Arcellx, Inc.

Arcellx, Inc. is a clinical-stage biotechnology company focused on developing immunotherapies for patients with cancer and other incurable diseases. The company aims to engineer immunotherapies that are safer, more effective, and more broadly accessible. Arcellx utilizes its novel synthetic binding scaffold, the D-Domain, to overcome limitations of traditional Chimeric Antigen Receptor T-cells (CAR-Ts). Existing CAR-T therapies, which often use a biologic-based, single chain variable fragment (scFv) binding domain, can be challenging to manufacture, benefit a limited patient segment, frequently result in high toxicity, and have narrow applicability. Arcellx is developing a new class of D-Domain powered immunotherapies, including classical single infusion CAR-Ts called "ddCARs" and dosable and controllable universal CAR-Ts called "ARC-SparX." These therapies are designed to address hematologic cancers, solid tumors, and non-oncology indications like autoimmune diseases. The company's lead program is anitocabtagene autoleucel, or "anito-cel" (formerly, CART-ddBCMA), a BCMA-targeting ddCAR product candidate. Anito-cel is currently being evaluated in the pivotal Phase 2 iMMagine-1, Phase 3 iMMagine-3, and Phase 2 GEM-AnitoFIRST trials for patients with multiple myeloma (MM). Arcellx has partnered anito-cel with Kite Pharma Inc., a Gilead company, through a co-development/co-commercialization collaboration agreement. In 2024, Arcellx completed dosing in its pivotal Phase 2 clinical trial (iMMagine-1) of anito-cel in patients with fourth line or later relapsed or refractory MM (rrMM). In December 2025, interim data from the pivotal iMMagine-1 study in patients with rrMM after three or more prior lines of therapy were presented at the 67th ASH Annual Meeting and Exposition. In 2024, Kite initiated a global Phase 3 randomized controlled clinical trial (iMMagine-3) of anito-cel in patients with second through fourth line rrMM.