Shortening the washout to 4 weeks when switching from natalizumab to fingolimod and risk of disease reactivation in multiple sclerosis.

BACKGROUND

There is limited evidence about the optimal length of washout when switching from natalizumab to fingolimod.

OBJECTIVE

To study if a washout period of 4 weeks is associated with less disease activity compared to 8 weeks.

METHODS

25 patients with Relapsing Remitting Multiple Sclerosis were included in an open label, prospective study with a follow-up of 108 weeks. The primary endpoint (PE) was defined as "time to first relapse or MRI disease activity up to week 56". In addition, a recurrent event analysis (REA) was performed up to week 108.

RESULTS

The PE was not met (HR 0.67, 95% CI [0.22,1.97], p = 0.462). Number of relapses before stopping natalizumab was positively associated with the hazard of relapse (HR 3.91, p = 0.0117, 95% CI [1.36, 11.28]). The REA showed a reduction of the hazard to develop a relapse by 77% (HR 0.23, 95% CI [0.08, 0.69], p = 0.00854) in favor of the cohort with 4 weeks washout.

CONCLUSIONS

Our study suggests that switching from natalizumab to fingolimod with a shorter washout of 4 weeks might reduce the risk of disease reactivation after switching.