From OGXI's email to Summer as quoted in her message:
"An interim look is scheduled by an independent data monitoring committee, but disclosure would only be triggered if there were an unexpectedly high number of adverse events in the custirsen arm warranting closure or early efficacy results warranting earlier submission before completion."
While neither of the above scenarios is likely, I would think the favorable one -- early efficacy results revealed in the interim look -- is the less unlikely of the two. Certainly if the P3 results were to approach the results of the randomized P2 -- which is asking a lot since the P2 results were a lot better than anticipated and you'd expect some regression to the mean in a bigger trial -- then maybe we could see an early end to the trial as happened with abiraterone. It's nice to fantasize about waking up one morning to news like that, since then you wouldn't have to worry about selling or hedging prior to the announcement of the P3 results. But even if it were to happen it would still be pretty far down the road, since it presumably have to be at least at least a few months after completion of enrollment, which will probably take at least 18 months.