Cost Per Treatment Success Of Thrombopoietin Receptor Agonists Vs "Watch And Rescue" Strategy For Treating Adult Non-Splenectomized Patients With Chronic Immune Thrombocytopenia: A Us Payer Perspective

Background : Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by low platelet count level and increased risk of bleeding. Non-splenectomized patients account for the vast majority of adult patients with ITP in US clinical practice (Cetin et al, Blood , 2014). Two thrombopoietin receptor agonists (TPO-RAs, romiplostim [once-weekly subcutaneous injection] and eltrombopag [once-daily oral agent]) are indicated for the treatment of non-splenectomized adults with chronic ITP who have had an insufficient response to corticosteroids or immunoglobulins. Both TPO-RAs have been shown to increase and maintain platelet counts and reduce the incidence of bleeding-related episode (BRE, defined as a bleeding event and/or use of therapy). Using a US payer perspective and recent price and cost data, this analysis estimates the cost relative to treatment success (measured as overall platelet response) of the two TPO-RAs and a watch and rescue strategy (monitoring patients until therapies [eg, intravenous immunoglobulin] are required) in non-splenectomized adults with chronic ITP. Methods : The analysis was conducted based on time horizon (24 weeks) and data for non-splenectomized patients of phase 3 registrational trials of romiplostim (Kuter et al, Lancet , 2008) and eltrombopag (Cheng et al, Lancet , 2011) in adult patients with chronic ITP. Rates of overall platelet response (see definitions based on number of weeks with platelet count ≥ 50 x 10 9 /L in Cooper et al, Int J Technol Assess Health Care , 2014) were estimated using trial data (Kuter et al, Lancet , 2008; NICE Appraisal of Eltrombopag, 2012): 87.8% for romiplostim, 71.8% for eltrombopag, and 14.5% for watch and rescue (from pooled data for placebo arms). Drug acquisition cost was calculated using wholesale acquisition cost values as of July 16, 2015 ($5.8256 per mcg for romiplostim, $4.0824 per mg for eltrombopag 25 mg tablet, $3.9875 per mg for eltrombopag 50 or 75 mg tablet) and average dose in the trials (317 mcg/week for romiplostim [assuming 100% wastage of unused dose in an opened vial], 55 mg/day for eltrombopag). Costs for drug administration (for romiplostim only, once per week), physician visit and platelet count monitoring (for all three strategies, once per week in weeks 1-4 and once every 4 weeks in weeks 5-24), and liver function monitoring (for eltrombopag only, once every 2 weeks in weeks 1-4 and once every 4 weeks in weeks 5-24) were obtained from CMS Physician Fee Schedule (July 2015 release) and Clinical Laboratory Fee Schedule (January 2015 release). Cost of BREs (ie, cost for treating bleeding events and/or cost for therapy) was derived on the basis of incidence rates of BRE (0.128 per patient-week for non-responder and 0.031 per patient-week for responder, calculated from data reported in Weitz et al, Curr Med Res Opin , 2012) and average treatment cost per BRE ($6,006, in inflation-adjusted June 2015 $) estimated from BREs identified during 2007-2013 in a study of a large US administrative healthcare claims database (Cetin et al, Blood , 2014). Cost per response was computed as total cost (summation of all the cost items aforementioned) divided by overall platelet response rate. Results : The cost per response results by treatment strategy are summarized in the Table. Compared to the watch and rescue strategy, use of any of the two TPO-RAs is associated with a fewer number of BREs, a lower cost for treating BREs, and a lower cost per response. Cost per response estimates of the two TPO-RAs are broadly comparable, with romiplostim associated with lower cost per response than eltrombopag. Conclusion : In non-splenectomized adults with chronic ITP, the use of TPO-RAs represents an efficient way in achieving treatment success, with lower cost per treatment success than the watch and rescue strategy. Disclosures Li: Amgen, Inc.: Employment, Equity Ownership. Sharma: Amgen Inc.: Employment, Other: stock ownership. Zhang: Amgen Inc.: Other: Internship. Campioni: Amgen Inc.: Employment, Other: stock ownership. Fust: Amgen Inc.: Consultancy, Research Funding; Optum: Employment. Lin: Amgen Inc.: Employment, Other: stock ownership. Parthan: Optum: Employment; Amgen Inc.: Consultancy, Research Funding. Wang: Amgen Inc.: Employment, Other: stock ownership. Zur: Optum: Employment; Amgen Inc.: Consultancy, Research Funding. Cetin: Amgen, Inc: Employment, Equity Ownership. Eisen: Amgen Inc: Employment, Other: stock ownership.