• The companies share design of global Phase 3 trial, iMMagine-3; will evaluate anito-cel in patients exposed to both an immunomodulatory (lMiD) drug and an anti-CD38 monoclonal antibody
• Anito-cel will be manufactured from Kite’s Frederick, Maryland facility for iMMagine-3 as the successful technical transfer is complete
• Remain on track to present preliminary data from the iMMagine-1 trial by end of the year

REDWOOD CITY, Calif. & SANTA MONICA, Calif. / May 09, 2024 / Business Wire / Arcellx, Inc. (NASDAQ: ACLX) and Kite, a Gilead Company (NASDAQ: GILD), today announced several key operational updates on their partnered anitocabtagene autoleucel (anito-cel) multiple myeloma program. Anito-cel is the first BCMA CAR T to be investigated in multiple myeloma that utilizes Arcellx’s novel and compact D-Domain binder.

The companies shared the design of a global, Phase 3 randomized controlled clinical trial, iMMagine-3, which Kite expects to start in the second half of this year. The trial will compare the efficacy and safety of anito-cel randomized against the standard of care (SOC) in patients with relapsed and/or refractory multiple myeloma (rrMM) who have received one to three prior lines of therapy, including an immunomodulatory drug (lMiD) and an anti-CD38 monoclonal antibody.

Kite’s facility in Frederick, Maryland will manufacture anito-cel for this trial. This follows the completion of the technical transfer from a third-party contract manufacturing organization to Kite, as well as the transfer of the Investigational New Drug (IND) application for anito-cel, which has been cleared by the U.S. Food and Drug Administration.

“Our global iMMagine-3 trial will evaluate anito-cel as a second through fourth line treatment in patients with multiple myeloma who were previously exposed to both an immunomodulatory drug and an anti-CD38 monoclonal antibody,” said Rami Elghandour, Arcellx’s Chairman and Chief Executive Officer. “The iMMagine-3 study allows us to maximize the impact of anito-cel as it captures what will become the largest second line patient population based on the current treatment paradigm, as anti-CD38 therapies move to front line treatment. This population represents an emerging significant unmet clinical need allowing us to provide access to a unique patient population. In addition, the completion of the technical transfer to Kite allowed us to accelerate our development program and launch iMMagine-3 globally, which will enable broader and earlier patient access to anito-cel.”

“We are pleased to start the Phase 3 pivotal trial, iMMagine-3, in the second half of this year given the tremendous unmet need that remains in patients with relapsed and/or refractory multiple myeloma,” said Cindy Perettie, Executive Vice President, Kite. “As we prepare for this pivotal program, we look forward to leveraging our manufacturing expertise to further position anito-cel as a potential best-in-class cell therapy. We know manufacturing quality, reliability, and speed are critically important as every day matters for these patients.”

About iMMagine-3 Global Phase 3 Randomized Controlled Clinical Trial

iMMagine-3 is a phase 3, randomized controlled trial designed to compare the efficacy and safety of anitocabtagene autoleucel (anito-cel) with SOC in patients with relapsed and/or refractory multiple myeloma (rrMM) who have received one to three prior lines of therapy, including an immunomodulatory drug (lMiD) and an anti-CD38 monoclonal antibody.

iMMagine-3 will enroll approximately 450 adult patients. Prior to randomization, investigator’s choice of SOC regimens include: pomalidomide, bortezomib, and dexamethasone (PVd); daratumumab, pomalidomide, and dexamethasone (DPd); carfilzomib, daratumumab and dexamethasone (KDd); or carfilzomib and dexamethasone (Kd). Patients in the anito-cel arm will undergo leukapheresis and optional bridging therapy (with the SOC regimen selected by the investigator prior to randomization) followed by lymphodepleting chemotherapy (fludarabine 30 mg/m²/d and cyclophosphamide 300 mg/m²/d for 3 days) and one infusion of anito-cel (115×10⁶ CAR+ T cells) on Day 1.

The primary endpoint is progression free survival (PFS) per blinded independent review according to the 2016 IMWG uniform response criteria for MM with the hypothesis that anito-cel will prolong PFS compared to SOC. Key secondary endpoints include complete response rate (CR/sCR), minimal residual disease negativity, overall survival, and safety.

