Researchers Uncover Major Clue In Predicting Response To Immunotherapy
Researchers at Memorial Sloan Kettering Cancer Center in New York have discovered that cancer cells with high numbers of faults in their DNA are more likely to respond to immune checkpoint inhibitors (ICI), a major class of immunotherapy drugs, which includes Keytruda. The study, published today in Nature Genetics adds important pieces to the puzzle as to why some cancer patients respond to immunotherapy whereas others do not. The researchers measured 'tumor mutation burden (TMB)', essentially counting how many DNA faults a tumor contains by looking for errors in the DNA sequence. "People assume that TMB is important in predicting response to immunotherapy in all cancers, but up until now, all we've had is data from small studies and clinical trials on mostly lung cancers and melanoma," said Luc Morris, MD, surgical oncologist at Memorial Sloan Kettering Cancer Center and one of the lead authors of the paper. The researchers studied the DNA of 1,662 patients with advanced cancer (classified as stage IV or metastatic disease) treated with one or more of several FDA-approved ICI drugs and DNA from 5,371 patients with advanced cancer who had not had ICI. They used a tool called MSK-IMPACT, which looks at just 3% of the coding-regions in DNA, but is correlated to the number of mutations in the genome. "Is TMB associated with likelihood that immunotherapy has benefit? Is this true in all cancers? We wanted to find out whether TMB had broad applicability," said Morris. The researchers found that if they took [...]