Company Announcements

-- The D-Domain binder has a fast off-rate and contributes to anito-cel’s differentiated pharmacology profile in multiple myeloma --

-- A simulation model of CAR T use ahead of bispecific antibodies in 4L+ RRMM is estimated to reduce the risk of progression or death by 64% and death by 48% over five years versus the reverse sequence, supporting CAR T before bispecific antibody as the sequence that delivers superior improved long-term outcomes in 4L+ RRMM --

-- Geographic inequities persist in CAR T access for MM patients marked by long travel, out-of-state care, and bypassed ATCs, highlighting systemic referral gaps and the need for ATC expansion to improve equitable access --

REDWOOD CITY, Calif.--(BUSINESS WIRE)--Jan. 21, 2026-- Arcellx, Inc. (NASDAQ: ACLX), a biotechnology company reimagining cell therapy through the development of innovative immunotherapies for patients with cancer and other incurable diseases, is advancing both its scientific foundation for its D-Domain platform technology and commercial preparedness for anito-cel for the potential treatment of multiple myeloma with three presentations at the 2026 Tandem Meetings. One presentation reinforces anito-cel’s unique ability to transiently engage BCMA, potentially resulting in tumor cell clearance without prolonged inflammation and providing a mechanistic rationale for the clinically differentiated efficacy and safety profile observed with anito-cel for multiple myeloma. Additionally, two new research studies are being presented, one on health economics and one on treatment sequencing outcomes. The meetings will be held February 4-7, 2026, at the Salt Palace Convention Center in Salt Lake City, Utah. Anito-cel is partnered with Kite, a Gilead Company.

Tandem Presentation Details
Title and ID: Anito-cel’s D-Domain Binder Has a Fast Off-Rate and Contributes to Its Differentiated Pharmacology Profile in Multiple Myeloma (abstract ID: 28119)
Speaker: Kevin C. Hart, PhD
Session: Engineered Immune Cells (CAR-T, NK, TCR): Basic/Preclinical - Antigen Finding, Safety
Session Date:Thursday, February 5, 2026
Session Time: 6:30 – 8:00 p.m. MT
Location:Hall AB

Title and ID: Impact of Treatment Sequencing with CAR T-cell Therapies and Bispecific Antibodies on Long-Term Survival in 4L+ RRMM in the U.S.: A Simulation Model (abstract ID: 27320)
Speaker: Jodi Lipof, MD
Session: Engineered Immune cells - clinical (toxicity, practice, economics, correlative, autoimmunity, malignant, and non-malignant indications)
Session Date:Thursday, February 5, 2026
Session Time: 6:30 – 8:00 p.m. MT
Location:Hall AB

Title and ID: Visualizing Geographic Variation and Systemic Inequities of Disease Burden and CAR T-cell Therapy Access in Multiple Myeloma in the U.S. (abstract ID: 27927)
Speaker: Brandon Blue, MD
Session: Health Services and Barriers to Access
Session Date:Thursday, February 5, 2026
Session Time: 6:30 – 8:00 p.m. MT
Location:Hall AB

About Multiple Myeloma

Multiple Myeloma (MM) is a type of hematological cancer in which diseased plasma cells proliferate and accumulate in the bone marrow, crowding out healthy blood cells and causing bone lesions, loss of bone density, and bone fractures. These abnormal plasma cells also produce excessive quantities of an abnormal immunoglobulin fragment, called a myeloma protein (M protein), causing kidney damage and impairing the patient’s immune function. MM is the third most common hematological malignancy in the United States and Europe, representing approximately 10% of all hematological cancer cases and 20% of deaths due to hematological malignancies. The median age of patients at diagnosis is 69 years with one-third of patients diagnosed at an age of at least 75 years. Because MM tends to afflict patients at an advanced stage of life, patients often have multiple co-morbidities and toxicities that can quickly escalate and become life-endangering.

About Anitocabtagene Autoleucel (anito-cel)

Anitocabtagene autoleucel (anito-cel, previously CART-ddBCMA) is the first BCMA-directed CAR T-cell therapy to be investigated in multiple myeloma that utilizes Arcellx’s novel and compact binder known as the D-Domain. The small, stable D-Domain binder enables high CAR expression without tonic signaling and is designed to quickly release from the BCMA target. This combination may allow for the effective elimination of multiple myeloma cells without severe immunotoxicity. Anito-cel has been granted Fast Track, Orphan Drug, and Regenerative Medicine Advanced Therapy Designations by the U.S. Food and Drug Administration.

About Arcellx and Kite Collaboration

Arcellx and Kite, a Gilead Company, formed a global strategic collaboration and license agreement to co-develop and co-commercialize anito-cel for patients with multiple myeloma. Anito-cel is currently being developed in a Phase 2 registrational pivotal study and a global Phase 3 randomized controlled study for relapsed and/or refractory multiple myeloma (RRMM). Kite and Arcellx will jointly commercialize the anito-cel asset in the United States, and Kite will commercialize the product outside the United States.

About Arcellx, Inc.

Arcellx, Inc. is a clinical-stage biotechnology company reimagining cell therapy by engineering innovative immunotherapies for patients with cancer and other incurable diseases. Arcellx believes that cell therapies are one of the forward pillars of medicine and Arcellx's mission is to advance humanity by developing cell therapies that are safer, more effective, and more broadly accessible. For more information on Arcellx, please visit www.arcellx.com. Follow Arcellx on X @arcellx and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements in this press release that are not purely historical are forward-looking statements, including, but not limited to, statements regarding: anito-cel’s pharmacology profile, including the potential benefits of the D-Domain; the expectation of anito-cel to be a significant or differentiated CAR-T treatment option for RRMM, the potential impact of treatment sequencing with CAR T-cell therapies and bispecific antibodies on long-term survival in 4L+ RRMM; and the potential impact of Arcellx’s product candidates and platforms on patients and cell therapy. The forward-looking statements contained herein are based upon Arcellx’s current expectations and involve assumptions that may never materialize or may prove to be incorrect. These forward-looking statements are neither promises nor guarantees and are subject to a variety of risks and uncertainties, including those set forth in Part II, Item 1A (Risk Factors) in the Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, filed with the Securities and Exchange Commission (SEC) on November 5, 2025, and the other documents that Arcellx may file from time to time with the SEC. These forward-looking statements are made as of the date of this press release, and Arcellx assumes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as required by law.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260121747816/en/

Investor Contact:
Myesha Lacy
Arcellx
ir@arcellx.com

Media Contact:
Kristalle Cooks
Arcellx
pr@arcellx.com

Source: Arcellx, Inc.