Retrospective US database analysis of persistence with glatiramer acetate vs. available disease-modifying therapies for multiple sclerosis: 2001-2010

Background: Long-term persistence to treatment for chronic disease is difficult for patients to achieve, regardless of the disease or medication being used. The objective of this investigation was to examine treatment persistence with glatiramer acetate (GA) relative to available disease-modifying therapies (DMT) for multiple sclerosis (MS) over 12-, 24- and 36-month periods. Methods: Data from Clinformatics (TM) for DataMart affiliated with OptumInsight was used to identify patients using DMT between 2001 and 2010. Patients with 12, 24, and 36 months of follow-up were included. Persistence was defined as continuous use of the same DMT for the duration of follow-up regardless of treatment gaps. Regimen changes including re-initiation of therapy following gaps of 15 days or more, switching therapy, and DMT discontinuation were investigated. Descriptive statistics were used to summarize the results. Results: Cohorts of GA users with 12 months (n = 12,144), 24 months (n = 7,386) and 36 months (n = 4,693) of follow-up were identified. Persistence rates with GA were 80% for all time periods; discontinuation rates declined over time while switching increased modestly. In contrast, the full DMT-treated cohorts showed persistent rates of 68.3% at 12 months (n = 35,312), 53.9% at 24 months (n = 21,927), and 70.1% at 36 months (n = 14,343). As with these full DMT-treated cohorts, the proportion of GA users remaining on their initial therapy without a gap of 15 days or more decreased with length of follow-up. However, the proportion of GA users with a gap in treatment who re-initiated GA increased over time (64.4% at 12 months; 75.1% at 24 months, and 80.1% at 36 months) while those in the full DMT-treated cohorts re-initiated therapy at rates of only 50-60%. Conclusions: Persistence rates for GA were 80% for the 12-, 24- and 36-month time periods in contrast with the full DMT-treated cohorts whose persistence rates never exceeded 70.0%. Although there were more gaps in therapy of 15 days or more with all DMT over time, the proportion of GA users re-initiating therapy increased with follow-up contributing to the steady persistence. Therapy persistence is essential to achieve the desired outcomes in MS.