GlaxoSmithKline today received Food and Drug Administration approval on two drugs intended to treat the most advanced form of skin cancer that can’t be removed by surgery.

In gaining regulatory approval on Tafinlar and Mekinist, GSK also gets steps into the arena for personalized medicine skin cancer therapies, territory already staked out by Roche. Like Roche’s Zelboraf, GSK’s two new skin cancer drugs will be administered only to patients that have a particular gene mutation showing that the drug will work for them.

A genetic test will show whether the GSK’s cancer drugs will work on the skin cancer. Along with approving Tafinlar and Mekinist, the FDA also gave marketing approval for a companion diagnostic, a genetic test called the THxID BRAF test.

Tafinlar is approved to treat melanoma patients whose tumors express the BRAF V600E gene mutation. Mekinist is approved to treat patients whose tumors express the BRAF V600E or V600K gene mutations. The FDA approved the two drugs separately and not as a combination therapy. But the genetic test that the FDA also approved will test for both gene mutations.

Melanoma is the leading cause of death from skin disease. The National Cancer Institute estimates 76,690 Americans will be diagnosed with melanoma and 9,480 will die from the disease in 2013.

“Advancements in our understanding of the biological pathways of a disease have allowed for the development of Tafinlar and Mekinist, the third and fourth drugs the FDA has approved for treating metastatic melanoma in the past two years,” Dr. Richard Pazdur director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research said in a statement.

Besides Roche’s Zelboraf, Bristol-Myers Squibb’s Yervoy was approved in 2011 for the treatment of metastatic or unresectable melanoma. Zelboraf generated $250 million in revenue last year for Roche, according to data compiled by Bloomberg.

Tafinlar may produce $279 million in sales in 2016 while Mekinist may generate $343 million, according to the average of eight analysts’ estimates compiled by Bloomberg. The drugs are among six new medicines GSK was counting on to gain U.S. regulatory approval this year.

While Tafinlar and Mekinist were approved separately, taken together the drugs delayed tumor progression 9.4 months compared with 5.8 months for patients taking Tafinlar alone, according data released last year by GSK. The company hasn’t submitted the combination data to the FDA, Melinda Stubbee, a GSK spokeswoman, told Bloomberg. Roche is also studying a similar combination.

The most serious side effects reported in patients who took Tafinlar in clinical trials included an increased risk of skin cancer, fevers complicated by low blood pressure and kidney failure. Those who took Mekinist reported serious side effects including heart failure and loss of vision.

The FDA approvals today are big wins for GSK and bioMerieux, two companies that have major operations in the Triangle. London-based GSK maintains its U.S. headquarters in Research Triangle Park. BioMerieux, based in France, operates its U.S. headquarters in Durham.