Melanoma vaccine shows promise in clinical trial

A vaccine made from a mixture of four melanoma molecules known as peptides has produced an immune response in 75 percent of the patients enrolled in a clinical trial at the University of Virginia Health System.

The results of the randomized, phase II clinical trial, which involved more than two dozen people with advanced melanoma, the most deadly form of skin cancer, were published in the Nov. 1 online Journal of Clinical Oncology (www.jco.org).

“There have been significant tumor regressions on this protocol of peptide vaccines against melanoma,” said Dr. Craig L. Slingluff Jr., professor of surgery and director of the Human Immune Therapy Center at U.Va. “This gives us hope that this approach may be useful for patients with advanced disease.”

In the trial, 26 patients with stage III or IV melanoma received six vaccinations of the multi-peptide mixture developed at U.Va., followed by a tetanus helper peptide and a low dose of an anticancer drug known as interleukin-2.

The vaccines used during the trial were prepared in two injectable forms. One form included an emulsion of granulocyte macrophage-colony stimulating factor (GMCSF), a type of protein secreted by immune-system cells that helps to regulate the immune response. Half the patients received the GMCSF emulsion, and their immune response was significantly improved over that of the other patients.

“Multi-peptide vaccines with this emulsion warrant continued investigation,” Slingluff said.

The research team is keeping the GMCSF arm of the melanoma vaccine trial open, and has offered booster vaccines to some patients with evidence of tumor regression or stable disease. The team is also evaluating the impact of low-dose interleukin-2 combined with the melanoma vaccine on the immune system’s killer or cytotoxic t-cell responses.

According to the American Cancer Society, more than 53,000 new cases of melanoma are expected this year.