B-lymphocyte-guided retreatment contributes to establish good effectiveness and safety profile in MS patients treated...

Rituximab is extensively used for multiple sclerosis (MS) treatment. However, the best dosage remains to be established. It has been proposed that retreatment could be guided by B lymphocyte (BL) percentages.

To establish the best BL value for retreatment with rituximab in MS and to confirm the safety and efficacy of this approach.

A prospective study was done with an exploratory cohort and a confirmatory cohort of MS patients treated with rituximab between 2017 and 2021. The first one comprised 10 MS patients with BL assessed every 3 months after rituximab infusion and retreatment done when BL values were ≥0.5%. The confirmatory cohort included 41 MS patients (41.5% women, 87.8% with secondary progressive MS, median age = 46.3 (interquartile range: 41.3-52.1) years, disease duration = 14.1 (9-19.6) years, EDSS score = 5.5 (4.0-6.5)). The confirmatory cohort was treated with rituximab following the pattern established in the exploratory cohort.

In the exploratory cohort, ≥0.2% BL was established as the best value for retreatment because in most cases, a substantial increase of BL counts was preceded by initial values of 0.2-0.3%. In the confirmatory cohort, rituximab reduced the annualized relapse rate (ARR 0.56 vs. 0.125, p < 0.001), proportion of patients with appearance of new/enlarged T2 lesions (63.4% vs. 12.2%, p < 0.001), gadolinium-enhancing lesions (39% vs. 0%, p < 0.001), and confirmed disability progression (55% vs. 27.5%, p = 0.037). There were 22 patients (53.7%) who achieved NEDA-3. No patients had severe infections, and 10.7% cases had reduced IgG levels.

Rituximab treatment guided by BL showed high effectiveness and a good safety profile for MS patients after one year of treatment.