Pegcetacoplan versus eculizumab in patients with paroxysmal nocturnal haemoglobinuria (PEGASUS): 48-week follow-up of a randomised, open-label, phase 3, active-comparator, controlled trial

Crovalimab in the paroxysmal nocturnal hemoglobinuria treatment landscape

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired, rare, life-threatening hematopoietic stem cell disorder that causes stem cell-derived cells to be vulnerable to complement-mediated lysis and manifests as hemolytic anemia, thrombosis, and peripheral blood cytopenias. C5 inhibitors, eculizumab, and ravulizumab, are recognized as the current standard of care for PNH treatment in countries where they are available. Crovalimab (PiaSky®), which is approved for the treatment of PNH, is a novel anti-C5 inhibitor with an every-4-weeks, low-volume, subcutaneous maintenance dosing regimen with the possibility for self-administration. Data from three phase III studies highlight the overall favorable benefit-risk profile of crovalimab, showing that crovalimab has promising potential to address the unmet medical and socioeconomic challenges in the PNH treatment landscape.

Population Pharmacokinetic and Pharmacokinetic/Pharmacodynamic Analyses of Pegcetacoplan in Patients with Paroxysmal Nocturnal Hemoglobinuria

BACKGROUND AND OBJECTIVE

Paroxysmal nocturnal hemoglobinuria is a rare blood disorder characterized by life-threatening hemolysis and thrombosis. Complement C5 inhibitor therapy improves symptoms and life prognosis; however, it can result in insufficient hemolysis control, with residual intravascular hemolysis and extravascular hemolysis in some patients. Pegcetacoplan, the first complement C3 inhibitor approved for patients with paroxysmal nocturnal hemoglobinuria, targets both intravascular and extravascular hemolysis. This analysis evaluated population pharmacokinetic/pharmacodynamic profiles of pegcetacoplan.

METHODS

Pooled clinical study data were used to predict pegcetacoplan concentrations and biomarker responses indicative of hemolysis (hemoglobin and lactate dehydrogenase) over time, including the impact of patient characteristics and prior or concurrent complement C5 inhibitor treatment, to support the approved dose of subcutaneous pegcetacoplan 1080 mg twice weekly.

RESULTS

The population pharmacokinetoc analysis included 284 subjects, and the pharmacokinetic/pharmacodynamic analysis included 165 subjects. Subcutaneous pegcetacoplan 1080 mg twice weekly resulted in rapid serum exposures and robust biomarker response within 4 weeks after treatment initiation. Steady-state serum concentrations demonstrated consistent exposure (median ≥ 600 µg/mL) with minimal peak-to-trough variation. The median effective half-life was 8.6 days in patients with paroxysmal nocturnal hemoglobinuria. Body weight significantly impacted pegcetacoplan exposure, and other covariates impacted hemoglobin (sex and creatinine clearance) or lactate dehydrogenase (prior or concurrent complement C5 inhibitor treatment); however, effects were not clinically meaningful.

CONCLUSIONS

The approved dose of pegcetacoplan is predicted to produce rapid and sustained exposure and robust hemoglobin and lactate dehydrogenase responses in adult patients with paroxysmal nocturnal hemoglobinuria, with no initial dose adjustments required for any specific patient population.

Role of Complement in Liver Diseases

This review aims to summarize recent research using animal models, cell models, and human data regarding the role of complement in liver disease. Complement is part of the innate immune system and was initially characterized for its role in control of pathogens. However, evidence now indicates that complement also plays an important role in the response to cellular injury that is independent of pathogens. The liver is the main organ responsible for producing circulating complement. In response to liver injury, complement is activated and likely plays a dual role, both contributing to and protecting from injury. In uncontrolled complement activation, cell injury and liver inflammation occur, contributing to progression of liver disease. Complement activation is implicated in the pathogenesis of multiple liver diseases, including alcohol-associated liver disease, metabolic dysfunction-associated steatotic liver disease, fibrosis and cirrhosis, hepatocellular carcinoma, and autoimmune hepatitis. However, the mechanisms by which complement is overactivated in liver diseases are still being unraveled.

Real-World Study of US Adults with Paroxysmal Nocturnal Hemoglobinuria Treated with Pegcetacoplan

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease characterized by complement-mediated hemolysis. OPERA is the first US longitudinal real-world study on C3 inhibitor therapy, known as pegcetacoplan. Methods: OPERA enrolled US patients with PNH, age ≥18, who were prescribed pegcetacoplan, and data were collected from routine care. Hemoglobin was reported by patients during regular follow-up (censored from transfusions). The Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue (0-52 score) and Patient-Reported Outcomes Measurement Information System scale for Cognitive Function Abilities (PROMIS-CF; 23.27-67.09 t-score) were completed electronically (low score = negative outcome). Patients self-reported incidence of healthcare resource utilization (HCRU). Results: By January 2024, 70 patients (mean age 44.6 years; 57.1% female) reported up to 9 months of pegcetacoplan treatment, with a median [IQR] follow-up of 6.6 [3.8] months. The latest reported hemoglobin levels improved by a mean (SD) of 2.6 (1.9) g/dL from baseline. At 3, 6 and 9 months, patients reported clinically meaningful improvements (≥5 points) in FACIT-F (53.3-69.0%) and (≥2 points) PROMIS-CF (46.7-55.2%). Patients reported a <10% incidence rate per person month of all HCRU events. Conclusions: This first longitudinal real-world US study indicates a positive trend in Hb, fatigue, and cognition with limited HCRU during pegcetacoplan treatment in adults with PNH.

