[Cost-per-responder analysis comparing romiplostim to rituximab in the treatment of adult primary immune thrombocytopenia in Spain].

Abstract Background and objective Romiplostim, a thrombopoietin-receptor agonist, is approved for second-line use in idiopathic thrombocytopenic purpura (ITP) patients where surgery is contraindicated. Anti-CD20 rituximab, an immunosuppressant, is currently used off-label. This analysis compared the cost per responder for romiplostim versus rituximab in Spain. Materials and method A decision analytic model was constructed to estimate the 6-month cost per responding patient (achieving a platelet count ≥50 × 10 9 /L) according to the most robust published data. A systematic literature review was performed to extract response rates from phase 3 randomised controlled trials. Romiplostim patients received weekly injections; rituximab patients received 4 weekly intravenous infusions. Medical resource costs were obtained from Spanish reimbursement lists. Treatment non-responders incurred bleeding-related event (BRE) management costs as reported in clinical trials. Medical resource utilisation and clinical practice were based on Spanish treatment guidelines and validated by local clinical experts. Results The literature review identified phase 3 romiplostim trials with a response rate of 83%. Due to a lack of phase 3 controlled rituximab trials, a systematic review of studies was selected as the best source, reporting a response rate of 62.5%. The mean cost per patient for romiplostim was €16,289 and €13,459 for rituximab. Rituximab resulted in a 10% higher cost per responder (€21,535 versus €19,625 for romiplostim). Romiplostim use reduced drug administration, intravenous immunoglobulin, and bleeding-related costs compared to rituximab. Conclusions Due to its high level of efficacy leading to lower BRE costs, romiplostim represents an efficient use of resources for adult ITP patients in the Spanish Healthcare System.