Replies to post #6271 on GTC Biotherapeutics (fka GTCB)

[lake11]

Thanks.

[croumagnon]

Re: Handicapping the US Atryn trial

I mostly agree with the content of that post Dew but I have a couple of questions.

"1. The primary efficacy endpoint is symptomatic DVT—not merely DVT observable with a ultrasound scan. Thus, the US trial has a more favorable endpoint for GTC than the “any DVT” endpoint used in the trial that supported EU approval. (There were two cases of DVT seen in the EU trial, but they were asymptomatic.)
2. The comparator arm in the US trial is plasma-derived antithrombin as determined by analysis of historical cases (#msg-5609005). There is no scientific reason to believe that ATryn will work less well than plasma-derived AT."

Doesn't the advantage of Symptomatic DVT (Versus any DVT diagnosis) also carry in the control arm? If so, how is that an advantage since it may show less DVT's in the control arm as well?

A related question is that I suppose GTCB is trying to merely determine non-inferiority of ATryn as compared to plasma-derived antithrombin for approval, is that correct? If that is correct, would you happen to know if the trial has an SPA and what that SPA specifies for the non-inferiority criteria for approval?