Merck & Co is planning to hand in US applications for two of its flagship medicines in cancer and hepatitis C during the first half of this year.

The US drugmaker said today it intends to file its first-in-class cancer immunotherapy Keytruda (pembrolizumab) for the treatment of non-small cell lung cancer patients (NSCLC) without ALK or EGFR mutations.

In September last year the drug became the first PD-1 inhibitor to win US Food and Drug Administration approval, as a treatment for advanced or unresectable melanoma.

The move sees the race to market heat up between Merck’s drug and Bristol-Myers Squibb’s rival PD-1 inhibitor Opdivo (nivolumab), which is also already on the market for melanoma and boasted a strong set of lung cancer data over the weekend.

B-MS said a key Phase III trial pitting Opdivo against the chemotherapy docetaxel in previously-treated patients with advanced, squamous cell NSCLC was stopped early after the drug demonstrated a significant survival benefit.

The company noted that this is the first time a survival advantage with an anti-PD1 immune checkpoint inhibitor in lung cancer has been indicated. But analysts still believe that Keytruda will initially pull in the lion’s share of sales, given that its label is expected to cover more patients on launch, according to media reports.

Meanwhile, Merck also revealed at the 33rd Annual JP Morgan Healthcare Conference that it is seeking US clearance for a once-daily combination of grazoprevir and elbasvir as a treatment for hepatitis C.