Dimethyl Fumarate in Relapsing Remitting Multiple Sclerosis: 24 Months Observations of the Effects of Dose Reduction on Lymphopenia (P6.347)

Objective: Report the effects of dimethyl fumarate (DMF) dose reduction on lymphopenia in relapsing-remitting multiple sclerosis (RRMS) patients, and monitor the subsequent clinical course and MRI activity. Background: Dimethyl fumarate is a first-line therapy for treatment of RRMS. At the standard dose of DMF 240 mg twice daily, lymphopenias of ≤ 0.6 k/μL are a concern. Dose reduction may lessen the degree of lymphopenia, but it is unknown if reduced dose therapy remains effective. Design/Methods: We performed a retrospective review of RRMS patients on oral DMF therapy from the University of Utah and Veterans Affairs Salt Lake City Health System databases (March 2013 to September 2017). Patients on reduced dose DMF due to lymphopenia were identified and included in this analysis Results: Of 425 patients identified through chart review, a total of 92 patients had lymphopenia ( Conclusions: Our findings a 2 or more years interval (ranges of 24–47 months) indicate that reduced dose DMF lessens the degree of lymphopenia, without increasing relapse rate or disease activity as assessed by clinical MRI scans. Our observation suggests that partial dose therapy may be an effective therapeutic option for patients with moderate lymphopenia. Disclosure: Dr. Wong has nothing to disclose. Dr. Marini has nothing to disclose. Dr. Nguyen has nothing to disclose. Dr Clardy has nothing to disclose. Dr. Cortez has nothing to disclose. Dr. DeWitt has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Biogen and Teva. Dr. Greenlee has received personal compensation in an editorial capacity for Associate Editor for Medlink. Dr. Klein has nothing to disclose. Dr. Paz Soldan has received research support from Biogen. Dr. Steffens has nothing to disclose. Dr. Rose has received research support from Biogen.