Preliminary findings from a phase III, multicentre trial, being presented at the American Society of Clinical Oncology 2009 meeting, show that adding a novel cancer vaccine – called gp100:209-217(210M) peptide – to standard therapy doubles response rates and extends progression-free survival in patients with metastatic melanoma, without causing significant side effects.

"This study is one of the first to show positive, promising results for a cancer vaccine in melanoma" said lead author Dr. Douglas Schwartzentruber, medical director of the Center for Cancer Care at Goshen Health System in Indiana and clinical associate professor of surgery at Indiana University. "Metastatic melanoma is a very difficult disease to treat successfully and is very resistant to most therapies. These results will give patients and the oncology community hope that we are making some progress against this disease."

The vaccine is made from a peptide that is part of the gp100 protein – an antigen found on the surface of melanoma cells that acts as a marker for melanoma cells. When administered, the vaccine stimulates T cells, a type of white blood cell, to multiply and to seek and attack melanoma cells by locating this gp100 antigen. It was administered with interleukin-2 (IL-2), a standard therapy for advanced melanoma that boosts the immune response to the vaccine.

In this study, response rate, progression-free survival (the time it took for cancer to progress), and overall survival were compared between 86 patients who were randomly assigned to receive the vaccine plus IL- 2, and 93 patients who received IL-2 alone. More than twice as many patients in the vaccine group responded to treatment with tumour shrinkage (22.1 per cent versus 9.7 per cent). Progression-free survival and overall survival were also longer in the vaccine group (2.9 months and 17.6 months, respectively) compared with the IL-2 only group (1.6 months and 12.8 months). Researchers reported a trend toward improved overall survival among patients who received it along with standard therapy, who lived nearly five months longer than those who received standard therapy alone.

The vaccine was well-tolerated; swelling and redness at the injection site were the only side effects. The investigators are continuing to follow the patients to see how long the vaccine remains effective and to assess its value in various patient subgroups