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Individual Variability of CD19+ B-Cell Repopulation in People With Multiple Sclerosis Treated With Extended Interval
Laura Hogenboom1, Lisa G Schoof1, Liza M Y Gelissen1
1MS Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam UMC Location VUmc, Amsterdam, the Netherlands.
Background And Objectives:
B-cell repopulation patterns in ocrelizumab treated patients with multiple sclerosis are highly variable between individuals, but the course of B-cell reoccurrence after subsequent doses within an individual is not yet determined. Our aim was to determine the intraindividual variability of CD19+ B-cell repopulation after each ocrelizumab dose when using CD19+ B-cell guided interval dosing.
Methods:
This was a prospective cohort study, as part of the ongoing BLOOMS trial, investigating participants randomised for B-cell guided interval dosing of ocrelizumab with ≥ 2 dosing intervals. Coefficients of variation were calculated for time from last ocrelizumab dose to first CD19+ B-cell measurement ≥ 0.01 × 109 cells/L.
Results:
Seventy-five participants with a total of 209 B-cell guided intervals were included. Time from last dose to first appearance of CD19+ B-cell count ≥ 0.01 × 109 cells/L showed wide variability between individuals (20.6-72.1 weeks), but the median variation was 5.6% (IQR: 3.1-8.4) within an individual. This translated to a variation of 2 weeks per dosing interval on average.
Discussion:
Time to CD19+ B-cell repopulation after each ocrelizumab dose is individually stable. This finding could pave the way for easier and more accessible future personalised interval dosing of B-cell depleting therapies if this stability is confirmed in long-term treatment.
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