NorthWest Biotherapeutics Inc (NWBO)

[Reefrad]

They kind of have to statistically. Otherwise there is potential for major selection bias. Put another way, one could hypothesize that those placebos who recurred and did not crossover were too sick to do so. In other words, those that did crossover were healthier recurrent GBMs and therefore cannot be compared with the external controls unless those too were exposed to a similar selection bias.