“The following study, using a medical insurance database, shows that persistent use of natalizumab is associated with lower relapse rates and lower healthcare utilization. Is this surprising? Not really; we showed this in the pivotal AFFIRM trial. This study reassuringly shows that real-life data mirrors that which was collected in the pivotal trial. It is a pity we don’t have more real-life data from this database; relapse rate is a poor proxy of efficacy and it would be nice to know how persistence of natalizumab usage impacts on quality of life, employment, anxiety and depression, fatigue, sleep, bladder function, etc. in real-life.”
McQueen et al. Increased relapse activity for multiple sclerosis natalizumab users who become nonpersistent: a retrospective study. J Manag Care Spec Pharm. 2015 Mar;21(3):210-8.
BACKGROUND: Natalizumab disease-modifying therapy for RRMS is efficacious in randomized controlled trials. Few studies have estimated the association between real-world natalizumab persistence behavior and relapse-related outcomes.
OBJECTIVES: To (a) examine the impact of using natalizumab consistently (i.e., persistent) on relapse-related outcomes as compared with transitioning to inconsistent natalizumab use (i.e., non-persistent) and (b) examine the impact of other treatment patterns on relapse-related outcomes for those who initiated natalizumab.
METHODS: Using the IMS PharMetrics Plus claims database (years 2006-2012), we identified MSers who initiated natalizumab (no natalizumab claims in year prior) and had at least 2 years of follow-up. Persistence in annual follow-up periods was defined as no 90-day or greater gap in natalizumab therapy. Relapse was an MS-related hospitalization or outpatient visit with intravenous or oral steroid burst claim within 7 days. Analyses compared observations based on changes in natalizumab persistence and natalizumab non-persistence status from 1 year to the next (e.g., transitioning from persistent to non-persistent), estimating differences in mean annual relapses and mean annual relapse-related costs.
RESULTS: A total of 2,407 natalizumab initiators had at least 2 years of follow-up, yielding 4,770 year-to-year natalizumab treatment patterns where each subject contributed 1, 2, or 3 year-to-year treatment patterns. In the year prior, 3,187 treatment patterns were persistent; 731 (22.9%) of these transitioned to non-persistence. The remaining 1,583 treatment patterns were non-persistent in the year prior; 132 (8.3%) of these transitioned to persistence. Persistent to non-persistent treatment patterns were associated with a mean relapse-rate increase of 0.23 (95% CI = 0.12, 0.35), and a mean increase in relapse-related costs of $1,346 (95% CI = $97, $2,595). Non-persistent to persistent treatment patterns were associated with a mean relapse-rate decrease of -0.15 (95% CI = -0.32, 0.017) and a mean decrease in relapse-related costs of -$1,369 (95% CI = -$2,761, $23).
CONCLUSIONS: Findings suggest that real-world persistent natalizumab users who become non-persistent have statistically significant increases in annual relapses and relapse-related costs. Those who transition from non-persistent to persistent have non-significant reductions in relapses and their associated costs.