Increased multiple sclerosis disease activity in patients transitioned from fingolimod to dimethyl fumarate: a case series.

backgroundFingolimod is a S1P CASE PRESENTATION: We present six patients with relapsing-remitting MS who developed an unexpected increase in disease activity after transitioning from fingolimod to DMF. All patients were clinically and radiologically stable on fingolimod for at least 1 year. The switch in therapy was due to significantly low CD4+ T lymphocyte count ≤65 cells/ul (normal range 490-1740 cells/ul), after discussing the results with the patients and the potential risk for opportunistic infections including cryptococcal infections. DMF was introduced following a washout period of 5 to 11 weeks to allow reconstitution of the immune system and for the absolute lymphocyte count to reach ≥500 cells/ul. Every patient who experienced a relapse had several enhancing lesions in the brain and/or spinal cord between 12 to 23 weeks after cessation of fingolimod and 1 to 18 weeks after starting DMF. All relapses were treated with intravenous methylprednisolone with good clinical responses.

conclusionThe anticipated beneficial response of DMF treatment to mitigate rebound after fingolimod therapy cessation was not observed. Our patients experienced rebound disease despite being on treatment with DMF. Additional studies are necessary to understand which treatments are most effective to transition to after discontinuing fingolimod.