Long term outcome of refractory cases of feline chronic gingivostomatitis treated with oromucosal application of recombinant feline interferon omega (rFeIFN-ω), preliminary results of a retrospective study from 2010 to 2024

Feline chronic gingivostomatitis (FCGS) is an immune-mediated debilitating chronic oral mucosal inflammatory disease in cats. Partial to full-mouth dental extractions remain the treatment of choice, improving quality of life in 60–70% of cases. Refractory cases showing little to no improvement following dental extractions may benefit from immunomodulatory therapy. Oromucosal recombinant feline interferon omega (rFeIFN-ω), cyclosporine, and mesenchymal stem cells have been studied and demonstrated clinical effectiveness. A study has reported the outcome of oromucosal rFeIFN-ω in 39 refractory cases.
This study aimed to assess whether previously reported response rates to oromucosal rFeIFN-ω (~45%) could be reproduced in a larger retrospective cohort of cats with refractory FCGS.
We reviewed the medical record of 162 cats diagnosed with refractory FCGS and treated with oromucosal rFeIFN-ω at our referral hospital between 2010 and 2024. They presented persistent clinical signs and oral lesions after extractions impairing quality of life, with dental radiographs confirming the absence of root remnants. Of the 162 cases identified, 94 were excluded due to deviation from protocol, use of forbidden treatments, or loss to follow-up before 3 months, resulting in a final cohort of 72 cats.
Collected data included age at treatment initiation, viral status (FCV, FHV, FeLV/FIV), pre-treatment bloodwork, and prior therapies. Clinical parameters such as pain-related signs, activity level, body weight, and diet changes potentially linked to oral discomfort were assessed at three time points: at the start and end of treatment, and during post-treatment follow-up. In addition, lesion characteristics — including type, anatomical location, and inflammation scores — were systematically evaluated at the same three time points to document the progression or resolution of the disease. A coding system developed for this study will be used to enhance the assessment of overall clinical outcome and support consistent inclusion or lesion characteristics in the statistical analysis.
Clinical remission was observed in 42% (30/72) of cats with complete outcome data, within 1 to 12 months. Among cats achieving remission, median treatment duration was 3.5 months, mean 4.0 months (range: 1–12). Thirteen cats were followed after the end of rFeIFN-ω treatment for 1 month to 4 years; one showed clinical relapse after one year.
These findings suggest that oromucosal rFeIFN-ω induces remission in a substantial proportion of refractory FCGS cases, with outcomes consistent with prior reports. Among this population, 50% achieved remission within 3.5 months. Ongoing statistical analysis will further assess the significance and predictive value of these outcomes.