Chris O'Brien
Analyst · Barclays. Please go ahead
Let me address that in two different ways. The first is our partnership with Mitsubishi is for Valbenazine in Asia. It's a broad partnership across multiple disease opportunities. And we know Mitsubishi is doing a very good job, and looking into tardive dyskinesia, for example, they're not solely focused on Huntington's, and they're interacting with the Japanese regulatory authorities, as well as regulatory authorities in other Asian countries about which indications they might go after first. So it's not restricted to Huntington's disease. And then, indeed, it may not even be the first indication that they go after. So, secondly about -- and they are continuing to do the requisite work necessary for understanding whether there are any potential differences between metabolism and exposure, PK in Asians rather than North Americans. We have no data to indicate there is a difference so far, but they're going good job on putting all those pieces in place. Now, from a mechanism point of view, I actually think we're in a very strong position of understanding that VMAT2 inhibition is unified across hyper kinetic movement disorders, that there is nothing that we actually don't understand that says Huntington's, Tourette's, tardive dyskinesia, all of these things are appropriate targets for VMAT2 inhibition with respect to involuntary movements. And I would say, as we have on prior calls, one could think a whole range of other involuntary movement syndromes that potentially would be appropriate, whether it's steroid piece [ph] in developmentally disabled patients or other kinds of hyper kinetic movements, those all potentially could be appropriate. I don't think we're missing anything. The challenge with Huntington's disease, and one of the reasons Neurocrine hasn't focused on Huntington's is obviously there are approved drugs on the market for Huntington's disease, Huntington's chorea and a form of Tetrabenazine. Of the number of patients who have chorea that's severe enough to warrant treatment at any given time is small, in that kind of 3,000 or 4,000 range I think out of the 30,000 diagnosed patients with HD. And so for us to do the investment of Valbenazine clinical development to go after that market doesn't make a lot of sense from a formal development point of view. Now, potentially would a once-a-day, well-tolerated VMAT2 inhibitor be useful and could we explore that in a kind of a post-approval environment. Sure, that's definitely worth thinking about post approval.