New melanoma drugs effective at stalling cancer's spread, studies find

Dr. Jon LaPook speaks to Russ Mitchell about a cancer study that reveals two new drugs could boost survival for some patients with metastatic melanoma.
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(CBS News) Two promising new melanoma drugs are showing promise against the deadly disease in experimental trials, researchers announced at the American Society of Clinical Oncology's annual meeting in Chicago.

Typically, patients diagnosed with late-stage metastatic melanoma face a short life expectancy against the deadly form of cancer. One study of patients with advanced melanoma found GlaxoSmithKline's trametinib kept the disease from worsening longer than chemotherapy did. Trametinib is a targeted therapy that hones in on the cancer's specific genes and proteins that contribute to its growth.

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Last year, a drug Zelboraf was approved as a targeted melanoma therapy, HealthPopreported, that targets a mutant gene called BRAF that's found in about half of people with melanoma. Zelboraf eventually stops controlling melanoma growth though, so scientists have been looking at other treatment options.

Trametinib targets a protein called MEK in people with the BRAF gene which affects melanoma growth and a study found the drug stopped melanoma growth in 22 percent of patients taking it, compared with eight percent of patients taking chemotherapy. After six months, 81 percent of patients taking trametinib were living with the disease, compared with 67 percent of those who received chemotherapy. The drug looked so effective in the trial that the scientists stopped the experiment and switched the remaining patients to trametinib.

"In melanoma, we are living something incredible," study author Dr. Caroline Robert, head of dermatology at the Institute Gustave Roussy in Paris, told the New York Times of the new research. Robert, who is a paid consultant to Glaxo and other pharmaceutical companies, said trametinib is likely to become another first-line treatment option for patients with advanced melanoma. The findings were also published in the June 4 issue of the New England Journal of Medicine.

Another targeted melanoma therapy from GlaxoSmithkline, dabrafenib , was tested against chemotherapy among 345 patients with inoperable late-stage melanomas. Dabrafenib also targets the BRAF gene, and the researchers saw melanoma growth stopped for 50 percent of patients taking it, compared with in 6 percent of patients taking chemotherapy. They estimate it will take melanoma about two times longer for it to worsen in patients taking dabrafenib than it would for those on chemotherapy.

Dr. Axel Hauschild, a professor of dermatology at University Hospital in Kiel, Germany who led the study, told HealthDay the next step is to see if a combination of both dabrafenib and trametinib could help patients with BRAF-sensitive melanoma.

According to the New York Times, Glaxo plans to apply for approval of both drugs in the near future.

Besides Zelboraf, the other currently approved melanoma drug is Bristol-Myers Squibb' Yervoy, a treatment that gets the immune system to fight cancer.

The U.S. will have an estimated 76,000 new cases of melanoma this year, according to the National Cancer Institute, with 9,180 deaths.

The Mayo Clinic has more on melanoma.