CAR T Anito cel Delivers Deep, Durable Responses in Relapsed or Refractory Multiple Myeloma

Arcellx’s Phase 2 iMMagine 1 trial of anito cel in heavily pretreated multiple myeloma delivered a 96% response rate, 74% complete responses, and 95% MRD negativity at 15.9 months. Progression free and overall survival remained high through 24 months, and no delayed neurotoxicities were observed, reinforcing anito cel’s potential as a safe and durable BCMA targeted CAR T option.

Arcellx has reported new results from its pivotal Phase 2 iMMagine 1 study, adding further momentum behind anitocabtagene autoleucel, the company’s BCMA directed CAR T cell therapy for heavily pretreated multiple myeloma. The updated analysis, presented at the 67th ASH Annual Meeting, reflects outcomes for all 117 patients as of the October 7, 2025 data cutoff with a median follow up of 15.9 months.

The patient population represents a high unmet need setting. Eighty seven percent were triple refractory, 41% were penta refractory, 18% had extramedullary disease, and 40% carried high risk cytogenetics. Patients had received a median of three prior lines of therapy. All participants received a single target dose of 115×10⁶ CAR positive viable T cells.

The therapy continues to show strong activity across efficacy endpoints. Overall response rate reached 96%, with complete or stringent complete responses in 74% of patients and responses deepening over time. Minimal residual disease negativity was achieved in 95 percent of evaluable patients at a sensitivity of 10⁻⁵, and 83% of those with sufficient follow up maintained negativity for more than six months. Progression free and overall survival outcomes remained favorable, with 12 month rates of 82.1% and 94%, and 24 month rates of 61.7% and 83%. Median PFS and OS have not yet been reached.

“These data are compelling and are an important advancement for patients living with multiple myeloma,” said Dr. Krina Patel, Associate Professor at UT of Texas MD Anderson Cancer Center and an investigator for iMMagine 1-3. “I am encouraged by the depth of responses in the iMMagine 1 study. For clinicians, we rely on therapies that deliver continued meaningful efficacy, a predictable safety profile, and reliable manufacturing. Anito cel demonstrates that it could become a significant new treatment option in our efforts to improve outcomes for patients with multiple myeloma.”

Safety findings are also noteworthy. No delayed or non ICANS neurotoxicities have been observed to date, including no Parkinsonism, cranial nerve palsies, Guillain Barré syndrome, or immune effector cell associated enterocolitis. All treated patients are more than 12 months post infusion, offering additional reassurance about long term neurological safety signals that have been a concern with other agents in the class.

Rami Elghandour, Arcellx’s Chairman and CEO, underscored the company’s confidence in its upcoming commercial trajectory. “The data from iMMagine 1 continue to reinforce our belief that anito cel is poised to become a category leader in treating multiple myeloma patients. Our plans for a 2026 commercial launch are well underway. We believe we can set a new standard for what’s possible with a CAR T treatment option for multiple myeloma.”

Anito cel is the first BCMA directed CAR T therapy to incorporate Arcellx’s D Domain binder, a compact and stable structure designed to support high CAR expression without tonic signaling and to disengage rapidly from its target. This architecture aims to improve tumor killing while reducing immunotoxicity. The therapy has received Fast Track, Orphan Drug, and RMAT designations from the US FDA.

Arcellx is co developing and plans to co commercialize anito cel in partnership with Kite, a Gilead company. The program includes the ongoing iMMagine 1 pivotal trial and a global Phase 3 randomized study. Kite and Arcellx will jointly commercialize the therapy in the United States, and Kite will lead commercialization outside the country.