Real-World Comparison of Relapse Rates in Multiple Sclerosis Patients Treated with Disease-Modifying Therapies
Objectives: To compare the annual relapse rate (ARR) of MS in patients initiating delayed-release dimethyl fumarate (DMF; also known as gastro-resistant DMF), glatiramer acetate (GA), interferon (IFN), fingolimod (FTY), and teriflunomide (TER).
Methods: This study used MarketScan, a large US commercial insurance database. Adult MS patients (18-64 years) who initiated a DMT of interest in 2013 were included. The main outcome of interest, ARR, was calculated based on the number of MS-related relapses (identified from inpatient and outpatient claims) within 1 year post-DMT initiation. Poisson regression was used to compare the adjusted ARR while controlling for the difference in demographics, comorbidities, MS symptoms, DMT use, and ARR at baseline. Subgroup analyses were conducted based on the DMT used within the year prior to index date.
Results: A total of 3,352 DMF, 1,057 GA, 884 IFN, 579 FTY, and 500 TER patients were included in the analysis. Baseline differences were seen in age (46.7, 43.5, 43.6, 43.8, and 49.6, respectively; p<0.01), proportion of females (76.6%, 79.0%, 78.6%, 76.2%, vs. 80.0%, respectively; p=0.21), proportion with other DMT in the prior year (68.7%, 15.7%, 13.5%, 64.2%, and 66.0%, respectively; p<0.01), and ARR in the prior year (0.43, 0.31, 0.37, 0.44, and 0.38, respectively; p<0.01). After DMT initiation, the unadjusted ARR was 0.30 for DMF, 0.33 for GA, 0.34 for IFN, 0.31 for FTY, and 0.35 for TER (p<0.01). Using DMF as the reference, the adjusted incidence rate ratio was 1.34 (95% confidence interval [CI]: 1.17–1.53) for GA, 1.27 (1.10–1.46) for IFN, 1.03 (0.88–1.21) for FTY, and 1.23 (1.05–1.45) for TER. Consistent findings were observed in the subgroups stratified by DMT use in the prior year.
Conclusions: DMF demonstrated significantly better effectiveness than GA, IFN, and TER in the real-world setting. No significant difference was observed between DMF and FTY.