Dr. Rotkowitz Describes Challenges Facing Immunotherapy

Michael Rotkowitz, MD, medical oncologist, Cancer Treatment Centers of America, Eastern Regional Medical Center, says that one of the main challenges and a leading goal of immunotherapy research is measuring response to justify the treatment and costs.

The scrutiny surrounding the immunotherapy sipuleucel-T (Provenge) stems from the fact that there is no tool to monitor response. Despite this scrutiny, other immunotherapies are also being researched for prostate cancer, including ipilimumab, GVAX, and PROSTAVAC.

Ipilimumab is being studied in a phase III trial compared to placebo in treatment-resistant metastatic prostate cancer patients.

GVAX was examined in a phase III trial comparing it to docetaxel plus prednisone for men with asymptomatic or minimally symptomatic castration-resistant prostate cancer (CRPC). The trial showed that the toxicity profile of GVAX was favorable to the combination arm but survival was not significantly improved.

The examination of PROSTVAC for asymptomatic or minimally symptomatic CRPC is underway in a phase III trial and uses pox viral vectors to stimulate the immune system.