US regulators have assigned a priority review to MSD’s application to market the immunotherapy Keytruda in combination with chemotherapy as a first-line treatment for squamous non-small cell lung cancer (NSCLC).

The application is based on data from the Phase III KEYNOTE-407 trial, in which Keytruda (pembrolizumab) plus chemotherapy cut the risk of death by 36 percent compared to chemotherapy alone, when used as a first-line treatment for patients with metastatic squamous NSCLC.

The addition of Keytruda to chemotherapy also significantly improved progression-free survival (PFS), with a reduction in the risk of disease progression or death of 44 percent, according to the results.

“Keytruda has already been established as an important treatment option for non-small cell lung cancer in the first-line setting, and with our broad development program in lung cancer, we are committed to improving survival for as many patients as we can,” said Dr Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories.

“We are pleased that our application for squamous cell carcinoma – a historically challenging-to-treat disease – is under priority review with the FDA.”

Keytruda is an anti-PD-1 therapy that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. The therapy is a humanised monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes.

The drug is already approved for various indications spanning lung cancer, head and neck cancer, classical hodgkin lymphoma, primary mediastinal large B-Cell lymphoma, urothelial carcinoma, microsatellite instability-high (MSI-H) cancer, gastric cancer, and cervical cancer.

In May the US Food and Drug Administration also agreed to undertake a priority review of Keytruda in combination with Eli Lilly's Alimta (pemetrexed) and platinum chemotherapy (carboplatin or cisplatin) as a first-line treatment for patients with metastatic non-squamous NSCLC.