Merck is first to cross the US regulatory finish line for PD-1 inhibitors. The FDA approved the drug previously known as pembrolizumab, now known as Keytruda, for patients with unresectable or metastatic melanoma who have already taken Bristol-Myers Squibb’s Yervoy (ipilimumab).

The FDA says melanoma accounts for around 5% of all new cancers diagnosed in the US. Merck’s new drug is the sixth new melanoma treatment the regulator has approved since 2011, but this approval is a breakout for a drug class that has become a magnet for industry watchers. Multiple manufacturers are banking on immuno-oncology treatments, including AstraZeneca, Bristol-Myers and Roche.

The Street’s Adam Feuerstein tweeted that a Merck spokesperson priced the new drug at $12,500 a month. A typical treatment will last 6.2 months.