Adherence and persistence among multiple sclerosis patients after one immunomodulatory therapy failure: Retrospective claims analysis

Abstract

There are no published data on patient adherence to, and persistence with, disease-modifying therapies (DMT) for multiple sclerosis (MS) after one immunomodulatory failure. The present study compares secondline DMT adherence and persistence among patients with MS. Patients with MS initiating a second-line treatment with natalizumab, intramuscular interferon beta-1a (i.m.-IFNβ-1a), subcutaneous (s.c.) IFNβ-1a, interferon beta-1b (IFNβ-1b), and glatiramer acetate (GA) from January 1, 2006 to October 4, 2008 were identified from a retrospective claims database associated with a large US health plan. Adherence was measured with medication possession ratio (MPR); adherence indicated MPR ≥ 0.80. Persistence was measured as time until a minimum 60-day gap in second-line therapy. Adherence and persistence were modeled with logistic and Cox proportional hazard regressions, respectively. The study population comprised 1381 patients. Multivariate analysis showed that the odds of adherence were significantly higher in the natalizumab cohort compared with all other second-line cohorts. The natalizumab cohort was more likely to be persistent compared with the i.m.-IFNβ-1a and IFNβ-1b cohorts. The natalizumab cohort was more adherent compared with the other second-line DMT cohorts, likely due in large part to active physician involvement and monitoring. Adherence to DMT, even after first-line failure, is critical to achieving optimal therapeutic benefit.