Iwfal:
Some 200 events were required for the Vital 1 interim; more than the total number of events in the combined 9901 and 9902a Ph3 trials. GVAX dosing is allowed to continue indefinitely in Vital 1 as long as no alternate therapy is commenced and Vital 2 is probably less than 70% fully enrolled at this point. If it isn't working and patients are dying faster on GVAX, patients should be informed and further dosing stopped. My limited understanding of the O'Brien Fleming method of allocating alphas lead me to believe that it also provides some sort of horizontal funnel plot that can be used to set some outer limits for futility and any stopping test for unexpected overwhelmingly positive results. (BTW, does anyone know if 9902b uses the same Haybittle Peto method of allocating an interim alpha as was used in 9901 and 9902a?)
IMO, GVAX still represents a pretty decent speculative investment.However, having said this, I am well aware of the risks in biotech, including the almost invaraiable hyping of results. Caveat emptor.
