Allogene Therapeutics provides additional ALLO-501/501A Phase 1 data

Allogene Therapeutics at the International Conference on Malignant Lymphoma in Lugano, Switzerland presented updated data from the Phase 1 ALPHA/ALPHA2 trials of ALLO-501/501A in 33 CAR T naive patients with relapsed/refractory large B-cell lymphoma treated with the Alloy manufacturing process material across different CAR T dosing and lymphodepletion regimens. Earlier in June, data from the 12 patients, a subset of these 33 CAR T naive patients, who received regimen being utilized in ongoing Phase 2 trials was presented at American Society of Clinical Oncology Annual Meeting. The updated analysis of ALPHA/ALPHA2 examined data from all 33 CAR T-naive patients with r/r LBCL who were treated with a single infusion or consolidation therapy of ALLO-501/501A manufactured using the Alloy manufacturing process. Patients received lymphodepletion with fludarabine and cyclophosphamide and varying doses of ALLO-647. The median time from enrollment to the start of therapy was three days and 100% of patients received product per specifications. No patients received bridging therapy. The dosing breakdown for the 33 patients included in this data set is as follows: 12 patients treated with a single dose of ALLO-501/501A and FCA90 lymphodepletion: 6 patients treated with a single dose of ALLO-501/501A and FCAless than90 lymphodepletion; 15 patients treated with consolidation dosing of ALLO-501/501A and split lymphodepletion. Seven of 12 (58%) patients receiving the Phase 2 regimen achieved a CR and five maintained a CR through Month 6. Of the five patients who were in CR at 6 months, four remained in CR. The fifth patient had disease progression at 24 months. The median duration of response was 23.1 months with three patients remaining in remission for over 24 months and the longest remaining in remission for over 31 months. Across all 33 patients the CR rate was 42% with 30% maintaining a CR at Month 6. These results indicate complete responses are more common with lymphodepletion regimens containing 90 mg of ALLO-647.. Median duration of response for both the overall population and the patients treated with the Phase 2 regimen was 23.1 months. Across the 33 patients, treatment was generally well tolerated with no incidences of Grade 3 or greater cytokine release syndrome, and no cases of immune effector cell-associated neurotoxicity syndrome or graft versus host disease. Cytopenia and infections were manageable and comparable to the experience with autologous CAR T cell therapies in patients with r/r LBCL. The ALPHA/ALPHA2 Phase 1 trials were designed to assess the safety, tolerability, and preliminary efficacy at increasing dose levels of ALLO-501 and ALLO-501A, allogeneic CAR T cell product candidates that target CD19. In addition to exploring multiple cell doses, these studies evaluated various doses of ALLO-647, Allogene’s proprietary lymphodepleting antibody designed to prevent premature rejection of AlloCAR T cells. Allogene is currently enrolling the potentially pivotal Phase 2 ALPHA2 trial of ALLO-501A in LBCL and expects to complete enrollment in 1H2024. The Company expects to open trial sites in Europe, Canada and Australia during 2023.