2 new drugs a 'major breakthrough' in treating deadly skin cancer

Two new drugs can significantly increase survival in patients with metastatic melanoma, the advanced and generally lethal form of skin cancer, researchers reported Sunday.

Results were so dramatic in a trial of one of the drugs that the study was halted early, researchers reported at a Chicago meeting of the American Society of Clinical Oncology. Studies on both drugs also were published online by the New England Journal of Medicine.

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The aborted trial is notable because the experimental agent called PLX4032, or vemurafenib, is the first chemotherapy agent that is directed at a specific mutation that is involved in the formation of skin tumors.

The development of the drug "is a major defining moment that will have an important effect on survival and quality of life," wrote Dr. Marc E. Ernstoff of the Dartmouth Medical School in Lebanon, N.H., in an editorial accompanying the report. But the mutation that is targeted by the drug occurs in only 47% of melanoma patients, and the drug appears to help only about half of them.

Many of the rest may benefit from the second drug, called ipilimumab, or Yervoy, which stimulates the immune system to fight off the tumors. Yervoy was approved by the Food and Drug Administration in March based on earlier results that showed it was more effective than a vaccine used to treat melanoma. The new findings reported Sunday showed that it also was better than the conventional chemotherapy.

The manufacturers of the two drugs are already planning trials to use both of the agents together to see if the combination can improve outcomes even more.

The new findings are "absolutely a major breakthrough for patients who have metastatic or unresectable melanoma," said Dr. Sylvia Adams, a melanoma immunotherapy expert at the New York University School of Medicine and a spokeswoman for ASCO.

The American Cancer Society estimates that about 68,000 new cases of melanoma are diagnosed in the United States each year, with 8,700 deaths. The incidence is increasing most rapidly among the elderly and among women ages 15 to 39, presumably because of excess exposure to ultraviolet radiation outdoors and in tanning salons. The conventional treatment now is with a drug called dacarbazine, which produces a median survival of 5.6 to 7.8 months after treatment is begun.

Vemurafenib targets the V600E mutation in a gene called BRAF, which is involved in cell growth. Small, early studies suggested the drug could be quite powerful.

In the new trial, a team headed by Dr. Paul Chapman of the Memorial Sloan-Kettering Cancer Center in New York enrolled 673 patients with the V600E mutation at 103 sites around the world. Half the patients took dacarbazine, and half were given vemurafenib.

At the first planned analysis at a median of three months, those receiving vemurafenib had a 73% reduction in progression of the disease and a 63% reduction in the risk of death. About 48.4% of the patients' tumors showed a response to the drug, compared with only a 5.5% response for dacarbazine.

The results were so powerful that the study's data-monitoring committee recommended halting the study and giving vemurafenib to all the patients.

The primary side effects were skin rashes, sensitivity to light and joint pain.

In the second study, a team led by Dr. Jedd Wolchok, also of Memorial Sloan-Kettering, enrolled 502 patients with metastatic melanoma who had never been treated before. Half received Yervoy plus dacarbazine, and half received dacarbazine and a placebo.

 After one year, 47.3% of patients who received the combination of drugs were still alive, compared with 36.3% of those receiving only dacarbazine. At two years, the figures were,to continue:http://www.latimes.com/health/la-he-melanoma-drugs-20110606,0,1330185.story