Thank you for standing by, and welcome to the Syndax Second Quarter 2021 Financial Results Conference Call. . As a reminder, today's conference call is being recorded. I would now turn the conference over to your host, Melissa Forst with Argot Partners. You may begin.

Thank you, Valerie. Welcome and thank you to those of you joining us on the line and the webcast this afternoon for a review of Syndax's second quarter 2021 financial and operating results. With me this afternoon to discuss the results and provide an update on the company's progress are Dr. Briggs Morrison, Chief Executive Officer; and Daphne Karydas, Chief Financial Officer. Also joining us on the call for the question-and-answer session is Michael Metzger, President and Chief Operating Officer; Dr. Michael Meyers, Chief Medical Officer; and Dr. Peter Ordentlich, Chief Scientific Officer. This call is being accompanied by a slide deck that has been posted on the company's website, so I'd ask that you please turn to the forward-looking statements on Slide 2. Before we begin, I would like to remind you that any statements made during this call that are not historical are considered to be forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these statements as a result of various important factors, including those discussed in the Risk Factors section in the company's most recent quarterly report on Form 10-Q as well as other reports filed with the SEC. Any forward-looking statements represent the company's views as of today, August 9, 2021, only. A replay of the call will be available on the company's website at the conclusion of the call. And with that, I'm pleased to turn the call over to you, Dr. Briggs Morrison, Chief Executive Officer of Syndax.

Thanks very much, Melissa, and thank you to everyone joining us on today's call and the webcast. Slide 3 provides a high-level summary of our current corporate priorities as we strive to realize a future in which people with cancer live longer and better than ever before. We have continued to make great progress in both of our clinical programs during the second quarter of this year. AUGMENT-101, our Phase I/II trial of SNDX-5613, our selective menin inhibitor, is progressing as anticipated with a meaningful FDA meeting coming up this quarter. Today, we are announcing that we are initiating 2 trials that capitalize on the favorable combinability profile of 5613 and importantly, one of the trials represents our first opportunity to move into the frontline therapy of AML. For axatilimab, our antibody against CSF-1R, enrollment is ongoing in our pivotal AGAVE-201 trial. We, therefore, remain on track to have 2 registrational programs ongoing this year for 2 first-in-class and potentially best-in-class medicines for 2 areas of important unmet medical need. Thanks to the support of our many committed investors, we are well financed to vigorously pursue both of our existing programs and to aggressively look for additional opportunities to bring targeted oncology drugs into our pipeline. Let's now turn to Slide 4, and our recent data disclosure from the Phase I portion of the AUGMENT-101 trial of SNDX-5613 for the treatment of leukemia. As we noted in our recent data disclosure, in our Phase I trial, 5613 has been well tolerated over multiple cycles with no patient discontinuing for a drug-related adverse event. We were, of course, excited to have also observed clear evidence of monotherapy activity in this population of patients with relapsed or refractory acute leukemia with either MLLr or NPM1c mutations with most responders achieving MRD-negative status.…

Thank you, Briggs. The results of our operations for the second quarter of 2021 and the comparison to the prior year quarter are included in our press release, so I won't repeat them in these remarks. Additional financial details are available in our first quarter report on Form 10-Q, which was filed earlier today. I would like to point out that our net loss for the quarter was $22.9 million, or $0.44 per share, compared to the $17.1 million, or $0.42 per share, for the same period last year. This net loss for the second quarter was below the guidance of $35 million to $40 million of total operating expenses for the quarter, due primarily to the shifting of timing for some CMC activities which shifted into the second half of this year. Turning to Slide 11. We ended the second quarter with $253.1 million in cash and cash equivalents and 51.9 million shares and prefunded warrants outstanding. This cash balance provides us cash runway into 2023 and importantly, covers the development costs for both our lead programs to achieve our corporate objectives and milestones during this period. Looking ahead, I'd like to provide financial guidance for the third quarter of 2021. For the third quarter, we expect R&D expenses to be $25 million to $30 million and total operating expenses to be $30 million to $35 million, including approximately $2.5 million of noncash stock compensation expense. Full year 2021 guidance remains unchanged, and we continue to expect R&D expenses to be $90 million to $100 million and total operating expenses to be $110 million to $120 million, including approximately $2.5 million of noncash stock compensation expense per quarter. With that, I would like now to turn the call back over to Briggs.

Great. Thank you so much, Daphne. Let me close the call by again noting that we have begun the registrational trial for axatilimab in chronic graft versus host disease and are on track to start the registrational program for SNDX-5613 shortly. This management team has been focused on obtaining regulatory approval for drugs that extend and improve the lives of people with cancer and other diseases, and we consider having 2 ongoing registration programs as a major achievement. We are also very excited about the broad franchise opportunities for both programs beyond their initial registration indication. We believe 5613 could have broad utility across a wide range of clinical settings in acute leukemia, and we are excited to be announcing our next steps in building out the SNDX-5613 franchise. Axatilimab also holds the promise of a broad franchise opportunity, both in chronic graft versus host disease and across a broad range of fibrotic disease. We are comfortable given our cash on hand that we have the financial resources to aggressively advance our programs and achieve key upcoming milestones. We remain optimistic that we can continue to identify and bring in novel molecules to deepen our portfolio. We have a proven track record of delivering on this pillar of our corporate strategy, and I believe this is a core strength of our company. As always, I'd like to thank the wonderfully talented team here at Syndax, our collaborators and most importantly, the patients, trial sites and investigators involved with our clinical programs. In addition, I'd like to thank our committed long-term investors, who are helping us build this great company. With that, I'd open the call for questions.

