Using 1 gram rituximab as maintenance therapy for inflammatory neurologic conditions such as neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) appears to be effective maintenance therapy. In contrast, 2 grams seem excessive, according to a recently published study in Multiple Sclerosis and Related Disorders.
Several studies have widely established the efficacy of rituximab in controlling inflammatory neurological conditions. The specific targeting of the CD20 antigen in B cells leads to a rapid clearance of circulating B cells for 6 months while plasma cells are unaffected.
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Initially, the maintenance dose for diseases such as NMOSD and MS was calculated using the treatment for rheumatoid arthritis as a reference, with a maintenance schedule consisting of 2 1-gram doses 2 weeks apart every 6 months. However, many practitioners prefer using lighter doses, and many have reported positive results.
“Given those data, in 2017 our team replaced the traditional maintenance regimen (infusion of 1 g of RTX on Day 1 and Day 15 every 6 months) by a reduced dosage maintenance regimen (only 1 infusion of 1 g of RTX every 6 months),” the authors wrote.
The aim was to compare B cell counts in patients who had received both regimes, emphasizing the moments just before the administration following the last dosage of each regimen. CD19 count (B-cell- specific) was used as the primary endpoint of the study. The study included 161 patients.
Results revealed no significant differences in B-cell repopulation between traditional and reduced regimens. 16 patients had B-cell repopulation after following a traditional regimen. In the remaining 145 patients without B- cell repopulation that later received the reduced regimen, only 16 suffered B-cell repopulation.
“Finally, our study suggests that as a maintenance therapy in inflammatory neurological diseases, 2 g of RTX every 6 months is probably an overtreatment, 1 g being more appropriate,” the authors concluded.
Reference
Rual C, Biotti D, Lepine Z, et al. 2 grams versus 1 gram rituximab as maintenance schedule in multiple sclerosis, neuromyelitis optica spectrum disorders and related diseases: What B-cell repopulation data tell us. Mult Scler Relat Disord Published online February 10, 2023. doi:10.1016/j.msard.2023.104563
