Merck's immunotherapy Keytruda has picked up yet another regulatory approval - this time in the US as a treatment for head and neck cancer.

Keytruda (pembrolizumab) is a humanised monoclonal antibody that boosts the ability of the body's immune system to help detect and fight tumour cells, already approved in the US for melanoma or lung cancer.

After an accelerated review, the US Food and Drug Administration has now cleared the drug's use to treat patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy.

The decision is based on data from the Phase Ib KEYNOTE-012 study, which showed an objective response rate (ORR) of 16 percent, complete response rate of five percent, with responses of six months or longer observed in 82 percent of patients responding to treatment.

On the safety side, the firm noted that immune-mediated adverse reactions occurred with Keytruda including pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis. Based on the severity of the reaction, the drug should be withheld or discontinued and corticosteroids administered, the regulator noted.

"Head and neck cancer is a complex disease that historically has been associated with high recurrence rates and poor long-term outcomes, highlighting the critical need for new treatment options," noted Dr Tanguy Seiwert, associate director of the Head and Neck Cancer Program and assistant professor of medicine at The University of Chicago.

"The approval of Keytruda for previously treated patients with recurrent or metastatic head and neck squamous cell carcinoma is an important step forward in treating this disease."