Vitaly, thanks so much for joining us as always on UroToday.
Vitaly Margulis: Good to be with you, Zach.
Zachary Klaassen: So we always start the discussion just the mechanism of action with VTP. This is for low-grade upper tract urothelial. Just tell our listeners at a high level what that mechanism is for this trial.
Vitaly Margulis: Well, first of all, just a little bit of background. I mean, again, the patients are the ones with low-grade upper tract urothelial cancer. There's an unmet need there because most of these folks end up with nephroureterectomy, even high level academic medical centers, mainly because endoscopic access is challenging. Yes, we know we can ablate those tumors, we can know lasers, but it requires a know how. So this is where this technology comes in. And so the way that this works, during the patient anesthetized, during the anesthesia induction, we inject a photosensitizing agent for about 10 minutes. Literally you insert ureteroscope and visualize the tumor and with the laser somewhere in the vicinity, you turn the light on for about 10 minutes, 10 minute elimination. You can do several eliminations per cycle. So if you have larger tumors or tumors in different locations, you can eliminate both of them. You can do that up to three times, for the clinical trial.
So separated a month apart. So the way that this works, the primary endpoint is complete response. Tumors up to two centimeters. We're included in this clinical trial. I think in clinical practice, you can treat larger tumors, but for the purpose of the trial, couldn't be more than two centimeters. Could have up to two tumors. We actually included ureteral tumors as well, unlike some other products in this space. Again, so after a month after initial treatment, you reassess. If there's still residual tumor, you can treat and you can treat again up to three times in that matter. If by third treatment you go in there, you visualize the entire upper tract and you find a recurrence. And the recurrence could be not in the primary treatment side. You would fail and you would be out of the trial. So you'd have to have completely clean upper tract, ipsilateral upper tract that you've treated. Negative cytology, negative visualization. If anything looks suspicious, you had to biopsy it. So relatively rigorous trial design. We now have it enrolled close to 80 plus patients with a total goal of 100. And after about 80, the primary endpoint would be evaluated.
Zachary Klaassen: That's great. So we're getting close to really getting some data that ... And you have some updated data that we'll talk about, but we're getting close to full enrollment and that complete response rate. What's the high level data presented at ASCO this week?
Vitaly Margulis: So the high level data is a little bit longer follow up. Our complete response rates seem to hold up. So overall response rate was close to 90%. Complete response rate was upward of 70%. But remember, you could have recurrence outside of the primary treatment site and that would count as a failure. So we now have patients that have had longer than 12 a month follow-up. If you look at the response in the primary sites, it's what you treat it. Remember, this is not a pan-urothelial treatment such as the other chemotherapy agents, which treat the entire upper tract. This treats a certain area. And if you look at specifically at response, greater than 12 months response in that rate, that response was upward to 90%. So not only the primary response in the primary site is excellent, but also seem to be durable past 12 months.
Zachary Klaassen: And that's what the patients want to know. They want to know, is this going to work? If it works, how long is it going to work for? I think from a pragmatic standpoint, I mean, two centimeter upper tract tumors are pretty good size, and I think this is probably the higher end of size criteria for some of these trials. Where do you see this going? I mean, we're getting close to enrollment. I'm sure hopefully approval down the road. How do you see this fitting into clinical practice?
Vitaly Margulis: Well, again, I think the immediate, the low hanging fruit would be that the lesions that are hard to reach. So the ones that are in the lower pole, you can deflect there. Literally, you don't have to even see the tumor. You possession the laser in the vicinity, you can activate it. And in folks that have maybe are not as experienced as with endoscopy and laser ablation, because it really makes it technically simple.
I think, again, I visualize this as one of the tools in our armamentarium. Could you combine it with some of the chemotherapy agents that treat the entire upper tract in adjuvant fashion? Yes, that makes total sense. But what this allows you to do is reliably treat the lesion that you can see. What we haven't talked about is the side effect profile. And again, with some of the other products, you can see stricture rates, et cetera, et cetera. We've seen minimal stricture rates. There are only no long-term stricture rates here, even though we've treated ureteral tumors. And it does require stenting afterwards, as long as you don't dilate the upper tract during your access. And the safety profile is great. The grade three toxicity is less than 10%. So yes, you see toxicity mainly related to access to the upper tractor. Hematuria, pain, colic, et cetera. So nothing unusual that's specific to the treatment itself.
Zachary Klaassen: Wonderful. Great conversation, as always, about ENLIGHTED. Any other takeaway points, anything we haven't hit on yet you want to discuss?
Vitaly Margulis: Well, the technology is exciting and it's being evaluated not only in other disease states, but for there are several efforts are ongoing for high-grade disease combined perhaps with immunotherapy, et cetera. So I think again, this hopefully will be a platform that we could use in the future.
Zachary Klaassen: And right in the urologist wheelhouse, as you mentioned, which is great.
Vitaly Margulis: Correct. Correct.
Zachary Klaassen: But Vitaly, thanks for your time. Appreciate it.
Vitaly Margulis: Good to be with you, Zach. Thanks.