EXPRESS: Clinical field study evaluating the safety and efficacy of allogeneic uterine-derived mesenchymal stem cells for refractory feline chronic gingivostomatitis (FCGS).

ObjectivesThe study evaluated the safety and efficacy of intravenous, allogeneic uterine-derived mesenchymal stem cells (UMSCs) for client-owned cats with refractory feline chronic gingivostomatitis (FCGS).MethodsThis was a 90-day prospective, multi-site, baseline-controlled, clinical trial involving 46 cats with refractory FCGS following partial- or full-mouth extractions. Cats received two doses of 20 million UMSCs, 14 days apart. Effectiveness was evaluated at Days 14, 28, 60 and 90 using owner-reported assessment of overall response (ORA), client-specific outcome measures (CSOM) of quality-of-life improvement and veterinarian-assessed oral lesion score (GOLS) tissue healing. Safety assessments included clinical observations and clinical pathology.ResultsTreatment success rates at Day 28, 60 and 90 were: 61.4% (27/44), 76.3% (29/38), 78.8% (26/33) for CSOM; 65.9% (29/44), 73.7% (28/38), 75.8% (25/33) for ORA; and 31.8% (13/44), 47.5% (18/38), 45.4% (15/33) for GOLS. CSOM and GOLS at Day 14 following a single dose were 52.3% (23/44) and 25.0% (11/44), respectively. Cats treated within six months of tooth extraction had greater improvement in GOLS. There were no statistically significant differences in outcomes between cats with partial- or full-mouth extractions. Adverse events were generally mild and transient, with most related to underlying disease. All six serious adverse events were either unlikely or in one case inconclusively attributed to UMSC therapy.Conclusions and relevanceRepeated intravenous UMSC therapy was well tolerated and demonstrated clinically meaningful improvement in quality-of-life in cats with refractory FCGS within two weeks of treatment. Additionally, oral lesions continued to improve over time. These results support the safe and effective use of UMSCs for this life-threatening condition.