. Our first question comes from Phil Nadeau of Cowen and Company.

A few from us. Just first, would you be willing to disclose the AUC or time above the IC90 for the recommended Phase II doses? Second, will the updated data at year-end include those phased -- the initial experience from the recommended Phase II doses? And then third, what clarity do you hope to get from the FDA meeting?

So Phil, I think your first question, if I heard it correctly, you wanted to know the AUC and time above IC90 for the intermediate doses?

Yes, if you'd be willing to disclose that.

Yes. I think we're going to. I just don't know that off the top of my head. So let me dig into that, and we can get back to you on that. Your second question was at the year-end, would we also have data from the intermediate doses, is that right? And the answer to that is yes. And then the FDA meeting, there are sort of 4 things that we'd like to get some agreement on. Number one, of course, is the recommended Phase II dose. Number two are the endpoints. We are pretty clear that at CR/CRh complemented by information on transfusion independence or infections or other palliative endpoints. Number three is the sample size, how many patients do we need to enroll? And number four is some endorsement that if the data is positive, that these Phase II expansion cohorts could be registrational. So those are some of the things that we want to get in our conversation with them.

Our next comes from Yigal Nochomovitz of Citigroup.

This is Ash Mubarak on for Yigal. Congrats on all the progress. I guess my first one will be on the venetoclax combo. Is it correct to think that there may be an exposure or PK extension benefit for 5613, given that venetoclax is a CYP3A4 inhibitor? And maybe how does that affect the need for 2 different doses depending on CYP3A4 usage? And I guess how are you thinking about the dosing strategy with venetoclax generally?

Right. So just to clarify, venetoclax actually is not a CYP3A4 inhibitor. Venetoclax is metabolized by CYP3A4. So if you look at the venetoclax label, what you'll see is that if you give venetoclax in combination with another drug, that inhibits CYP3A4. There's a dose adjustment for venetoclax, just as we anticipate there is for 5613. So venetoclax should not inhibit the metabolism of 5613, and 5613 should not affect metabolism of venetoclax. So we're pretty optimistic that the combination of 5613 plus venetoclax azacitidine, we should be able, given the safety profile of 5613, to be able to get full doses of both our drug and Vanesa in the triplet.

Okay. I guess my second question would then be on axatilimab and maybe how you're thinking about the evolving landscape, especially with the recent approval of belumosudil and the recent PDUFA extension for ruxolitinib. It sounds like the FDA is being cautious with the JAK. So I'm just kind of wondering how you and maybe physicians for GVHD are perceiving that.

Yes. I mean the initial data we presented at ASH last year, we were quite encouraged to see efficacy from axatilimab in patients who had previously received rux or had previously received belumosudil. So we think there is an evolving now sort of approval landscape for drugs in chronic graft versus host disease. And we think that axatilimab will provide a complementary mechanism that, again, either as monotherapy in patients who have received other therapies or in combination with some of these emerging therapies, we think offers a very promising opportunity for those patients.

Our next question comes from Joel Beatty of Baird.

Congrats on the progress. So it's great to see that there's no dose-limiting toxicities or Grade 3 QTcs in the expansion or any intermediate doses. I think in the prepared remarks, you mentioned that, that may be attributed to efforts at clinical sites to minimize those. Could you tell us more about those efforts?

Yes. Sure, Joel. So the observation has been made by some of our investigators and our clinical staff that a little more, I should say, aggressive correction of electrolytes which, again, is this oral supplementation. It's not very complicated. It's a very straightforward thing. But rather than having patients who have their electrolytes in the normal range, the observations some have made is if you can keep patients in the high normal range, you tend to see less QT prolongation from any agent that is known to cause QT prolongation. So we've been working with the sites to help them with that and educate them on that, and it seems to be paying off. Again, it's pretty straightforward. It's just oral supplementation of their electrolytes. But once we get them into the right range, they do seem to be, again, small number, they do seem to be seeing less QT prolongation.

Great. And then maybe one more question. It's on the Beat AML trial that was announced today. Could you tell us a little bit more about the trial design? And it sounds like there may be multiple phases to it. I guess I'm curious, is there a point in time where there may be a go/no-go decision that may be made for you to decide whether the drug continues or not? And if so, what could that decision be based on?

