Abstract
Biochemical and immunological negative regulators converge to inhibit tumor-reactive Chimeric Antigen Receptor T (CAR-T) cells, which may explain clinical failures of CAR-T cell therapies against solid tumors. Here, we developed a multifaceted approach to genetically engineer allogeneic (‘off -the-shelf’) CAR-T cells resistant to both biochemical (adenosine) and immunological (PD-L1 and TGF-β) inhibitory signaling. We multiplexed an adenine base editor with a CRISPR-Cas12b nuclease to manufacture a CAR-T cell product comprising six gene edits to evade allorejection (B2M, CIITA), prevent graft-versus-host disease (CD3E) and resist major biochemical (ADORA2A) and immunological (PDCD1, TGFBR2) immunosuppressive barriers in solid tumors. Combinatorial genetic disruption in CAR-T cells enabled superior anti-tumor efficacy leading to improved tumor elimination and survival in humanized mouse models that recapitulated the suppressive features of a human tumor microenvironment (TME). This novel engineering strategy conferred CAR-T cells resistance to a diverse TME, which may unlock the therapeutic potential of CAR-T cells against solid tumors.
One Sentence Summary Multiplex genome engineered CAR-T cells resistant to allorejection and the convergence of biochemical and immunological negative regulators within the tumor microenvironment exhibit superior efficacy against solid tumors.
Competing Interest Statement
R.M., A.M., H.S., J.R., F.M., A.C., G.C., C.M., were employees of Beam Therapeutics when the work was conducted and are shareholders in the company. Beam Therapeutics has filed patent applications on this work.
