A research group at Hokkaido University and Tohoku University revealed that radiotherapy before starting anti-PD-L1 antibody therapy, an immune checkpoint inhibitor, enhances the therapeutic effect in the treatment of canine malignant melanoma. bottom.
In human medicine, immunotherapy with immune checkpoint inhibitors has been reported to have good therapeutic results in various tumors including malignant melanoma and lung cancer.Recent clinical studies also suggest that a combination of radiation therapy and immune checkpoint inhibitors induces potent systemic anti-tumor immunity in cancer patients.
In dogs, the world's first immune checkpoint inhibitor for dogs (canine chimeric anti-PD-L1 antibody targeting PD-L1, one of the immune checkpoint molecules) developed by our group brings tumor regression. However, only a limited number of dogs have shown efficacy.Therefore, in this study, we investigated whether the combination of radiotherapy and anti-PD-L1 antibody would lead to better therapeutic effects in dogs with malignant melanoma. was analyzed retrospectively.
The subjects of analysis were 1 dogs that had been treated with anti-PD-L39 antibody so far, of which 20 dogs were in the "no RT group" with no effect of radiation therapy (RT), and anti-PD-L1 antibody treatment was started. We compared three groups: a "RT pretreatment group" of 9 dogs who had previously received radiotherapy, and a "RT simultaneous treatment group" of 1 dogs who received anti-PD-L3 antibody treatment and radiotherapy almost at the same time.
As a result, compared to the "no RT group", the "RT pretreatment group" had a significantly longer overall survival time from the start of anti-PD-L1 antibody treatment, and the rate of reduction and maintenance of lung metastases (clinical useful rate) was also significantly higher.On the other hand, the "RT simultaneous treatment group" was equivalent to the "non-RT group", and no statistically significant difference was observed.
From the above, it became clear that a better therapeutic effect may be obtained by applying radiotherapy before starting immune checkpoint inhibitors.The results of this research are expected to lead to the provision of new therapeutic methods for canine tumors, and to serve as therapeutic models for human tumors.
Paper information:[Cancers] Enhanced Systemic Antitumor Immunity by Hypofractionated Radiotherapy and Anti-PD-L1 Therapy in Dogs with Pulmonary Metastatic Oral Malignant Melanoma
