SATURDAY, June 5 (HealthDay News) -- Scientists say that a new drug to treat melanoma, the first in its class, improved survival by 68 percent in patients whose disease had spread from the skin to other parts of the body.

This is big news in the field of melanoma research, where survival rates have refused to budge, despite numerous efforts to come up with an effective treatment for the increasingly common and fatal skin cancer over the past three decades.

"The last time a drug was approved for metastatic melanoma was 12 years ago, and 85 percent of people who take that drug have no benefit, so finding another drug that is going to have an impact, and even a bigger impact than what's out there now, is a major improvement for patients," said Timothy Turnham, executive director of the Melanoma Research Foundation in Washington, D.C.

The findings on the drug, called ipilimumab, were reported simultaneously Saturday at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago and in the June 5 online issue of the New England Journal of Medicine.

Ipilimumab is the first in a new class of targeted T-cell antibodies, with potential applications for other cancers as well.

Both the incidence of metastatic melanoma and the death rate have risen during the past 30 years, and patients with advanced disease typically have limited treatment options.

"Ipilimumab is a human monoclonal antibody directed against CTLA-4, which is on the surface of T-cells [which fight infection]," explained lead study author Dr. Steven O'Day, director of the melanoma program at the Angeles Clinic and Research Institute in Los Angeles. "CTL is a very important break to the immune system, so by blocking this break with ipilimumab, it accelerates and potentiates the T-cells. And by doing that they become activated and can go out and kill the cancer. This drug is targeting not the tumor directly, but turning the T-cells on by blocking their brakes and allowing the T-cells to do their work, which is very different from chemotherapy and other targeted therapies directed at cancer cells."

The drug was developed and the study funded by Bristol-Myers Squibb and Medarex.

For this study, 676 patients at 125 centers around the world were randomly assigned to one of three treatment groups: ipilimumab plus gp100, a peptide vaccine which has shown some benefit in melanoma cases; ipilimumab on its own; or gp100 alone. All participants had stage 3 or 4 melanoma, and had been previously treated.

Those in both the combination arm and the ipilumumab-alone arm lived a median of 10 months vs. 6.4 months in the gp100-alone arm, a 68 percent increase in survival time.

"This is important because this is a disease where the average survival is six to nine months, so an increase on average by an additional four months is a very large difference in this population," O'Day said. "Even more importantly than the median survival are the one- and two- year landmark survivals, which were nearly doubled in the two ipilimumab arms, going from 25 to 46 percent at one year and 14 to 24 percent at two years."

Fourteen of the patients (2.1 percent) died because of reactions to the treatment, seven of those from immune system problems.

It's not entirely clear at this point which patients will benefit most but, Turnham pointed out, a large proportion of patients benefited from this therapy, whereas other therapies help only 5 percent to 15 percent of patients with metastatic melanoma.

The drug has not yet received approval from the U.S. Food and Drug Administration, but it is available at many medical centers and some patients may be able to get access to it, O'Day said.

More information

The Skin Cancer Foundation has more on melanoma.