new product launch on tvsn, page-20

Very quick answer - off the top of my head.

The primary outcome is lesion count. This will be scored by a dermatologist during clinical examination. That person, in theory, wont know the arm the subject is in (hence investigator blind).

In actual practice what happens is that the subject tells the investigator data what arm they were in eg - wow this new cream you guys have developed has really worked well. This is why its difficult to support a new efficacy claim without double blinding.

Go back a step. Ask POH how the sample size was calculated. My bottom dollar is it is not powered on primary outcome because the N is way too small. The sample size was agreed with the FDA around the parameters for new acne drugs in terms of safety - adverse events. Which from a FDA guidance from somewhere I have seen required 15 evaluable patients in each arm. This guidance also used a 12 week follow-up - so thats where that idea came from.

The highly confusing thing is that you see the word "efficacy" in the trial title - and so naturally assume thats what it is about. Its more subtle - and turns out to be a combination of phase plus regulatory pathway. PRR is another biotech with a P2 trial which I think is misunderstood on HC - but I'm regularly wrong about lots of things.

All imo etc Southoz