Briggs Morrison
Analyst · BTIG
Thank you very much, Melissa, and thank you to everyone joining us on today's call and webcast. This afternoon, I will share the progress we've made during the third quarter as we continue to execute on our corporate strategy in support of our primary mission: to realize a future in which people with cancer live longer and better than ever before. Slide 3 provides a high-level summary of our corporate strategy, and I will touch on each of these strategic pillars during today's call. We just held a call on October 25 to discuss some of our programs, so my prepared remarks will be brief. Slide 4 is a summary of the near-term investment thesis for Syndax. We'd like to remind investors that 2019 is shaping up to be a very significant year for Syndax with multiple opportunities to unlock tremendous value for shareholders. There are 2 overall survival interim analyses for E2112, our Phase III trial in hormone receptor-positive HER2-negative breast cancer. And I want to again emphasize that a positive OS trial in hormone receptor-positive HER2-negative breast cancer would be a landmark result and could be transformative for Syndax and its shareholders. We also have readouts from our randomized Phase II trials, ENCORE 602 and 603, exploring the combination of entinostat and a PD-1 pathway antagonist in triple-negative breast and ovarian cancer. Both ENCORE 602 and 603 are randomized placebo-controlled trials, which allow very straightforward interpretation of trial results. If either is positive, that would represent one of the first randomized trials to validate a novel mechanism that adds to the efficacy of a PD-1 pathway antagonist. We anticipate having early clinical data from our chronic graft versus host disease trial with SNDX-6352. And finally, we are on track to file the IND and start clinical trials for our amended inhibitor, which we have now named SNDX-5613. As we continue to learn more about the potential of SNDX-5613 in acute leukemia, we see this molecule becoming an additional and important value driver for our company. So again, 2019 is shaping up to be a very significant year for Syndax. Let me now turn to Slide 5 and give you an update on our Phase III trial of entinostat in hormone receptor-positive HER2-negative breast cancer. Slide 5, again, summarizes the trial design. The trial has now randomized 608 patients to exemestane plus placebo versus exemestane plus entinostat, and the focus of this trial is now clearly and unequivocally on overall survival. As we've noted before, overall survival interim analyses are done approximately every 6 months, so the next interim OS analyses will be around May and November of 2019. Positive outcome at any of these OS interim analyses or upon achieving the final number of events lead us to conclude the study with allow us to file for regulatory approval based upon the terms of our special protocol assessment with the FDA. We remain very confident in the possibility that E2112 will achieve a survival benefit. Recall that it was the Phase II overall survival results that led to the granting of the Breakthrough Therapy designation by FDA. And as I summarized on our call on October 25, based upon the results of the Phase II trial, combined with the statistical design of E2112, we've always believed that the OS endpoint was more likely to be positive than the PFS endpoint in E2112. Hence, the fact that PFS did not achieve the very high statistical hurdle of a p-value of 0.002 does not, in any way, diminish our confidence in the possibility of achieving a survival benefit in E2112. We also know that overall survival is the most valued endpoint for patients, for physicians, for regulators and for payers, and hence, a positive OS trial would enable both rapid regulatory review in the U.S. and in Europe and potentially rapid payer access. Slide 6, again, emphasizes potential for the entinostat-exemestane regimen to be the preferred agent after CDK4/6 therapy for HER2-positive - for HR-positive breast cancer. We know that CDK4/6 therapies, most notably, Ibrance, are being used increasingly as first-line agent, but that there's a clear desire to understand what therapies will be effective when the patients would stop responding to a CDK4/6 inhibitor. Our current estimate is that between 30% and 50% of patients in E2112 will have received a CDK4/6 inhibitor prior to entering the trial, and thus, we will have a highly relevant dataset in this population. This population of patients is relatively large with an estimated 34,000 patients each year who'll go on to receive hormone therapy after failing first-line therapy and could therefore potentially be eligible to receive entinostat. Slide 7 summarizes our ENCORE clinical trial program, which we are testing entinostat in combination with PD-1 pathway antagonists, either PD-1 antibodies or PD-L1 antibodies. We've now communicated our plan for non-small cell lung cancer, and we are continuing to follow patients in the melanoma cohort of ENCORE 601. Our randomized placebo-controlled trials of triple negative and ovarian cancer are fully enrolled; as is our single-arm colorectal cancer trial, with readouts anticipated in the first half of next year for all 3 indications. We've previously communicated, as we complete our initial clinical trials in each tumor type, we will prioritize which indications to advance to registration trials based upon a combination of unmet medical need, the competitive landscape and our ability to generate an attractive return on our investment. Taking those factors into account, we announced that we are moving forward with a biomarker-based registration trial in non-small cell lung cancer patients whose disease has progressed after both platinum-based combination chemotherapy and the PD-1 antagonist. Slide 8 summarizes the emerging area of clear unmet medical need for patients with non-small cell lung cancer whose tumors have progressed after both a platinum-based combination chemo and a PD-1 antagonist. Slide 8 also points out that the use of biomarkers for selecting