Arcellx Inc. (NASDAQ:ACLX) rallied 13.6% in premarket trading Monday after releasing encouraging data from its pivotal Phase 2 iMMagine-1 trial evaluating anitocabtagene autoleucel (anito-cel) in patients with relapsed or refractory multiple myeloma.
In the latest update, the company reported a 96% overall response rate and a 74% complete response/stringent complete response rate at a median 15.9-month follow-up, noting that responses continued to deepen over time. Among patients assessed for minimal residual disease, 95% achieved negativity.
Twelve-month progression-free survival reached 82.1%, while overall survival came in at 94.0%. At 24 months, the rates were 61.7% and 83.0%, respectively. Arcellx also underscored that no delayed or non-ICANS neurotoxicities have been detected to date, with every participant dosed at least 12 months earlier.
The findings were shared during the 67th American Society of Hematology Annual Meeting on December 6, 2025, and reflect outcomes from all 117 patients enrolled in the study.
Commenting on the results, Dr. Krina Patel, Associate Professor at The University of Texas MD Anderson Cancer Center and an investigator on the trial, said, “These data are compelling and are an important advancement for patients living with multiple myeloma.”
Arcellx, which is co-developing anito-cel with Kite, a Gilead company, reaffirmed its plan for a commercial launch in 2026. The company also highlighted that the trial enrolled a highly refractory population, with 87% of patients classified as triple refractory and 41% as penta refractory.