Arcellx Reports Positive Results from iMMagine-1 Study in Relapsed/Refractory Multiple Myeloma

Arcellx, Inc., a biotechnology firm based in Redwood City, California, is pioneering advancements in cell therapy by developing innovative immunotherapies targeting cancer and other incurable diseases. Recently, the company released encouraging data from its pivotal Phase 2 iMMagine-1 trial involving anitocabtagene autoleucel, known as anito-cel, for patients with relapsed or refractory multiple myeloma (RRMM). This promising data will be shared at the upcoming EHA2025 Congress in Milan on June 14, 2025, in collaboration with Kite, a Gilead Company.

The Phase 2 iMMagine-1 study, with a data cutoff on May 1, 2025, included 117 patients who had a median follow-up period of 12.6 months. Patients were treated with a single infusion of anito-cel, targeting a dose of 115×106 CAR+ viable T cells. The study highlighted that 86% of participants were triple refractory, while 41% were penta refractory. Additionally, patients had undergone a median of three previous therapy lines, with 51% having received three prior lines.

The trial exhibited an impressive overall response rate of 97%, with 68% achieving complete or stringent complete responses, and 85% showing very good partial responses or better, evaluated using criteria from the International Myeloma Working Group. Moreover, among those tested for minimal residual disease (MRD), 93.3% reached MRD negativity with a sensitivity threshold of 10-5. Progression-free survival rates stood at 91.9% at six months and 78.8% at twelve months, while overall survival rates were 96.6% and 95.2% at the respective intervals. Notably, median progression-free and overall survival have yet to be determined.

Importantly, anito-cel's safety profile has been favorable, with no reported cases of delayed or non-immune effector cell-associated neurotoxicity syndrome (ICANS), including Parkinsonism, cranial nerve palsies, or Guillain-Barré syndrome. Furthermore, no immune-mediated enterocolitis has been observed, nor have any additional therapy-related fatalities or severe cytokine release syndrome or ICANS events occurred since the previous data presentation in December 2024.

The preliminary results from the iMMagine-1 trial underscore significant and sustainable responses with manageable safety for patients with fourth-line or higher RRMM, including those with triple- and penta-class refractory disease. Rami Elghandour, Chairman and CEO of Arcellx, expressed confidence in anito-cel's potential to meet the needs of myeloma patients and healthcare providers. He emphasized the absence of a cure for multiple myeloma and highlighted the unmet need for efficacious, safe, and accessible CAR-T therapies. Anito-cel stands out due to its unique technology, robust clinical data, and strategic partnership with Kite. The company plans a commercial launch in 2026 alongside Kite and looks forward to sharing their findings at EHA2025.

Multiple Myeloma (MM) is a hematological cancer characterized by the proliferation of diseased plasma cells in the bone marrow, which disrupts healthy blood cell production and leads to various complications such as bone lesions and kidney damage. It is the third most prevalent hematological malignancy in the United States and Europe, accounting for roughly 10% of such cancer cases and 20% of deaths associated with hematological cancers. MM predominantly affects individuals in advanced stages of life, often complicating treatment due to co-morbidities.

Anitocabtagene autoleucel, previously known as ddBCMA, represents a novel BCMA-directed CAR T-cell therapy utilizing Arcellx's compact D-Domain binder. This innovative approach enables high CAR expression without tonic signaling, potentially allowing effective multiple myeloma cell elimination without severe immunotoxicity. The U.S. FDA has granted anito-cel Fast Track, Orphan Drug, and Regenerative Medicine Advanced Therapy designations.

Arcellx has partnered with Kite, a Gilead Company, to co-develop and commercialize anito-cel for multiple myeloma patients. The collaboration entails joint commercialization in the United States and Kite's efforts outside the country. Arcellx, Inc. is dedicated to advancing cell therapies to make them safer, more effective, and broadly accessible, with a mission to enhance healthcare outcomes for patients with cancer and other incurable diseases.