(HealthDay News) — The first genetic marker to predict response to pembrolizumab (Keytruda) has been identified by researchers, according to findings published online May 30 in the New England Journal of Medicine to coincide with presentation at the annual meeting of the American Society of Clinical Oncology, held from May 29 to June 2 in Chicago.
The marker – mismatch repair (MMR) deficiency – predicted responses to the drug in patients with several different types of cancer, the study authors said. Among patients with colon cancer, 62% of those with MMR-deficient tumors showed response when taking pembrolizumab, compared with 0% in patients without this genetic signal. The overall response rate among patients with other MMR-deficient cancers was 60%. Responses were detected in patients with advanced endometrial cancer and several types of advanced gastrointestinal cancers.
“This study is really about bridging immunotherapy and genomics for the benefit of patients, and it has implications for a broad range of cancers,” lead author Dung Le, MD, said in a news release from the American Society of Clinical Oncology. Le is an assistant professor of oncology at the Johns Hopkins Kimmel Cancer Center in Baltimore.
Testing for MMR-deficiency is widely available and may help doctors identify a larger number of cancer patients who might benefit from pembrolizumab and similar drugs, the researchers said. “Opening the door to this effective new therapy would be a breakthrough for this subset of patients with metastatic colon cancer and other hard-to-treat cancers,” Le added.