PRO34 Cost-Effectiveness Analysis of Caplacizumab in Combination with Plasmapheresis and Immunosuppression in Patients with Acquired Thrombotic Thrombocytopenia Purpura (ATTP) in Italy

Abstract

To evaluate the cost-effectiveness of caplacizumab in combination with plasmapheresis (PE) and immunosuppression compared to PE and immunosuppression alone in the treatment of acute episodes of aTTP. A Markov’s model was designed with acute and remission phases, each comprising four mutually exclusive states. The analysis was conducted from the Italian healthcare perspective over a life-time horizon (60 years). Clinical data derived from HERCULES phase 3 clinical trial and systematic literature review. Economic input included direct costs only. Utility and disutility values were obtained from the literature considering analogue clinical conditions validated when aTTP-specific data were not available. Data on healthcare resources were retrieved from HERCULES, literature, aTTP guidelines and published reimbursement tariffs for Italy. Caplacizumab cost was based on the ex-factory price net of temporary discounts by law (base case). Results are presented in terms of incremental cost-effectiveness ratio (ICER) per Quality Adjusted Life Year (QALY) gained, considering an annual discount rate of 3.5% for outcomes and costs. The ICER per QALY was tested for several options of additional discount levels of caplacizumab cost. The use of caplacizumab in combination with PE and immunosuppression is associated with significantly lower intensive care-related costs when compared to PE and immunosuppression alone (€ 14,170.09 vs € 7,032.56) and to a positive difference in survival of 2.99 years (22.47 vs 19.48) and 2.80 QALY (20.20 vs 17.40). The use of caplacizumab leads to an ICER of €45,049 per QALY. The ICER per QALY of caplacizumab is €37,582 with an additional discount of -15%, €35,093 (-20%), €32,603 (-25%) and 30,114 (-30%). Caplacizumab in addition to immunosuppression and PE is considered cost-effective, allowing the healthcare system to achieve greater efficiency in managing the burden of a life-threatening disease such as aTTP.