The agency granted Keytruda priority review status with a target action date of 9 August 2016.
Keytruda was approved in 2014 to treat melanoma. In October 2015, it was cleared for use in patients with metastatic non-small cell lung cancer whose tumors express PD-L1 with disease progression on or after platinum-containing chemotherapy.
Merck is now seeking approval for the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma with disease progression on or after platinum-containing chemotherapy.
For this indication, Keytruda will be used as a single agent at a dose of 200 mg administered intravenously every three weeks.
Merck Research Laboratories senior vice president and therapeutic area head, oncology late-stage development Roger Dansey said: "Starting in the early days of our development program, we have explored the role of Keytruda for patients with head and neck cancer, a difficult-to-treat and debilitating disease with very few treatment options.
"We are encouraged by the data emerging from our program in this type of cancer, and welcome today’s news as this is an important step toward making Keytruda available to these patients."
Keytruda helps the immune system fight tumor cells by blocking the interaction between PD-1, a cell surface receptor on T cells and pro-B cells, and its ligands PD-L1 and PD-L2.
Keytruda is indicated in the US to treat patients with unresectable or metastatic melanoma.
Image: Keytruda was approved in 2014 to treat melanoma. Photo: courtesy of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, N.J., U.S.A.