The impact of very short transition times on switching from Natalizumab to Fingolimod on imaging and clinical effectiveness outcomes in multiple sclerosis.

Background Due to the recurrence of disease activity in multiple sclerosis (MS) patients, a washout period of <3 months has been suggested for the transition from natalizumab (NTZ) to fingolimod (FTY). However, very short transition periods of <1 month may be more beneficial. Methods Retrospective analysis of patients from the Rocky Mountain MS Center at the University of Colorado who were: a) on NTZ for ≥6 months prior to switching to FTY; b) had a transition period ≤ 6 months; and c) initiated FTY treatment prior to November 2013. Transition periods were grouped as follows: <1 month, 1–2 months, and 3–6 months. Outcomes assessed include clinical and MRI measures within one year of FTY initiation. Results Thirty-seven, 56 and 24 patients had a transition period < 1 month, 1–2 months and 3–6 months, respectively. Baseline characteristics were well matched: mean age 45–49 years ( p  = 0.17), disease duration 11–13 years ( p  = 0.42), and ~70% women ( p  = 1.00). Following the switch (including transition period), clinical relapses were observed in 0% (<1 month), 12.5% (1–2 months), 37.5% (3–6 month) ( p  < 0.001) of patients. New gadolinium enhancing lesions occurred in 3.3% (<1 month), 13% (1–2 months), 21.4% (3–6 months) ( p  = 0.13) patients. New T2 lesions were observed in 11.1% (<1 month), 16.3% (1–2 months), 33.3% (3–6 months) ( p  = 0.28) of patients. There were no unexpected adverse events or PML observed. Conclusions Minimizing transition times from NTZ to FTY was beneficial and safe. [ABSTRACT FROM AUTHOR]