Systematic review of immunomodulatory drugs for the treatment of people with multiple sclerosis: is there good quality evidence on effectiveness and cost?

OBJECTIVE: To review the clinical effectiveness and costs of a range of disease modifying drugs in multiple sclerosis. Drugs included are azathioprine, cladribine, cyclophosphamide, intravenous immunoglobulin, methotrexate, and mitoxantrone. METHODS: Electronic databases and bibliographies of related papers were searched for randomised controlled trials (RCTs) and systematic reviews, and experts and pharmaceutical companies were contacted for further information. Inclusion and quality criteria were assessed, data extraction undertaken by one reviewer and checked by a second reviewer, with discrepancies being resolved through discussion. Costs were obtained and cost-effectiveness papers sought. RESULTS: Seventeen studies met the inclusion criteria for the review. Evidence for the clinical effectiveness of the drugs showed some reductions in relapse rates and/or progression to disability for people with MS, although benefits may be lessened by wide ranging side effects. Annual drug costs/patient are estimated to range from 60 pounds to 10200 pounds. No cost effectiveness studies were found. CONCLUSION: Evidence for the effectiveness of these drugs in multiple sclerosis is problematic because there are few good quality trials for each drug. Trials often have methodological limitations and use different treatment regimes, patient groups, and outcome measures. Well conducted trials using outcome measures with clinical significance for groups of patients with different types of multiple sclerosis and long term follow up are needed if the evidence base of treatment for the disease is to be improved.