Arcellx is a clinical-stage biotechnology company developing CAR-T cell therapies for cancer and autoimmune diseases. Arcellx's core technology is its proprietary D-Domain, a synthetic antigen-binding scaffold that replaces the conventional scFv used in traditional CAR-T therapies. Arcellx argues D-Domains offer higher transduction efficiency, better CAR surface expression, and lower tonic signaling, which reduces T-cell exhaustion and improves manufacturing reliability. Arcellx's lead product is anitocabtagene autoleucel (anito-cel), a BCMA-targeting autologous CAR-T for relapsed or refractory multiple myeloma, administered as a single infusion. Arcellx submitted a BLA to the FDA in December 2025, with a PDUFA action date of December 23, 2026. Arcellx co-develops and plans to co-commercialize anito-cel in the U.S. with Kite Pharma (a Gilead company), which also handles manufacturing and all ex-U.S. commercialization. Beyond anito-cel, Arcellx is developing ARC-SparX, a modular CAR-T platform where a separately-dosed protein activates the T cell, allowing physicians to adjust or combine antigen targets without reengineering the T cell. ARC-SparX programs include ACLX-001 (BCMA/rrMM, partnered with Kite) and ACLX-002 (CD123/AML, wholly-owned), both in Phase 1. In February 2026, Gilead announced plans to acquire Arcellx for $115 per share in cash plus a CVR worth $5 per share if anito-cel achieves $6B in cumulative worldwide sales by end of 2029.