Papers

Modelling the cost effectiveness of interferon beta and glatiramer acetate in the management of multiple sclerosis

Jim Chilcott, technical director, ^a Chris McCabe, senior lecturer in health economics, ^b Paul Tappenden, operational research analyst, ^b Anthony O'Hagan, director, ^c Nicola J Cooper, research associate in health economics, ^d Keith Abrams, professor of medical statistics, ^d Karl Claxton, senior lecturer in health economics, ^e on behalf of the Cost Effectiveness of Multiple Sclerosis Therapies Study Group.

^a School of Health and Related Research Rapid Reviews Group, School of Health and Related Research, University of Sheffield, Sheffield S1 4DA, ^b School of Health and Related Research, ^c Centre for Bayesian Statistics in Health Economics, Department of Probability and Statistics, University of Sheffield, Sheffield S3 7RH, ^d Department of Epidemiology and Public Health, University of Leicester, Leicester LE1 6TP , ^e Centre for Health Economics, Department of Economics and Related Studies, University of York, York YO10 5DD

Correspondence to: C McCabe c.mccabe{at}sheffield.ac.uk

Objective: To evaluate the cost effectiveness of four disease modifying treatments (interferon betas and glatiramer acetate) for relapsing remitting and secondary progressive multiple sclerosis in the United Kingdom.
Design: Modelling cost effectiveness.
Setting: UK NHS.
Participants: Patients with relapsing remitting multiple sclerosis and secondary progressive multiple sclerosis.
Main outcome measures: Cost per quality adjusted life year gained.
Results: The base case cost per quality adjusted life year gained by using any of the four treatments ranged from £42 000 ($66 469; 61 630) to £98 000 based on efficacy information in the public domain. Uncertainty analysis suggests that the probability of any of these treatments having a cost effectiveness better than £20 000 at 20 years is below 20%. The key determinants of cost effectiveness were the time horizon, the progression of patients after stopping treatment, differential discount rates, and the price of the treatments.
Conclusions: Cost effectiveness varied markedly between the interventions. Uncertainty around point estimates was substantial. This uncertainty could be reduced by conducting research on the true magnitude of the effect of these drugs, the progression of patients after stopping treatment, the costs of care, and the quality of life of the patients. Price was the key modifiable determinant of the cost effectiveness of these treatments.

What is already known on this topic Interferon beta and glatiramer acetate are the only disease modifying therapies used to treat multiple sclerosis Economic evaluations of these drugs have had flaws in the specification of the course of the disease, efficacy, duration of treatment, mortality, and the analysis of uncertainty None of the existing estimates of cost effectiveness can be viewed as robust What this study adds The cost per quality adjusted life year gained is unlikely to be less than £40 000 for interferon beta or glatiramer acetate Experience after stopping treatment is a key determinant of the cost effectiveness of these therapies Key factors affecting point estimates of cost effectiveness are the cost of interferon beta and glatiramer acetate, the effect of these therapies on disease progression, and the time horizon evaluated