Briggs Morrison
Analyst · Barclays
Great. Thank you very much, Melissa, and thank you to everyone for joining us on today's call and webcast. Let me start my comments by welcoming Daphne Karydas to Syndax as our new Chief Financial Officer. Daphne completed her formal education at MIT and Harvard and has a distinguished professional career at North America's most prestigious financial and pharmaceutical firms. We are truly honored to have her joining our team. You'll hear more from her later in the call. I'd also like to take this opportunity to thank Rick Shea for his exceptional contributions to Syndax and wish him every success in his well-earned retirement. Let me now turn to Slide 3, which 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. The second quarter of this year was quite eventful for Syndax. We were extremely disappointed when ECOG informed us that E2112, the Phase III trial of entinostat in hormone receptor positive HER2-negative breast cancer, did not achieve the primary endpoint of demonstrating a critically significant overall survival benefit. Entinostat has been deprioritized in our portfolio. And as Daphne will discuss, our go-forward budget forecast includes only closeout costs for entinostat. We continue to collect encouraging data that will further clarify the potential of our anti-CSF-1R antibody, axatilamab, to treat chronic graft versus host disease. And at AACR, we presented the first clinical evidence that inhibition of the menin-MLL1 interaction by SNDX-5613, our menin inhibitor, can induce response in patients with MLL-r acute leukemia. In the second quarter, we were granted orphan designation by FDA for 5613 for the treatment of adult and pediatric AML. We also announced the successful addition of over $100 million to our balance sheet under attractive terms. Let's now turn to Slide 4 and 5613, our genetically targeted agent for the treatment of leukemia. As we noted previously, there's extensive validation of both MLL-r and NPM1 mutations has molecular targets in leukemia, and well-established diagnostic tests routinely identify patients with these genetic mutations. Premier publications provide the scientific rationale and preclinical validation of our ongoing clinical trial, and there are historic precedents that support a rapid regulatory path for such targeted agents in acute leukemias. At AACR this year, we presented preclinical and early clinical data for 5613, showing that our molecule is a potent and specific inhibitor of the menin-MLL interaction. The only off-target activity of note is its relatively weak binding to the HER channel, and of clinical relevance, it's primarily metabolized by CYP3A4. On Slide 5, we summarize the detailed experiments that were conducted to drive a model of the plasma exposures, we think, will be needed in patients to drive efficacy. We were, of course, pleased that, as shown on Slide 6, the second patient in the trial and the first patient in the trial with an MLL-r rearrangement had plasma exposures that exceeded the levels we anticipated would be required for efficacy and achieved a complete response. Importantly, this patient safely experienced a deep and rapid response. She was in CR by day 28 of therapy while experiencing nothing more than grade 2 adverse events. Of note, this patient was on a concomitant medication that inhibits the activity of CYP3A4, which may account for the disproportional PK exposure relative to what we had anticipated. Full details on additional patients are included in the AACR presentation that's available on our website. The schema for the updated ongoing AUGMENT-101 trial, the first-in-human trial in the accelerated understanding of menin or AUGMENT program, is shown on Slide 7. The Phase I portion is a dose escalation trial designed to identify the maximum tolerated dose and recommended Phase II dose of 5613 in 2 independent cohorts of patients with relapsed or refractory leukemia. Arm A enrolls patients who are not on a strong CYP3A4 inhibitor and Arm B enrolls patients who are on CYP3A4 inhibitor at the time of enrollment. The first 28 days of dosing serve as the period when safety is evaluated for determining dose escalations. And our intent is to define a recommended Phase II dose for each cohort. In June of this year, we participated in an FDA Pediatric Oncology Drug Advisory Committee meeting regarding our development strategy for SNDX-5613. We were quite pleased with the uniform enthusiasm of the committee and FDA and the support of comments made by several physicians during the public comment session. It's clear to us that the pediatric oncology community and the physicians participating in our trials are excited about the progress we are making. In addition to the ODAC meeting, we have been working closely with FDA to continue to modify AUGMENT-101 as our data accumulates. The split into arm A and arm B is one such example. More recently, based upon the totality of our accumulating data both in AUGMENT-101 and in our pediatric compassionate use experience, we have worked with FDA to further modify the Phase I portion of AUGMENT-101 in 3 important ways. First, FDA has agreed that we can now focus enrollment exclusively to patients with MLL-r or NPM1 mutations. You may recall that the trial initially was open to all adults with relapsed or refractory leukemia. Second, they have agreed to allow us to backfill any dose level up to a total of 12 patients in either arm A or arm B if efficacy has been observed in that dose level. These backfill slots will open up enrollment. It will provide more PK and safety data in an expanded Phase I trial and will give us greater certainty as we enter Phase II and could potentially accelerate our path to eventual approval. And third, FDA has strongly encouraged us to enroll pediatric patients, including any patient over 30 days of age. We believe their encouragement