Jarrod Longcor
Chief Operating Officer
Yes. And Aydin, if I may follow up a little bit. So, the interesting piece, and I'll put it back into the hypothetical, the interesting piece of your question is - the hypothetical piece is, can you identify essentially the weakest drug to go against to ensure success? And I'll come to why we don't really care in a moment. I think it'll make a lot more sense, but at the end of the day, no matter what drug you pick or pair of drugs you pick, whatever you pick as the investigator choice, you obviously have the FDA to approve those choices. And the FDA wants to stick to what is the most common treatment paradigm that is ongoing right now. Obviously, physicians aren't likely to prescribing drugs that they know are failing rapidly. That said, one of the things that I think leads to this is when you get into the second line and the third line, like Jim said, and you're in this sort of already coming into salvage therapy, frequently, what you actually see is physicians are just satisfied with patients not having a major response, but achieving stable disease or suppression of the sequela associated with the disease, so peripheral neuropathy, maybe reduction in their fatigue, what have you. And that's what they're really trying to do. They're not actually trying to alter the disease course. They're just trying to ameliorate symptoms and signs of the disease essentially. What's interesting is what does that mean? That means, as Jim said, most of these other drugs, at least from what we're seeing, have very low major response rates and very short progression-free survival. So, as we said, rituximab or even some of the rituximab combinations range in and around this 10% to 30% maximum major response rate in sub six months of progression-free survival. And so, we feel very confident that with our near 60% major response rate, which I think was 58.2% in the overall patient population, that we will easily be able to demonstrate with major response rate the potential of iopofosine here. And then when you look at the PFS, again, if you're looking at sub six months and you look at what our ongoing PFS was in the study the last time we reported, which was north of 11 months, again, we think we have a very strong compelling position as it relates to any comparative that we will select. And we do think with the discussions with the agency, the selection here is really about a fixed course therapy that compares with our fixed course therapy. And so, that means you're basically rituximab and rituximab combinations only as your alternative. I think on the other piece, when you think about eligibility, you asked the question about, is there a way to enhance the eligibility to ensure, again, better patient population for iopofosine? And we think we've done that. Fundamentally, this post BTKI patient population that we're pursuing, keeping in mind that now with ibrutinib approved in the first line, you're seeing a lot more utilization of BTKI in combination with rituximab in that first line setting. What does that mean and why is that important? What we've seen through both anecdotally and then also through the claims data that Jim referred to, what you see is that patients who've had a BTKI, tend to fail almost every subsequent treatment after that. However, as you will note from our study and in our press release, I think this morning, when we look at the post BTKI population with iopofosine, you're looking at a 15.9%, or essentially a 60% or 59%, sorry, 59% major response rate in that patient population. So, again, we don't see a change and we think that just select that patient population enriches a true separation and really identifies the need for iopofosine.