Risk of fingolimod rebound after switching to cladribine or rituximab in multiple sclerosis.

Background: A sudden onset of extensive disease activity, including severe clinical relapse and extensive brain or spinal magnetic resonance imaging (MRI) lesions, termed "rebound" disease activity has been reported after withdrawal of fingolimod in patients with multiple sclerosis (MS).

Objective: To compare the risk of rebound after switching from fingolimod to cladribine or rituximab in MS.

Methods: All patients switching from fingolimod to cladribine or rituximab were included in a retrospective cohort study utilizing prospectively collected data from two university hospitals with different treatment strategies.

Results: A total of 73 patients with at least 6 months follow-up after switching were identified, 33 patients had switched from fingolimod to cladribine and 40 patients to rituximab. No patients in the rituximab group and seven (21.1%) in the cladribine group qualified for rebound disease activity. Ten (30.3%) of the patients using cladribine and five (12.5%) of the patients using rituximab experienced a relapse. MRI disease activity was seen in 18 (54.5%) and eight (20.0%) of the patients using cladribine and rituximab, respectively. Younger age and previous high relapse rate were associated with increased risk of rebound in the cladribine group.

Conclusions: We identify a lower risk of rebound during the first year after switching from fingolimod to rituximab compared to cladribine, indicating a better initial clinical outcome with the former treatment strategy.