FDA expands Merck drug’s approval to treat lung cancer

Pembrolizumab (Keytruda, Merck) is approved in conjunction with the PD-L1 IHC 22C3 pharmDx test, a companion diagnostic created to detect PD-L1 expression in NSCLC tumors. “This important news means that we now have a new immunotherapy option to help patients with squamous and non-squamous metastatic non-small cell lung cancer with disease progression on or after platinum-containing chemotherapy and whose tumors express PD-L1”.

The Food and Drug Administration approved Keytruda for advanced non-small cell lung cancer patients who have seen their tumors spread after taking other therapies. But it is expected that Opdivo will get approval for a broader label for second-line use, with FDA backing in all forms of the disease, regardless of whether patients test positive for the PDL1 biomarker targeted by the med. That would give Bristol-Myers’ candidate an edge.

The Keytruda approval is based on clinical trials that showed tumors shrank in 41 percent of patients, and the effect lasted between two and nine months.

Side effects of the drug include fatigue, shortness of breath as well as more severe problems involving the immune system in a few patients.

Pregnant women should not take Keytruda, which could harm a developing fetus, the agency warned.

Keytruda and another similar treatment from Bristol-Myers Squibb Co called Opdivo are created to block a protein called PD-1, whose natural function is to put checks on the immune system. NSCLC is the most common type of lung cancer.

Lung cancer is the leading cause of cancer death in the United States, with about 221,000 new cases and 158,000 deaths in 2015, according to the U.S. National Cancer Institute.

In a study Merck conducted, about 22 percent of lung cancer patients had significant levels of PD-L1, though it’s not yet definitively known how the levels might change over time, or if there’s a firm level of the protein below which drugs targeting the pathway won’t work.