Researchers at The University of Texas M. D. Anderson Cancer Center conducted a phase III trial that assessed the use of a peptide vaccine, known as gp100:209-217 (200M), in combination with Interleukin-2.
Advanced melanoma is one of the most lethal cancers and its incidence is increasing at a rapid pace. In 2009, almost 69,000 people in the United States are projected to receive a melanoma diagnosis and almost 9,000 will succumb to their disease. Now, there is further evidence that a vaccine may provide hope for those faced with this devastating diagnosis.
Researchers at The University of Texas M. D. Anderson Cancer Center conducted a phase III trial that assessed the use of a peptide vaccine, known as gp100:209-217 (200M), in combination with Interleukin-2 (IL-2). The study included 185 patients at 21 centers across the United States. All patients had advanced metastatic melanoma and were stratified for cutaneous metastasis, which is a known indicator of response to IL-2. Patients were randomized to receive either high dose IL-2 (n = 94) or IL-2 and vaccine (n = 86; 91 had been enrolled). Those receiving the vaccine had a significant response rate and progression-free survival compared with those who did not; 22.1% and 2.9 months versus 9.7% and 1.6 months, respectively. While the median overall survival was not statistically significant, it trended positive, with 17.6 months observed for those receiving the vaccine versus 12.8 months for those who did not.
According to Patrick Hwu, MD, professor and chair of M. D. Anderson's department of melanoma medical oncology, who presented these findings, “While more follow up is needed, this study serves as a proof-of-principle for vaccines' role in melanoma and in cancer therapy overall. If we can use the body's own defense system to attack tumor cells, we provide a mechanism for ridding the body of cancer without destroying healthy tissue.” Currently, the vaccine can only be given to half of those with melanoma because it has to match a patient's tissue type. One of the major priorities for the investigators will be to figure out how to broaden their approach and use mixtures of peptides so that more patients are eligible for treatment. They also hope to improve the vaccine by including other immune-stimulatory agents, such as anti-CTLA4, which is an antibody that, according to Dr. Hwu, “can take the breaks off the immune cells.”