Brexucabtagene Autoleucel for Relapsed/Refractory Mantle Cell Lymphoma: Real World Experience from the US Lymphoma CAR T Consortium

Introduction: Brexucabtagene autoleucel (brexu-cel) was approved by US FDA for relapsed/refractory (R/R) mantle cell lymphoma (MCL) on July 24, 2020 based on results from the pivotal ZUMA-2 (NCT02601313) study, in which an objective response rate (ORR) of 93% and a complete response (CR) rate of 67% were achieved among the 60 treated patients with at least 7 months of follow-up. The study had stringent eligibility criteria, including prior treatment with a BTK inhibitor (BTKi), and only allowed BTKi and/or corticosteroid for bridging therapy. We report here the safety and efficacy of brexu-cel in standard of care practice among centers in the US Lymphoma CAR-T Consortium. Methods: Fourteen centers participated in this retrospective study. Patients who underwent leukapheresis by 6/15/2021 with an intent to manufacture brexu-cel were included. Baseline clinical characteristics, bridging therapy, adverse events after brexu-cel infusion, and post-infusion outcome data were collected. Eligibility for ZUMA-2 was retrospectively determined based on characteristics at the time of leukapheresis. Duration of response (time from initial response to disease progression or death from any cause), progression-free survival (PFS; time from infusion to disease progression or death from any cause) and overall survival (OS; time from infusion to death from any cause) were analyzed using the Kaplan-Meier method. Results: At the data cut-off date of 7/9/2021, 107 patients underwent leukapheresis, among whom 93 (87%) completed brexu-cel infusion, 2 (2%) were waiting for infusion, and 12 (11%) did not receive infusion (manufacture failure n=6, organ dysfunction n=1, death n=5). Baseline clinical characteristics of the 93 infused patients are shown in Table 1. The median age was 67 years and 81% were male. 32% had high risk simplified MIPI, 77% had Ki-67≥30%, 45% had blastoid or pleomorphic variant, 46% had TP53 alteration, 29% had complex karyotype, and 7% had CNS involvement. The median number of prior lines of therapy was 3. Eighty-two percent had prior BTKi treatment, and 44% had refractory disease to the last line of therapy. Sixty-eight (73%) patients would not have met ZUMA-2 eligibility criteria. Reasons for ineligibility included ECOG PS ≥2 (n=8), CNS involvement by lymphoma (n=6), prior therapies (n=33), cytopenia (n=11), renal or hepatic dysfunction (n=13), other medical conditions (n=18), and active infection (n=2). Sixty (65%) of the 93 patients received bridging the