Arcellx Closes $115 Million Series C Financing to Advance its Pipeline of Adaptive and Controllable Cell Therapies

GAITHERSBURG, Md., April 13, 2021 (GLOBE NEWSWIRE) – – Arcellx, a privately held clinical-stage biopharmaceutical company, today announced that it raised $115 million in a Series C financing to advance its pipeline of adaptive and controllable cell therapies. The proceeds will support the company’s development of CART-ddBCMA, a BCMA-specific CAR-modified T-cell therapy currently in Phase 1 and anticipated to begin a pivotal trial in 2022. In addition, the funding will support initiation of clinical trials evaluating ACLX-001 and ACLX-002, cell therapies derived from Arcellx’s uniquely controllable ARC-SparX platform, in multiple myeloma (MM) and acute myelogenous leukemia (AML), respectively.

This financing follows FDA clearance of Arcellx’s IND for ACLX-001, the first ARC-SparX program to enter clinical trials, and Arcellx’s initial release of clinical results at the 2020 American Society of Hematology (ASH) meeting. In the ASH release, the CART-ddBCMA data showed all six multiple myeloma patients responded per IMWG criteria, withfour of those patients achieving stringent complete response. The therapy was also well-tolerated, and CAR-T related toxicities resolved rapidly.

Participants in the Series C financing include both existing and new investors to Arcellx. The financing was co-led by Samsara BioCapital and CAM Capital, joined by new investors Adage, Asymmetry, CaaSCapital, Cambrian Bio, Sixty Degree, Soleus Capital, Surveyor Capital (a Citadel company), Suvretta, and Terra Magnum Capital Partners, and existing investors NEA, Novo Holdings, SR One, Takeda Ventures, LG Tech, and Clough Capital.

“With support from this high caliber syndicate, Arcellx is poised to elevate the field of cell therapy by advancing our treatments for a range of cancers,” said Rami Elghandour, Chairman and Chief Executive Officer of Arcellx. “Our platform of both single infusion and controllable CAR-Ts based on our novel synthetic binding domain is built to address the limitations of cell therapy with the opportunity to improve efficacy, reduce toxicity, and shorten the time to intervention while expanding into new indications. This financing positions us to advance to a registrational study in multiple myeloma and to initiate a Phase 1 study in AML in 2022 as well as progress our solid tumor targets toward the clinic. It’s alsoa reflection of our incredibly talented and diverse team that is powering Arcellx forward. We appreciate the support of our new and existing investors as we advance our novel therapies to the benefit of cancer patients most in need.”

“Based on the early clinical data, we believe that CART-ddBCMA represents a potential best-in class therapy for multiple myeloma and with the support of this financing will be positioned to move into pivotal trials next year. We’re also excited about the opportunity for CART-ddBCMA to move into earlier lines of treatment for multiple myeloma based on the safety profile in this early data set. In addition, the ARC-SparX platform will be the first adaptive and controllable CAR-T system to enter the clinic and provides a unique approach to building next generation cell

therapies. We look forward to partnering with the Arcellx team to help bring these important therapies to patients,” said Mike Dybbs, Ph.D., Partner, Samsara BioCapital.

About Arcellx, Inc.

Arcellx is a clinical-stage biopharmaceuticalcompany developing adaptive and controllable cell therapies for the treatment of patients withcancer and autoimmune diseases. The Arcellx vision is to utilize our novel proprietary platform to bring superior cell therapies tomore patients through the care of academic and community practices worldwide. More information can be found at www.arcellx.com.

Media:

Zara Lockshin Solebury Trout 646-378-2960

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Investors:

Alan Lada Solebury Trout 646-378-2927

alada@soleburytrout.com

John Graziano Solebury Trout 646-378-2942

jgraziano@soleburytrout.com