cemacabtagene ansegedleucel (ALLO-501A)

"Allogene Therapeutics...and Foresight Diagnostics (Foresight)...announced a strategic partnership to develop a minimal residual disease (MRD) in-vitro diagnostic (IVD) to determine eligibility in ALPHA3, the first pivotal trial for first line (1L) consolidation treatment of large B-cell lymphoma (LBCL). The ALPHA3 trial uses Foresight’s investigational PhasED-Seq™ ctDNA-MRD platform to identify patients with MRD after 1L treatment for LBCL. The study will evaluate whether such patients benefit from consolidation with cemacabtagene ansegedleucel, or cema-cel (previously known as ALLO-501A)....The ALPHA3 pivotal Phase 2 trial in first line (1L) consolidation for the treatment of LBCL is expected to begin mid-2024."

We identified 11 patients with relapsed/refractory large B-cell lymphoma treated on the ALPHA-2 phase 1 trial (NCT04416984) with ALLO-501A, a healthy donor-derived CD19 CAR T with T cell receptor (TCR) knockout...We revealed the impact of recipient alloreactive CD8+ T cells in allogeneic CAR T rejection and identified expansion of identical allogeneic CAR T clonotypes with retained clonal hierarchy in multiple patients. While patient factors such as tumor burden and target antigen expression likely play a role as well, our results suggest that strategies to eliminate alloreactive recipient cells and enhance allogeneic CAR T fitness through improved product design, manufacturing and lymphodepletion could improve allogeneic CAR T expansion, persistence and efficacy.

Conditioning with a regimen of fludarabine (F)/cyclophosphamide (C)/ALLO-647 (A, a humanized anti-CD52 monoclonal IgG1) targets host CD52+ immune cells for elimination while allowing subsequently infused CD52-knock-out ALLO-501/501A cells to persist. A single dose of AlloCAR T therapy following FCA90 conditioning provided durable responses with a manageablesafety profile in autologous CAR T-naïve pts with r/r LBCL. Among 8 pts who received FCA90 and ALLO-501/501A and had the opportunity to be evaluated for 6 months, 50% maintained that response for at least 6 months, with a median DOR of 23.1 months. These findings support broader evaluation of ALLO-501A/ALLO-647 in the ongoing, first potentially pivotal phase 2 trial (ALPHA2) of AlloCAR T therapy.