SAR442085 has a higher binding affinity for activating FcγRIIa and FcγRIIIa than daratumumab and isatuximab. (A-B) Binding of SAR442085, daratumumab, or isatuximab to FcγRIIIa-158V and FcγRIIIa-158F was evaluated by SPR using purified human proteins. Graphs represent the mean and individual KD data. Statistical differences between groups were determined by an unpaired Student t-test. (C-F) Cellular binding of SAR442085, daratumumab, or isatuximab to FcγRIIa and FcγRIIIa receptor variants was evaluated by flow cytometry on HEK293T cells overexpressing each variant. Graphs represent the pooled binding curves of up to 3 independent experiments with the mean and individual values of apparent Kd and maximum binding (Bmax) for each binding curve. MFI, mean fluorescence intensity; KD, dissociation constant; Bmax, maximal amount of antibody bound at the cell surface. Statistical differences between groups were determined by a ratio paired t test. *P < .05; **P < .01, ***P < .001.