Arcellx, Inc.

Arcellx, Inc. is a clinical-stage biotechnology company focused on developing immunotherapies for cancer and other incurable diseases, utilizing its proprietary D-Domain platform ¹. The company's core business model revolves around engineering D-Domain powered immunotherapies, including classical single infusion CAR-Ts called "ddCARs" and dosable and controllable universal CAR-Ts called "ARC-SparX" ². Revenue generation is currently through collaboration agreements, such as the one with Kite Pharma, Inc., a Gilead company, which involves upfront cash payments and potential milestone payments ³. The company aims to address limitations of traditional CAR-Ts, such as manufacturing difficulty, limited patient segments, high toxicity, and narrow applicability, by engineering a new class of D-Domain powered immunotherapies ⁴.

The company's lead product candidate is anitocabtagene autoleucel, or "anito-cel," a BCMA-targeting ddCAR, which is being evaluated in pivotal Phase 2 iMMagine-1, Phase 3 iMMagine-3, and Phase 2 GEM-AnitoFIRST trials for patients with multiple myeloma (MM) ⁵. In 2024, the company completed dosing in its pivotal Phase 2 iMMagine-1 clinical trial for anito-cel in patients with fourth line or later relapsed or refractory MM (rrMM) ⁶. Interim data from the iMMagine-1 study, presented in December 2025, showed a 96% overall response rate (ORR) ⁷ and 74% of patients achieving complete response (CR) or stringent complete response (sCR) ⁸ among 117 dosed patients with a median follow-up of 15.9 months ⁹. Median progression-free survival (PFS) and overall survival (OS) were not reached ¹⁰. The safety profile indicated no delayed neurotoxicities, including no Parkinsonism, cranial nerve palsies, Guillain-Barré syndrome, or immune effector cell-associated enterocolitis ¹¹. The company submitted a Biologics License Application (BLA) for anito-cel to treat patients with fourth line or later rrMM to the FDA on December 23, 2025 ¹², which was accepted on February 20, 2026, with an anticipated PDUFA action date of December 23, 2026 ¹³.

Arcellx is also advancing several ARC-SparX programs. ACLX-001 targets BCMA in rrMM, for which Kite exercised its option to negotiate a license in November 2023 ¹⁴. The wholly-owned ACLX-002 targets CD123 in relapsed or refractory acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) ¹⁵, and ACLX-004 targets CD33 and CD123 in relapsed or refractory AML ¹⁶. The company also initiated a Phase 1 trial in generalized Myasthenia Gravis (gMG) in the second half of 2025, evaluating anito-cel for non-oncology indications ¹⁷.

For the fiscal year ended December 31, 2025, the company reported net losses of $228.9 million ¹⁸, compared to $107.3 million for the year ended December 31, 2024 ¹⁹. As of December 31, 2025, the accumulated deficit was $725.8 million ²⁰. The company had cash, cash equivalents, and marketable securities of $520.1 million as of December 31, 2025 ²¹.

In 2024, the company achieved a clinical milestone for anito-cel and received $68.3 million from Kite relating to enrollment in the iMMagine-1 trial ²². The technical transfer of the cell manufacturing process to Kite was completed in May 2024 ²³, and Kite is now responsible for manufacturing activities for future clinical trials, including the ongoing iMMagine-3 trial, and for commercial supply of anito-cel ²⁴.

Management's specific guidance for the upcoming period includes the expectation that the FDA may approve or make a decision regarding the company's Biologics License Application (BLA) for anito-cel for patients with relapsed or refractory multiple myeloma (rrMM) on or before the anticipated target Prescription Drug User Fee Act (PDUFA) date of December 23, 2026 ²⁵. The company believes its current cash and cash equivalents and marketable securities are adequate to fund operations into 2028 ²⁶.

