The US Food and Drug Administration (FDA) has approved Merck & Co.’s Keytruda (pembrolizumab) monotherapy, the company's anti-PD-1 (programmed death receptor-1) therapy, to treat a form of lung cancer. Specifically, the FDA approved the drug at a dose of 2 mg/kg every three weeks for treating patients with metastatic non-small cell lung cancer whose tumors express PD-L1 as determined by an FDA-approved test and who have disease progression on or after platinum-containing chemotherapy.

In parallel with the approval of Keytruda, the FDA has also given pre-market approval to the first predictive companion diagnostic for use in detecting PD-L1, an immune-related biomarker expressed on some tumor cells: the PD-L1 IHC 22C3 pharmDx kit made by Dako North America, Inc., part of Agilent Technologies.

Keytruda is an immunotherapy that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby helping the immune system to detect and fight cancer cells. Keytruda can also cause the immune system to attack normal organs and tissues.

Merck & Co.'s Keytruda is positioned as a potential blockbuster for Merck with 2019 projected sales of $3.466 billion, according to a recent Thomson Reuters analysis. Keytruda was approved in the US in 2014 for the treatment of patients with unresectable or metastatic melanoma and disease progression following ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor. In July 2015, the European Commission approved Keytruda for treating advanced (unresectable or metastatic) melanoma in adults.

Source: Merck & Co.