Yes. So it's a program that essentially we have collaborated with the Beat AML team. The first part, of course, is just is a Phase I to Ash's earlier question of can you get -- what is the right dose of the triplet for each of the agents in the triplet? So that's the Phase I portion. Once we have confirmed that 5613, we have to know the right dose to give a Vanesa, then it goes into a randomized trial of Vanesa versus Vanesa plus 5613. And we'll say more in the future, Joel, about exactly what those -- the go/no-gos are from Phase II to Phase III, but it is sort of set up as sort of -- the initial thought is it'll be a seamless Phase II/III, and there will be a go/no-go, which we'll say more about in the future.

Our next question comes from Peter Lawson of Barclays.

Just on -- as we think about patients rolling over to the Phase II pivotal for your menin inhibitor, how many patients do you think you could have as the Phase II pivotal starts?

Yes. So again, Peter, remember, we had said we could potentially -- what the agency has said is as you continue to backfill cohorts where you've already seen efficacy, those could count. We haven't really said yet how many patients those are, but it just gives you a little bit of a head start as we head into the Phase II. But again, we don't know the final number of patients to be enrolled in the Phase II. So hard to say exactly what the percent of the total Phase II population that represents.

Got you. And then on AUGMENT-102, what chemotherapies are you looking to combine with?

Yes. Michael Meyers, are you on? Can you say more about that? I don't know if Michael is still on.

Sorry, I had trouble getting myself off mute. So yes, Peter, what we were going to combine with would be 2 different regimens that are typically used in relapsed/refractory AML, one being a FLAG-based regimen for AML and then the other would be a 4-drug regimen typically used in ALL.

Okay. And then I guess the final question would just be about other frontline trials that you want to run to and nice to see the one that's about to start, but are there other ones you want to run frontline? And would that go through academic, pharma or non-for-profit organization?

Yes. So we -- I think as we've talked about before, we've been doing quite a bit of work trying to understand what are the various development opportunities. Obviously, a combination with Vanesa, we think is timely and important given its increasing use of standard of care in patients who are not candidates for induction chemotherapy, combining with so-called 7+3 in patients who are candidates for induction chemotherapy also makes sense. And then there are other aspects of the program that we'll be saying more about as the year progresses.

Our next question comes from Justin Walsh from B. Riley Securities.

I have a couple on the Beat trial. So I guess the first is, is there a possibility that a competitor menin inhibitors could get added to that or is it most likely 1 drug from a single class? And then the other question related to Beat is, are you guys actually running the trial yourselves? And how much control do you have over those data releases?

Yes. So the first question, I think we probably have to defer to the LLS team. I don't believe in the arrangement we have with them that they can't include another menin inhibitor if they wish to. I don't -- that's about all I can say. I don't know if they wish to. And then the second question is part of the reason of working with the Beat AML team is because this trial is already up and the sites are all up and the Beat AML team is sort of ready to go, we will let them run the trial. They've proven that they can do this quite efficiently and effectively, we think the trial actually will start faster because they already have all their sites opened. This is just another arm added into the trial, and we've worked closely with them on data disclosures. I think they are as excited to present data as we are.

And our next question comes from David Lebowitz of Morgan Stanley.

When you look at the menin data to date thus far, could you, I guess, elaborate on the efficacy across the doses and how that plays into the ultimate dose selection?

Yes. So again, David, the dose selection -- the recommended Phase II dose selection is not based on efficacy. The dose selection is based upon safety, tolerability and PK. What we have said previously is that when we were looking at the 113 Arm B, 226 Arm A, the efficacy in that population is roughly the same as it is in the overall population, which is really the way that we presented the data. And obviously, we'll have a lot more to say about efficacy by dose, by arm and by mutational status at the end of the year at a medical conference. And as I said in my prepared remarks, we'll also -- we're excited to be able to show the initial durability of the CR/CRh responses as well.

And with respect to the QT elongation, I guess you spoke about how practices were handling, I guess, the newer patients on the different doses differently. Is there any way you could elaborate on how that changed and why those 2 doses seem to have no QT elongation, whereas lower doses did in the prior release?

Yes. So again, if you look at 113 Arm B and the 226 Arm A, there was 1 DLT in each of those. And again, in Arm B, relatively large number of patients. As I said, with the helping sites to make sure that they're adequately or supplementing electrolyte seems to be helping on those intermediate doses, but we'll sort of see how that plays out as we enroll more patients. I think what we had said at the last -- when we presented the data in April is that at the recommended Phase II dose, we were seeing somewhere around 8% or 9% Grade 3 QTc prolongation. It's possible with this closer interaction with the sites and people getting more comfortable with what needs to be done that, that rate could come down as we enroll more patients.

I'm showing no further questions at this time. I'd like to turn the call back over to Dr. Morrison for any closing remarks.

Thanks so much, operator, and thanks, everybody, for joining us on the call. Again, we think it was a very productive quarter. We're excited about the data that we'll be updating at the end of the year at a medical conference, and we're excited to be able to start our first first-line trial. And as Daphne pointed out, I think we're well financed to be able to get through a lot of this work. So thank you all for your attention and your questions. If there's anything else we can do, please get in touch with us.

Thank you. Ladies and gentlemen, this does conclude today's conference. Thank you all for participating. You may all disconnect. Have a great day.