GTC Biotherapeutics (fka GTCB)

[DewDiligence]

There’s a lot of sloppily used nomenclature out there, and this is yet another example. (However, it’s not as bad as websites’ referring to antiplatelet drugs as anticoagulants as per the discussion in #msg-26739622.) No phase-3 trial I’ve ever heard of is genuinely dose ranging in the sense of seeking the maximum tolerated dose; a phase-2 trial is typically dose-ranging only when it is part of a phase-1/2 combination study with both a dose-ranging and a proof-of-concept component.

>Putting aside the semantics, I think you are saying that sometimes you do a study to determine the maximum dose before material side effects appear, whereas in other studies, you try to find the best (most therapeutic) dose -- which is not always the maximum tolerated dose. That distinction certainly makes sense, and the Leo trial is in the latter class.<

Clearly. The ATryn doses in the Leo trial are fixed—patients are randomized to a given trial arm where they receive the pre-specified dose for that arm. The protocol may allow for dose reduction for a given patient if there are severe side effects, but this is an altogether different matter.