High death rate brings prostate ca vaccine trial to a halt

ABSTRACT: Cell Genesys says it will review data from VITAL-2 trial before continuing Gvax development; calls for analysis of VITAL-1.

SOUTH SAN FRANCISCO-Cell Genesys terminated VITAL-2, the second of two phase III clinical trials of Gvax immunotherapy for prostate cancer.

Cell Genesys ended the trial after its independent data monitoring committee observed a high number of deaths among patient receiving the drug versus those on another treatment regimen.

The trial was designed to compare Gvax immunotherapy in combination with docetaxel (Taxotere) to docetaxel plus prednisone (Deltasone) in patients with advanced-stage prostate cancer. VITAL-2 had enrolled 408 patients. The committee suggesting halting the trial after 114 deaths, 67 of which occurred in the Gvax plus docetaxal combination treatment arm; 47 deaths occurred in the control arm.

“At this time, a specific cause for the imbalance in deaths has not been identified and the IDMC reported no new safety issues for Gvax when administered in combination with Taxotere,” the company said in a written statement.

Cell Genesys also reported that it plans to fully analyze the clinical data from these patients to attempt to understand the potential cause for the higher rate of deaths observed in the combination arm.

Cell Genesys also has asked the monitoring committee to perform a futility analysis of VITAL-1, the other phase III clinical trial of Gvax immunotherapy for prostate cancer.

VITAL-1 compares Gvax cancer immunotherapy as a monotherapy to doectaxel chemotherapy plus prednisone in earlier stage hormone-refractory patients with metastatic disease who are asymptomatic with respect to cancer-related pain.

The primary endpoint of the trial is an improvement in survival. In 2007, the VITAL-1 trial completed enrollment with 626 patients.

Less than a year ago, Cell Genesys announced that the committee had completed a pre-planned interim analysis for VITAL-1 and recommended that the study continue. The futility analysis is slated to take about a month.