Feline chronic gingivostomatitis (FCGS) is a challenging disease with unknown exact causes and limited treatment options. The most effective treatment for FCGS is the extraction of the affected teeth. However, 79% of cats require additional drug treat...
Feline chronic gingivostomatitis (FCGS) is a challenging disease with unknown exact causes and limited treatment options. The most effective treatment for FCGS is the extraction of the affected teeth. However, 79% of cats require additional drug treatment for refractory FCGS even after extraction. We hypothesized that the combination of interferon-ω (IFN) and cyclosporine (CsA) would improve clinical outcomes. This study aimed to evaluate the efficacy of IFN and CsA in FCGS using stomatitis disease activity index (SDAI) scores and effectiveness of treatment (EOT) scores. The treatment process was divided into two stages. In the surgical stage (Stage 1), all cats underwent tooth extraction combined with submucosal IFN injection. In the immunomodulatory stage (Stage 2), additional IFN/CsA treatment was administered to cats with persistent lesions or clinical signs post-surgery. The therapeutic response was monitored throughout the treatment period using the SDAI scores. Additionally, EOT scores were assessed at the end of treatment, and the patients were classified into five groups according to their EOT scores: Group A (Surgical Remission), Group B (Complete Remission or Partial Remission), Group C (Transient Improvement), and Group D (No response). Patients achieving complete or partial remission were classified into Group A and B, making up 70.9% of all cases. Group C accounted for 27.5% of cases, while Group D accounted for 1.7%. In addition, SDAI scores showed statistically significant differences across prognostic groups at all timepoints. ROC analyses identified key SDAI thresholds for early classification: a T1 score cutoff of 6.5 and a T0–T1 score change cutoff of –14.5 effectively distinguished A group. Additionally, a T1–T3 score change cutoff of –7.5 moderately differentiated Group CR/PR from Group TI/NR. This study showed that the combination of IFN and CsA was effective for long-term control of refractory FCGS. It can be considered as a treatment alternative that may induce clinical improvement in patients with refractory stomatitis.