Paroxysmal Nocturnal Hemoglobinuria, Pathophysiology, Diagnostics, and Treatment

Background

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by intravascular hemolysis (IVH) due to diminished or absent inhibition of the complement system because of deficient expression of cell-anchored complement regulating surface proteins. IVH leads to heterogeneous symptoms such as anemia, abdominal pain, dyspnea, fatigue and increased rates of thrombophilia. Inhibitors of the terminal Complement cascade can reverse IVH leading to a significant reduction of disease burden such as thrombembolic events and also mortality.

Summary

Therapeutic inhibitors of the terminal complement cascade such as eculizumab or ravulizumab significantly improve overall survival through IVH-inhibition. However, not all patients experience complete disease control with normalization of hemoglobin levels and absolute reticulocyte counts (ARC) under terminal complement inhibition as a significant part of patients develop extravascular hemolysis (EVH). EVH can be clinically relevant causing persistent anemia and fatigue. New proximal complement inhibitors (CI) mainly targeting complement component C3 or factors of the amplification pathway such as pegcetacoplan, danicopan, and iptacopan became available and are meanwhile approved for marketing. Additional complement-inhibiting strategies are under clinical development. A switch from terminal to proximal CI in patients with significant EVH can achieve hemoglobin and ARC normalization and significant improvement in quality of life (QoL). Additional approvals of proximal CI agents for the treatment of hemolytic PNH in the first line are available for pegcetacoplan and iptacopan. So far, no evidence-based algorithm is available for decision-making in first-line treatment of which type of drug should be used for individual patients.

Key Messages

Terminal CIs in hemolytic PNH patients can block IVH and have led to a dramatically improved survival. Proximal CIs ameliorate anemia and improve QoL in patients with relevant EVH. However, more (real-world) data are needed to demonstrate long-term improvement in all patients with hemolytic PNH, especially those under first-line treatment with proximal CI.

Oral complement factor D inhibitor danicopan for paroxysmal nocturnal hemoglobinuria

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder characterized by episodic hemolysis, with additional clinical manifestations including thrombosis and bone marrow failure. The US FDA approved a complement factor D inhibitor, danicopan (Voydeya™), previously known as ACH-4471, for the treatment of extravascular hemolysis in adults with PNH on 29 March 2024. The primary purpose of this review is to examine the clinical efficacy and safety of danicopan.

AREAS COVERED

We systematically searched for articles on PubMed, Web of Science, and three publishers Springer, Elsevier, Wiley up to 6 May 2024.

EXPERT OPINION

Danicopan acts on the alternative pathway of the complement cascade, preferentially controlling C3 fragment-mediated extravascular hemolysis. Recommended dosage is 150 mg orally three times a day, which can be increased to 200 mg three times a day when necessary. Vaccination is required before administration to prevent infections by encapsulated bacteria. In a pivotal phase 3 trial ALPHA, danicopan significantly increased hemoglobin levels compared to placebo (p < 0.0001), 60% of patients experienced an increase in hemoglobin levels of at least 2 g/dL, compared to none in the placebo group (adjusted difference of 47%; p < 0.0001). Common adverse events during danicopan treatment include headache and upper respiratory tract infection.

Navigating the Complement Pathway to Optimize PNH Treatment with Pegcetacoplan and Other Currently Approved Complement Inhibitors

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and potentially life-threatening hematologic disorder caused by a somatic mutation in a relevant portion of hematopoietic stem cells. Mutation of the phosphatidylinositol glycan biosynthesis class A (PIGA) gene prevents the expression of cell-surface proteins, including the complement regulatory proteins CD55 and CD59. With decreased or a lack of CD55 and CD59 expression on their membranes, PNH red blood cells become susceptible to complement-mediated hemolysis (symptoms of which include anemia, dysphagia, abdominal pain, and fatigue), leading to thrombosis. State-of-the-art PNH treatments act by inhibiting the dysregulated complement at distinct points in the activation pathway: late at the C5 level (C5 inhibitors, eculizumab, ravulizumab, and crovalimab), centrally at the C3 level (C3/C3b inhibitors and pegcetacoplan), and early at the initiation and amplification of the alternative pathway (factor B inhibitor, iptacopan; factor D inhibitor, danicopan). Through their differing mechanisms of action, these treatments elicit varying profiles of disease control and offer valuable insights into the molecular underpinnings of PNH. This narrative review provides an overview of the mechanisms of action of the six complement inhibitors currently approved for PNH, with a focus on the C3/C3b-targeted therapy, pegcetacoplan.

