Cost-utility of Intravenous Immunoglobulin (IVIG) compared with corticosteroids for the treatment of Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) in Canada

OBJECTIVES Intravenous immunoglobulin (IVIG) has demonstrated improvement in chronic inflammatory demyelinating polyneuropathy (CIDP) patients in placebo controlled trials. However, IVIG is also much more expensive than alternative treatments such as corticosteroids. The objective of the paper is to evaluate, from a Canadian perspective, the cost-effectiveness of IVIG compared to corticosteroid treatment of CIDP. METHODS A markov model was used to evaluate the costs and QALYs for IVIG and corticosteroids over 5 years of treatment for CIDP. Patients initially responding to IVIG could remain a responder or relapse every 12 week model cycle. Non-responding IVIG patients were assumed to be switched to corticosteroids. Patients on corticosteroids were at risk of a number of adverse events (fracture, diabetes, glaucoma, cataract, serious infection) in each cycle. RESULTS Over the 5 year time horizon, the model estimated the incremental costs and QALYs of IVIG treatment compared to corticosteroid treatment to be $124,065 and 0.177 respectively. The incremental cost per QALY gained of IVIG was estimated to be $687,287. The cost per QALY of IVIG was sensitive to the assumptions regarding frequency and dosing of maintenance IVIG. CONCLUSIONS Based on common willingness to pay thresholds, IVIG would not be perceived as a cost effective treatment for CIDP.