OBJECTIVES: Caplacizumab is a humanized anti-von Willebrand factor monoclonal antibody fragment indicated for the treatment of acquired thrombotic thrombocytopenic purpura (aTTP). Clinical trials have demonstrated its efficacy and safety along with shorter hospital length of stay (LOS) and intensive care unit (ICU) duration. However, there is limited real-world data on effectiveness of caplacizumab. This study compares healthcare resource utilization (HCRU) in aTTP patients treated with or without caplacizumab in clinical practice in France.

METHODS: A retrospective study was conducted using data from a French national hospital discharge database (Programme de Médicalisation des Systèmes d'Information, PMSI). All hospitalized patients receiving caplacizumab between August 2018 and December 2019 and diagnosed with aTTP using a previously published algorithm were evaluated. A cohort of control patients (i.e. not treated with caplacizumab) was selected from a population of patients hospitalized between January 2015 and August 2018 and matched 2:1 with caplacizumab treated patients by sex, age group and hospitalization at reference centres. HCRU outcomes including hospital LOS, ICU duration and the number of plasma exchanges (PEX), were compared between cohorts using the Wilcoxon signed-rank test.

RESULTS: A total of 89 aTTP patients who were on caplacizumab treatment were identified (67.4% females; mean [SD] age, 46.5 [16.1] years). The control cohort included 178 patients (67.4% females; mean [SD] age, 46.3 [16.1] years). Caplacizumab-treated patients had significantly shorter hospital LOS (mean [SD], 18.8 [13.2] vs. 26.2 [16.9] days, p<0.0001), ICU duration (mean [SD], 9.7 [7.2] vs. 12.9 [12.5] days, p=0.027) and fewer number of PEX (mean [SD], 8.1 [7.9] vs. 11.5 [9.9], p<0.0001) than control cohort.

CONCLUSIONS: In a real-world setting, caplacizumab treatment is associated with a significantly lower HCRU, and may reduce the hospitalization costs and burden in aTTP patients in France. These findings also corroborate data from the pivotal trial (HERCULES).