Three Years On: The Role of Pegcetacoplan in Paroxysmal Nocturnal Hemoglobinuria (PNH) since Its Initial Approval

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterized by complement-mediated hemolysis and potentially life-threatening complications. Pegcetacoplan, an inhibitor of complement components C3 and C3b, was approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) in 2021. A recent expansion to its indication by the EMA has made pegcetacoplan available for the treatment of both complement inhibitor-naïve and -experienced patients with PNH who have hemolytic anemia, a similarly broad patient population as in the US. This approval was based on results from the Phase 3 PEGASUS study, where pegcetacoplan showed superiority over the C5 inhibitor eculizumab with regard to improving the hemoglobin level in patients with anemia despite eculizumab treatment, and the Phase 3 PRINCE study, where pegcetacoplan showed superiority over supportive care with regard to hemoglobin stabilization and improving the lactate dehydrogenase level in complement inhibitor-naïve patients. In light of this recent indication expansion by the EMA, this article describes how the strong efficacy of pegcetacoplan is linked to its mechanism of action, which provides broad hemolysis control over both intravascular and extravascular hemolysis to improve a range of disease markers and enhance patients' quality of life. Furthermore, additional data and learnings obtained from over 3 years of experience with pegcetacoplan are summarized, including long-term efficacy and safety results, real-world clinical experiences, pharmacokinetic characteristics, and extensive practical guidance for the first-to-market proximal complement inhibitor for PNH.

Moving toward Individual Treatment Goals with Pegcetacoplan in Patients with PNH and Impaired Bone Marrow Function

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, potentially life-threatening haematological disease characterised by chronic complement-mediated haemolysis with multiple clinical consequences that impair quality of life. This post hoc analysis assessed haematological and clinical responses to the first targeted complement C3 inhibitor pegcetacoplan in patients with PNH and impaired bone marrow function in the PEGASUS (NCT03500549) and PRINCE (NCT04085601) studies. For patients with impaired bone marrow function, defined herein as haemoglobin <10 g/dL and absolute neutrophil count <1.5 × 109 cells/L, normalisation of the parameters may be difficult. Indeed, 20% and 43% had normalised haemoglobin in PEGASUS and PRINCE, respectively; 60% and 57% had normalised LDH, and 40% and 29% had normalised fatigue scores. A new set of parameters was applied using changes associated with clinically meaningful improvements, namely an increase in haemoglobin to ≥2 g/dL above baseline, decrease in LDH to ≤1.5× the upper limit of normal, and an increase in fatigue scores to ≥5 points above baseline. With these new parameters, 40% and 71% of PEGASUS and PRINCE patients had improved haemoglobin; 60% and 71% had an improvement in LDH, and 60% and 43% had an improvement in fatigue scores. Thus, even patients with impaired bone marrow function may achieve clinically meaningful improvements with pegcetacoplan.

Improvements in hematologic markers and decreases in fatigue with pegcetacoplan for patients with paroxysmal nocturnal hemoglobinuria and mild or moderate anemia (hemoglobin ≥10 g/dL) who had received eculizumab or were naive to complement inhibitors

BACKGROUND

Although complement component 5 inhibitors (C5is) eculizumab and ravulizumab improve paroxysmal nocturnal hemoglobinuria (PNH) outcomes, patients may experience persistent anemia. This post hoc analysis investigated whether the complement component 3-targeted therapy pegcetacoplan also improved hematologic outcomes and reduced fatigue in patients with PNH and mild/moderate anemia.

METHODS

Patients with PNH and hemoglobin ≥10.0 g/dL at baseline of PADDOCK (N = 6), PRINCE (N = 8), and PEGASUS (N = 11) were included. Before receiving pegcetacoplan, PADDOCK and PRINCE patients were C5i-naive; PEGASUS patients had hemoglobin <10.5 g/dL despite stably dosed eculizumab. Hemoglobin concentrations, percentages of patients with concentrations ≥12 g/dL, and sex-specific normalization were assessed at baseline and after 16 weeks of pegcetacoplan, as were absolute reticulocyte counts (ARCs) and normalization and fatigue scores and normalization.

RESULTS

From baseline to week 16, mean (SD) hemoglobin concentrations increased in C5i-naive patients (PADDOCK: 10.5 [0.4] to 12.7 [1.1] g/dL; PRINCE: 11.3 [1.0] to 14.0 [1.3] g/dL) and those with suboptimal eculizumab responses (PEGASUS: 10.2 [0.2] to 12.8 [2.6] g/dL). Percentage of patients with hemoglobin ≥12 g/dL increased (PADDOCK: 0 to 60.0% [3 of 5 patients]; PRINCE: 25.0% [2 of 8] to 87.5% [7 of 8]; PEGASUS: 0 to 72.7% [8 of 11]). Sex-specific hemoglobin normalization at week 16 occurred in 40.0% (2 of 5) (PADDOCK), 62.5% (5 of 8) (PRINCE), and 63.6% (7 of 11) (PEGASUS). In all studies, mean ARCs decreased from above normal to normal and ARC normalization increased. Mean Functional Assessment of Chronic Illness Therapy-Fatigue scores improved from below to above or near normal. Two patients had serious adverse events (PEGASUS: post-surgery sepsis, breakthrough hemolysis); breakthrough hemolysis resolved without study discontinuation.

CONCLUSION

Patients with PNH and mild/moderate anemia who were C5i-naive or who had suboptimal hemoglobin concentrations despite eculizumab treatment had improved hematologic outcomes and reduced fatigue after initiating or switching to pegcetacoplan.

