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Abstract: TH-PO506

Impact of First-Line Use of Caplacizumab on Treatment Outcomes in Immune Thrombotic Thrombocytopenic Purpura: News From the REACT-2020 Cohort

Session Information

Category: Glomerular Diseases

  • 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials


  • Volker, Linus A., University Hospital of Cologne, Cologne, NRW, Germany
  • Kaufeld, Jessica Katharina, Medical School Hannover, Hannover, Niedersachen, Germany
  • Kuehne, Lucas, University Hospital of Cologne, Cologne, NRW, Germany
  • Osterholt, Thomas, University Hospital of Cologne, Cologne, NRW, Germany
  • Grundmann, Franziska, University Hospital of Cologne, Cologne, NRW, Germany
  • Kann, Martin, University Hospital of Cologne, Cologne, NRW, Germany
  • Brinkkoetter, Paul T., University Hospital of Cologne, Cologne, NRW, Germany

The von Willebrand factor-directed nanobody caplacizumab has greatly changed the treatment of immune thrombotic thrombocytopenic purpura (iTTP) in recent years. While data from randomized controlled trials established efficacy and safety, there has been a lack of information regarding patient selection, tailoring of therapy duration, effect on adjunct treatment, and outcomes in the real-world setting. Here, we report 113 iTTP episodes treated with standard of care including caplacizumab and 119 historical control episodes treated without caplacizumab.


Patients with an episode of iTTP defined by an ADAMTS13 activity below 10 percent or relapsing
thrombotic microangiopathy in patients with an established diagnosis of iTTP and 18 years of age or
older were eligible. REACT-2020, registered at as #NCT04985318, is an observational retrospective cohort study. From October 2018 until May 2021, data from patients in Germany and Austria with an acute episode of iTTP receiving caplacizumab were gathered retrospectively.


Caplacizumab may lower iTTP-related mortality and refractoriness and decrease the number of daily plasma exchange and hospital stay. These benefits, however, vanish in patients not receiving caplacizumab first-line within 72 hours after diagnosis and until at least partial ADAMTS13 remission. In addition, we observed an increase in use of rituximab over time. Exacerbations were less frequent in caplacizumab-treated patients (14 % vs. 39 %). In an aggregated analysis of all available iTTP cohorts, caplacizumab resulted in significant absolute risk reduction of 2.87 % for iTTP-related mortality (number needed to treat 35) and a relative risk reduction of 59 %.


Caplacizumab may improve patient-centered outcomes if given in the first-line within 72 hours and until at least partial ADAMT13 remission.