Eltrombopag or Intravenous Immunoglobulin as a Bridge to Splenectomy in Adults With Chronic Idiopathic Thrombocytopenic Purpura: A Canadian Economic Analysis

Abstract

Abstract Background Chronic idiopathic thrombocytopenia purpura (ITP) in adults is a potentially serious disorder affecting 6000 to 7000 Canadians. Initial treatment consisting of corticosteroids usually begins when the platelet count is persistently below 20 × 109/L or if the patient has bleeding complications. In cases in which corticosteroid resistance develops or in which they are contraindicated, splenectomy is the recommended second-line therapy. In many of these patients, intravenous immunoglobulin (IVIG; 1 g/kg/day for 2 days then 1 g/kg/day monthly) is often used as a bridge to surgery. Eltrombopag is a new orally administered agent that activates the thrombopoietic receptor and stimulates human megakaryocytes. Clinical trials have demonstrated that eltrombopag is safe and effective in the treatment of adults with chronic ITP. Therefore, it represents an attractive option to IVIG for use as a bridge to splenectomy. In this study, a cost-minimization analysis was conducted to test the hypothesis that eltrombopag is a cost-effective alternative to IVIG for this indication. Patients and Methods The economic analysis was conducted from the Canadian societal perspective using a 4-month time horizon. Estimates for direct medical costs in these patients were obtained from 6 hematologists from across Canada. The base case analysis considered direct costs for drug therapy, outpatient pharmacy fees, medical consultations and visits, laboratory and diagnostic procedures, as well as costs for secondary pharmacotherapy in cases in which the primary agent had to be discontinued because of side effects. For IVIG, the analysis also included visits to the infusion clinic, chair time to receive the infusion, nursing time, pharmacy preparation, as well as indirect costs (eg, time off work, patient travel). A 1-way sensitivity analysis was then undertaken on the key cost drivers to test the stability of the primary findings. Results Total direct and indirect costs for IVIG were $24,134 for 4 months of therapy with drug cost contributing to 84% of the total. In contrast, total costs for eltrombopag were approximately $14,651 for an overall savings of $9,543 per patient. The sensitivity analysis suggested that the base case findings were stable and were only modestly affected by variations in drug cost and duration of therapy. Conclusion Given its oral route of administration and cost-saving potential, eltrombopag would be an economically attractive alternative to IVIG when the intent of therapy is to create a bridge to surgery.