It’s been about six weeks since GlaxoSmithKline (NYSE:GSK) secured separate regulatory approvals on two new skin cancer drugs. Now GSK wants the Food and Drug Administration to approve the use of both drugs together.

GSK today submitted supplemental New Drug Applications to the FDA for the use of the drug dabrafenib in combination with trametinib to treat patients with the most advanced form of melanoma that cannot be removed by surgery.

The drugs, dabrafenib and trametinib, only work on patients who show a particular gene mutation on the BRAF gene. Dabrafenib is a BRAF inhibitor. Trametinib blocks the MEK protein. GSK’s submission requesting approval of the drug combination is not a surprise. Even when GSK studied the two compounds separately, the company also conducted studies of the drugs used together. GSK said that its drug applications are based on data from randomized phase I and II studies comparing dabrafenib alone to the combination of dabrafenib and trametinib in patients with the BRAF gene mutations for melanoma.

London-based GSK, which operates its U.S. headquarters in Research Triangle Park, received FDA approval on both dabrafenib and trametinib on May 29. Dabrafenib is now marketed as Tafinlar and trametinib is now called Mekinist. When the approval decisions were announced, the FDA made clear the approvals were for the use of the drugs separately and not in combination.

The dabrafenib/trametinib combination is not yet approved anywhere in the world, though GSK is also seeking approval in Europe for use of trametinib alone as well as together with dabrafenib. The two GSK cancer drugs are the latest in emerging personalized medicine treatments for cancer. Roche’s melanoma drug Zelboraf received FDA approval in 2011. Because these drugs work only on patients who have a particular genetic mutation, doctors make treatment decisions using a companion diagnostic that tests patients for the mutation.

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.