Expanding Spectrum Of Opportunistic Infections Associated With Dimethyl Fumarate

Background:Only progressive multifocal leukoencephalopathy (PML) is currently described in the dimethyl fumarate (DMF) prescribing information.Objectives:To describe opportunistic infections (OIs), other than PML, reported in association with DMF.Methods:The FDA Adverse Event Reporting System (FAERS) and medical literature were searched.Results:We retrieved 34 cases of serious OIs with a causal association with DMF, including 11 central nervous system (CNS) infections and 23 extra-CNS infections. Six OIs occurred with normal circulating absolute lymphocyte counts. The median latency from DMF initiation was 13 months and was variable.Conclusion:DMF is associated with the development of OIs that require invasive diagnostic and/or therapeutic procedures. Patients should be monitored for OIs when treated with DMF regardless of circulating absolute lymphocyte counts.