Briggs Morrison
Analyst · Cowen
Thank you, Melissa, and thank you, everyone, for joining us today for today's call. This afternoon I'll walk you through our clinical pipeline and share the progress we've made during the second quarter. Slide 3 provides a snapshot of our clinical stage programs, which include two potential best-in-class molecules; entinostat and SNDX-6352 being tested in five ongoing clinical trials across six different indications. As you can see on Slide 4, the second quarter was marked by a substantial progress, most notably in our ENCORE 601 trial. As a remainder, ENCORE 601 is our Phase 1b/2 clinical trial, evaluating the combination of entinostat plus Merck's anti-PD-1 blocking therapy, KEYTRUDA, or pembrolizumab. In May, we announced that the PD-1 refractory non-small cell lung cancer cohort satisfied the pre-specified efficacy criteria for advancement into the second and definitive stage of the Phase 2 trial. Earlier in the year, we had announced that the PD-1 refectory melanoma cohort had also satisfied the pre-specified efficacy criteria for advancement into the second stage of the Phase 2 trial. And in June, we presented positive results from the stage one of the melanoma cohort at the American Society of Clinical Oncology annual meeting. We also had a very productive Type B meeting with the FDA to review these results in melanoma patients and to discuss potential registration pathways for entinostat, including a potential path for accelerated approval. We are currently evaluating specific development options and will provide you with updates on our plans by the end of the year. Slide 5 summarizes the status of our ENCORE 601 trial. Notably, we are pleased to announce that enrolment in the second stage of the melanoma cohort of ENCORE 601, which has now enrolled a total of 34 patients, has completed ahead of schedule. We anticipate being able to share biomarker data from stage one of this cohort at the Society of Immunotherapy for Cancer annual meeting, the SITC meeting, in the fourth quarter of this year. And the full results from both stage one and stage two of this cohort at the Medical Congress in the first half of 2018. As I mentioned earlier in the call, during the second quarter, we announced that the PD-1 refractory non-small cell lung cancer cohort of ENCORE 601 had met the pre-specified objective response threshold to advance into the second stage of the Phase 2 trial. The decision to proceed to the second stage for the PD-1 refractory non-small cell lung cancer cohort used a revised criteria, which required a minimum of three responses out of 31 patients versus the previous benchmark we had discussed, which was at least two responses out of 20. This revision was made by our investigators and the Chief Medical Officer to incorporate the Phase 1b patients, who had received the 5 milligram dose of entinostat. So we have a total of 31 patients now. Enrolment in this cohort will continue until a total of 56 patients are enrolled, which we expect will occur sometime in the fourth quarter of this year. We anticipate presenting data from the full cohort at the Medical Congress in the first half of 2018. The cohort of non-small cell lung cancer patients, who are naïve to PD-1 or PD-L1 therapy, continues with the number of patients remaining on the entinostat-KEYTRUDA combination. In this cohort as well the go/no go criteria had been adjusted to include the Phase 1b patients who are treated with entinostat at five milligram. So for this cohort to the revise criteria now requires a minimum of four responses out of 17 patients versus the previous communicated benchmark of at least three responses out of 13 to determine whether or not to progress this cohort into the second stage. While we had hoped to make the decision on this cohort by the end of June, we now anticipate the decision will occur no later than the end of the year. We anticipate sharing data from stage one of both ENCORE 601 non-small cell lung cancer cohort at SITC in the fourth quarter of this year. Finally, we are pleased to note that our first patient has been dosed in the ENCORE 601 cohort enrolling patients with microsatellite stable colon cancer. As with the rest of the ENCORE 601 cohorts, the trial will employ a Simon two-stage design, with enrollments set at 13 patients in the first stage. A minimum of two confirmed objective responses are required to proceed to the second stage, which would then enroll additional 21 patients for a total of 34. We anticipate a decision on whether to advance the colorectal cohort into the second stage of the trial sometime in the first half of 2018. We believe that the microsatellite stable colorectal cancer population represents a significant unmet need accounting for approximately 85% of the overall colorectal cancer population. And they have been minimal responsive to anti-PD-1 monotherapy. We expect that the current single arm trial design could rapidly provide us with a meaningful signal in the first half of next year that could inform our development strategy in this indication. Shifting gears back to melanoma for a minute. On Slide 6, we illustrate what we believe is the clear unmet need for new treatment options for the roughly 10,000 melanoma patients, who fail the PD-1 antagonist, either given alone or in combination with a CTLA-4 inhibitor. Despite the advances made over the past two years and the availability of a number of new medicines for patients with metastatic melanoma, we believe a significant