Cancer targeting vaccines: surrogate measures of activity.

Recent FDA approval of sipuleucel-T and Ipilimumab as indicated immunologic therapy in patients with advanced prostate cancer and melanoma, respectively, has established a foothold for broader utilization of vaccine based technology in managing cancer.  Despite difficulty of cell harvest and processing with sipuleucel-T and modest toxicity to Ipilimumab, when matched up with the appropriate cancer patient these immunologic approaches have provided significant benefit and have stimulated exciting forward progress in the development of new potent and less toxic (more targeted) vaccines.  However, surrogate measures of activity to optimally define more sensitive subset populations and to determine length of treatment time in order to optimize management with other treatment options remain elusive.  Key clinically tested vaccines under development which demonstrate correlation of patient benefit to induced immune responsiveness will be discussed.  Results suggest with some vaccines correlation of patient benefit and surrogate measures of activity actually do exist.  Examples will be discussed.