Dr. Gulley Discusses Vaccine Responses

James L. Gulley, MD, PhD, Head, Clinical Trials Group, Deputy Laboratory Chief, National Cancer Institute, discusses measuring response to vaccines.

The best definition of vaccine response, Gulley says, is the length of a patient's survival, as there are very few PSA responses and objective responses.

In the completed phase II trial analyzing PROSTVAC, robust responses were seen, as the placebo arm had a median overall survival of 16.1 months compared with about 25 months in the vaccine arm. In this trial, there was a PSA response of less than 5%.