New Drug May Treat Advanced Melanoma
No Cure, but Study Shows New Melanoma Drug Far Better Than Standard Treatment
Aug. 25, 2010 -- It's no cure, and it works only for about half of melanoma patients, but a new drug extends progression-free survival in patients dying of advanced melanoma.
The vast majority of patients with advanced, metastatic melanoma gain only a few months extra survival from standard treatment. But early tests show that an experimental drug, dubbed PLX4032 by Plexxikon and Roche Pharmaceuticals, offers far greater benefits.
The findings are particularly amazing as they come from a very early, phase I clinical trial. Study leader Keith T. Flaherty, MD, is director of developmental therapeutics at Massachusetts General Hospital.
"For those who respond to treatment, the average duration of progression-free survival is nine months," Flaherty tells WebMD. "Some patients are over a year and a half and cruising to two years. In melanoma, that is good. ... The average time for standard treatment is two months."
There is a catch. The drug targets a specific genetic mutation that helps melanoma tumor cells grow. Some 40% to 60% of melanoma patients have tumors with this mutation.
For those who don't, the drug offers no help and possible harm. Fortunately, a simple genetic test identifies patients likely to respond to the drug.
In its initial phase, the study enrolled 55 patients, 49 with metastatic melanoma. An additional 32 patients with metastatic melanoma enrolled in the study's extension phase. All patients carried the BRAF mutation targeted by the new drug.
The result: 81% of patients with BRAF-positive melanoma responded to treatment. Duration of response ranged from two to over 18 months. Three of the melanoma patients no longer had detectable tumor in their bodies, although Flaherty says such "complete responses" are not the same as cures.
"These results represent a major breakthrough," write Keiran S.M. Smalley, PhD, and Vernon K. Sondak, MD, of Tampa's Moffitt Cancer Center in an editorial that accompanies the Flaherty team's report in the Aug. 26 issue of the New England Journal of Medicine. Smalley and Sondak were not involved in the Flaherty study.
The drug "seems to be extremely effective and causes a very high response rate that happens pretty quickly," Sondak tells WebMD. "It can cause improvement even in people who failed standard treatments. It shows a benefit even in patients with tumors in their livers and other places where traditional treatment bogs down a lot."