On February 13, 2025 Allogene Therapeutics, Inc. (Nasdaq: ALLO), a clinical-stage biotechnology company pioneering the development of allogeneic CAR T (AlloCAR T) products for cancer and autoimmune disease, reported the publication of data from its Phase 1 ALPHA and ALPHA2 clinical studies of cemacabtagene ansegedleucel (cema-cel; formerly ALLO-501/A) in relapsed/refractory (R/R) large B-cell lymphoma (LBCL) as a Rapid Communication in the Journal of Clinical Oncology (Press release, Allogene, FEB 13, 2025, View Source [SID1234650240]). These results represent the largest dataset of LBCL patients treated with an allogeneic CAR T product and, with a minimum of two years of follow-up, the longest follow-up to date.

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"Publication of the Phase 1 ALPHA/ALPHA2 trials in R/R LBCL mark a landmark moment for the field. These findings represent the most robust allogeneic CAR T experience yet presented and show, for the first time, that an "off-the-shelf" CAR T can induce durable complete remissions in a large fraction of patients with heavily pretreated LBCL," said Frederick L. Locke, MD, Chair of the Department of Blood and Marrow Transplant and Cellular Immunotherapy at Moffitt Cancer Center and Research Institute (Tampa, FL). "These peer-reviewed results highlight how cema-cel development is on the cutting edge of lymphoma care, particularly with the ALPHA3 trial targeting only those patients who are MRD positive at the end of first-line treatment. If successful, ALPHA3 and cema-cel could transform the treatment paradigm for newly diagnosed patients."

"With multiple patients in ongoing complete remissions beyond four years, the lingering question of whether an allogeneic CAR T could deliver durable responses has now been answered," said Zachary Roberts, M.D., Ph.D., Executive Vice President, Research and Development and Chief Medical Officer of Allogene. "Furthermore, these results provide potent evidence supporting the use of CAR T in patients with low disease burden and the unique opportunity for the ALPHA3 trial to achieve something novel in this disease – predict and intervene before relapse. Opportunities to redefine the standard of care in oncology are rare, but if successful, ALPHA3 has the potential to achieve precisely that."

Key Findings from the Publication
The ALPHA/ALPHA2 studies were single-arm, multicenter, open-label, Phase 1 trials. As of the data cutoff date (September 26, 2024), 87 heavily pretreated patients with R/R non-Hodgkin lymphoma (NHL) were treated in the ALPHA/ALPHA2 studies between May 2019 and September 2022. In total, 33 CD19 CAR T-naive patients with R/R LBCL received cema-cel/ALLO-501 manufactured with the process selected for use in pivotal studies and were the focus of this publication.

Overall Response Rate (ORR) and Complete Response (CR) Rate: ORR and CR rates in the ALPHA/ALPHA2 trials were consistent with those observed with approved autologous CD19 CAR T cell products for patients with R/R LBCL after two or more lines of systemic therapy. All treatment regimens studied demonstrated clinical benefit. The selected Phase 2 regimen (fludarabine/cyclophosphamide lymphodepletion with 90 mg of ALLO-647 (FCA90) followed by a single dose of CAR+ cells) yielded the highest ORR and CR of 67% and 58%, respectively.
Durability of Response (DOR): Patients who achieved a CR had excellent outcomes with a median DOR, PFS (progression free survival) and OS of 23.1 months, 24 months, and not reached, respectively. For patients receiving the selected Phase 2 regimen, median DOR was 23.1 months and median OS was not reached.
Safety Profile: The overall safety profile, including incidence of cytopenias and infections, was manageable and consistent with that of approved autologous CD19 CAR T cell therapies. There were no dose-limiting toxicities, graft-versus-host disease (GvHD), immune effector cell-associated neurotoxicity syndrome (ICANS), or high-grade cytokine release syndrome (CRS). The most common any-grade treatment emergent adverse events (TEAE) (≥25%) were neutropenia (85%), anemia (67%), thrombocytopenia (58%), infusion-related reactions (IRRs; 58%), fatigue (52%), and pyrexia (49%), nausea (39%), lymphopenia (36%), hypotension (36%), peripheral edema (33%), decreased white blood cell count (30%), CMV reactivation (30%), decreased appetite (30%), chills (30%), and hypoxia (27%).
Time to Treatment: The median time to start of treatment was two days from study enrollment. In contrast, autologous CAR T cell products require wait times often longer than 1 month despite incremental advancements in manufacturing and supply chains.
Potential in Low Disease Burden Settings
A growing body of evidence indicates that treatment with CAR T at times when the disease burden is low leads to improved safety and efficacy outcomes and this study reported similar findings. Among patients with baseline tumor burden <1000 mm² or normal lactate dehydrogenase (LDH) levels prior to treatment, a blood test that indicates low disease activity, the CR rate was 100% (6/6) and 82% (9/11), respectively. These CR rates in this subpopulation support cema-cel as a promising therapeutic option in patients with minimum residual disease (MRD), the population currently being studied in the ALPHA3 trial.

Foundation for the ALPHA3 Trial
These results serve as a foundation for the ongoing ALPHA3 trial, which is evaluating cema-cel as a consolidation therapy in LBCL patients who are in remission following 1L treatment but remain positive for minimal residual disease (MRD) as detected by an ultrasensitive ctDNA based blood test, using Foresight Diagnostics’ investigational CLARITY powered by PhasED-Seq. These patients have extremely low disease burden, a key subgroup who demonstrated excellent disease outcomes in the ALPHA/ALPHA2 trials.

The groundbreaking randomized controlled ALPHA3 trial, initiated in June 2024, is the first to evaluate CAR T treatment as part of 1L consolidation treatment regimen for LBCL patients who achieve remission but test positive for MRD following initial therapy. The ALPHA3 trial is designed to predict and intervene before relapse. Cema-cel is administered only to patients at high risk for relapse as a one-time consolidation dose before disease recurs.

About Cemacabtagene Ansegedleucel (cema-cel)
Cemacabtagene ansegedleucel, or cema-cel, is a next generation anti-CD19 AlloCAR T investigational product for the treatment of large B cell lymphoma (LBCL). In June 2022, the U.S. Food and Drug Administration granted Regenerative Medicine Advanced Therapy (RMAT) designation to cema-cel in r/r LBCL. The ALPHA3 pivotal Phase 2 trial in first line (1L) consolidation for the treatment of LBCL launched in June 2024. Allogene has oncology rights to cema-cel in the US, EU and UK with options for rights in China and Japan.

About the ALPHA3 Trial
Over 60,000 patients are expected to be treated for LBCL annually in the US, the EU and the UK. While first line (1L) R-CHOP or other chemoimmunotherapy is effective for most patients, approximately 30% will relapse and require subsequent treatment. The current standard of care (SOC) after 1L treatment has been simply to "watch and wait" to see if the disease relapses. The pivotal Phase 2 ALPHA3 study takes advantage of cema-cel as a one-time, off-the-shelf treatment that can be administered immediately upon discovery of MRD following six cycles of R-CHOP or other chemoimmunotherapy, positioning it to become the standard "7th cycle" of frontline treatment available to all eligible patients with MRD.