Cellectis announces preliminary data for UCART22, UCART123

Cellectis will host a live webcast reviewing updated clinical data on its Phase 1/2a BALLI-01 clinical trial and on its Phase 1 AMELI-01 clinical trial that were presented in an oral session on December 12, 2022 at the 64th Annual Meeting of the American Society of Hematology, ASH. BALLI-01 is a Phase 1/2a open-label dose-escalation trial evaluating the safety and clinical activity of UCART22 given at escalating dose levels after lymphodepletion with either fludarabine and cyclophosphamide or FC with alemtuzumab in patients with relapsed or refractory acute lymphoblastic leukemia. Alemtuzumab was added to the LD regimen to sustain host T-cell and Natural Killer cell depletion and to promote UCART22 cell expansion and persistence. Compared to the last clinical update on BALLI-01 at ASH 2021, the webcast presented data from five additional patients who received UCART22 at dose level 3 5×106 cells/kg after lymphodepletion with FCA. No dose limiting toxicities, Grade 2 or higher cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome or adverse events of special interest were observed. Evidence of UCART22 anti-tumor activity was observed in 60% (n=3) of the five patients at DL3 after lymphodepletion with FCA: A patient experienced a durable minimal residual disease negative complete response with incomplete count recovery that continues beyond 6 months. A patient experienced an MRD negative complete response that continues beyond Day 56. A patient experienced a morphologic leukemia-free state that continues beyond Day 84. All three of the responders failed multiple lines of prior therapy including chemotherapy, CD19-directed autologous CAR T cell therapy, and allogeneic stem cell transplant. Additionally, the patient with the MRD negative CR also failed both prior blinatumomab and inotuzumab. Overall, these preliminary data support the continued administration of UCART22 after FCA lymphodepletion in patients with r/r ALL. The Company is now enrolling patients in BALLI-01 with product candidate manufactured fully in-house at DL2 after FCA lymphodepletion. The first patient has been dosed at dose level 2 1×106 cells/kg. The next data set is expected to be released in 2023.