Melanoma vaccines: what we know so far

Vaccines are a promising but still experimental treatment for melanoma. They are intended to stimulate immune responses against melanoma and by so doing, increase resistance against and slow the progression of this cancer. Key requirements for vaccines to be effective are that they contain antigens that can stimulate tumor-protective immune responses and that some of these antigens are present on the tumor to be treated. Unfortunately, these antigens are still not known. To circumvent this problem, polyvalent vaccines can be constructed containing a broad array of melanoma-associated antigens. Several strategies are available to construct such polyvalent vaccines; each has advantages and disadvantages. Clinical trials have shown that vaccines are safe to use and have much less toxicity than current therapy for melanoma. Vaccines can stimulate both antibody and T-cell responses against melanoma, with the type of response induced, its frequency, and its magnitude depending on the vaccine and the adjuvant agent used. A growing body of evidence suggests that vaccines can be clinically effective. This evidence includes correlations between vaccine-induced antibody or T-cell responses and improved clinical outcome, clearance of melanoma markers from the circulation, improved survival compared to historical controls, and most convincingly, two randomized trials in which the recurrence-free survival of vaccine-treated patients was significantly longer than that of control groups.