as I take it, one dosing level is showing good results. however, w only total 75 participants and 3 dosing cohorts, each is only 25 w 50% getting drug. therefore a request for 20 in only one group suggests attempt to confirm efficacy with 10 more patients getting drug. this group, 25 + 20 for 45 will provide the data on which to base phase 3 trial. I believe that's why stock took off at end of day. tell me why I am wrong.
oh, and any delay is more than made up by positive signal for efficacy and value that bestows. if no efficacy, study would have been completed w/o request or more info and p2 data would have been a bust. imho