NorthWest Biotherapeutics Inc (NWBO)

[f3tt3f]

I wouldn't want to speculate.
Regardless, it's a nice safety net to have the potentially longest surviving patients in the treatment arm come from those with, generally, the poorest prognosis (mesenchymal expression = more aggressive growth).
This helps us two-fold in the separation of the KM curves in the early stages.
We're effectively taking the patients that would ordinarily die first and shifting them to the end of the curve, if you like.

This could mean the DMC are comparing those who progressed first in the control arm (who most likely have the mesenchymal gene), with the group to first progress in the treatment arm (the ordinarily longer surviving proneural and proliferative expressers)

It may artificially skew the results to the treatment arm's advantage in the earlier stages, so the DMC will have to take that into account with any projections.
(or maybe we just get an early termination for efficacy...)