NorthWest Biotherapeutics Inc (NWBO)

[Rkmatters]

This was covered a long time ago. It’s a once and done approach they plan to pursue because patient white blood cell counts can obscure the data. Plus If did the SAP the moment they crossed the PFS endpoint then most of Germany and Canada’s data wouldn’t have been included as Germany didn’t start enrolling until late 2014 and Canada didn’t start until 2015. Remember a good 50% of patients were not enrolled until sometime after May of 2014. You don’t want to do the analysis on a subset of data, which is what they would have done if they unblinded at first chance. It’s best to do it when you have all the data on all the patients as you get the worse of the data to affect the placebo arm (under the assumption the vaccine is an effective product). This is especially important to delay looking at OS this trial under enrolled — meaning it didn’t go to 348 patients as planned — it makes sense to capture all PFS and OS data on the full 331 patients. Waiting until the end of the trial ensures they get all the worst PFS data from every site is included. Remember it’s four countries data they would be looking at. And it’s about separation between the placebo and vaccine arms (1:2 randomization). If they did PFS analysis once they passed 248 events they would only capture all the worst 248 progression data from 248 patients of 331 enrolled patients. Now we know they will be capturing the worse 248 progression events from up to 331 patient events and then unblinking. It is quite possible have the best shot on reaching significance as there is a large pool of patients to look at the 1:2 difference of the worst 248 progression events. They obviously are trying to get the best out of the full patient data pool. That I support.