Immunotherapy drug approved by U.S. FDA

The U.S. Food and Drug Administration (FDA) expanded approval on Oct. 24 for breakthrough drug pembrolizumab, a first-line treatment for certain patients with metastatic non-small cell lung cancer (NSCLC).

Lung cancer is one of the deadliest cancers, according to The American Lung Association, and more than 158,000 people in the U.S. are predicted to die from lung cancer this year. More than half of those diagnosed with lung cancer will die within a year of their diagnosis. NSCLC, one of the two main types of lung cancers, accounts for 85 to 90 percent of all lung cancer diagnoses.

Traditionally, NSCLC patients would undergo chemotherapy, a treatment that involves a combination of powerful drugs that stop or slow the growth of cancer cells, which divide and grow at a fast rate.

However, since the drugs are nonspecific, healthy cells that divide relatively quickly — such as those in the intestine — may also get destroyed in the process. This could lead to side effects such as fatigue, pain, hair loss and blood disorders.

Pembrolizumab, marketed by Merck under the brand name Keytruda, has a different mechanism. It works by binding to programmed death 1 (PD-1) receptors on T cells, which blocks the PD-1 pathway and elicits an immune response.

In 2015, the FDA granted the drug accelerated approval as a treatment for those with NSCLC. The catch? Only patients who had undergone chemotherapy and expressed PD-L1 on at least 50 percent of their cancer cells were allowed to receive the drug. Now, patients who express PD-L1 on at least 50 percent of their cancer cells may be given pembrolizumab before chemotherapy.

“It is exciting to have an expanded group of patients who are now eligible for this drug,” Edward Garon, a cancer researcher at UCLA’s Jonsson Comprehensive Cancer Center whose clinical research helped lead to the FDA’s announcement, said in a press release. “What is particularly encouraging is that we are now able to select, based on features in the tumor, approximately a quarter of advanced lung cancer patients who can receive immunotherapy as their initial treatment. This will allow them to live longer while delaying, and in some cases potentially avoiding, the side effects of traditional chemotherapy.”

Currently, researchers are performing more experiments to determine if the drug has similar effects on patients with other types of cancers, as well as the efficacy of the drug when combined with other therapies.