Serial NK cell assessments in patients on study over time. (A) Normalized % IPH2101(+) NK cells (compared with predose) over time in cycle 1. This did not appear to change over time or be influenced by baseline peripheral NK cell count. (B) Representative finding of NK cell and T cell % KIR occupancy from a patient on cohort 4 (0.075 mg/kg). In most patients, the number of T cells recognized by IPH2101 was too low for evaluation; however, in n = 9 evaluable patients, % KIR occupancy between NK and T cells appeared closely correlated as shown. Peripheral absolute (C) and percent (D) NK cell counts over time (normalized to NK cell count obtained just before first administration of IPH2101). Neither absolute nor percent NK cell count appeared to change significantly from baseline over the duration of IPH2101 therapy. (Note patient n per time points shown varies as not all patients received all 4 cycles of planned therapy.)