Fc receptor engagement lets anti-CD25 antibodies deplete intratumoral Tregs, experts explain

Experts on ImmuneZoom discuss how anti-CD25 antibodies deplete intratumoral Tregs through Fc receptor mechanisms. A non-IL-2-blocking CD25 antibody (NIB) achieved 100% complete regression as a single agent in inflamed tumors, and in a glioblastoma model, combined with an anti-EGFRv3 antibody, also reached 100% complete regression via IL-2-driven CD8 expansion and IFN-gamma activation of macrophages. The humanized anti-CD25 RG6292 depleted Tregs in blood and was well tolerated but achieved under 2-fold, unstable intratumoral depletion, which may explain clinical failure; the team now studies boosting Fc receptor activity in the tumor microenvironment.