Real-world adherence and persistence to oral disease-modifying therapies in multiple sclerosis patients over 1 year

Abstract

BACKGROUND: Disease-modifying therapies (DMTs) are indicated to reduce relapse rates and slow disease progression for relapsing-remitting multiple sclerosis (MS) patients when taken as prescribed. Nonadherence or nonpersistence in the real-world setting can lead to greater risk for negative clinical outcomes. Although previous research has demonstrated greater adherence and persistence to oral DMTs compared with injectable DMTs, comparisons among oral DMTs are lacking. OBJECTIVE: To compare adherence, persistence, and time to discontinuation among MS patients newly prescribed the oral DMTs fingolimod, dimethyl fumarate, or teriflunomide. METHODS: This retrospective study used MarketScan Commercial and Medicare Supplemental claims databases. MS patients with = 1 claim for specified DMTs from April 1, 2013, to June 30, 2013, were identified. The index drug was defined as the first oral DMT within this period. To capture patients newly initiating index DMTs, patients could not have a claim for their index drugs in the previous 12 months. Baseline characteristics were described for patients in each treatment cohort. Adherence, as measured by medication possession ratio (MPR) and proportion of days covered (PDC); persistence (30-day gap allowed); and time to discontinuation over a 12-month follow-up period were compared across treatment cohorts. Adjusted logistic regression models were used to examine adherence, and Cox regression models estimated risk of discontinuation. RESULTS: 1,498 patients newly initiated oral DMTs and met study inclusion criteria: fingolimod (n = 185), dimethyl fumarate (n = 1,160), and teriflunomide (n = 143). Patients were similar across most baseline characteristics, including region, relapse history, and health care resource utilization. Statistically significant differences were observed across the treatment cohorts for age, gender, previous injectable/infused DMT use, and comorbidities. Adherence and time to discontinuation were adjusted for age, gender, region, previous oral and injectable/infused DMT use, relapse history, and Charlson Comorbidity Index score. Relative to fingolimod patients, dimethyl fumarate and teriflunomide patients were significantly less likely to have an MPR = 80[%] (OR = 0.18; 95[%] CI = 0.09-0.36; P < 0.001 and OR = 0.19; 95[%] CI = 0.08-0.42; P < 0.001, respectively). Similarly, relative to fingolimod patients, dimethyl fumarate and teriflunomide patients were significantly less likely to have PDC = 80[%] (OR = 0.47; 95[%] CI = 0.33-0.67; P < 0.001 and OR = 0.37; 95[%] CI = 0.23-0.59; P < 0.001, respectively). Additionally, the HR for discontinuation was about 2 times greater for dimethyl fumarate (HR = 1.93; 95[%] CI = 1.44-2.59; P < 0.001) and teriflunomide patients (HR = 2.27; 95[%] CI = 1.57-3.28; P < 0.001) compared with fingolimod. CONCLUSIONS: In a real-world setting, patients taking fingolimod had better adherence and persistence compared with patients taking other oral DMTs over 12 months. Coupled with clinical factors, medication adherence and persistence should be important considerations when determining coverage decisions for MS patients.