Black patients with MS, NMOSD experience faster return of B cells after anti-CD20 therapy
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Black patients with MS or neuromyelitis optica spectrum disorder experienced faster repopulation of B cells 6 to 12 months after rituximab or ocrelizumab infusion compared with white patients, according to preliminary results.
llya Kister, MD, of NYU Grossman School of Medicine in New York and a Fellow of the American Academy of Neurology, and colleagues also found that relative distribution of B-cell subsets — including CD19, CD20 and others — was similar between Black and white patients. The researchers presented their findings at the American Academy of Neurology annual meeting, which is being held virtually.
“While previous research has shown that this type of infusion therapy is effective for people with those diseases, we also know that Black people tend to have more severe courses of MS,” Kister said in a press release. “We wanted to compare how quickly the B-cells came back in Black people and white people after treatment.”
The researchers retrospectively obtained demographic data, disease-related information and anti-CD20 treatment history for patients with MS or NMOSD who were treated at the New York University MS Care Center. They also obtained flow cytometry results for patients following infusion with rituximab (Rituxan; Genentech, Biogen) or ocrelizumab.
Kister and colleagues evaluated B-cell subsets, including CD19, CD20, lgD and CD27 cluster analysis, from the date closest to the infusion using flow cytometry. They defined B-cell repopulation as “any detectable number” of CD19-positive cells.
The study included 168 patients, most of whom had MS (n = 134). The remaining patients (n = 32) had NMOSD. Among all patients, 29.8% (n = 50) had detectable B-cell repopulation, with a median of 6.8 months after anti-CD20 infusion.
The researchers reported the following ratios of B-cell subsets, or the percentage of CD19-positive cells, in patients with B-cell repopulation: IgD-positive/CD27-negative (80.3% ±24.9%); IgD-negative/CD27-positive (11.6% ±21.5%); IgD-negative/CD27-negative (6.2% ±13.4%); and IgD-positive/CD27-positive (1.8%; ±1.4%). They observed B-cell repopulation in zero of 40 less than 4 months after anti-CD20 infusion; in 18 of 79 patients (23%) between 4 and 6 months; and in 25 of 41 patients (61%) between 6 and 12 months after anti-CD20 infusion.
Kister and colleagues saw no difference in the rate of B-cell repopulation between Black patients (5/24; 20.8%) and white patients (5/28; 17.9%) between 4 and 6 months after infusion. However, at 6 to 12 months after infusion, Black patients experienced a significantly increased rate of B-cell repopulation (16/21; 76.2%) compared with white patients (4/12; 33.3%; P = .02). The researchers observed no differences in B-cell subset ratios among repopulated samples between Black and white patients, according to the study results.
The analysis of the available results at different times after infusion, as opposed to taking measurements among all patients at the same prespecified times, represented a limitation of the study results, according to the press release. The researchers noted that future studies should examine whether faster return of B cells in Black patients indicates that they are more likely to experience increased disease activity.
“Our findings raise the question of whether the same therapy dose may be equally effective for all people, and that could have implications for the way Black people with autoimmune diseases like MS and [NMOSD] are treated in the future,” Kister said.