Assessing the contribution of rADAMTS13 to the treatment of congenital thrombotic thrombocytopenic purpura in Spain using Multi-Criteria Decision Analysis (MCDA)

Objective: Congenital thrombotic thrombocytopenic purpura (cTTP) is an ultra-rare disease caused by ADAMTS13 deficiency that can be fatal without treatment. Current cTTP treatment is focused on replenishing ADAMTS13 levels, mainly with plasma infusions, which are time-consuming and have associated complications. rADAMTS13 is a recombinant ADAMTS13 enzyme replacement therapy recently approved by U.S. Food and Drug Administration for the prophylactic and on-demand treatment of adult and paediatric patients with cTTP. Here, we aimed to assess the value contribution of rADAMTS13 to the management of cTTP in Spain compared with plasma-based therapies using multi-criteria decision analysis (MCDA). Methods: A literature review was performed to populate an evidence matrix, composed of quantitative and contextual criteria, based on an MCDA framework for orphan drugs. A multidisciplinary expert panel of nine experts (haematology, hospital pharmacy, nursing, hospital management, health economics, patient advocacy, and psychology) scored the criteria of the MCDA framework. Results were analysed and discussed in a group meeting. Scores were weighted to assess the overall contribution of the treatments. Results: cTTP was considered a severe disease with significant unmet needs (mean score ± standard deviation 4.2 ± 0.7 for disease severity and 4.3 ± 0.5 for unmet needs, on a scale of 0 to 5). rADAMTS13 was perceived as a more effective therapeutic option, with a superior safety profile and tolerability, and the ability to provide significant improvement in quality of life compared with plasma-based therapies (3.8 ± 1.2, 3.6 ± 1.3, and 3.6 ± 1.4, respectively, on a scale of -5 to 5). rADAMTS13 could result in lower other medical costs and indirect costs (1.6 ± 1.8 and 2.8 ± 1.7, respectively), mainly based on the shorter time required to administer rADAMTS13. Conclusions: MCDA was used to assess the value contribution of rADAMTS13 against plasma-based therapies in the treatment of cTTP in Spain. rADAMTS13 was considered to have a positive and better overall contribution than plasma-based therapies. Key words: Congenital thrombotic thrombocytopenic purpura (cTTP), rADAMTS13, Multi-criteria decision analysis (MCDA), Enzyme replacement therapy, Health technology assessment.