TRIAL REGISTRATION

Trial registration numbers: PADDOCK (NCT02588833), PRINCE (NCT04085601; EudraCT, 2018-004220-11), PEGASUS (NCT03500549).

Development of a target concentration intervention to individualize paroxysmal nocturnal hemoglobinuria treatment with pegcetacoplan

Pegcetacoplan (Aspaveli®/Empaveli™) is a factor C3 inhibitor that is approved for the treatment of paroxysmal nocturnal hemoglobinuria. An individualized dosing strategy might be useful to improve patient-friendliness and cost-effectiveness of this very expensive drug. Therefore, the aim of this study was to develop an individualized treatment regimen for pegcetacoplan based on the pharmacokinetic-pharmacodynamic data of the manufacturer. We conducted a clinical trial simulation with the approved dosing regimen of 1080 mg twice-weekly and a target concentration intervention-based dosing regimen in patients with and without prior eculizumab use. For eculizumab-naïve patients, the target concentration intervention-based dosing regimen resulted in a comparable fraction of patients with LDH normalization (LDH < 226 U/L) and hemoglobulin normalization (> 12 g/dL) compared to the approved regimen (LDH 50.2% and 50.0% respectively and hemoglobulin 45.6% and 44.4%). A modest dose reduction of ~ 5% was possible with target concentration intervention-based dosing. An intensified dosing interval was necessary in 2.3% of the patients however an interval prolongation was possible in 28.2% of the patients. Similar results were obtained for patients prior treated with eculizumab. In this study we show the potential of an individualized dosing regimen of pegcetacoplan with can improve patient friendliness in approximately 30% of the patients and improve therapy in approximately 2% of the patients at slightly reduced costs.

Consensus recommendations for optimising the diagnosis and treatment of paroxysmal nocturnal haemoglobinuria in Singapore

Introduction

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare haematologic disease characterised by intravascular haemolysis, thrombophilia and bone marrow failure. There is a lack of established clinical guidance on the screening, diagnosis and manage-ment of PNH in Singapore. A relatively low level of awareness among healthcare professionals regarding PNH manifestations further contributes to diagnostic delays. Additionally, limited access to complement inhibitors, like eculizumab, may delay treatment and impact patient outcomes.

Method

Nine haematologists from different institu-tions in Singapore convened to formulate evidence-based consensus recommendations for optimising the diagnosis and management of patients with PNH and improving access to novel treatments. The experts reviewed the existing literature and international guidelines published from January 2010 to July 2023, focusing on 7 clinical questions spanning PNH screening, diagnostic criteria, investigations, treatment and monitoring of subclinical and classic disease, PNH with underlying bone marrow disorders, and PNH in pregnancy. A total of 181 papers were reviewed to formulate the statements. All experts voted on the statements via 2 rounds of Delphi and convened for an expert panel discussion to finetune the recommendations.

Results

Sixteen statements have been formulated for optimising the screening, diagnosis and management of PNH. Upon confirmation of PNH diagnosis, individuals with active haemolysis and/or thrombosis should be considered for anti-complement therapy, with eculizumab being the only approved drug in Singapore.

Conclusion

The current recommendations aim to guide the clinicians in optimising the screening, diagnosis and management of PNH in Singapore.

Hemolysis events in the phase 3 PEGASUS study of pegcetacoplan in patients with paroxysmal nocturnal hemoglobinuria

ABSTRACT

Patients with paroxysmal nocturnal hemoglobinuria (PNH) experience complement-mediated intravascular hemolysis leading to anemia, fatigue, and potentially life-threatening thrombotic complications. Pegcetacoplan, a C3 inhibitor, demonstrated sustained improvements in hematologic and clinical parameters in the phase 3 PEGASUS trial in patients with PNH who remained anemic despite C5 inhibitor therapy. The present post hoc analysis describes 26 hemolysis adverse events (AEs) experienced in 19 patients during pegcetacoplan therapy in PEGASUS and baseline patient characteristics potentially associated with increased hemolysis risk. Lactate dehydrogenase (LDH) ≥2× the upper limit of normal (ULN) was observed in 19 events, including 2 with LDH ≥10× ULN. All patients experienced decreased hemoglobin during hemolysis (mean decrease, 3.0 g/dL). In 16 events (62%), a potential complement-amplifying condition underlying the event could be identified. Hemolysis AEs led to study discontinuation in 5 patients. However, of 26 hemolysis AEs, 17 (65%) were manageable without pegcetacoplan discontinuation. A greater proportion of patients with hemolysis AEs (n = 19) had key characteristics of higher disease activity at baseline compared to patients without hemolysis AEs (n = 61), namely higher-than-label eculizumab dose (53% vs 23%), detectable CH50 (total complement function; 74% vs 54%), and ≥4 transfusions in the previous 12 months (68% vs 51%). These characteristics may be useful predictors of potential future hemolysis events. This trial was registered at www.ClinicalTrials.gov as #NCT03500549.