A major growth vector for the company is the advancement of anito-cel to treat MM patients in the United States and abroad, in collaboration with Kite ²⁷. This includes seeking regulatory approval for anito-cel based on results from the Phase 1 and pivotal Phase 2 iMMagine-1 clinical trials ²⁸. Furthermore, the company, in collaboration with Kite, plans to pursue expanded access to anito-cel through other label expansion clinical trials, including iMMagine-3, GEM-AnitoFIRST, and others ²⁹. Kite initiated a global Phase 3 randomized controlled clinical trial (iMMagine-3) of anito-cel in patients with second through fourth line rrMM in 2024 and expects the trial to be fully enrolled by mid-2026 ³⁰. The GEM-AnitoFIRST study in frontline MM patients is ongoing, serving as a safety lead-in to future pivotal trials in the frontline MM setting ³¹. Through its ex-U.S. partner, Kite, the company will pursue clinical development of anito-cel in other key geographies, such as Europe and Asia ³².

Another significant growth area involves evaluating anito-cel for the treatment of certain non-oncology indications, including selected autoimmune disorders ³³. The company began dosing patients in a Phase 1 trial in generalized Myasthenia Gravis (gMG) in the second half of 2025 ³⁴. The company estimates that gMG affects over 100,000 people in the United States ³⁵. The company also plans to develop a comprehensive ARC-SparX AML/MDS program, pursuing AML/MDS with a library of SparX proteins, starting with the wholly-owned ACLX-002 program, which is in a Phase 1 clinical trial, and continuing with the ACLX-004 program ³⁶. The company received FDA clearance of an IND application for ACLX-004, which targets CD33 and CD123, for the treatment of AML in 2025 ³⁷.

Operationally, the company and its partners at Kite are planning manufacturing capacity to capture the majority of 4L+ rrMM within 12 months of approval and targeting a turnaround time of 17 days ³⁸. Kite will manufacture anito-cel and bear the CMC commercial readiness costs and associated capital expenses, while the parties will continue to split manufacturing costs for clinical material ³⁹. The company also received IND clearance to manufacture anito-cel in its cGMP facility in Redwood City, CA for its Phase 1 trial in gMG ⁴⁰.

The company's planned capital allocation includes continued investment in process improvements to reduce overall process time and improve costs ⁴¹. The company also plans to leverage AI, machine learning, and other novel technologies to drive its discovery efforts ⁴².

The company explicitly flagged structural headwinds and execution risks, including the uncertainties surrounding the proposed transaction with Gilead Sciences, Inc. (Gilead) and Ravens Sub, Inc. ⁴³. The tender offer and subsequent merger may not be completed in a timely manner or at all, and the obligation to complete the merger is subject to certain closing conditions ⁴⁴. If the merger agreement is terminated under specified circumstances, the company would be required to pay Gilead a termination fee of $260.0 million ⁴⁵. The announcement or pendency of the proposed transaction may disrupt business, divert management's attention, and disrupt relationships with third parties and employees ⁴⁶. Geopolitical tensions and conflicts, such as the Russia and Ukraine conflict and the conflict in the Middle East, may increase security risks and disrupt the supply chain ⁴⁷.

Management's message to shareholders conveys a focus on advancing innovative immunotherapies and maximizing the impact of its proprietary D-Domain binders to create safer, more effective, and broadly accessible cell therapies. The company emphasizes its promising preliminary clinical data for anito-cel, which supported the BLA filing, and its strategic partnership with Kite Pharma, Inc., a Gilead company, as key to achieving significant market share and transforming the CAR-T market. Management anticipates that the FDA may approve or make a decision regarding the BLA for anito-cel for rrMM on or before the anticipated PDUFA date of December 23, 2026 ⁴⁸. The company believes its current cash and cash equivalents and marketable securities are adequate to fund operations into 2028 ⁴⁹. The three strategic priorities emphasized for the period ahead are: in collaboration with Kite, advancing anito-cel to treat MM patients in the United States and abroad; evaluating anito-cel for the treatment of certain non-oncology indications, including selected autoimmune disorders; and developing a comprehensive ARC-SparX AML/MDS program.