His explanation was that the trials are not done yet, which means that people are still unprogressed or alive. He said you don't get second chances with FDA and they want to be sure that they approach with the best NDA possible.
My personal take on this is that there are still some monotherapy survivors and some combination and SCLC therapy unprogressed patients. Once the studies are done, they can freeze the database and perform 30-60 days of statistical work. He mentioned some concerns about statistical outliers, which probably means getting FDA to agree to toss some of the worst care quality locations (which also scored lower in terms of aldox response).
All in all, the delays are the only bad part, in terms of aldoxorubicin performance and chance of FDA approval, all bodes well.