But they didn't hit it on May 7, 2015, and LP stated, in response to a question at that time, the 1st interim analysis should occur in the "coming month(s)."
Not a whole lotta months between June and October. It's very possible it still had not happened by July, August September or even mid October.
Remember, people are living longer than expected, there is a retrospective study of 91 trials that finds a correlation between PFS and OS in GBM.
Therefore, people, at least those receiving treatment, are likely PFS eventing later than expected as well.