Obinutuzumab and lenalidomide mechanism of action. Obinutuzumab is a glycoengineering antibody to CD20 with a defucosylated Fc region and a modified elbow hinge binding site. These modifications increase effector cell binding and reduce lipid raft formation and hence internalization of CD20, leading to loss of antigen expression. Lenalidomide has a multitude of effects through binding to the cereblon (CRBN) complex. Transcriptional effects ultimately lead to G₀/G₁ cell-cycle arrest, increase apoptosis in tumor cells, and immune modulatory effects on bystander immune cells. This leads to increased humoral responses and alters the balance of pro- and anti-inflammatory cytokines by shifting toward an anti-inflammatory profile. Ab, antibody; IFNγ, interferon γ; IL-2, interleukin-2; NK, natural killer. Professional illustration by Patrick Lane, ScEYEnce Studios.