NorthWest Biotherapeutics Inc (NWBO)

[exwannabe]

If they did perform an efficacy analysis, why then did the alpha remain unchanged afterward?
Answer: They did not perform an efficacy analysis.

You do realize that the SAP disclosed it happened and noted the alpha adjustment,.

The overall one-sided type I error for the study was set at 2.5%. One of the two planned interim
efficacy analysis was conducted in March 2015 after 56.4% of subjects had completed 6 months
follow up. The O’Brien-Fleming one-sided alpha level for the final analysis (i.e. the stage 2 alpha
level) is 2.409%.

But it is even worse. The math basis for the O'Brien-Flemming analysis requires the dataset be the same but with additional points added to the final. That is why the O-F adjust is so small. But the IA was totally unrelated data so O-F is invalid.