NWBO -- the sponsor in this case (Think fire walled off Marnix Bosch) -- has limited but significant discretion to accept or stay a DMC recommended halt for efficacy. I'm not saying this is happening, I'm saying that there is a reason there are ethicists, independent statisticians, open review exchanges on limited matters, independent/firewalled committees, etc. (I'm not talking about the individual clinicians, I'm talking about the trial sponsor)