Peer-reviewed veterinary case report
Anti-PD-1 antibody treatment for dogs with oral melanoma
By Igase, Masaya et al.·Published in Journal for immunotherapy of cancer·2026·Joint Faculty of Veterinary Medicine, Japan·View original on PubMed →
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Original publication title: Caninized PD-1 monoclonal antibody in oral malignant melanoma: efficacy and exploratory biomarker analysis.
- Species:
- dog
Plain-English summary
A group of 150 dogs with advanced oral malignant melanoma (a type of aggressive mouth cancer) received a new treatment called a caninized anti-PD-1 monoclonal antibody, given through an IV every two weeks. About 15% of the dogs showed a positive response to the treatment, and while some experienced mild to moderate side effects, the overall safety was manageable. Researchers found that certain blood markers could help predict how well the dogs would respond to the treatment and how long they might survive. This study suggests that this new therapy could be a promising option for dogs with this serious condition.
People also search for: dog oral melanoma treatment · canine cancer immunotherapy · symptoms of mouth cancer in dogs
Abstract
BACKGROUND: Canine oral malignant melanoma (OMM) is a highly aggressive tumor, with several available treatment options, though few achieve durable response or complete remission. Because of its biological similarity to human mucosal melanoma, canine OMM represents a valuable spontaneous model for translational immunotherapy studies. Anti-programmed cell death protein 1 (PD-1) antibody therapy has shown promise in canine OMM; however, predictive biomarkers for treatment response and survival have not been identified. METHODS: We conducted a multicenter, prospective, investigator-initiated clinical trial to evaluate the safety and efficacy of a caninized anti-canine PD-1 monoclonal antibody (ca-4F12-E6) in 150 dogs with advanced OMM. The dogs were administered 3 mg/kg ca-4F12-E6 intravenously every 2 weeks. Treatment response was assessed using cRECIST V.1.0. Biomarker analyses included peripheral blood parameters, cytokine/chemokines, peripheral lymphocyte subsets, microsatellite instability (MSI), immunohistochemistry for immune cell and mismatch repair protein markers, and RNA sequencing of the tumor tissue. Associations with clinical outcomes were determined by logistic regression and Cox proportional hazards models. RESULTS: The overall response rate was 14.7%, with a best overall response rate of 16.7%. Treatment-related adverse events occurred in 40.0% of the dogs, which were primarily grade 1-3. Increased baseline white blood cell, neutrophil count, and C reactive protein levels were significantly associated with poor response, shorter progression-free survival, and reduced overall survival (OS). MSI-high tumors were associated with significantly prolonged OS compared with MSI-low/microsatellite stable tumors. Transcriptome analysis revealed differentially expressed genes and enriched immune-related pathways in responders, though limited by sample size. CONCLUSION: ca-4F12-E6 exhibited durable antitumor activity with manageable safety profile in dogs with OMM. Baseline systemic inflammatory markers and MSI status may serve as predictive biomarkers for clinical outcomes. The results support the use of canine OMM as a comparative model for human immuno-oncology and biomarker discovery.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41571458/