Macrophage Activation By Dual PI3K-δ/γ Inhibition Enhances Anti-CD47-Mediated Phagocytosis and Prolongs Survival in DLBCL

Intro: Relapsed/refractory diffuse large B cell lymphoma (r/r DLBCL) is associated with poor outcomes, and remains an area of unmet clinical need. Emerging data indicate that a key macrophage immune checkpoint termed CD47 can be effectively targeted in r/r DLBCL. CD47 is a potent “don’t eat me” signal and impairs tumor cell phagocytosis by engaging the inhibitory macrophage receptor, SIRPα. Importantly, early clinical studies demonstrate that blocking CD47-SIRPα interactions with an anti-CD47 antibody (magrolimab) yields promising activity in r/r DLBCL patients, particularly when combined with rituximab, which further potentiates lymphoma cell phagocytosis via its Fc domain. Moving forward, it will be crucial to identify combinatorial strategies that improve the efficacy of anti-CD47 therapy in r/r DLBCL.