Relapse outcomes, safety, and treatment patterns in patients diagnosed with relapsing-remitting multiple sclerosis and initiated on subcutaneous interferon β-1a or dimethyl fumarate: a real-world study

Abstract

Objective: To estimate real-world treatment patterns, safety, and relapse outcomes of subcutaneous (sc) interferon (IFN) β-1a (Rebif) vs dimethyl fumarate (DMF; Tecfidera), to treat relapsing-remitting multiple sclerosis (RRMS).

Methods: A US retrospective chart review of 450 randomly selected adults newly diagnosed with RRMS who received sc IFN β-1a (n = 143) or DMF (n = 307) was conducted. Patients were either (a) treatment-naïve, initiating first-line treatment with sc IFN β-1a or DMF, or (b) previously treated, switching to sc IFN β-1a or DMF. Two years’ follow-up data were captured. Patient characteristics, persistence, and adverse events between treatment groups were compared using t-tests or Chi-square tests. Kaplan-Meier curves with log-rank tests and Cox proportional hazards models were used to compare time to, and risk of non-persistence. Annualized Relapse Rates (ARR) were calculated using a robust variance Poisson model adjusting for covariates. Propensity scores were used to address possible selection bias.

Results: One hundred and twelve patients became non-persistent, most commonly due to an adverse event (n = 37). No difference was observed in time to overall non-persistence between sc IFN β-1a and DMF patients. Among treatment-naïve patients, those receiving DMF had 2.4-times the risk (HR = 2.439, 95% CI = 1.007–5.917, p = .0483) of experiencing a discontinuation than patients receiving sc IFN β-1a. Non-persistent patients receiving DMF had 2.3-times the risk (HR = 2.311, 95% CI = 1.350–3.958, p = .0023) of experiencing an adverse event at a given time point than patients prescribed sc IFN β-1a. No differences in relapse risk or ARR between sc IFN β-1a- and DMF-treated patients were observed.

Conclusions: sc IFN β-1a-treated patients had comparable persistence and relapse outcomes, and better safety outcomes vs DMF-treated patients across 2 years.

Keywords:

• Multiple sclerosis
• relapsing-remitting
• interferon β-1a
• dimethyl fumarate
• observational study

Transparency

Declaration of funding

This work was supported by EMD Serono Inc., a business of Merck KGaA, Darmstadt, Germany.

Declaration of financial/other relationships

PB is an employee of Indegene, Inc., which received a fee for services related to the development and execution of this study, and for the tabulation, analysis, and reporting of its results. FE and RE were employees of Indegene while the study was being conducted. SW is an employee of EMD Serono Inc., a business of Merck KGaA, Darmstadt, Germany. Peer reviewers on this manuscript have received an honorarium from CMRO for their review work, but have no other relevant financial relationships to disclose.

Acknowledgments

Medical writing assistance was provided by Duncan Marriott of inScience Communications, Chester, UK, and supported by EMD Serono Inc., a business of Merck KGaA, Darmstadt, Germany. Frank Ernst is currently an employee of CTI Clinical Trial and Consulting Services, Cincinnati, OH.