A Roche Holding AG subsidiary submitted a drug for treating people treating patients with an advanced form of skin cancer to U.S. regulators, the company said Monday, starting the process for potential approval of the therapy.

Genentech, Roche’s U.S.-based biotechnology subsidiary, said it had submitted a new drug application for its cobimetinib treatment to be used in combination with the existing Zelboraf treatment for patients with mutation-positive advanced melanoma.

Genentech made the submission on the basis of results of a Phase III study, the final stage of human testing, that showed patients who received the combined treatment lived longer without their disease worsening compared with Zelboraf alone.

Basel-based Roche acquired Genentech in 2009. The unit makes many of the Swiss company’s top-selling drugs, including a franchise of breast cancer therapies.

Melanoma is a rarer but more deadlier form of skin cancer which is likely to claim roughly 9,700 lives in the U.S. this year, according to the American Cancer Society. The disease accounts for less than 2 percent of skin cancer cases but causes most skin cancer deaths, the society said.

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