Keytruda, the multi-indication oncology drug manufactured by US Merck & Co, has won approval from the Food and Drug Administration (FDA) for both monotherapy and combination therapy in previously untreated head and neck cancer.

With the green light, Keytruda becomes the first in its class of PD-1/PD-L1 drugs to be used in this indication.

The monotherapy indication covers patients whose tumors bear the biomarker PD-L1. In the combination variation it is matched with a commonly used chemotherapy regimen in patients, regardless of PD-L1 status.

The FDA’s green light follows a fast-track review agreed in February of this year after data from Phase 3 trials showed that, when compared with a certain standard treatment, Keytruda could lower the risk of death by 22% in PD-L1 positive patients.

When combined with a commonly used chemotherapy regimen, the Merck drug was shown to slash the risk of death by 23% regardless of patients’ PD-L1 status.

The US drugmaker said 65,000 patients with head and neck cancers could potentially profit from access to Keytruda

Merck’s new Keytruda indication puts it ahead of Bristol-Myers Squibb, whose Opdivo treatment is approved only for patients who have already failed on chemotherapy.

The trade journal Fierce Pharma points out that BMS has already ceded the lead in lung cancer, immuno-oncology’s most lucrative market, to Keytruda. In kidney cancer, an area historically important to Opdivo sales, Merck recently won approval for  competing combination treatment.