Multiple Sclerosis Treatment with Natalizumab: Analysis of a Hospital-Based Cohort

Introduction: Natalizumab is licensed as monotherapy for relapsing-remitting multiple sclerosis. Since pivotal studies showing natalizumab efficacy, several subsequent studies confirmed the reduction in annualized relapse rate and the slowing of disability progression. Nevertheless, 'real-world' data, namely in Portugal, are still scarce. We intend to report demographic and clinical data of the cohort of patients treated with natalizumab in the multiple sclerosis Clinic of Centro Hospitalar Sao Joao, based on daily practice. Material and Methods: We have conducted a retrospective study of multiple sclerosis patients who had been treated with natalizumab (at least one dose) from January 2007 to May 2013 in our Center. We have gathered information about demography, baseline disease, natalizumab treatment, and outcome. Results: We have found 66 patients treated with natalizumab since 2007 in our center. The majority (65.2%) were female, with a mean age of 35 years, and mean disease duration of 9.5 years. Almost all patients (93.9%) had received a prior multiple sclerosis immunomodulatory therapy. Patients have been treated with natalizumab on an average time of 24 months, with a statistically significant reduction in Annualized Relapse Ratio (-1.9, p < 0.001) and Expanded Disability Status Scale score (-0.8, p < 0.001). One patient has developed progressive multifocal leukoencephalopathy; other adverse effects have been uncommon. Discussion: In general, our results fit those earlier reported in other post-marketing studies. Lack of MRI data and retrospective design are the most important limitations of our study. Conclusion: Our study confirms natalizumab efficacy and safety in the treatment of relapsing-remitting multiple sclerosis in a 'realworld' practice.