Grant: Project Grant

Acute myeloid leukemia (AML) is an aggressive blood cancer with poor outcomes, particularly for patients who cannot proceed to transplant due to active disease and for those who relapse after transplant. For these high-risk groups, treatment options are limited. CAR-T cell therapy has largely failed in AML. Major barriers include damage to healthy blood-forming stem cells, relapse driven by leukemia heterogeneity, and inflammatory signals from conventional CAR-T cells that can promote AML survival. We propose a novel "off-the-shelf" therapy using donor-derived Double-Negative T cells (DNTs). DNTs can be manufactured in advance and naturally kill AML through endogenous mechanisms, even when leukemia cells lack a specific engineered target. In a first-in-human study in relapsed AML, DNTs showed clinical feasibility and a strong safety profile, supporting their use as a CAR platform. Our strategy integrates three innovations: 1. A DNT-based CAR platform: Unlike conventional CAR-T cells, DNTs retain endogenous anti-leukemic activity, enabling them to target antigen-negative AML subclones and reduce relapse. 2. CD4 as a selective AML target: We identified CD4 as frequently expressed on AML blasts but largely absent from healthy blood stem-progenitor cells. We engineered CD4-targeting CAR4-DNTs to enhance potency while minimizing hematopoietic toxicity seen with other AML targets. 3. A logic-gated safety design: To prevent long-term CD4 T-cell depletion, we developed a dual-target "AND-gate" CAR that activates only when both CD4 and CD33 are present. Because AML cells often express both markers, while healthy T cells and stem cells do not, this design aims to preserve normal immunity and blood formation. We will evaluate CAR4-DNTs as a bridge-to-transplant therapy and develop AND-gated CAR-DNTs as a safer standalone option. Our goal is to deliver a potent, accessible, and clinically translatable immunotherapy for AML patients with urgent unmet needs.