Rafael Amado
Analyst · Cowen and Company. Your line is now open
Thank you, David, and I hope you are all staying safe. I'm extremely pleased to report that the initial data from our Phase I ALPHA trial from ALLO-501 presented in an oral session at the virtual ASCO meeting in May exceeded our expectations. Responses were observed across all cell doses and tumor histologies, diffuse large B-cell lymphoma and follicular lymphoma, with an overall response rate of 63% and a complete response rate of 37%. With a median follow-up of 3.8 months, nine of the 12 responding patients or 75% remained in response until the data cutoff. Included in their overall efficacy analysis are 3 patients who were refractory to prior autologous CAR-T therapy. The best response for these patients was disease progression within 3 months. None of these patients responded to AlloCAR T therapy. In CAR-T naive patients, the ORR was 75% and the CR rate was 44%. As David noted, a higher dose ALLO-647 was associated with a higher complete response rate of 50%, deeper lymphodepletion and delayed host T cell recovery, while sparing neutrophils and platelets. One of the ongoing responders was a patient with an initial PR who progressed by month two. This was a patient that David referred to earlier, who achieved a complete response after retreatment with the same dose of ALLO-501, a 90-milligram dose of ALLO-647. I would like now to put this data into context. Firstly, the enrolled population was heavily pretreated. The median number of regimens was poor. 95% have stage 3 or stage 4 disease, and 86% of the 22 patients were refractory to the last regimen as defined by progression within 12 months of therapy. We treated a mix of follicular lymphoma and diffuse large B-cell lymphoma patients. This was done to collect as much information as possible in this Phase I study. We were able to gain clear signals of activity in both patients subsets. You may recall from our ASCO investor meeting that we juxtaposed our initial data from the CAR-T naive patients in the ALPHA study with the results published from a range of autologous CAR-T studies. The point of that analysis was not to make direct comparisons that this study's varying composition, size, Phase II development, enrollment criteria and a number of other parameters, but rather to illustrate what may be possible with our CAR-T. The results of this analysis showed clear similarities between autologous and AlloCAR-T in response rates at this early time point. While these promising initial findings will need to be confirmed with more patient experience and longer follow-up times, we believe we have answered yes to several important questions that the ALPHA trial aimed to address, namely, ALLO-501 can be successfully manufactured; ALLO-501 can be safely administered without causing clinically relevant graft-versus-host disease; ALLO-647 can be safely administered and it leads to dose-dependent lymphodepletion that associates with ALLO-501 expansion; and ALLO-501 can provide complete responses across multiple histologies. Beyond these questions, we've also gained important understanding as to which patients may not respond to Allo CAR-T therapy, how we may be able to improve patient outcomes with redosing, which continues in the current protocol and how to optimize lymphodepletion. In addition, the promising safety profile demonstrated by ALLO-501 and ALLO-647 opened up the potential to explore dosing in the outpatient setting. Overall, these findings enhance our enthusiasm for what may ultimately be possible with the AlloCAR-T therapy platform. We look forward to our next data readout from the ALPHA trial, which we expect to be in late 2020 or early 2021. Meanwhile, our Phase I/II ALPHA2 study is actively enrolling patients. ALPHA2 is a single-arm, open-label multicenter study of ALLO-501A in non-HLA-matched adult patients with relapsed/refractory large B-cell lymphoma. Patients with follicular lymphoma are excluded. Patients must have received at least two prior lines of therapy, including an anthracycline and an anti-CD20 monoclonal antibody. While prior autologous CAR-T therapy is ALLO, if the tumor remains CD19-positive in patients who previously responded to autologous CD19 CAR-T therapy, we are considering whether to enroll autologous CAR-T patients as we learn more from the ALPHA trial experience about the outcome of patients who had a meaningful response to autologous treatment. The primary objective of Phase 1 is to evaluate the safety and tolerability of escalating doses of ALLO-501A in combination with ALLO-647, cyclophosphamide and fludarabine. Key secondary objectives include ALLO-501A cell kinetics, ALLO-647 pharmacokinetics and depth and