Normalization of Hemoglobin, Lactate Dehydrogenase, and Fatigue in Patients with Paroxysmal Nocturnal Hemoglobinuria Treated with Pegcetacoplan

BACKGROUND AND OBJECTIVES

We determined normalization rates for hemoglobin, lactate dehydrogenase (LDH), and fatigue in patients with paroxysmal nocturnal hemoglobinuria (PNH) treated with pegcetacoplan (PEG) in the PEGASUS (NCT03500549) and PRINCE (NCT04085601) phase III trials.

METHODS

Enrolled patients had PNH and hemoglobin < 10.5 g/dL despite ≥ 3 months of eculizumab (ECU) [PEGASUS], or were complement component 5 (C5) inhibitor-naive, receiving supportive care only, with hemoglobin less than the lower limits of normal (LLN) [PRINCE]. Hematologic and fatigue normalization endpoints were hemoglobin greater than or equal to the LLN (females: 12 g/dL; males: 13.6 g/dL) in the absence of transfusion; LDH ≤226 U/L in the absence of transfusion; and Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue ≥ 43.6, the general population norm. Safety was assessed by investigators using standardized terms and definitions for seriousness and severity.

RESULTS

Hemoglobin normalization occurred in 34.1% (14/41) of PEG-treated patients at Week 16 (randomized controlled period) in PEGASUS (vs. 0% [0/39] of ECU-treated patients) and in 45.7% (16/35) of PEG-treated patients at Week 26 in PRINCE (vs. 0% [0/18] of supportive care-treated patients). At Week 48 (open-label period) in PEGASUS, 24.4% of PEG-treated patients (PEG-to-PEG) and 30.8% of patients treated with ECU through Week 16 who switched to PEG through Week 48 (ECU-to-PEG) had hemoglobin normalization. Rates of LDH normalization in PEGASUS were 70.7% (PEG-treated patients) and 15.4% (ECU-treated patients) at Week 16, and 56.1% (PEG-to-PEG) and 51.3% (ECU-to-PEG) at Week 48. In PRINCE, 67.5% of PEG-treated patients at Week 26 had normalized LDH concentrations. Rates of FACIT-Fatigue score normalization in PEGASUS were 48.8% and 10.3% in PEG- and ECU-treated patients, respectively, at Week 16, and 34.1% and 51.3% in PEG-to-PEG- and ECU-to-PEG-treated patients, respectively, at Week 48. In PRINCE, 68.6% of PEG-treated patients and 11.1% of supportive care patients had FACIT-Fatigue score normalization at Week 26. PEG was safe and well tolerated. Injection site reactions, mostly mild, were the most common adverse event of special interest in PEG-treated patients in the PEGASUS randomized controlled period (36.6%) and in PRINCE (30.4%).

CONCLUSION

PEG is superior to ECU and supportive care in hemoglobin, LDH, and FACIT-Fatigue score normalization for patients with PNH and persistent anemia despite ≥3 months of treatment with ECU, and in C5 inhibitor-naive patients.

CLINICAL TRIAL REGISTRATION

The PEGASUS trial (NCT03500549) was registered on 18 August 2018, and the PRINCE trial (NCT04085601) was registered on 11 September 2019.

Exploring treatment strategies for paroxysmal nocturnal hemoglobinuria: an overview of registered clinical trials

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired disease in which blood cells lack anchored proteins that regulate the complement system. The erythrocytes are then destroyed because of uncontrolled complement activity, leading to intravascular hemolysis (IVH) and a high risk of thrombosis outcome. A huge alteration in the treatment of the disease was the development of terminal complement inhibitors, with the achievement of IVH blockade, reduction or abolishment of red blood cell (RBC) transfusions, and thromboembolic events prevention. However, patients treated with these inhibitors can still present extravascular hemolysis (EVH) caused by C3 activation and residual IVH or clinically relevant levels of breakthrough hemolysis (BTH). Proximal complement inhibitors turned out to be the key to the solution of this problem by targeting components of the proximal complement pathway, avoiding intra and extravascular hemolysis. FDA approved eculizumab, ravulizumab (terminal inhibitors), pegcetacoplan, iptacopan, and danicopan (proximal inhibitors) as a treatment for PNH so far. Various clinical trials are underway to find the most effective method to treat patients with PNH. This review aimed to summarize 71 registered clinical trials in the ClinicalTrials.gov database with the various treatment drugs, possible mechanisms, and novel findings related to PNH treatment.

