NorthWest Biotherapeutics Inc (NWBO)

[f3tt3f]

I think there's validity in the theory that the DMC could be deliberating on how to respond to a statistically significant benefit seen in a subgroup.
This would be a discussion between the ethicist vs the scientists.
The scientists would be loathe to unblind a subsection of the trial which could, in turn, potentially under-power the remaining groups.
The ethicist would argue that keeping placebo patients (who are in that subgroup) from a safe, potentially life-extending treatment is unethical.

It really is a tough call, if the subgroup (probably mesenchymal, which tends to progress more aggressively) is taken out of the placebo arm, this could artificially extend PFS of the placebo group making it harder to eventually approve the treatment at the end of trial - If the margins are closer than we might hope.