Ann: Plans for Phase 3 trial in Rett syndrome, page-41

My only thought with the 12 week treatment arm is that this is being labelled a disease modifying agent. So 12 weeks is sufficient in pure terms of “capturing” a disease modifying effect .  The follow on open label phase will obviously add some data and “robustness” to the data and this is for a undisclosed length of time. 

so by 12 weeks we are going to see a few different scenarios.

1) a ceiling/plateau - which we still hadn’t seen by week 6 and happens from 6-12 weeks
2) still no ceiling after 12 weeks-  so this is great and the open label will shed more light on this

3) Nil effect or a result of some description we don’t want/ unexpected from p2b

so I’m comfortable this 12 weeks gives a balance of adequate response (when looked at in conjunction with the open label arm ) with a time efficient trial . If there was no open label period after I would be very luke warm on this . 

the fda are obviously very content with the safety profile and dosing regime here to allow a trial design like this . It’s definitely a short sharp one but that is the good thing aout treating a condition where no alternatives are available . Let’s hope they can capture the efficacy in a compelling way this time around .

I want a continual improvement to week 12 no ceiling seen yet ... not much to ask