duration of host lymphocyte depletion. The study will replicate certain aspects of the ALPHA study to corroborate the findings from that trial. We initiated dosing with ALLO-501A at 40 million Allo CAR-T positive cells, a dose cohort that was abbreviated to a single patient. The trial will follow a 3-plus-3 design with patients enrolling a dose level two cohort of 120 million cells, and a dose level cohort of 360 million Allo CAR-T cells. We're using a total dose of 90 milligrams of ALLO-647 administered concomitantly with flu/cy. We continue to target moving into the Phase II portion of this study in 2021. Our additional clinical focus is our Anti-BCMA Allo CAR-T cell therapy for the treatment of relapsed/refractory multiple myeloma. We have a 3-pronged clinical strategy targeting BCMA. UNIVERSAL, our Phase I trial with ALLO-715 is well underway, and we are on track to report initial data from this trial in the fourth quarter of this year. This study was initially designed to explore optimal dosing of all the components of the lymphodepletion regimen, including ALLO-647, fludarabine and cyclophosphamide with patients receiving ALLO-715 at 1 of 3 doses: 40 million, 160 million and 320 million cells in a 3-plus-3 dose-escalation design. As David noted, we have recently completed the initial dose-escalation portion of the UNIVERSAL trial using 39 milligrams of ALLO-647 and enrolling in other lymphodepletion cohorts, which admit fludarabine. The endpoints being assessed are safety, tolerability, death and duration of lymphodepletion, cell expansion and antitumor activity, including minimal residual disease rate. Given the complexities of this disease and propensity for disease progression for patients with multiple myeloma, we are excited to explore regimens, which include both lower and higher doses of ALLO-647. We also look forward to applying all the lessons learned across our platforms, such as redosing as we evaluate ways to optimize therapy for this patient population in need of novel treatment. The other two prongs of our BCMA strategy include exploring the use of a gamma secretase inhibitor in combination with ALLO-715 and investigating our Turbo CAR-T echnology platform to potentially enhance the efficacy of an anti-BCMA CAR-T therapy in myeloma. Since our last earnings call, we have advanced a regulatory discussion on how to best evaluate the combination of ALLO-715 with the gamma secretase inhibitor, nirogacestat, from our partners at SpringWorks Therapeutics. We expect to file an IND to support the clinical evaluation of this combination this year. The innovation behind TurboCAR could be a breakthrough as this technology has the potential to expand Allo CAR-T cell viability and efficacy while reducing CAR-T cell dose requirement and overcoming exhaustion. These properties may enable CAR-T therapies in harder to treat hematologic malignancies and solid tumors. ALLO-605 will be our first TurboCAR clinical candidate. We are excited about what this technology may mean for next-generation AlloCAR-T therapy in multiple myeloma and anticipate submitting an IND for ALLO-605 in 2021. At the American Society of Gene and Cell Therapy Annual Meeting in May, we presented preclinical findings on our Turbo CAR-T echnology. The versatility of this technology could allow us to harness the signaling of different cytokines. And we believe TurboCAR could eventually become a standard for Allo CAR-T platform. As our clinical teams focus on clinical trial progression for ALLO-501, ALLO-501A and ALLO-715, our research teams continue to progress our preclinical activities. Our preclinical work on ALLO-316, our anti-CD70 candidate, continues as we look to traverse the use of cell therapy from hematologic malignancies into solid tumors. Our ALLO-316 IND is planned by the end of this year in treatment-resistant renal cell carcinoma with the potential to study other malignancies in the future. In addition to the above, preclinical work continues on candidates, such as ALLO-819, an investigational AlloCAR-T therapy targeting Flt3 as a novel treatment for acute myelogenous leukemia as well as earlier stage technologies, such as our induced pluripotent stem cell program. We are relentless in our pursuit to bring Allo CAR-T therapy to patients and are very excited by the strong momentum we've achieved across both our clinical and preclinical pipeline. I look forward to continuing to provide updates at scientific congresses. While we continue to leverage our internal capabilities and our existing partners, we will also pursue innovation externally as we advance additional pipeline candidates and next-generation technology. I'd like to now turn the call over to Eric to review financials.