Appropriate use of the anti-CD19 B-cell depleting antibody inebilizumab (INEB) in the treatment of neuromyelitis optica spectrum disorder (NMOSD). The goal of this study was to examine the correlation between peripheral blood B-cell subsets, aquaporin 4 (AQP4) immunoglobulin G (IgG) titers, and NMOSD attacks in people who took part in the N-MOmentum study (NCT02200770). In the randomized controlled period (RCP), subjects took 300 mg of INEB or a placebo (PBO) on days 1 and 15, with further dosing at 6-month intervals throughout the open-label period (OLP). Using flow cytometry (RCP + OLP), the absolute numbers of CD20+ B cells and CD27+ memory B cells were determined. Gene expression in plasma cells (PCs) was evaluated by PCR (RT-qPCR) in the RCP. The cell-based assay was used to quantify AQP4-IgG titers (RCP only). The peripheral blood was sampled for all the measurements. There were statistically significant increases in CD20+ B cells and CD27+ memory B cells between the time of the attack and the previous visit (P<0.05) in the PBO group. Visits before this 1 showed increases in PC subgroups compared to baseline (P<0.01). About 4/20  (10%) CD20+B cells, 3/19 (16%) memory B cells, and 11/20 (55%) PC showed a more than 2-fold increase from baseline throughout the assault. INEB resulted in a dramatic reduction of all subgroups of B cells. Compared to the last visit, the INEB group did not show any increases in any B cell subsets at the time of the assault. The correlation between the change in AQP4-IgG titer from pre-treatment to acute phase was not statistically significant (P=0.15). At the conclusion of the RCP, 9/50 (18%) of the PBO group and 59/159 (37%) of the INEB group exhibited a drop in AQP4-IgG of more than equal to 2-fold (0% vs. 11% ⩾ 8-fold decrease, P=0.008). In contrast to the INEB group, the PBO group showed elevated levels of B-cell subsets at the time of the assault, notably the PC subset. In certain patients, inebilizumab medication was linked to a decrease in AQP4-IgG.

 

Reference: ECTRIMS 2022