Mythili Koneru
Analyst · Oppenheimer
Thank you, Peter. As you just heard, this has been an important quarter for us as we begin enrolling in the safety lead-in portion of our Phase II clinical trial in patients with post-transplant AML. To briefly recap, in February 2020, we announced that the FDA lifted the clinical hold on this trial, permitting us to initiate the safety lead-in portion, which is expected to enroll approximately 6 patients. 3 patients will be dosed with zelenoleucel, or MT-401, our lead product candidate, manufactured with the legacy reagent, which was used in the Phase I trial conducted by our partners at the Baylor College of Medicine. The remaining 3 patients will be dosed with study drug manufactured using a new reagent from an alternative supplier. The study remains on partial clinical hold pending the review of the final data, and subsequent acceptance of certificate of analysis for this new reagent by the FDA. In parallel to working with our supplier to receive the required information satisfactory for lifting the partial hold, which we anticipate could be in Q1 of 2021, our team remains hard at work identifying trial sites and enrolling eligible patients in currently open sites. At this time, we have 4 sites that have been activated and can enroll patients, and we plan to have additional 2 to 3 sites by year-end. Moreover, beginning next year, we will open approximately 20 sites in total for the Phase II portion of the study. We are making solid progress and have already enrolled our first patient and anticipate treating this patient by January or earlier. To give you a clearer picture of the treatment challenges faced by oncologists today and why we are so encouraged by this data in the post-transplant AML setting, I would like to briefly review some important details about this devastating disease. According to the American Cancer Society, there will be about 60,000 new cases of leukemia in 2020 with about 20,000 of those representing AML patients. The mainstay treatment today is chemotherapy, sometimes in combination with bone marrow transplant. But unfortunately, approximately half of the patients will relapse post-transplant, many within the first year, thereby highlighting the unmet medical need. Our cell therapy was designed to address the shortcomings of current treatments while maintaining patient safety. Many cellular therapies in development today are pursuing a single or even dual target. However, this approach has demonstrated limited improvements in patient outcomes. In contrast, we believe our multi-antigen approach has the potential to induce a lasting antitumor effect by allowing the patient's own T cells to expand and kill cancer cells. By targeting multiple antigens and epitopes present within the tumor, we believe our Multi-TAA T cell therapy can effectively address the tumor heterogeneity, while recruitment of the endogenous immunity leads to amplification of immune response by epitope spreading. The Phase II study represents our first company-sponsored clinical trial. As a reminder, MT-401 was granted orphan drug designation in post-transplant AML and has been well tolerated in an ongoing Phase I clinical trial conducted by our partners at the Baylor College of Medicine in this setting. As reported in March 2019, 11 of the 13 patients in the adjuvant setting, dosed with the MultiTAA-specific T cell therapy after receiving an allogeneic stem cell transplant derived, ranging from 6 weeks to 2.5 years postinfusion, while 9 of these remaining patients and continuing complete remission, or CR. Survival of the 6 patients with active disease range from 4 to 21 months as compared to historical survival rate of approximately 4.5 months for patients who received the standard of care post-transplant. In the Phase I study conducted by our academic collaborators at BCM, our products show to be well tolerated with no incidence of cytokine release syndrome, neurotoxicity or grade 3 to 4 GvHD in the post-allogeneic setting. Importantly, it demonstrated an antitumor effects as well as significant in vivo expansion of T cells. To this end, we believe our novel MultiTAA-specific T cell therapy could potentially offer clinical benefit for these patients without the toxicities of standard-of-care treatment. We continue to be encouraged by this early data and are looking forward to working with our clinical sites to continue enrolling patients in our Phase II study. As a reminder, this multicenter AML study will be evaluating the clinical efficacy of our product in patients with AML in both an adjuvant and active disease setting, following an allogeneic stem cell transplant. The dose administered will be the maximum tolerated dose from the Baylor-sponsored Phase I study. In the adjuvant setting, approximately 120 patients will be randomized 1:1, either MT-401 at 90 days post-transplant versus standard-of-care observation, while about 40 patients with active disease will receive MT-401 as part of the single-arm group. The primary objectives of the trial are to evaluate relapse-free survival in the adjuvant group and determine the complete remission rate and duration of complete remission in the active disease patients. Additional objectives include, for the adjuvant group: overall survival in graft-versus-host disease; relapse-free survival; while additional objectives for the active disease group include: overall response rate; duration of response; progression-free survival; and overall survival. And with that, I'd like to hand the call over to Dr. Juan Vera, our Chief Development Officer.