Reduced sick leave in multiple sclerosis after one year of natalizumab treatment. A prospective ad hoc analysis of the TYNERGY trial.

BACKGROUND: In a retrospective study, we have previously shown that work ability was improved after the initiation of natalizumab treatment in relapsing-remitting multiple sclerosis (RRMS). In another prospective trial (TYNERGY) the effect on MS-related fatigue was evaluated after 12 months of treatment with natalizumab. A comprehensive Capacity for Work Questionnaire (CWQ) was used to collect data regarding number of working hours and sickness absence. The predefined intention-to-treat analysis regarding work ability did not, however, show significant results.

OBJECTIVES: The objective of this paper is to assess the amount of sick leave in RRMS before and after one year of natalizumab treatment and correlate it to fatigue and walking ability.

METHODS: This is a post-hoc analysis of the complete data from the CWQ used in the TYNERGY trial.

RESULTS: MS patients receiving sickness benefit before start of treatment reduced their sickness benefit by an absolute change of 33% after one year of natalizumab treatment. Younger age and improvement of walking ability correlated significantly with reduction of sick leave.

CONCLUSIONS: This ad-hoc analysis of prospectively collected data supported our previous retrospective study and thus indicates a positive relationship between natalizumab treatment and improvement in work ability.