Cancer drug trial suggests combination therapy more effective against skin cancer

By Carolyn Y. Johnson, Globe Staff

Targeted drugs that cause tumors to dramatically melt away have provided powerful new weapons for doctors and patients against some cancers. But victories are almost inevitably short-lived, with the cancers growing back aggressively when the disease develops resistance to therapy.

Now, a study of 247 patients with the deadly skin cancer melanoma, led by oncologists at Massachusetts General Hospital, shows that launching a multipronged attack on a cancer may prolong patients’ responses.

In the study, published online by the New England Journal of Medicine, researchers gave melanoma patients whose tumors carried a particular genetic mutation a combination of two drugs: one that targeted the mutation and another that targeted the molecule that was activated by the mutated gene, which is called BRAF. They compared those patients with a group that received only the BRAF-targeted drug.

In the group given the drug combination, the cancers didn’t begin to grow again for 9.4 months, compared with less than six months before tumors began to progress in those who received only the single drug. The side effects were also reduced with the drug combination.

Already, one drug that targets the mutation in the BRAF gene, Roche’s vemurafenib, is approved. The GlaxoSmithKline drugs tested in this trial, dabrafenib and trametinib, are being considered for approval by the US Food and Drug Administration. Dr. Keith Flaherty, director of developmental therapeutics at Mass. General, said that a combination approach could change practice.

“If it were available, would I offer it to patients in place of BRAF therapy alone? Yes, absolutely,” Flaherty said. “If there were a greater toll to pay in terms of toxicity, I might say we need more evidence, to show it’s justified to put patients at greater risk. But because, if anything, the toxicities seem to be less ... because of that I’d say that’s an extra bonus.”