Importance

Equecabtagene autoleucel (eque-cel), a fully human-derived B-cell maturation antigen-targeting chimeric antigen receptor (CAR) T-cell therapy, has exhibited potential for the treatment of relapsed or refractory multiple myeloma (RRMM), and further investigation in a larger cohort is necessary.

Objective

To evaluate whether eque-cel can benefit patients with RRMM and determine the overall response rate postinfusion.

Design, Setting, and Participants

The FUMANBA-1 trial was a single-arm, open-label, phase 1b/2 trial that evaluated eque-cel in adult patients with RRMM. Enrollment began in April 2020, and patients who received eque-cel will be monitored for a minimum of 15 years following the infusion. As of September 2022, patients with heavily pretreated RRMM who received at least 3 prior courses of therapy from 14 centers were enrolled. Data were analyzed from April 2020 to September 2022.

Interventions

Patients received a single infusion of eque-cel at 1.0 × 10⁶ CAR-positive T cells/kg after the lymphodepletion.

Main Outcomes and Measures

Efficacy was the primary objective, and safety, pharmacokinetics, and pharmacodynamics were secondary objectives.

Results

Of 103 patients who received an eque-cel infusion, 55 (53.4%) were male, and the median (range) age was 58 (39-70) years. A total of 101 patients were evaluable for efficacy. At a median (range) follow-up of 13.8 (0.4-27.2) months, the overall response rate was 96.0% (97 of 101), with 74.3% (75 of 103) achieving a complete response or better. Among the 12 patients who had prior CAR T-cell treatment, 75% (9 of 12) achieved a response. The median progression-free survival was not reached, with a 12-month progression-free survival rate of 78.8% (95% CI, 68.6-86.0). A total of 96 patients (95.0%) achieved minimal residual disease negativity at a sensitivity threshold of 10⁻⁵. Adverse events were favorable: 96 of 103 patients (93.2%) experienced cytokine release syndrome (grade 1 to 2 in 95 patients [92.3%]) and 2 (1.9%) experienced immune effector cell–associated neurotoxicity syndrome (grade 1 to 2). All cases of immune effector cell–associated neurotoxicity syndrome and 94 of 96 cases of cytokine release syndrome resolved with treatment. Additionally, only 20 patients (19.4%) developed antidrug antibodies. Cellular kinetic analysis confirmed CAR-positive T cells in all patients, with the longest duration at 735 days.

Conclusions and Relevance

In this trial, eque-cel led to early, deep, and durable responses in patients with heavily pretreated RRMM with a manageable safety profile. Patients with prior CAR T-cell therapy also benefitted from eque-cel.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2000033946