Peginterferon beta-1a versus other self-injectable disease-modifying therapies in the treatment of relapsing-remitting multiple sclerosis in Scotland: a cost-effectiveness analysis

Aims: Peginterferon beta-1a 125mcg administered subcutaneously every 2 weeks, a new disease-modifying therapy (DMT) for relapsing-remitting multiple sclerosis (RRMS), was approved in January 2015 by the Scottish Medicines Consortium. This study assesses long-term clinical and economic outcomes of peginterferon beta-1a compared with other self-injectable DMTs (interferon beta-1a [22mcg, 30mcg, and 44mcg], interferon beta-1b, and glatiramer acetate 20mg) in the treatment of RRMS, from the National Health Service and Personal Social Services perspective in Scotland. Methods: A previously published, validated Markov cohort model was adapted for this analysis. The model estimates changes in patient disability, occurrence of relapses, and other adverse events, and translates them into quality-adjusted life years and costs. Natural history data came from the ADVANCE trial of peginterferon beta-1a, the London Ontario (Canada) database, and a large population-based MS survey in the UK. The comparative efficacy of each DMT vs placebo was obtained from a network meta-analysis. Costs (2015 British Pounds) were obtained from public databases and literature. Clinical and economic outcomes were projected over 30 years and discounted at 3.5% per year.Results: Over 30 years, peginterferon beta-1a was dominant compared with interferon beta-1a (22, 30, and 44mcg), and interferon beta-1b, and cost-effective compared with glatiramer acetate 20mg. Results: were most sensitive to variations in each DMT's efficacy and acquisition costs. Deterministic and probabilistic sensitivity analyses confirmed the robustness of the results.Limitations: The impact of improved adherence with peginterferon beta-1a on clinical and economic outcomes and the impact of subsequent DMTs after treatment discontinuation were not considered. Oral and infused DMTs were not included as comparators. Conclusion: Long-term treatment with peginterferon beta-1a improves clinical outcomes, while its cost profile makes it either dominant or cost-effective compared with other self-injectable DMTs for the treatment of RRMS in Scotland.