I went back and skimmed through Eric Campeau's Zenith presentation at the Epigenetics: Cancer and Beyond April 2017 meeting. One key thing I heard (I knew this, but then kind of forgot) is that the single agent ZEN-3694 trial starts in a dose escalation phase to find the maximally tolerated dose prior to expanding in to a larger patient cohort.

After reaching this maximally tolerated dose in the dose escalation portion of the single agent trial, two things happen: 1) they will expand the single agent trial at the dose determined by the maximally tolerated dose (I think one level below) to a larger patient cohort to increase the sample size to determine efficacy; and 2) they will scale back the ZEN-3694 dose (I'm not sure how much) and start the dose escalation portion of the ZEN-3694/enzalutamide combo therapy trial. Once the maximally tolerated dose is found in the dose escalation portion of the combo therapy trial, they will expand to a larger cohort of patients at the optimized ZEN-3694/enzalutamide combo therapy dose.

Therefore, reaching the maximally tolerated dose in the dose escalation portion of the ZEN-3694 single agent trial is a key milestone. Have they reached the maximally tolerated dose yet? Of course efficacy is important too. Have they seen efficacy at ZEN-3694 levels below the maximaly tolerated dose? These are great questions that I hope we get answers to at the AGM corporate update or via a news release soon.