Affiliation:
1. Department of Pharmacology, Institute of Postgraduate Medical Education and Research, Kolkata, West Bengal, India
2. Department of Neuromedicine, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
Abstract
Abstract
Introduction:
Rituximab (RTX), initially approved for various blood cancers, is additionally used for the management of primary central nervous system (CNS) demyelinating disorders. This study aimed to quantify the % of B cells following RTX therapy in patients with primary CNS demyelinating disorders, so as to establish a correlation, if any, between the degree of B-cell depletion and clinical response(s).
Materials and Methods:
A prospective, observational study was conducted from February 2020 to August 2021 in 15 adults diagnosed with primary CNS demyelinating disorders. The % of B cells was quantified in terms of CD20 by flow cytometry, and clinical evaluation was by Expanded Disability Status Scale (EDSS) scores. Following the first dose of RTX, the %CD20 counts were measured 2 and 24 weeks later; subsequently, depending on the %CD20, RTX was administered. Accordingly, patients were divided into Group 1 (n = 7, %CD20 ≥ 1.5) and Group 2 (n = 8, %CD20 < 1.5) and followed up on the basis of CD counts till the completion of the study or until they were lost to follow-up. Safety was evaluated by recording of treatment-emergent adverse drug reactions (ADR).
Results:
In patients with CNS demyelinating disorders (n = 15), their median (interquartile range [IQR]) %CD20 and EDSS at baseline was 9.8 (5.6–18.8)% and 8.0 (7.5–8.0)%, respectively. In Group 1 (n = 7, %CD20 ≥ 1.5), there was a gradual decrease of %CD20 and EDSS, whereas in Group 2 (n = 8, %CD20 < 1.5), despite withholding RTX, patients remained asymptomatic, and their %CD20 remained <1.5 and EDSS showed a gradual decrease. 87% of patients experienced at least one ADR, the median (IQR) of ADRs per patient was 3 (0–3), and all 31 ADRs were infusion-related, with 100% recovery.
Conclusion:
RTX was relatively safe to use in these disorders, and monitoring its efficacy was adequately achieved using EDSS, with no additional benefits accrued by measuring %CD20 counts.