Real-world experience of pegcetacoplan in paroxysmal nocturnal hemoglobinuria

Pegcetacoplan significantly improves outcomes for patients with paroxysmal nocturnal hemoglobinuria (PNH) experiencing extravascular hemolysis (EVH) on eculizumab, leading to approval in 2021/2022 (USA/Europe). We report the first collaborative real-world evidence on pegcetacoplan use in UK and France. A total of 48 patients were either currently receiving or previously received pegcetacoplan (2019-2023). A total of 12 patients had participated in the PEGASUS clinical trial, continuing treatment after trial completion. Five patients were on combination treatment of C5 inhibition and pegcetacoplan. Mean pegcetacoplan duration was 20.2 months. Indication for pegcetacoplan was EVH on C5 inhibitors (Eculizumab, n = 29, Ravulizumab n = 16, others n = 3) with 35/48 patients requiring blood transfusion within the previous 12 months. Mean hemoglobin and reticulocyte count at pegcetacoplan commencement and after 3 months: 91 g/L and 205 × 109/L and 115.8 g/L and 107 × 109/L, respectively, resulting in mean Hb change of 22.3 g/L. Mean LDH pre- and post-pegcetacoplan was unchanged. Six patients have stopped pegcetacoplan. A total of 32 breakthrough hemolysis (BTH) events occurred in 13/48 patients. A total of 14 events were within clinical trials (reported separately). Six patients experienced 18 acute BTH events outside clinical trials, 7/18 associated with complement activating conditions. Successful clinical management included daily pegcetacoplan subcutaneously for 3 days or single eculizumab doses; these events are manageable with prompt intervention. Pegcetacoplan is effective for patients with PNH experiencing EVH. In this large patient cohort, treatment was well tolerated with improved hemoglobin and reticulocytes and maintained LDH control. Although BTH occurs, this is manageable by acute dose modification, with the majority of patients being maintained on pegcetacoplan.

Safety and Efficacy of Pegcetacoplan in Adult Patients with Paroxysmal Nocturnal Hemoglobinuria over 48 Weeks: 307 Open-Label Extension Study

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening disease characterized by complement-mediated hemolysis and thrombosis. Pegcetacoplan, the first targeted complement component 3 (C3) PNH therapy, was safe and efficacious in treatment-naive and pre-treated patients with PNH in five clinical trials.

METHODS

The 307 open-label extension (OLE) study (NCT03531255) is a non-randomized, multicenter extension study of long-term safety and efficacy of pegcetacoplan in adult patients with PNH who completed a pegcetacoplan parent study. All patients received pegcetacoplan. Outcomes at the 48-week data cutoff (week 48 of 307-OLE or August 27, 2021, whichever was earlier) are reported. Hemoglobin concentrations, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scores, and transfusion avoidance were measured. Hemoglobin > 12 g/dL and sex-specific hemoglobin normalization (i.e., male, ≥ 13.6 g/dL; female, ≥ 12 g/dL) were assessed as percentage of patients with data available and no transfusions 60 days before data cutoff. Treatment-emergent adverse events, including hemolysis, were reported.

RESULTS

Data from 137 patients with at least one pegcetacoplan dose at data cutoff were analyzed. Mean (standard deviation [SD]) hemoglobin increased from 8.9 (1.22) g/dL at parent study baseline to 11.6 (2.17) g/dL at 307-OLE entry and 11.6 (1.94) g/dL at data cutoff. At parent study baseline, mean (SD) FACIT-Fatigue score of 34.1 (11.08) was below the general population norm of 43.6; scores improved to 42.8 (8.79) at 307-OLE entry and 42.4 (9.84) at data cutoff. In evaluable patients, hemoglobin > 12 g/dL occurred in 40.2% (43 of 107) and sex-specific hemoglobin normalization occurred in 31.8% (34 of 107) at data cutoff. Transfusion was not required for 114 of 137 patients (83.2%). Hemolysis was reported in 23 patients (16.8%). No thrombotic events or meningococcal infections occurred.

CONCLUSION

Pegcetacoplan sustained long-term improvements in hemoglobin concentrations, fatigue reduction, and transfusion burden. Long-term safety findings corroborate the favorable profile established for pegcetacoplan.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03531255.

Thrombosis and meningococcal infection rates in pegcetacoplan-treated patients with paroxysmal nocturnal hemoglobinuria in the clinical trial and postmarketing settings

Background

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic disease characterized by complement-mediated hemolysis and thrombosis. Complement component 5 (C5) inhibitors have decreased PNH-related thrombosis rates and reduced mortality compared with those of age-matched controls. A small but significantly increased risk of life-threatening Neisseria infections, especially N meningitidis, represents a long-term safety risk of complement inhibition.

Objectives

To evaluate the rates of thrombosis and meningococcal infections in patients with PNH treated with the complement component 3-targeted therapy pegcetacoplan.

Methods

Cumulative patient-year exposure to pegcetacoplan was calculated, and thrombotic events and meningococcal infections were reviewed in 7 clinical trials and in the postmarketing setting. The clinical trial protocols and pegcetacoplan labeling required vaccination against Streptococcus pneumoniae, N meningitidis, and Haemophilus influenzae before pegcetacoplan use; the label allowed for prophylactic antibiotic use if pegcetacoplan must be administered before vaccination.

Results

As of November 13, 2022, 464 patients with PNH had 619.4 patient-years of pegcetacoplan exposure in completed/ongoing clinical trials and the postmarketing setting. Seven thrombotic events were reported: 5 in clinical trials (2 in the same patient) and 2 in the postmarketing setting. The overall thrombosis rate was 1.13 events per 100 patient-years (clinical trials: 1.22 events/100 patient-years in 409.4 years; postmarketing: 0.95 events/100 patient-years in 210.0 years). No infections with meningococcal bacteria were reported.

Conclusion

Event rates for thrombosis were comparable between pegcetacoplan and previously reported rates of C5 inhibitors in patients with PNH, and no cases of meningococcal infection were reported with pegcetacoplan. Continued follow-up is required.

