Business Description

Overview We are a clinical-stage biotechnology company focused on delivering a new class of innovative immunotherapies for patients with cancer and other incurable diseases. We believe immunotherapies are one of the forward pillars of medicine, and our mission is to advance humanity by engineering immunotherapies that are safer, more effective and more broadly accessible. Although Chimeric Antigen Receptor T-cells (CAR-Ts) have shown benefits to date, they have primarily been constrained to existing biologic structures, which has limited their impact and opportunity. Our novel synthetic binding scaffold, the D-Domain, is designed to overcome the limitations of traditional CAR-Ts. Existing CAR-T therapy solutions, most of which use a biologic-based, single chain variable fragment (scFv) binding domain, tend to be difficult to manufacture, beneficial to a limited segment of patients, often result in high toxicity, and have narrow applicability in treatable indications. We believe we can address these limitations by engineering a new class of D-Domain powered immunotherapies, including classical single infusion CAR-Ts called “ddCARs” and dosable and controllable universal CAR-Ts called “ARC-SparX”, to address hematologic cancers, solid tumors, and indications outside of oncology, such as autoimmune diseases. Our lead program is a BCMA-targeting ddCAR product candidate called anitocabtagene autoleucel or “anito-cel” (formerly, CART-ddBCMA), which is currently being evaluated in our pivotal Phase 2 iMMagine-1, Phase 3 iMMagine-3, and Phase 2 GEM-AnitoFIRST trials in patients with multiple myeloma (MM). We have partnered anito-cel with Kite Pharma Inc., a Gilead company (Kite), through our co-development/co-commercialization collaboration agreement, as described in more detail in “Licenses and Collaborations” below (the Kite Collaboration Agreement). In 2024, we completed dosing in our pivotal Phase 2 clinical trial (iMMagine-1) of anito-cel in patients with fourth line or later relapsed or refractory MM (rrMM). In December 2025, we announced interim data from our pivotal iMMagine-1 study in patients with rrMM after three or more prior lines of therapy, which were presented during an oral presentation at the 67th ASH Annual Meeting and Exposition. In 2024, Kite initiated a global Phase 3 randomized controlled clinical trial (iMMagine-3) of anito-cel in patients with second through fourth line rrMM. Kite is manufacturing anito-cel for iMMagine-3 and expects the trial to be fully enrolled by mid-2026. This follows the completion of the technical transfer to Kite, which was announced in May 2024, as well as the transfer of the Investigational New Drug (IND) application for anito-cel in MM, which has been cleared by the U.S. Food and Drug Administration (FDA). On December 23, 2025, we submitted a BLA for anito-cel to treat patients with fourth line or later rrMM to the FDA. On February 20, 2026, the FDA notified us that it has accepted our BLA with an anticipated PDUFA action date of December 23, 2026. On February 22, 2026, we entered into an Agreement and Plan of Merger (the Merger Agreement) with Gilead and Purchaser, as described in more detail in "Pending Acquisition by Gilead" below (the Merger). Outside of our collaboration with Kite, we intend to evaluate anito-cel for the treatment of certain non-oncology indications, including some autoimmune disorders. We began dosing patients in a Phase 1 trial in generalized Myasthenia Gravis (gMG) in the second half of 2025. We also are advancing several ARC-SparX programs: ACLX-001, which targets BCMA in rrMM and for which Kite exercised its option under the Kite Collaboration Agreement to negotiate a license in November 2023; our wholly-owned ACLX-002, which targets CD123 in relapsed or refractory acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS); and our wholly-owned ACLX-004, which targets CD33 and CD123 in relapsed or refractory AML. In December 2025, at the American Society of Hematology (ASH) Annual Meeting, we presented interim data from our pivotal Phase 2 iMMagine-1 trial evaluating anito-cel, in patients with rrMM after three or more prior lines of therapy. We believe these results further demonstrate that our D-Domain technology can potentially provide meaningful clinical benefits. As of the October 7, 2025 data cutoff date for the iMMagine-1 ASH presentation, the 117 patients dosed in the study had a median follow-up of 15.9 months.…