I think that’s probably how they are going about it.
Two thoughts.
This is not typical, because this is an immunotherapy trial originally designed more like a chemotherapy trial. Dr. Hoos essentially states this forces granddaddy trials (like DCVax-l) to run the gauntlet of slings, arrows and mostly time. (I’m obviously extravagantly paraphrasing.). NWBO is doing this to succeed, and it is also doing it to establish a shorter template for future DCVax trials and combinations. Therefore, this tail of data in 2019 is precious. However with aging attrition, tail maturation is entering the realm of diminishing returns soon, imo. Therefore, I think they’ll fight for this year’s first two quarters of survival data to be included. FDA 2011 cancer vaccine guidelines, if I recall, which I think LP gave input to, is very clear that the FDA should recognize/honor the tail analysis in these types of trials if a tail develops.
LP and Dr. Liau in particular have been champions of nonproportional analysis, even though neither one calls it that.
So, in short, I think it is atypical but necessary and understood that the later survival data must be included in the analysis, which is why I believe Dr. Bosch stated they will use data up to the point of data lock. It will require real time validation, imho, in the form of data sweeps for survival events.
I think the SAB wanted 75% OS events instead of just 70%. Now I think we are running into a flat line KM graph, and NWBO is asking for a little guidance from the FDA in the form of a response to their SAP. I think the FDA will provide a response that allows NWBO to wrap this up, perhaps just shy of what I suspect the SAB recommended, because it would otherwise take too long to complete this trial.