Dr. Gomella Suggests Provenge Benefit Understated

Leonard G. Gomella, MD, Bernard W. Godwin Jr. professor of prostate cancer and chairman of the Department of Urology, director of Clinical Affairs, Jefferson Kimmel Cancer Center, explains the understatement of overall survival (OS) benefits in the IMPACT trial, which examined the immunotherapy sipuleucel-T (Provenge) for men with castrate-resistant prostate cancer.

The IMPACT trial provided patients on the placebo arm the option to receive APC8015F, a cryopreserved version of sipuleucel-T, following disease progression. Patients that received APC8015F experienced life-extension beyond those receiving placebo alone.

However, when results of the trial were initially calculated patients receiving the frozen product were added to those receiving only placebo. This compilation of patients decreased the differences between the control and treatment arms.

In a further analysis, Gomella examined all subsets of patients and treatments on the trial, which included those receiving placebo alone, APC8015F, and sipuleucel-T alone. This breakout revealed a marked increase in OS over placebo for patients receiving the cryopreserved agent. Without the addition of this information to the placebo arm, the added OS benefit for sipuleucel-T approaches 10-11 months, when compared to placebo alone.