Arcellx to Present Preclinical Data of its Novel ARC-sparX Platform Technology in Targeting HER2+ Solid Tumors at the 2020 American Society of Clinical Oncology Virtual Annual Meeting

Gaithersburg, Md. – May 13, 2020 – Arcellx, a clinical-stage biopharmaceutical company developing novel, adaptive and controllable cell therapies for the treatment of patients with cancer and autoimmune diseases, today announced that it will present at the 2020 American Society of Clinical Oncology (ASCO) Annual Meeting, taking place virtually May 29-31, 2020.

The presentation details the recent preclinical studies of the ARC-sparX platform demonstrating tumor clearance with administration of HER2-targeting sparX protein and a single dose of human-derived ARC-T cells in a mouse xenograft model of HER2+ human cancer. In vitro studies demonstrate that a bi-valent, affinity-enhanced sparX-HER2 protein preferentially kills HER2- overexpressing breast cancer cells, with minimal targeting of cells that express lower levels of HER2 typical of normal tissues. Taken together, these data highlight the potential of Arcellx’s ARC-sparX technology to treat patients with HER2-overexpressing cancers while avoiding the ontarget, off-tumor toxicity observed with conventional CAR-T cell therapies. More broadly, these results suggest that sparX proteins may be engineered to increase the therapeutic index of ARCsparX treatments targeting a wide range of solid tumors.

Presentation details are as follows:
Title: Selective targeting of HER2-overexpressing solid tumors with a next-generation CAR-T cell therapy
Authors: Mu, J. et al.
Session: Developmental Therapeutics – Immunotherapy
Date/Time: Available on-demand starting May 29, 2020, at 8:00 a.m. ET
Abstract Number: 3041

The full abstract can be accessed through the ASCO Virtual Scientific Program. The poster presentation will be available through the ASCO Virtual Scientific Program on Friday, May 29, 2020, at 8:00 a.m. ET and will also be posted on the Arcellx website at www.arcellx.com.

ARC-sparX Platform Technology
The ARC-sparX platform separates the tumor-recognition and tumor-killing functions of conventional CAR-T cell therapies: (1) sparX (soluble protein antigen-receptor X-linkers) proteins recognize and bind specific antigens on diseased cells and flag those cells for destruction; and (2) ARC-T (Antigen Receptor Complex-T) cells bind the sparX proteins and kill the flagged cells. Arcellx has developed a collection of sparX proteins that bind different cell surface antigens. Administration of alternate sparX proteins can redirect ARC-T cells to different disease antigens to potentially address relapsed and refractory disease due to tumor heterogeneity or antigen escape. Additionally, ARC-T cell activity can be curbed as needed by controlling the dose and frequency of sparX administration.

About Arcellx, Inc.
Arcellx is a clinical-stage biopharmaceutical company developing novel, adaptive and controllable cell therapies for the treatment of patients with cancer and autoimmune diseases. More information can be found at www.arcellx.com.

Contact:
Solebury Trout

Zara Lockshin (media)
Tel: +1 646-378-2960
Email: [email protected]

Alan Lada (investors)
Tel: +1 646-378-2927
Email: [email protected]