Related Experiment Video
Updated: Jul 27, 2025
Saline Lavage for Sampling of the Canine Nasal Immune Microenvironment
Published on: December 27, 2024
Enhanced Systemic Antitumour Immunity by Hypofractionated Radiotherapy and Anti-PD-L1 Therapy in Dogs with Pulmonary
Tatsuya Deguchi1, Naoya Maekawa2, Satoru Konnai2,3
1Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0819, Japan.
Abstract:
Although immune checkpoint inhibitors (ICIs), such as the anti-programmed death-ligand 1 (PD-L1) antibody, have been developed for the treatment of canine malignant melanoma, desirable clinical efficacies have not been achieved. Recent studies in humans have suggested that radiation therapy (RT) combined with ICIs induces robust systemic antitumour immunity in patients with cancer. This study retrospectively examined the therapeutic efficacy of combination therapy (hypofractionated RT and anti-PD-L1 antibody [c4G12]) in dogs with pulmonary metastatic oral malignant melanoma. The intrathoracic clinical benefit rate (CBR)/median overall survival (OS) in the no RT (n = 20, free from the effect of RT), previous RT (n = 9, received RT ≤8 weeks prior to the first c4G12 dose), and concurrent RT (n = 10, c4G12 therapy within ±1 week of the first RT fraction) groups were 10%/185 days, 55.6%/283.5 days (p < 0.05 vs. no RT group), and 20%/129 days (p > 0.05 vs. no RT group), respectively. The adverse events were considered to be tolerable in the combination therapy. Thus, hypofractionated RT before the initiation of c4G12 therapy can be an effective approach for enhancing the therapeutic efficacy of immunotherapy, with acceptable safety profiles. Further prospective clinical studies are required to confirm the findings of this study.
Insights
Combining radiation therapy (RT) with anti-PD-L1 antibody (c4G12) improved outcomes for dogs with melanoma. Pre-treatment with RT before immunotherapy showed enhanced clinical benefit and survival rates.
Area of Science:
- Veterinary Oncology
- Immunotherapy
- Radiation Oncology
Background:
- Immune checkpoint inhibitors (ICIs) like anti-PD-L1 antibodies have limited efficacy in canine malignant melanoma.
- Human studies suggest combining radiation therapy (RT) with ICIs enhances systemic anti-tumor immunity.
Purpose of the Study:
- To evaluate the therapeutic efficacy of combining hypofractionated RT with an anti-PD-L1 antibody (c4G12) in dogs with pulmonary metastatic oral malignant melanoma.
Main Methods:
- Retrospective study of dogs with metastatic oral malignant melanoma treated with c4G12.
- Analysis of clinical benefit rate (CBR) and overall survival (OS) in groups: no RT, previous RT, and concurrent RT with c4G12.
Main Results:
- The group receiving RT prior to c4G12 showed a significantly higher CBR (55.6%) and median OS (283.5 days) compared to the no RT group (10%/185 days).
- Concurrent RT with c4G12 did not improve outcomes compared to no RT.
- Adverse events were generally tolerable.
Conclusions:
- Hypofractionated RT administered before initiating anti-PD-L1 antibody therapy may enhance immunotherapy efficacy in canine malignant melanoma.
- This combination approach demonstrates acceptable safety.
- Further prospective studies are warranted to validate these findings.
