Read the protocol, crossover was a rescue medication for naive GBM patients that had recurrence (Had progression). The trial was designed for naive GBM.
NWBO has repeated stated that the crossover caused confounding of the OS metric:
"Both of these endpoints were confounded: the PFS endpoint by pseudo-progression, and the OS endpoint by the “crossover” provision in the trial design, which allowed all of the patients in the trial to cross over to DCVax-L treatment after tumor recurrence (while remaining blinded as to which treatment they received before tumor recurrence). " From two 10K SEC filings.
NWBO should be the most reliable source of information as they do all the regulatory filings.
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