Biotech Values

[DewDiligence]

AGN re: Incremental Botox sales for migraine

Patients enrolled in the two phase III studies were the worst cases… and they got 150-200 units of Botox per patient. I don't know why [Corey Davis] wrote 200 units or more.

In a non-clinical-trial setting, 150-200 units is effectively 200 units because Botox comes in 100-unit vials. Where Davis went wrong is in implying that 200 units is 8x as much Botox as what a 25-unit cosmetic procedure requires. As I noted in #msg-41294358, you can’t calculate Botox usage that way (unless you are talking about the practice of a high-volume injector who sees manifold cosmetic patients closely spaced in time).

Because of wastage from the unused portion of a vial, I would estimate that the average cosmetic patient effectively uses about 70 units of Botox rather than the 25 units that Davis figured. Thus, a headache patient who needs two vials will use about 3x as much Botox as an average cosmetic patient—not 8x as much, as Davis surmised. This, combined with the existing off-label use of Botox for headache, means that Davis’ numbers for the incremental sales from a headache approval are substantially too high, IMO.