Moleculin Biotech, Inc. (NASDAQ:MBRX) Q3 2023 Earnings Call Transcript

Walter Klemp: Thanks, Jon. For quite some time now, we’ve been touting the non-cardiotoxic nature of Annamycin, but there is just no substitute for data. We’ve now treated 66 patients, most of whom were taken well above the lifetime maximum allowable dose, and not a single one has exhibited any signs of cardiotoxicity. But the absence of cardiotoxicity is meaningless without efficacy. And up until now, that’s been the big unanswered question. Could Annamycin actually deliver enough activity in a phase 2 setting to be worthy of marketing approval? Well, that question is now being answered. Yes, the data are preliminary, and we need to substantiate what we’ve shown you with a few more patients. But with those caveats in mind, Annamycin is delivering, and it has everything it needs in order to become what we believe will be a multi-billion dollar drug.

And it all comes back to our core belief. The most important tool for AML and advanced STS, as well as a host of other hard-to-treat cancers, is an anthracycline. Those anthracyclines haven’t been improved in decades. Annamycin finally represents a real improvement in anthracyclines, and we’re going to make this tool available to those patients who, until now, have been denied this opportunity. So that wraps up our prepared presentation for the quarter, Jenene. We’d be happy to handle any questions folks have.

Operator: Thank you. We will now be conducting a question and answer session. [Operator Instructions] Our first questions come from the line of Jonathan Aschoff with ROTH MKM. Please proceed with your questions.

Jonathan Aschoff: Thanks. Good morning. Congrats on the data, but what I wanted to ask about it, can you really exclude from the percent CR rate analysis in AML, the Cytarabine, SAA, SAE, as well as the stroke patient? Shouldn’t that denominator be 10?

Walter Klemp: Paul, I think you’re probably best to address the statistical basis for establishing CR rates. You want to tackle this one?

Paul Waymack: Yes. Certainly, in a pivotal trial with the intent to treat analysis, you would include them all. As a Phase 2 study, we do things differently. In a pivotal trial, because the person had an allergic reaction to Cytarabine, we would have just continued treating with Annamycin alone since in the 105 monotherapy trial, we were getting similar results of a CR rate around 40%. We just wanted to present here patients who had finished. I would point out we’ve got another patient in this trial who finished their therapy. We have verbal confirmation from the site that they had a CR, but we don’t put that in the slide deck until we have the written documentation. So we are trying to be very specific in a Phase 2 study with patients who have documented data and who exactly followed the protocol, whereas in the pivotal Phase 3 trial, it would be more broadly in the intent to treat analysis.

Jonathan Aschoff: Okay. Is it fair to say that for the STS LM data set in today’s press release that it is no new data compared to the update a week ago?

Walter Klemp: Yes. John, you’re most familiar with what’s been publicly shared. Do you want to dial that in?

Paul Waymack: No. I would disagree, Jonathan. If you look at the chart that we presented on slide 19 and also in the queue and also believe the press release, when you start, remember we took all comers into this trial. We took up to people with up to 11 prior therapies. If you look at the right-hand side of that chart, you get down to where you’re looking at second and third line therapies. Add a dose that we zeroed in on, and we’re getting substantially better data. I’d look at that waterfall. I’d look at that waterfall data.

Jonathan Aschoff: But it’s the same N of patients that was prior reported on. It’s just greater duration data, correct?

Paul Waymack: No. We reported the 67% was Phase 1B, and then we moved on, and now we’re presenting the Phase 2 data. And so what we did was we added 17 patients, and you can see the waterfall data, how it goes across that chart. And so we end up, once we start looking at the 330 milligrams and below patients, we found out that 360 and 390 was just too much, and people with less prior therapies. We got better results. We got results, comparative to dacarbazine and trabectadine. And worse ones.

Jonathan Aschoff: To be fair to me, though, I mean, I’ve written up notes in the past of three Phase 1B patients at the recommended Phase 2 dose and 14 Phase 2 patients, all of whom must be taking the recommended Phase 2 dose, and that adds up to 17.

Walter Klemp: Yes, I think the point here, Jonathan, is since that last report, we now have updated PFS, updated OS, as well as segment data that just hadn’t been elucidated. So I take your point, but I think there’s important new information that we’re sharing for the first time in this release.

Jonathan Aschoff: All right. Now, lastly, how many patients do you expect to have to enroll in a pivotal trial for both AML and STS-LM?

Walter Klemp: So, Paul, you spent more time than anybody focusing on the proposed pivotal trial protocols, and I know you’ve had lengthy discussions both with investigators and statisticians, so you want to tackle that one?

Paul Waymack: The ultimate answer is whatever the FDA demands. For soft tissue sarcoma, we have not finalized the plans for the pivotal trial yet because, as I mentioned, patients are still going on, and we have not reached median overall survival and the like. We would anticipate it will be in the few hundreds, but we can’t give you an exact number yet because that trial, the efficacy data are still coming in. For the AML, as we have mentioned before, we would like to go for first-line therapy. The 106-trial we’re doing now, we are now enrolling first-line therapy patients to get data to make sure that the results are similar, if not better, than what we have seen to date. Based on FDA guidance documents, we would propose going to the FDA and getting approval based on a single trial.