity and pharynx. Conventional management typically involves medical therapy and full-mouth or partial-mouth extractions (FME/PME). Despite aggressive intervention, a substantial number of cats fail to respond—resulting in what’s known as refractory FCGS.
Now, emerging research points to a regenerative breakthrough. A newly published clinical trial from Gallant offers compelling evidence that stem cell therapy may offer a long-term solution—by addressing FCGS at its source. The study, appearing in the Journal of Feline Medicine and Surgery2, reports that treatment with allogeneic, off-the-shelf uterine-derived mesenchymal stromal (i.e., stem) cells (UMSCs) led to clinically meaningful improvements in quality of life and oral healing in cats with refractory FCGS.
Investigation Methods
This 90-day prospective clinical trial was conducted across nine veterinary dental specialty centers in the United States under the supervision of board-certified veterinary dentists with expertise in managing FCGS. The study enrolled 46 client-owned cats diagnosed with refractory FCGS—defined as persistent clinical signs of FCGS at least two months following either full-mouth or partial-mouth dental extractions.
Each cat received two intravenous doses of 20 million UMSCs, administered 14 days apart. Following each administration, patients were monitored for 2 hours to assess for any adverse reactions.
The efficacy of the stem cell treatment was evaluated at Days 14 (prior to second dose), 28, 60, and 90 following treatment administration using three outcome measures:
- Client-Specific Outcome Measures (CSOM): change in owner-reported quality-of-life individualized daily activities (e.g., grooming, eating, social interaction).
- Overall Response Assessment (ORA): global owner impression of clinical response.
- Global Oral Lesion Score (GOLS): veterinarian-assessed mucosal healing.
General Improvements from the Early Stages
Early signs of clinical benefit were evident after just a single dose of stem cell therapy. By Day 14 following treatment administration, 52.3% of cats (23/44) demonstrated improvement in CSOM, reflecting gains in comfort and daily function. In addition, 25% (11/44) showed improvement in GOLS, indicating early tissue healing.
By Day 90 following treatment:
- 79% of cats (26/33) met the threshold for treatment success based on owner-reported quality-of-life outcomes (CSOM).
- 76% (25/33) were rated as improved by their owners (ORA).
- 45% (15/33) exhibited measurable improvement in oral lesions (GOLS).
No significant difference in treatment response was observed between cats that had undergone full-mouth extractions versus partial-mouth extractions, with both groups showing comparable outcomes across all measures. Cats treated within six months of their extractions demonstrated significantly greater improvement in oral lesion healing, suggesting that earlier intervention may enhance treatment effectiveness.
Safety Profile
Treatment with UMSCs was generally well-tolerated and most adverse events were mild and transient, including vomiting, anorexia, and hypersalivation. A total of six serious adverse events were reported during the study; all were deemed either unlikely or, in one case, inconclusively related to the UMSC therapy.
Routine clinical pathology parameters—including hematology, serum biochemistry, and urinalysis—remained stable throughout the study period, with no trends indicating systemic toxicity. Further research is needed to assess long-term healing and immune modulation mechanisms.
A Regenerative Shift in FCGS Treatment
Gallant’s clinical trial supports the safe and effective use of intravenous UMSC therapy in cats with refractory FCGS. Nearly 80% of treated cats showed meaningful improvement in quality of life and clinical condition by Day 90—many after just one dose. Earlier intervention appeared to enhance healing outcomes, highlighting the potential value of introducing stem cell therapy sooner in the treatment process.
The Gallant UMSC therapy for FCGS could reach the market in summer of 2026. It is currently progressing through the FDA approval process and has recently achieved “technical section complete” for reasonable expectation of effectiveness—a key milestone toward conditional approval. Available on demand and designed to be ready-to-use, the Gallant UMSC product will be delivered frozen and administered via intravenous injection after thawing. Pending FDA authorization, Gallant could deliver a new therapeutic category to veterinary medicine: an FDA-approved, disease-targeting drug that makes regenerative care accessible to all pets in need.
References
1. Soltero-Rivera M, Goldschmidt S, Arzi B. Feline chronic gingivostomatitis current concepts in clinical management. J Feline Med Surg. 2023;25(8):1098612X231186834. doi:10.1177/1098612X231186834
2. Williams V, Schneider JL, Parrish RS, et al. EXPRESS: Clinical field study evaluating the safety and efficacy of allogeneic uterine-derived mesenchymal stem cells for refractory feline chronic gingivostomatitis (FCGS). Journal of Feline Medicine and Surgery. 2025;0(ja). doi:10.1177/1098612X251385852
