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 125 mcg 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 [22 mcg, 30 mcg, and 44 mcg], interferon beta-1b, and glatiramer acetate 20 mg) 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 44 mcg), and interferon beta-1b, and cost-effective compared with glatiramer acetate 20 mg. 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.