Results of sustained long-term use of interferon beta-1a in a community-based cohort of patients with relapsing multiple sclerosis

Abstract

Background:

Few studies have evaluated long-term efficacy of interferon beta-1a in large community-based cohorts.

Objective:

Evaluate time to relapse, relapse rate, and disability progression in patients treated with intramuscular interferon beta-1a.

Methods:

A retrospective review of medical records from 2000–2010 was performed. Adult patients with relapsing-remitting MS or clinically isolated syndrome treated with interferon beta-1a were included. Primary outcomes were time to relapse, annualized relapse rate, and changes in Expanded Disability Status Scale score. Other outcomes included factors associated with time to first relapse, risk of having a relapse while receiving interferon beta-1a, and discontinuation of therapy.

Results:

In total, 364 of 696 patients screened were enrolled, with a mean age of 51 ± 12.1 years, disease duration of 9.39 ± 7.02 years, and duration of therapy of 4.03 ± 2.56 years. Mean time to first on-therapy relapse was 5.58 ± 0.26 years, annualized relapse rate was 0.30 ± 0.55 years, and mean increase in sustained Expanded Disability Status Scale score was 0.018. Relapse risk was associated with higher baseline Expanded Disability Status Scale score, age at disease onset, and number of relapses in the 12 months prior to therapy initiation.

Conclusions:

This study demonstrates favorable clinical outcomes observed in a large community-based cohort, and serves to emphasize the continued therapeutic importance of interferon beta-1a, despite the development of newer agents with greater convenience of use, but also more potential risk of serious morbidity.

Keywords: :

• Beta interferon
• Disease modifying therapy
• Relapsing remitting multiple sclerosis
• Time to relapse

Transparency

Declaration of funding

This study was funded by Biogen Idec.

Declaration of financial/other relationships

SC has disclosed that he serves on advisory boards for Biogen Idec, Novartis, and Sanofi Genzyme, has received research support from Biogen Idec, Novartis, Sanofi Genzyme, Opexa, Teva, Mallinckrodt and Roche, and has received speaker honoraria from Biogen Idec, Novartis, Sanofi Genzyme and Acorda. CC, EB, TS, LG, and MR have no relevant financial relationships to disclose. JDA Peer Reviewers on this manuscript have no relevant financial relationships to disclose.

Acknowledgments

Stanley Cohan and Chiayi Chen had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.