to include pediatric patients so early in the drug development process is based on the results to date in AUGMENT-101 as well as what we are seeing in the compassionate use treatment setting. We continue to receive request to provide drug to children currently ineligible to enroll in AUGMENT-101. And so we've continued to support these compassionate use treatments aligned with the dose levels that have been studied in AUGMENT-101. As we've gotten to doses which can achieve our prespecified PK thresholds, physicians are starting to see activity in these pediatric patients as well. Indeed, we recently received results from an adolescent who was treated on compassionate use, and his clinical course is strikingly similar to patient number two, illustrated on Slide 6. The child had refractory MLL-r AML, received SNDX-5613 at the equivalent of dose level 2 on arm B, that's 226 milligrams by mouth twice a day, in combination with a strong CYP3A4 inhibitor. The patient had plasma exposures that exceeded the levels we anticipated would be required for efficacy, achieved a complete response on day 28 and experienced only grade 1 adverse events. One can only imagine how ecstatic the parents of this child are to have renewed hope for their youngster. We're eager to share publicly the observations that have allowed us to modify AUGMENT-101. Our goal has been to present the completed Phase I portion of AUGMENT-101 in its entirety. And we had hoped to do so by the end of this year. We continue to anticipate identifying a recommended Phase II dose and completing Phase I by the end of this year, and yet these exciting trial enhancements that I've described will now move our presentation of the completed Phase I data into early 2021. As a reminder, the Phase II trial will proceed to enroll 3 distinct expansion cohorts, each of which consists of a specific genetically defined relapsed or refractory acute leukemia. The 3 cohorts are shown on Slide 8 and will include patients with MLL-r ALL, patients with MLL-r AML and patients with NPM1 mutant AML. The Phase II portion will further characterize the safety of 5613 and will provide an initial estimate of the complete response rate as the primary measure of therapeutic benefit. Like the changes to the Phase I, Phase II will enroll both pediatric and adult patients, thereby providing us a potential path to regulatory approval with a broad label, including both adults and pediatrics. We look forward to continuing to update you on the progress of AUGMENT-101 as the year progresses. Let me now turn to Slide 9 in axatilamab, which is formerly known as SNDX-6352, our potential best-in-class monoclonal antibody therapy targeting the CSF-1 receptor. Results from the multiple ascending dose trials exploring axatilamab alone and in combination with durvalumab in patients with solid tumors was presented during this year's AACR meeting, and these results demonstrated the tolerability and robust PD biomarker modulation of axatilamab. It underscored its ability to promote rapid and sustained depletion of circulating pro-inflammatory monocytes at all dose levels tested. As you know, we initiated a trial testing axatilamab as monotherapy in chronic graft versus host disease, and the rationale for that is shown on Slide 10. Chronic graft versus host disease is a frequent complication of hematopoietic stem cell transplantation, wherein the donor-derived immune cells contribute to the initiation and development of fibrosis in the myriad manifestations of this disease. In preclinical models, blocking the CSF-1/CSF-1R with anti-CSF-1R antibodies can result in depletion of donor macrophages and thereby both prevent and reduce chronic graft versus host disease. Last year, we released initial data from our Phase I trial, which is diagrammed on Slide 11. The Phase I portion is a dose escalation trial designed to identify the maximum tolerated dose and a recommended Phase II dose of axatilamab for the treatment of chronic GVHD. We've released data from the first 5 patients enrolled in the first 3 cohorts and have now modified the trial to include a Phase II cohort at the 1 mg per kg dose. We will continue the Phase I trial to more formally define the recommended Phase II dose and may open one or more additional Phase II cohorts as well. We anticipate presenting the Phase I data for approximately 10 to 15 patients at the end of this year at a medical conference. In addition, we are in discussions with regulators concerning the design of a registrational program for chronic graft versus host disease. We anticipate providing full details of the registrational program at our next quarterly call and hope to initiate our registration trial as early as the end of this year. We believe that chronic GVHD represents a high unmet medical need and an important commercial opportunity with approximately 14,000 patients suffering from GVHD in the U.S. today. With the recent positive pivotal results from both Incyte's Jakafi and Kadmon's KD025, we may soon see commercial launches that will begin to delineate the commercial opportunity in chronic graft versus host disease. Despite recent advances in this area, we believe the data generated to date with axatilamab suggests it has the potential to play an important role in the treatment for GVHD. Finally, Slide 12 summarizes the transactions that led to the acquisition of the menin-MLL-r and axatilamab programs. We believe that we will be able to continue to expand our pipeline through the acquisition or in-licensing of quality, differentiated assets. We believe that we have the necessary scale to evaluate and identify high-quality assets and the clinical development experience to bring these compounds through valuable inflection points. We expect to remain among preferred partners of such transactions. I will now turn the call over to Daphne to review our financial results.