The U.S. Food and Drug Administration (FDA) has approved Merck’s Keytruda® (pembrolizumab) immunotherapy drug as a treatment for advanced non-small cell lung cancer (NSCLC) recently. Keytruda® is the second drug the FDA has approved for NSCLC patients this year. Earlier this year, the FDA expanded its approval for Opdivo, another immunotherapy drug used to treat advanced NSCLC.
Keyrtruda® is an immunotherapy drug that works by blocking the cellular pathway known as PD-1/PD-L1, which are the proteins found on the body’s immune cells and some cancer cells. By targeting the proteins, the body’s immune system can better fight the cancer.
This approval is great news for NSCLC patients, of course, but other patients in the cancer community are also celebrating Keytruda® approval. Mesothelioma, a rare cancer caused by asbestos exposure, can sometimes express a similar PD-1/PD-L1 protein (about 20-40% of mesothelioma tumors). This means the success of Keytruda® could lead to new and improved treatments for mesothelioma patients, and potentially other cancers as well.
In fact, Keytruda® received accelerated approval and is granted the ability to be used with a companion diagnostic test, the PD-L1 IHC 22C3 pharmDx test. This test is marketed by Dako North America Inc. and is the first of its kind that can detect PD-L1 expression in NSCLC—and hopefully mesothelioma cases as well.
“Today’s approval of Keytruda® is the result of our deep commitment to bring the benefits of immunotherapy to cancer patients,” said Dr. Roger M. Perlmutter, President of Merck Research Laboratories. “Together with scientists and physicians around the world, we endeavor to improve the lives of patients suffering from these grievous illnesses.”
“Our growing understanding of underlying molecular pathways and how our immune system interacts with cancer is leading to important advances in medicine,” said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.
From the beginning, Keytruda® had many positive results coming from its early clinical trials in treating lung cancer, melanoma, and mesothelioma. Approval of Keytruda® was granted for treatment of NSCLC (and melanoma) because Merck demonstrated evidence that the drug may offer a substantial improvement over other therapies currently on the market.
Even better, the results were so great that Keytruda® got “priority review status,” which is only given to drugs with the “potential to be a significant improvement in safety or effectiveness in the treatment of a serious condition.”
“Today’s approval of Keytruda® gives physicians the ability to target specific patients who may be most likely to benefit from this drug,” said Dr. Pazdur.
For mesothelioma patients treated with Keytruda® in a clinical trial, about every 3 out of 4 mesothelioma patients were helped, about half of the tumors stopped growing (48%), and about 1 in 4 mesotheliomas shrank at least 30%.
There is a follow up clinical trial recruiting for mesothelioma patients to be treated with Keytruda® occurring now.