US regulators will undertake a speedy review of Merck & Co’s immunotherapy Keytruda as a first-line treatment for unresectable or metastatic melanoma.

Last September Keytruda (pembrolizumab) became the first PD-1 inhibitor to win US approval with a license to treat advanced melanoma following disease progression after therapy with Bristol-Myers Squibb’s Yervoy (ipilimumab) and, if BRAF V600 mutation positive, a BRAF inhibitor. 

Merck is seeking to expand the drug’s scope, and the US Food and Drug Administration said it will make a decision on first-line use by December 19. If positive, it would give patients much earlier access to the treatment.

The filing is partially based on data from the Phase III KEYNOTE-006 trial, which was stopped early after Keytruda showed a statistically significant and clinically meaningful improvement in overall survival and progression-free survival compared to Yervoy.

According to the results, one-year survival for Keytruda was 74% versus 58% for Yervoy, while the risk of death was cut by 37%, the drugmaker said.

Meanwhile, the regulator also said its action date on a separate application for use of Keytruda in patients with ipilimumab-refractory advanced melanoma has been extended until December 24, to allow full consideration of new data submitted by Merck.