GenVec Stock Hit by Pancreas Study's Details

The interim analysis Wednesday was conducted after the 92nd patient in the study died. The next interim analysis will be conducted after the 184th death, expected in late 2009. When that second interim analysis occurs, my guess is that the 25% reduction in the risk of death observed Wednesday will shrink considerably.

This is not just an off-the-cuff prediction. Other TNFerade data announced by GenVec Wednesday provides enough evidence to be wary about the drug's chances for success.

At 12 months, 39.9% of TNFerade-treated patients were alive compared to 22.5% of patients in the study's control arm. At 18 months, overall survival for TNFerade patients was 30.5% compared to 11.3% in the control arm. Both analyses favor TNFerade.

However, at 24 months, only 10.6% of patients treated with TNFerade were still alive compared to 11.3% of patients in the control arm. In other words, the benefit of TNFerade vanished.

Moreover, median survival in the study to date was 9.9 months for both TNFerade and the control arms. No difference.

One more data point: In late 2006, GenVec looked at a similar survival analysis of 51 patients done after 12 deaths were recorded in the study. At 12 months, 70.5% of TNFerade patients were alive compared to 28% of patients in the control arm.

Compare this early survival analysis based on 51 patients to what was announced Wednesday with more than 200 patients now enrolled and you'll see that time is not kind to TNFerade. The overall survival benefit observed today in terms of the hazard ratio of 0.75 might be largely a byproduct of those first 51 patients.