The U.S FDA approved Merck’s Keytruda (Pembrolizumab) to treat patients suffering with advance non-small cell lung cancer (NSCLC). This approval is limited to those patients for whom the cancer has continued to progress despite other NSCLC treatments. Keytruda is the first and only anti-PD1 therapy approved for both squamous and non-squamous metastatic NSCLC.
Keytruda belongs to the new class of cancer drugs called programmed T cell death 1 (PD-1) inhibitors. In a normal case, the protein PD-1 is used to suppress activity of T cells, which are responsible for the body’s immunity. This protects the body from autoimmune diseases where the body’s immune system attacks normal cells. However, some cancerous tumors cause PD-1 to be over-activated, which in turn suppresses the required T cell activity for destroying the tumor. PD-1 inhibitors work by targeting this pathway and preventing PD-1 from suppressing the body’s immune activity.