Infection Risks Among Patients With Multiple Sclerosis Treated With Fingolimod, Natalizumab, Rituximab, and Injectable Therapies

Although highly effective disease-modifying therapies for multiple sclerosis (MS) have been associated with an increased risk of infections vs injectable therapies interferon beta and glatiramer acetate (GA), the magnitude of potential risk increase is not well established in real-world populations. Even less is known about infection risk associated with rituximab, which is extensively used off-label to treat MS in Sweden.

To examine the risk of serious infections associated with disease-modifying treatments for MS. Design, Setting, and Participants: This nationwide register-based cohort study was conducted in Sweden from January 1, 2011, to December 31, 2017. National registers with prospective data collection from the public health care system were used. All Swedish patients with relapsing-remitting MS whose data were recorded in the Swedish MS register as initiating treatment with rituximab, natalizumab, fingolimod, or interferon beta and GA and an age-matched and sex-matched general population comparator cohort were included. Exposures: Treatment with rituximab, natalizumab, fingolimod, and interferon beta and GA. Main Outcomes and Measures: Serious infections were defined as all infections resulting in hospitalization. Additional outcomes included outpatient treatment with antibiotic or herpes antiviral medications. Adjusted hazard ratios (HRs) were estimated in Cox regressions.