In other words, NWBO beleives the FDA was wrong so rubbing their face in it before they say "May I sell this drug" may not be the wisest decision. Now what could the FDA have been wrong about?
Hypothetically
FDA: "Looks like there is earlier progression in the DCVAX ARM"
NWBO: "It's not "progression", it is immune activated swelling, exactly what we want to see, here look at these other images"
FDA: "Well we haven't quite looked at images like that before so progression is still progression"
NWBO: "You win for now, everyone from here on out will get the drug and we will wait an exceptionally long time so that we can provide proof without a doubt that this was not true progression and also some of the true progression patients also improved once the VAX got warmed up. The vaccine will show that there is improved survival and these will not be estimations it will be actual proof. Since one of the inputs we use to estimate future survival is progression, and this is in contention, this will muddy our estimates, so we will have to wait all patients have been in the study for 3+ years."
just spit balling.