Efficacy, Safety and Quality of Life of Pegcetacoplan in Japanese Patients With Paroxysmal Nocturnal Hemoglobinuria Treated Within the Phase 3 PEGASUS Trial

INTRODUCTION

Pegcetacoplan, the first approved proximal complement C3 inhibitor, showed superiority to eculizumab in improving hemoglobin levels and clinical outcomes in the phase 3 PEGASUS study in patients with paroxysmal nocturnal hemoglobinuria (PNH) and inadequate response to eculizumab.

METHODS

This analysis evaluates the efficacy and safety of pegcetacoplan for Japanese patients in PEGASUS, as they are known for different clinicopathologic features compared to non-Asian patients. Ten Japanese patients were enrolled to receive pegcetacoplan (n=5) or eculizumab (n=5) during the 16-week randomized controlled period. All patients received pegcetacoplan monotherapy during the open-label period until Week 48.

RESULTS

Treatment with pegcetacoplan improved hemoglobin with a mean change from baseline of 2.4 g/dL at Week 16, which was sustained through 48 weeks. Pegcetacoplan-treated Japanese patients experienced sustained improvements in key secondary efficacy endpoints, including freedom from transfusion, lactate dehydrogenase level, reticulocyte count, and FACIT-Fatigue score. The safety profile was consistent with previously reported data from pegcetacoplan studies. No events of hemolysis, meningococcal infection, or thrombosis were reported in the Japanese population and all Japanese patients remained on treatment throughout the study.

CONCLUSION

These data suggest that Japanese patients with PNH can be effectively and safely managed with pegcetacoplan.

CLINICALTRIALS

gov identifier: NCT03500549.

Management of acute breakthrough hemolysis with intensive pegcetacoplan dosing in patients with PNH

ABSTRACT

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by complement-mediated intravascular hemolysis leading to anemia, fatigue, and potentially life-threatening thrombotic complications. Breakthrough hemolysis (BTH) was first described in patients with PNH treated with terminal complement C5 inhibitors when intravascular hemolysis reoccurred despite treatment. Pegcetacoplan, the first proximal complement C3 inhibitor, offers broad hemolysis control in patients with PNH. While experience of managing BTH on C5 inhibitors is documented, very limited guidance exists for proximal complement inhibitors. This interim analysis assessed the effect of intensive treatment with pegcetacoplan following an acute BTH event in a subset of patients enrolled in the ongoing open-label extension study of pegcetacoplan in PNH. Thirteen patients with acute BTH included in the analysis received either a single IV dose of 1080 mg (n = 4) or 1080 mg subcutaneous (SC) dosing on 3 consecutive days (n = 9). A potential, clinically-relevant complement-amplifying condition, such as infection or vaccination, was reported in approximately half of the patients experiencing an acute BTH. Lactate dehydrogenase (LDH) levels decreased between day 1 and day 2 in 8 of 12 evaluable patients and in all 13 patients at day 7 to 12. Nine of 13 patients (69%) achieved LDH <2× the upper limit of normal by day 14 to 19. All adverse events associated with the acute BTH event were considered resolved by the investigators. Overall, intensive treatment with pegcetacoplan was safe and well tolerated. These novel data support effective management of acute BTH events in patients on pegcetacoplan with intensive IV or SC pegcetacoplan dosing. This trial was registered at www.clinicaltrials.gov as #NCT03531255.

Paroxysmal nocturnal hemoglobinuria: Review of the patient experience and treatment landscape

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder caused by complement-mediated hemolysis and thrombosis through the alternative pathway. The most common symptom of PNH is fatigue due to chronic anemia, which can negatively impact quality of life (QoL) and affect overall well-being. The currently approved therapies for PNH significantly limit intravascular hemolysis (IVH) and reduce the risk of thrombosis; however, they are associated with an infusion schedule that can become burdensome, and not all patients experience complete disease control. Several new complement inhibitors are in development that address the need for convenient routes of administration and aim to provide better disease control. With the variety of new treatment options on the horizon, hematologic markers as well as QoL concerns, patient opinion, and lifestyle factors should be considered to choose the optimal PNH treatment for each specific patient.

Complement in human disease: approved and up-and-coming therapeutics

The complement system is recognised as a protector against blood-borne pathogens and a controller of immune system and tissue homoeostasis. However, dysregulated complement activity is associated with unwanted or non-resolving immune responses and inflammation, which induce or exacerbate the pathogenesis of a broad range of inflammatory and autoimmune diseases. Although the merit of targeting complement clinically has long been acknowledged, the overall complement drug approval rate has been modest. However, the success of the humanised anti-C5 antibody eculizumab in effectively treating paroxysmal nocturnal haemoglobinuria and atypical haemolytic syndrome has revitalised efforts to target complement therapeutically. Increased understanding of complement biology has led to the identification of novel targets for drug development that, in combination with advances in drug discovery and development technologies, has resulted in a surge of interest in bringing new complement therapeutics into clinical use. The rising number of approved drugs still almost exclusively target rare diseases, but the substantial pipeline of up-and-coming treatment options will possibly provide opportunities to also expand the clinical targeting of complement to common diseases.

