dennisdave,
The exceptions pathway allows NWBO to submit to FDA because of established proof that measures to adjudicate PFS were inadequate which required a change to OS primary which was compromised because of an inadequate comparator caused by the crossover. This would be the basis for following the exceptions to adequate and well controlled studies.
FDA was in close consultation with NWBO all the way through the trial process because of this trial being for an orphan disease so they realized that the crossover mandate was the right thing to do for patients but this created a situation with confoundment with OS as well. This trial could not be run without leukapheresis procedures which was the reason given for FDA demanding a crossover trial design. If FDA was going to demand patient level data when NWBO could not force others to give it to them then FDA created a trial design demand which would potentially force the trial to fail by comparing the treatment arm to an active comparator. Not only this but a comparator in which a greater number by percentage (~85% vs 45-50%) would carry phenotypic mesenchymal signature tumor tissue which is a known favorable prognostic indicator for DC treatment benefit. Whoops!
So even if most voting advisory committee members might want to agree that the ECAs as presented by NWBO are sufficient, the room for dissent created by the subjective nature of decisions allowed for and big pharma influence just made going to FDA first too risky. Even if Flaskworks was fully operational, not having strict guidelines that guarantees approval with full compliance to them can be seen as leaving too much to chance. Approving instead of just “accepting” the SAP with a sound guidance based rational, written out in a pre BLA submission comment form, would greatly reduce or eliminate the chance for outside influence late in the process but FDA does not do this. Best wishes.