Effect of eculizumab treatment in patients with paroxysmal nocturnal hemoglobinuria with or without high disease activity: Real-world findings from the International Paroxysmal Nocturnal Hemoglobinuria Registry

Background: The effects of eculizumab treatment in paroxysmal nocturnal hemoglobinuria (PNH) patients with or without high-disease activity (HDA), defined by LDH ≥ 1.5 × ULN and history of major adverse vascular events (MAVEs; including thrombotic events [TEs]); anemia; and/or physician-reported abdominal pain, dyspnea, dysphagia, erectile dysfunction, fatigue, and/or hemoglobinuria, in the International PNH Registry were evaluated. Methods: Registry patients were stratified by baseline HDA and eculizumab-treatment status. Longitudinal changes in laboratory and clinical PNH-related endpoints were evaluated using linear mixed models (continuous variables) or Poisson regression (incidence rates). Results: As of May 1, 2017, 3009 patients (HDA/eculizumab-treated, n = 913; HDA/never-treated, n = 651; no-HDA/eculizumab-treated, n = 173; no-HDA/never-treated, n = 1272) were analyzed. Higher proportions of eculizumab-treated patients had HDA and history of MAVEs. In patients with and without HDA, respectively, eculizumab treatment resulted in reductions from baseline for (1) LDH ratio (mean [SD]: −5.3 [4.0] and −2.3 [3.8]); (2) incidence rate ratio (IRR) for MAVEs (−80% and −70%); (3) IRR for TEs (−80% for both); and (4) units of red blood cell transfusions per year (from 6.8 to 2.8 and 3.6 to 2.5 units). Conclusions: Eculizumab treatment in a real-world setting improved outcomes, including substantial decreases in hemolysis, MAVE rates, TEs, and transfusions in PNH patients regardless of HDA.