Rebound activity after fingolimod cessation: A case - control study.

BACKGROUND: There has been an increase in the number of reports of multiple sclerosis (MS) rebound activity (RA), which is usually defined as a severe disease reactivation after natalizumab or fingolimod withdrawal that exceeds pre-treatment baseline inflammatory activity. The frequency and risk factors that could predict RA remain unknown. Fingolimod is currently the most frequently prescribed disease modifying therapy for MS in Argentina, so that there is a need to determine possible predictors of RA. OBJECTIVES: To identify risk factors for developing RA after fingolimod cessation; to describe RA characteristics, management and evolution. METHODS: The study was a multicenter, retrospective, case-control study of patients with MS who had discontinued fingolimod and were followed up to nine months after discontinuation. Demographic, clinical and paraclinical data was extracted, including age, gender, MS phenotype, reason for discontinuation, number of relapses during the year prior to suspension, time treated with fingolimod, EDSS before, during and after rebound, MRI findings. RESULTS: 26 cases of RA were matched 1:1 with patients without RA. The median time elapsed to RA was 50 days. 68% showed worsening of the EDSS in the evaluation at 3 months of RA. When compared with the control group, no difference was found in terms of age, gender, phenotype, EDSS at the moment of suspension, reason for discontinuation, number of relapses in the previous year, and time on therapy. CONCLUSION: In this case-controlled study, no risk factors could be identified to predict RA after fingolimod cessation. Further controlled, prospective, better powered studies are needed to confirm these findings.