unmet need remains for patients whose disease has continued to progress despite these approved therapies. I'd like to now briefly review the remainder of the ENCORE program. On Slide 7, we depict the trial designs for our ENCORE 602 and ENCORE 603 trials. ENCORE 602 is a Phase 1b/2 trial exploring the combination of entinostat with Roche/Genentech's anti-PD-1 antibody, TECENTRIQ, in women with metastatic triple negative breast cancer, who have received one or two prior lines of systemic therapy. The primary endpoint of the trial is progression-free survival, with secondary endpoints evaluating overall response rate and overall survival. Enrollment in the randomized Phase 2 portion of the trial after five milligram dose of entinostat remains ongoing and we anticipate to complete enrollment in the fourth quarter. ENCORE 603 is our Phase 1b/2 trial testing entinostat in combination with BAVENCIO, an anti-PD-L1 antibody developed by the Pfizer/Merck KGaA alliance in women with advanced ovarian cancer, who have previously received three to five lines of therapy. Similar to ENCORE 602, the ENCORE 603 trial design includes the safety if running components followed by a randomized Phase 2 component. As with ENCORE 602, the primary endpoint of the Phase 2 part of the trial is PFS, with secondary endpoints evaluating overall response rate and overall survival. Enrollment in the randomized Phase 2 portion of the trial at the five milligram dose in entinostat began last month and we expect to complete enrollment sometime in the first half of 2018. Next turning to Slide 8, we'd like to update you on E2112, our ongoing Phase 3 registration trial of entinostat plus exemestane, an aromatase inhibitor, in 600 patients with advanced hormone receptor positive, HER2 negative breast cancer who progressed following treatment with standard of care. E2112 represents the first Phase 3 trial involving a novel mechanism of action in this setting since the approval of agents targeting CDK4/6. We are conducting this trial in collaboration with the ECOG-ACRIN Cancer Research Group and the National Cancer Institute under a special protocol assessment with the FDA. Notably the terms of this special protocol assessment allows for a potential registration filing on the basis of a positive outcome for either PFS or overall survival. As of the end of July of this year, 78% of the patients have been enrolled and ECOG has advised us that they anticipate their PFS analysis to be available in the first half of 2018, directly following the completion of enrollment. As a reminder, the FDA has granted the combination of entinostat and exemestane Breakthrough Therapy Designation for hormone receptor positive, HER2 negative breast cancer based upon positive results from our Phase 2b clinical trial, where treatment with entinostat plus exemestane demonstrated approximately an eight-month improvement in overall survival versus exemestane alone. As shown on Slide 9, we believe that entinostat had blockbuster potential as a second or third line therapy for hormone receptor positive, HER2 negative metastatic breast cancer. We estimate that there are approximately 34,000 patients who want to receive hormone therapy after failing first line therapy and who could therefore potential be eligible to receive entinostat. Based on feedback from ECOG-ACRIN, we anticipate that about a third or more of the patients enrolled in the E2112 trial will have previously received a CDK4/6 inhibitor and will provide initial evidence of entinostat efficacy in this significant and growing patient population. Let me now turn to SNDX-6352, our monoclonal antibody therapy targeting the CSF-1 receptor. We view SNDX-6352 as a potential best-in-class therapeutic candidate because of its unique profile that includes its high binding affinity, it's ability to prevent binding of both ligands, that is both IL-34 and CSF-1 to the CSF-1 receptor and its potential synergistic activity with other therapeutic class. As depicted on Slide 10, SNDX-6352 functions by blocking the ligand binding domain of the cell surface protein receptors, CSF-1R, which plays a critical role in regulating proliferation, survival and differentiation of tumor-associated macrophages. Tumor-associated macrophages are immunosuppressant cells found in the tumor microenvironment that can inhibit the ability of tumor infiltrating lymphocytes to attack and kill tumor cell. We believe that SNDX-6352 has potential to be used in combination with either checkpoint inhibitors, cell therapy, chemotherapy or radiotherapy, due to the potentially complementary or synergistic effects of such combinations. SNDX-6352 may also be synergistic with entinostat, which has been shown in preclinical experiments to inhibit two other clinically immunosuppressive cells in the tumor microenvironment the myeloid derived suppressor cells and regulatory T cells. We believe that more effective treatment of a variety of cancers will necessitate novel combination strategies to overcome the intense immunosuppression in the tumor microenvironment. The Phase 1 single ascending dose trial of SNDX-6352 in healthy volunteers has completed and we anticipate presenting the results in the fourth quarter of this year. Additionally we anticipate starting the multiple ascending dose trial later this quarter in patients with various solid tumors. Let me pause here and turn the call over to Rick Shea, our Chief Financial Officer to discuss our financial results and update you on our balance sheet.