My guess is because those OM patients had already finished the trial, IPIX was able to unblind which group they were in (I have no clinical trial experience, this is just a guess).
I'm assuming if we only see 6 week data from P, no one will have technically finished the trial at 6 weeks, so we can't unblind the data. If we get a mixture of data, then maybe we get some unblinded data from those who have finished???