SPRX-001

SPRX-001 is a protein component of Arcellx's ARC-SparX platform, a "soluble protein antigen-receptor x-linker" (SparX) that serves as a tumor-targeting adapter molecule for modular CAR-T (ARC-T) cell therapies. In this platform, ARC-T cells are engineered to recognize and kill only when bound by a specific SparX protein—such as SPRX-001—which targets tumor antigens and bridges them to the T-cell, thereby providing external, customizable, and controllable cytotoxic activity. SPRX-001, by enabling this modular recognition, allows for enhanced targeting specificity and the ability to control anti-tumor activity through dose and timing of the adapter. SPRX-001 is a distinct SparX adapter, possibly designed for a specific tumor antigen, in the ARC-SparX platform developed by Arcellx for the treatment of hematological malignancies and potentially solid tumors.