patients for appropriate therapy is common practice today in non-small cell lung cancer. Assuming a positive outcome from our focused biomarker-driven trial, which we are now calling ENCORE 607, we believe the novel biomarker we are evaluating could transition easily into this treatment landscape. Turning to Slide 9, I'd like to briefly, again, review ENCORE 607, the registration trial we designed for entinostat-KEYTRUDA combination based on discussions with non-small cell lung cancer experts as well as input from the FDA. To enroll in the study, patients must have received a platinum double-based chemotherapy in pembrolizumab. Pembrolizumab must be their immediately last therapy before entering the trial. We anticipate that the majority of patients will have received the triplet of pembrolizumab, pemetrexed and cisplatin, a regimen used in KEYNOTE-189, and will have progressed while on maintenance pembrolizumab. Patients will also be allowed to enter if they have received platinum-based chemotherapy as first-line treatment followed by pembrolizumab as second line. We will first assess the level of classical monocytes in the purple blood using a validated assay. Patients with low monocytes will be treated with entinostat plus KEYTRUDA. Those with high monocytes will be randomized to be treated with standard-of-care chemotherapy of the investigator's choice versus the entinostat-KEYTRUDA combination. Following discussions with FDA, the primary endpoint of the trial is PFS based upon the PFS data we saw in Phase II. Let me again call out two key points about this focused biomarker-driven trial. The trial is designed both to validate the classical monocyte biomarker and to demonstrate that the combination therapy of entinostat plus KEYTRUDA is superior to standard-of-care chemotherapy in the high monocyte population. The trial will enroll approximately 180 patients with data potentially available within 2 years, second half of 2020. This could position us to be the first novel therapy with regulatory approval both in the U.S. and EU in the sizable population of lung cancer patients. Slide 10 summarizes designs for ENCORE 602 and 603. ENCORE 602 is our Phase II trial exploring the combination of entinostat with atezolizumab at triple negative breast cancer in patients who have received at least 1 but no more than 2 prior lines of therapy. And ENCORE 603 is our Phase II trial exploring the combination of entinostat with avelumab in ovarian cancer for patients who have received at least 3 but no more than 6 lines of prior therapy, including at least one course of platinum-based therapy. Both ENCORE 602 and 603 are randomized placebo-controlled trials, which allows very straightforward interpretation of trial results. And we anticipate results from ENCORE 603 in the first quarter of 2019, results from ENCORE 602 in the second quarter. In summary, as shown on Slide 11, we expect multiple exciting value inflection points across our ENCORE I/O combination trials over the next month. Again, as we complete our initial clinical trials in each tumor type, we will prioritize which indications to advance to registration trials based upon unmet need, the competitive landscape and our ability to generate an attractive return on our investment. We've already announced that we will go forward with registration trial in non-small cell lung cancer patients whose disease has progressed after both platinum-based combination chemotherapy and a PD-1 antagonist. We will consider further investments as data matures in our other proof-of-concept trials. Let me now turn to Slide 12 and SNDX-6352, our potential best-in-class monoclonal antibody therapy targeted as CSF-1 receptor. We presented the Phase I healthy volunteer data at SITC in November of 2017. And the multiple ascending dose study in cancer patients is ongoing as is the combination trial of 6352 with IMFINZI, AZ's PD-L1 inhibitor. We anticipate selecting a recommended Phase II dose sometime in the second quarter of '19. Our chronic graft versus host disease trial is now underway, and we anticipate data from that trial about a year from now. Last, but certainly not least, on Slide 13, I summarized our Menin-MLL-r program. As mentioned earlier, we've now selected a development candidate, which we call SNDX-5613, and remain on track to file an IND in the first half of 2019. To date, we've generated a significant amount of preclinical evidence suggesting that these molecules can target two genetically-defined leukemias, MLL rearranged leukemias and the NPM1 mutant leukemias, which together represent a fairly sizable patient population. We presented exciting positive data at this year's AACR demonstrating efficacy in PDX models of both of these leukemic subsets, and those presentations can be found on our website. There will also be 2 presentations highlighting our Menin-MLLr program at the ASH Annual Meeting next month, including an overview of the field by Dr. Scott Armstrong from the Dana-Farber and additional data on the role of the Menin-MLL-r interaction in NPM1 mutant leukemia. We plan to continue exploring indications where these agents could make an impact, especially focused on settings where Menin has been implicated as a driver of disease. I want to emphasize that we see a rapid and straightforward clinical development path for SNDX-5613 like the path that was taken for patients with TRK fusions or IDH1 mutation. We expect that the molecules or should have a single-agent activity. We will, of course, target patients who have either an MLL rearrangement or NPM1 mutation. These patients are readily identifiable in clinical practice today and present an area of high unmet medical need. It's quite possible that we could observe clinical activity early in the clinical development path, again unlocking significant value for Syndax shareholders. As we continue to learn more about the potential of SNDX-5613 in acute leukemia, we see this molecule becoming an additional and important value driver for our company. Now with that, I'll turn it over to Rick for the financial update.