Scientists develop new therapeutic antibody for dog cancers

Tokyo: Japanese researchers have developed an antibody that induces immune responses, which significantly suppresses malignant cancers in dogs as well as increases their survival rate.

As seen in humans, dogs too have malignant cancers that cannot be treated by existing therapies such as surgery, radiotherapy and chemotherapy. 

Oral malignant melanoma (OMM), a highly invasive cancer in dogs and account for 30-40 per cent of all oral tumours in dogs. 

They are seen along the gums, the lip, palate and sometimes the tongue. 

The newly developed chimeric anti-PD-L1 antibody was found to induce immune responses, thus causing tumour regression among dogs with malignant cancers.

"Chimerisation of the antibody is now proven as a simple and effective strategy to develop therapeutic antibodies in veterinary medicine," said lead author Satoru Konnai, professor at the Hokkaido University, Japan.

The researchers first revealed that PD-L1 is expressed in the cells of OMM and another type of cancer called undifferentiated sarcoma, confirming that these two cancers are likely targeted by the immunotherapy. 

Using a rat anti-PD-L1 antibody, they developed a rat-dog chimeric antibody. 

When this antibody was administered to dogs, their immune system received it well and lead to tumour regression. No allergic reaction was observed.

Moreover, the study, detailed in the journal Scientific Reports, suggested that the treatment may have prolonged survival in dogs.

"Although further clinical studies are needed, other PD-L1-positive cancers could be targeted by the antibody we have developed," Konnai said. 

"Given the similarity between humans and dogs in cancer biology, our study should provide a beneficial model for human preclinical studies."