Dr. Dan Skovronsky
Analyst
Okay. Three great questions, Umer. Thanks. So the first question, you asked if we'd use interim data, I commented that we'll take a safety cut of data in the right way to support that submission. We don't plan to support that submission or do we see the need to support that submission with any looks at efficacy data. We have adequate efficacy data supporting the plaque lowering, which would be the basis of submission and approval under accelerated approval. Your second question is once plaque clears, how long does it take to come back? We have some data on that that was also presented at AAIC. I didn't highlight it this morning. But what we found is that off therapy, there is very slow, negligible, really, regrowth of plaque. I think if you sort of extrapolate it out, it might take 14 or 15 years or something like that to regrow amyloid plaque. The average age of patients in this trial is 75. And remember, we haven't fully halted progression of disease. So that doesn't feel like a near-term thinking on redosing will be necessary to keep them clear. But we'll have the ability to follow patients for many, many years and confirm that. Finally, I think you've correctly summarized the situation, which is that in our initial analysis, we didn't see a correlation and now we are reporting that we do see a correlation. Why is that? And of course, correlation can't prove causation so it is just a correlation. So why do we see it now? I think what we learned was quite interesting. And that's that the amount of plaque you remove depends a lot on how much plaque you have to start with. So if you only have 50 centiloids of plaque, there's only so much you can remove. If you have 100 centiloids of plaque based on, you can remove a lot more. So that turns out to be a pretty important compound in these kinds of correlations. The people who are -- have the more severe disease, perhaps longer duration, lower cognitive performance, older age, they might have more plaque at baseline, you can remove more but they still might be the worst progressors than people who have lower plaque and you remove less. So, I think our thinking initially, and maybe the field thinking, was a little bit backwards on this to look for a straight correlation between change and change without adjusting for all of those important baseline covariance.