A cross-sectional analysis of persistence to disease-modifying therapies in treatment naïve and experienced patients with relapsing multiple sclerosis at a health-system specialty pharmacy

Abstract

Background: Patients with relapsing multiple sclerosis (RMS) are maintained on disease-modifying therapy (DMT) to prevent disease progression. Reported persistence rates to DMTs are varied and concerningly low. Limited data exists on long-term persistence rates and reasons for DMT discontinuation in patients with RMS. This study evaluated long-term DMT persistence, rates and reasons for DMT discontinuation or switch, specialty pharmacist involvement in DMT treatment transitions, and predictors associated with non-persistence in treatment naïve and experienced patients.

Methods: We performed a single-center retrospective, cross-sectional review of patients with RMS and ≥3 fills of DMT from a health-system specialty pharmacy (May-October 2017). Patients were followed for 3 years to determine DMT persistence, defined as the time a patient remained on index DMT. Descriptive statistics were used to summarize sample characteristics and outcomes. The Kaplan-Meier estimation method was used to estimate the probability of remaining persistent and we used the Cox proportional hazards regression model to analyze the primary outcome. Rates and reasons for DMT discontinuation were identified via pharmacy claims and confirmed via chart review of the electronic health record.

Results: The study included 540 patients, of which 41 (7.6%) were treatment naïve. Over 3 years, 193 (36%) patients remained on index DMT. The probability of remaining persistent for 3 years was 0.51 (95% confidence interval [CI] 0.47-0.56) and median time on index DMT was 642 days (interquartile range 317-1096). For the 347 patients that did not continue index DMT: 91 (26%) discontinued, 136 (39%) switched to a new DMT, 92 (27%) transferred care to a new specialty pharmacy or provider, 21 (6%) were lost to follow-up, and 7 (2%) died. Common reasons for DMT discontinuation or switch were insurance formulary change, side effects, clinical decline, and stable disease. Specialty pharmacists initiated 6 (7%) DMT discontinuations and 49 (36%) DMT switches. A strong non-linear relationship existed between age and risk of non-persistence (p = 0.003). Patients on an injectable index DMT were 1.5 times more likely to be non-persistent than those on an oral DMT (95% CI 1.1-2.1, p = 0.012) and patients with non-commercial insurance were 1.4 times more likely to be non-persistent (95% CI 1.02-2.0, p = 0.040).

Conclusions: Long-term persistence to DMTs is low, with many patients switching or discontinuing DMT treatment. Specialty pharmacists identify the need for DMT discontinuation or switch and are uniquely positioned to assist during therapy transitions.

Keywords: Disease-modifying therapy; Multiple sclerosis; Persistence; Pharmacists; Pharmacy.