Washington, D.C. - Former U.S. President Jimmy Carter credits the cancer drug Keytruda for making his brain tumors completely vanish. His stage four melanoma had spread throughout his body, but Keytruda helped the immune system to fight off tumors on its own.
“It’s as good of an outcome as someone with advanced melanoma can hope for,” said Deputy Chief Medical Officer for the American Cancer Society, Dr. Len Lichtenfeld.
Most immunotherapy drugs empower the body’s immune system to fight the cancer, but Keytruda gets in the way of tumors being resistant from immune cells. It targets PD-1 and PD-L1 because these genes can let some tumors get past the immune cells.
PD-1 stops immune cells from destroying healthy cells by accident. Tumor cells cause PD-L1 to turn on PD-1 when immune cells are encountered. However, Keytruda is an engineered immune protein that disrupts the interaction and allows the immune cells to destroy the tumors.
Carter’s most recent doctor’s appointment showed his tumors shrunk completely. “And when I went this week, they didn’t find any cancer at all, so I have good news,” Carter told his Sunday school class.
The U.S. Food and Drug Administration granted Keytruda accelerated approval due to a study that resulted in tumors shrinking in about one-third of patients by 90%. Dr. Antoni Ribas led the study and noted that 70% to 80% of patients whose tumors shrank are still getting smaller to this day.
“One hopes that by using immunotherapy the body can respond to whatever happens, but cancer cells are clever and can develop workarounds for the various treatments,” said Dr. Lichtenfeld.
It’s unclear if Keytruda got rid of Carter’s brain tumors or if his radiation and the removal of a large tumor on his liver helped, too.
“It’s always tough to label someone cancer-free because there may be cells that doctors haven’t detected, but it’s possible that removing the mass in his liver several months ago allowed his immune system—along with radiation and the drug Keytruda—to fights the four lesions in his brain.”
President Carter’s treatment success with Keytruda gives hope to other cancer patients too. The FDA granted accelerated approval to Keytruda for lung cancer and mesothelioma, as well as melanoma cancer. Like melanoma, some mesothelioma tumors express the PD-L1 protein, and early studies indicate a high success rate of tumors shrinking or tumor growth stopping after treatment with Keytruda.