The iMMagine-3 trial is expected to initiate in the second half of 2024 at ~130 study sites across North America, Europe, and rest of world.

About Arcellx and Kite Collaboration

Arcellx and Kite, a Gilead Company, formed a global strategic collaboration to co-develop and co-commercialize Arcellx's anito-cel candidate for the treatment of patients with relapsed or refractory multiple myeloma currently in a pivotal Phase 2 trial. Kite and Arcellx will jointly develop and commercialize the anito-cel asset in the United States, and Kite will commercialize the product outside the United States.

About anitocabtagene autoleucel (anito-cel)

Anito-cel is a BCMA CAR T that utilizes a novel binder (or CAR) known as the D-Domain. Its small size (8kDa) facilitates high T-cell transduction and expression, resulting in more CAR positive cells and more CARs expressed per T-cell.

Anito-cel has been granted Fast Track, Orphan Drug, and Regenerative Medicine Advanced Therapy designations by the U.S. Food and Drug Administration.

About Kite

Kite, a Gilead Company, is a global biopharmaceutical company based in Santa Monica, California, focused on cell therapy to treat and potentially cure cancer. As the global cell therapy leader, Kite has treated more patients with CAR T-cell therapy than any other company. Kite has the largest in-house cell therapy manufacturing network in the world, spanning process development, vector manufacturing, clinical trial production, and commercial product manufacturing.

About Gilead Sciences

Gilead Sciences, Inc. is a biopharmaceutical company that has pursued and achieved breakthroughs in medicine for more than three decades, with the goal of creating a healthier world for all people. The company is committed to advancing innovative medicines to prevent and treat life-threatening diseases, including HIV, viral hepatitis and cancer. Gilead operates in more than 35 countries worldwide, with headquarters in Foster City, California. Gilead acquired Kite in 2017.

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. Arcellx's lead product candidate, anito-cel (formerly CART-ddBCMA), is being developed for the treatment of relapsed or refractory multiple myeloma (rrMM) in a Phase 2 pivotal trial.

Arcellx is also developing its dosable and controllable CAR T therapy, ARC-SparX, through two Phase 1 programs, ACLX-001 for rrMM and ACLX-002 in relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome. For more information on Arcellx, please visit www.arcellx.com. Follow Arcellx on X (Twitter) at @arcellx and LinkedIn.

Arcellx 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 Arcellx's expectations regarding the timing, design and outcomes of clinical trials for its product candidates, including expected timing of presentation on clinical data and the breadth and uniqueness of the patient population being addressed; expectations around manufacturing; and the potential impact of its 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 risks that may be found in the section entitled “Part II, Item 1A (Risk Factors) in the Quarterly Report on Form 10-Q for the quarter ended March 31, 2024, filed with the Securities and Exchange Commission (SEC) on May 9, 2024, and other documents that Arcellx files 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.

Gilead Forward-Looking Statements

This press release includes forward-looking statements, within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including Gilead’s ability to realize the anticipated benefits from the collaboration with Arcellx; Gilead and Kite’s ability to increase its CAR T-cell therapy manufacturing capacity, timely manufacture and deliver such therapies (or otherwise reduce the time to manufacture such therapies), or produce an amount of supply sufficient to satisfy demand for such therapies, including the production of anito-cel for the iMMagine-3 clinical trial and any future commercial manufacturing; the ability of Gilead and Kite to initiate, progress or complete clinical trials within currently anticipated timelines or at all, and the possibility of unfavorable results from ongoing or additional clinical studies, including those involving anito-cel; uncertainties relating to regulatory applications and related filing and approval timelines, including FDA approval of anito-cel for treatment of multiple myeloma; the risk that CAR T-cell therapy will not be broadly accepted by physicians, patients, hospitals, cancer treatment centers, payers and others in the medical community; and any assumptions underlying any of the foregoing. These and other risks, uncertainties and factors are described in detail in Gilead’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2024, as filed with the U.S. Securities and Exchange Commission. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. The reader is cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties, and is cautioned not to place undue reliance on these forward-looking statements. All forward-looking statements are based on information currently available to Gilead and Kite, and Gilead and Kite assume no obligation and disclaim any intent to update any such forward-looking statements.