Rituximab in the treatment of refractory rheumatoid arthritis in a tertiary academic hospital

Lovelock, Tamsin
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Background Significant disability results from rheumatoid arthritis (RA) when treatment is delayed or inadequate. Rituximab is approved for use in RA in South Africa, but there is a paucity of data on its use in Sub-Saharan African populations. Objectives To determine the response to rituximab in refractory RA patients by measuring disease activity and functional status over a 6-month period. To describe predictors of response to rituximab, and to document short term adverse events. Methods A single centre retrospective study of adult patients with RA receiving treatment with rituximab at Chris Hani Baragwanath Academic Hospital, between January 2012 and September 2016. Demographics, clinical and laboratory data were collected. The European League Against Rheumatism (EULAR) response criteria and minimal clinically important improvement (MCII) in Health Assessment Questionnaire Disability Index (HAQ-DI) were applied as outcome measures. Baseline characteristics of responders to rituximab therapy were compared with those of non-responders. Results Of the 53 patients with RA refractory to at least 3 synthetic disease modifying anti-rheumatic drugs (DMARDs), 75.5% were African and 88.7% were female. At initiation of rituximab the mean age (SD) was 50.8 (10.7) years and disease duration was 12.6 (6.6) years. Over 90% of patients were rheumatoid factor and anti-cyclic citrullinated peptide antibody positive, 41.5% had extra-articular features and the majority (69.8%) had high disease activity by the simplified disease activity index. The baseline mean (SD) HAQ-DI was 2.3 (0.6). At 3 months, 81.1% of patients achieved a good or moderate EULAR response. Predictors of response to rituximab included higher tender joint counts (p=0.0473) and higher SDAI scores (p=0.0467). A clinically meaningful decrease in HAQ-DI scores was observed in 44 (83%) of patients. Improvements were not sustained at 6 months, although clinical parameters were still better than at initiation. No early adverse events were recorded. Conclusion Rituximab therapy was safe and effective in controlling disease activity in addition to improving functional disability in this cohort of predominantly African patients with severe established RA. The findings underscore the need to identify appropriate patients for predictable responses to biologic therapies in prospective longitudinal studies in southern Africa.
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Internal Medicine. Johannesburg, 2019