Caplacizumab Is Effective in Treating Immune-Mediated Thrombotic Thrombocytopenic Purpura in Real-World Scenarios and May Lower Mortality: An Aggregative Analysis

Introduction: The treatment of acquired thrombotic thrombocytopenic purpura has been a subject to change lately due to the introduction of caplacizumab as a novel, and potentially life-saving agent. Here, we compare patient-centered outcomes of a historic cohort of 119 aTTP-patients and an extended real-world caplacizumab-treated cohort of 113 aTTP-patients from Germany and Austria in the context of multiple recently published international cohorts of aTTP patients.

Methods: From October 2018 until May 2021, data from German and Austrian patients presenting with an acute episode of aTTP as defined by an ADAMTS13 activity below 10 % treated with caplacizumab were gathered retrospectively. We aggregated data from two published randomized controlled trials (TITAN, HERCULES), one single-arm prospective trial and two retrospective cohorts with a historical control cohort. In total, we report 846 aTTP cases, 396 of those treated with caplacizumab and 450 without. For data analysis, placebo groups from randomized trials and historical controls from retrospective analyses were combined.

Results: All cohorts combined reported 30 aTTP-related deaths, predominantly in the non-caplacizumab cohort. Mortality in the caplacizumab-cohort (8 cases total) was mainly driven by 5 reported deaths in the UK-cohort, which have been ascribed to a delayed use of caplacizumab by the authors. The number of daily PEX was significantly less in the caplacizumab-treated cohort (7.2 vs 10.2 days). In line, the number of hospital (14.0 vs 18.1) and ICU (4.7 vs 8.9) days differed significantly. Exacerbations (14% vs 39%) were significantly reduced in the caplacizumab-group. In view of all treatment-related outcomes, the data presented herein argues strongly in favor of an early and consistent use of caplacizumab in all instances of aTTP.