The U.S. Food and drug Administration (FDA) signalled a go ahead to Roche's Cotellic drug to be used in combination with the company's Zelboraf for treatment of melanoma.

The combination therapy approved Tuesday is intended to help patients with an advanced form of melanoma that has spread to other body parts and to treat BRAF V600E or V600K mutation-positive advanced melanoma.

The Reuters reported that Roche is backing up on Cotellic to revive the dropping sales of its five-year-old drug Zelboraf. The latter's sale dropped by 25 percent during the first three quarters of 2015. The drug is facing a fierce competition from its rival drugs, who have largely moved their standard care to combination therapy.

Cotellic prevents or slows down cancer growth by blocking the activity of an enzyme called MEK, which is a part of the larger signalling pathway. On the other hand, Zelboraf is a BRAF inhibitor that affects some other part of the same pathway. The FDA has cautioned that a physician should confirm the presence of a BRAF V600 E or V600K in their patients before starting the combination therapy of Cotellic with Zelboraf.

“As we continue to advance our knowledge of tumor biology, we have learned that cancer cells have a remarkable ability to adapt and become resistant to targeted therapies. Combining two or more treatments addressing different cancer-causing targets may help to address this challenge,” said Richard Pazdur of the FDA’s Center for Drug Evaluation and Research, in an FDA press release.

Pazdur further said that the combination therapy seems to work better than Zelboraf alone in patients with BRAF mutation-positive melanoma.