First of all, Brandon, thank you for being on the call and I'm going to answer your second question first, that's an easy one. So, safe to proceed letter is typically, what you do technically after you file. This had to be filed as a separate IND because it's a different drug. And with that said, safe to proceed letter is the official green light from the FDA to move forward. There are no other hurdles. And so all we are doing now is we have to do - we've got everybody engaged. We have a CRO ready and ready to go. And just a pause for a moment, let me tell you why this is unique and maybe it didn't come across in the call. What we're doing is, we're actually asking - if you look at the population of the patients in the greater than 40 and less than 40, the same population of patients, these are patients that have received at least two estrogen-blocking agent and a CDK4/6 inhibitors, they are all third line. So when they come into the study, then the companion diagnostic or in this case will be CLIA test, look for the AR status. If their AR status is greater than 40, greater and equal to 40, then they go on to the AR test study. If it's less than 40, then they go to the Phase 2b study. So in some ways, they're sister companion studies. And so we're being incredibly efficient with money. Because that same patient, instead of being told, you can't be in the study and you chalk that up as a screen failure, whatever you call that. Now we have an opportunity to capture that patient in one or the other study. So it really is a very efficient way to fill that study. So maybe that didn't come across as loudly as I would like it to. But with that said, there are no hurdles. And in fact, we're starting to collect patients for recruitment because if your test study is up and running, and we do have patients that are less than 40. So it will be pretty efficient. So our thinking was that since we know less than 40s and not going to respond the way to greater than 40s do, let's take advantage with another one of our assets. As it relates to the second question, I'll frame the question. We're very fortunate to have here Dr. Gary Barnette will answer the question. And that was basically for the COVID-19 study, looking at the control arm. Just to remind you again what that control arm was in the Phase 2b and then what the control arm is in the Phase 3. And then the other part of your question was dialogue with the FDA in relation to that endpoint and how comfortable they are with that endpoint. Gary?