Melanoma Drug Trials Show Significant Promise
By targeting immune system, new treatments extend average survival
By Dennis Thompson
MONDAY, June 2, 2014 (HealthDay News) -- A relatively new drug appears effective in boosting survival for patients battling advanced melanoma, the deadliest form of skin cancer, according to a pair of preliminary studies.
The drug Yervoy (ipilimumab) "takes the brakes off the immune system," improving the body's ability to target and attack melanoma, said Dr. Philip Friedlander, a medical oncologist at Icahn School of Medicine at Mount Sinai, in New York City.
The two trials report that Yervoy can dramatically extend survival for patients with stage 3 and stage 4 melanoma, adding months and years to their lives both on its own and in combination with another cancer drug.
"It's a major breakthrough," Friedlander said of the medication, which the Food and Drug Administration approved in 2011. "It's a novel immune approach that's harnessing one's own immune system to fight cancer."
The results of both trials are scheduled for presentation Monday at the American Society for Clinical Oncology's annual meeting in Chicago. As such, the data and conclusions should be considered preliminary until published in a peer-reviewed medical journal.
The five-year survival rate for someone with stage 4 melanoma -- cancer that has spread to other parts of the body -- now stands at 15 percent to 20 percent, according to the American Cancer Society.
Yervoy works by blocking a receptor called CTLA-4 that normally deactivates the body's lymphocytes, which are white blood cells that form the leading edge of an immune system response. By blocking CTLA-4, the drug unleashes the immune system to attack cancer cells.
In one of these trials, doctors extended the median survival of 53 patients with inoperable advanced melanoma by roughly three and a half years, said presenting study author Dr. Mario Sznol, a professor of medical oncology at Yale School of Medicine. They did this by combining Yervoy with another immune system drug called nivolumab.
The combination therapy nearly doubled the overall survival found in previous studies of either drug alone, the researchers reported.
Nivolumab, which is not yet approved by the FDA, works by disarming the tumor's defense against attacks from the immune system, said Sznol.
"You're really hitting two molecules that control immune activation at different locations," Sznol said. "There are multiple ways that lymphocytes are inhibited. Maybe if you hit two of those mechanisms you get better results than if you just hit one."
Sznol said he's "never seen anything quite like" the results from using the two drugs in combination.
"If you look at all 53 patients we've treated, the one-year survival is 85 percent and the two-year overall survival is 79 percent," he said. "It's hard to compare across studies, because it's a small study, but no matter how we select the patients, I've never seen a trial that had even close to a two-year survival of 79 percent."