Real-world clinical characteristics and treatment outcomes in PNH patients prescribed pegcetacoplan across europe, the United States and Canada

Abstract Background Paroxysmal nocturnal hemoglobinuria (PNH) is an ultra-rare blood disease characterized by uncontrolled complement activation with potentially life-threatening complications. Therapeutic options comprise both terminal complement inhibition, targeting C5 to prevent intravascular hemolysis (IVH), and proximal complement inhibition, intervening upstream within the complement cascade to address IVH and extravascular hemolysis (EVH). Pegcetacoplan, the first C3 and C3b inhibitor, demonstrated efficacy and safety in complement inhibitor (CI)–experienced (CIexp) and –naïve (CInaive) patients in two phase 3 studies with a three year follow up (PEGASUS NCT03500549 and PRINCE NCT04085601). The aim of this study was to describe real world clinical and treatment outcomes in CIexp and CInaive PNH patients prescribed pegcetacoplan. Methods Data were drawn from the Adelphi PNH II Disease Specific Programme™, a real-world cross-sectional survey of hematologists and their consulting PNH patients. Data were collected from November 2023–January 2025 in Canada, France, Germany, Italy, Spain, the UK, and the US. Patients prescribed pegcetacoplan for ≥3 months were included and described as CIexp if they had previously been treated with CI, or CInaive if patients had never been prescribed CI therapy. Physicians reported patient demographics, clinical characteristics, and treatment outcomes. Patients provided data on patient-reported outcomes, including the EQ-5D-5L and Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue. Response to pegcetacoplan was categorized as no, minor, partial, good, major or complete response per SAAWP-response criteria (Risitano et al, 2019). Analyses were descriptive. Results Overall, 54 physicians provided data for 77 patients prescribed pegcetacoplan (54 CIexp patients and 23 CInaive patients). Median (interquartile range IQR) age was 45.0 (33.5–55.0) years (CIexp, 47.0 37.0–60.8; CInaive, 39.0 30.0–45.0), 63.6% (Cexp, 64.8%; Cnaive, 60.9%) were male, 57.9% (CIexp, 50.9%; CInaive, 73.9%) were in employment. Median (IQR) time since diagnosis was 2.4 (1.3–4.9) years (Cexp, 3.1 2.0–5.5; Cnaive, 1.3 0.8–2.3) with median (IQR) time since start of pegcetacoplan initiation being 0.6 (0.4–1.0) year (CIexp, 0.6 0.4–0.9; CInaive, 0.6 0.5–1.2). Clinical outcomes were measured at treatment initiation and the time of survey, and reported as median (IQR). Hemoglobin levels increased from 9.0 (8.0–9.2) to 11.0 (10.3–12.1) g/dL, and 9.0 (7.0–10.5) to 11.5 (10.6–12.0) g/dL, for Cexp (n=52) and Cnaive (n=21), respectively. Lactate dehydrogenase levels decreased from 490 (295–594) to 260 (189–377) U/L for Cexp (n=53), and 275 (214–775) to 220 (187–278) U/L for Cnaive (n=18). Absolute reticulocyte counts decreased from 200 (135–275) to 113 (105–217) x109/L for Cexp (n=19) and 160 (113–250) to 110 (100–134) x109/L for CInaive (n=7). Positive movement by at least one response category since pegcetacoplan initiation were observed in 85.2% CIexp (n=27) and 61.5% CInaive (n=13); with patients classified as having a ‘good’, ‘major’ or ‘complete’ response increasing from 3.7% to 74.1% for CIexp and 23.1% to 69.2% for CInaive. Perceived severity of PNH improved after pegcetacoplan initiation, with ‘mild’ severity increasing from 13.0% to 68.5% and 34.8% to 87.0%; patients experiencing no fatigue increased from 5.6% to 57.4% and 8.7% to 65.2%, for CIexp and CInaive, respectively. For both CIexp and CInaive, complete treatment adherence was reported for 87.0% of patients. Since pegcetacoplan initiation, proportion of ‘well’ or ‘very well’ controlled PNH patients increased from 14.8% to 96.3% for CIexp and 52.2% to 100.0% for CInaive. Overall, 25 patients self-reported data (n=14 CIexp; n=11 CInaive). Patients reported a mean (Standard Deviation SD): EQ-5D VAS score of 66.8 (16.0) and 76.7 (18.7); EQ-5D utility score of 0.86 (0.16) and 0.91 (0.13); FACIT-Fatigue 41.1 (9.5; n=13)and 37.1 (12.2; n=11) for CIexp and CInaive, respectively. Conclusion Improvements in clinical values, perceived PNH severity, control of PNH, and both physician and patient-reported fatigue were observed in CIexp and CInaive patients. These data suggest that pegcetacoplan has positive outcomes regardless of prior CI exposure. These findings indicate that the efficacy of pegcetacoplan in a real-world clinical practice is consistent with results from clinical trials and other real-world evidence for both CIexp and CInaive patients.