Cell Genesys shares crash 70% after deaths in GVAX trial

Cell Genesys has terminated VITAL-2, the second of two Phase III trials of its GVAX immunotherapy for prostate cancer, due to patient deaths. On the day of the news, August 26, shares in the US drugmaker crashed 69.9% to $0.85.

Testing the product in combination with Taxotere (docetaxel) to Taxotere plus prednisone in patients with advanced-stage prostate cancer, the study showed "an imbalance in deaths between the two treatment arms," according to a company statement, and the Independent Data Monitoring Committee recommended the study be halted.

To date, VITAL-2 enrolled 408 patients. The IDMC based its recommendation on 114 deaths, of which 67 occurred in the GVAX plus Taxotere combination treatment arm and 47 in the Taxotere 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.