NorthWest Biotherapeutics Inc (NWBO)

[Doktornolittle]

Question for anyone regarding efficacy bars for subgroups:

The question regards the patient polulations required to show SS efficacy in subgroups. In general, not just here for DCVax-L.

Example:

Take a normal phase 3 randomized trial without crossover that goes full term with OS as the primary endpoint. If 9 months improvement over the control group was the base threshold for efficacy, based on the enrollment, then what would the thresholds be for the following subgroups?

Say there are two subgroups that split the population 50:50. If the subgroups both showed 9 months improvement in OS, then they would both have met the primary bar, and ignoring the fact that many other factors are considered for approval, base SS efficacy would have been demonstrated.

But if you look at the subgroups seperately... the patient population would be half that of the main trial, so the efficacy bar would have to be higher to achieve SS, ie, higher than 9 months improvement.

These two views appear to conflict.