Efficacy of complement inhibitors for patients with paroxysmal nocturnal hemoglobinuria: a systematic review and meta-analysis

Background

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired hematological disease. The development of complement inhibitors such as eculizumab, ravulizumab, and pegcetacoplan has revolutionized the management of PNH, leading to improvements in overall survival and quality of life for patients.

Objectives

This systematic review aims to provide comprehensive evidence of the efficacy of complement inhibitors in relation to treatment duration.

Design

This is a systematic review and meta-analysis.

Data sources and methods

A thorough literature search was conducted in MEDLINE, EMBASE, and the Cochrane Library up to 3 May 2022. We included all prospective interventional studies including single-arm trials. The primary outcomes of interest were lactate dehydrogenase (LDH) levels, hemoglobin (Hb) concentrations, transfusion avoidance, and Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) scores.

Results

Our study included a total of 27 studies, comprising 5 randomized controlled trials and 11 single-arm trials, with a total of 912 patients with PNH. We stratified the studies according to treatment duration, based on the most frequently reported period of 26 weeks. Our analysis showed that treatment-naïve patients who received complement inhibitors had a pooled estimate of a decrease in LDH levels from baseline by -1462.0 U/L (95% CI: -1735.6 to -1188.5) for treatment ⩽26 weeks and -1696.5 U/L (95% CI: -2122.7 to -1270.2) for treatment >26 weeks. The mean Hb levels were increased by 1.4 g/dL (95% CI: 0.5-2.3) and 1.9 g/dL (95% CI: 0.7-3.1) in each group. Treatment with any complement inhibitor prevented the need for transfusion in at least 50% of patients with PNH in all treatment periods. Clinically meaningful improvements in FACIT-F were observed both before and after 26 weeks, with a pooled estimate of 6.8 (95% CI: 6.0-7.6) and 9.5 (95% CI: 7.0-12.0), respectively.

Conclusion

Our findings suggest that complement inhibitors can result in positive treatment outcomes and sustained benefits for patients with PNH.

Injection Site Reactions with Long-Term Pegcetacoplan Use in Patients with Paroxysmal Nocturnal Hemoglobinuria: A Brief Report

INTRODUCTION

Pegcetacoplan is a targeted complement component 3 (C3) therapy approved for adults with paroxysmal nocturnal hemoglobinuria (PNH; US) or PNH plus anemia despite C5-targeted therapy for ≥ 3 months (EU). Patients with PNH receiving pegcetacoplan in the phase 3 PEGASUS trial who experienced injection site reactions (ISRs) mostly experienced mild events. We evaluated ISR incidence and severity with longer-term treatment in the PEGASUS cohort of the Study 307 open-label extension (307 OLE).

METHODS

Patients from PEGASUS enrolled in the 307 OLE continued pegcetacoplan subcutaneous self-administration twice or three times weekly or every 3 days for an additional 48 weeks. ISRs were coded as adverse events (AEs) or treatment-emergent AEs (TEAEs) and summarized by MedDRA System Organ Class and Preferred Term.

RESULTS

As of August 27, 2021, 58/64 patients from PEGASUS completed an additional 48 weeks of treatment in the 307 OLE (median treatment duration 337.0 [range 55-344] days); 95.3% (61/64) of patients achieved compliance ≥ 80%. ISRs occurred in 9/64 (14.1%) patients in the 307 OLE, which was lower than observed at PEGASUS completion (20/77; 26.0%). Most patients with ISRs in the 307 OLE had events with a maximum severity of mild (7/9 patients; 77.8%). Injection site erythema and induration were the most common overall (4/64 patients each; 6.3%) and pegcetacoplan-related (3/64 patients each; 4.7%) ISRs. The exposure-adjusted rates of these events were each 6.5 per 100 patient-years. No ISRs were classified as severe or serious TEAEs or led to drug discontinuation.

CONCLUSION

Though ISRs were common, most were mild, and the percentage of patients reporting ISRs declined from PEGASUS through the 307 OLE. Patient compliance remained high, and no patients discontinued because of ISRs, suggesting that ISRs do not pose a barrier to long-term pegcetacoplan treatment.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT03500549 (PEGASUS) and NCT03531255 (307 OLE).

Analysis of Costs per Responder in US Adults with Paroxysmal Nocturnal Hemoglobinuria with a Suboptimal Response to Prior Eculizumab Treatment

European Society for Blood and Marrow Transplantation (EBMT) hematologic response categories comprehensively assess complement inhibitor responses in patients with paroxysmal nocturnal hemoglobinuria (PNH). Using data from the 16-week randomized controlled period of the phase 3 PEGASUS trial (N = 80), we estimated the treatment cost per responder by the EBMT response category for pegcetacoplan and eculizumab in adults with PNH and a suboptimal response to eculizumab. Average drug costs per responder, number needed to treat, and incremental drug costs per responder were estimated using dosages administered during the trial (base case). A US payer perspective (2020 US dollars) was used. Scenario analyses were conducted for various costs, dosages, treatment durations, patient populations, and settings. In total, 30 of 41 (73%) who switched to pegcetacoplan and 2 of 39 (5%) patients who continued eculizumab had a good, major, or complete response (good-to-complete responders) at Week 16. Average weekly drug costs per good-to-complete responder were USD 15,923 with pegcetacoplan and USD 216,100 with eculizumab; average weekly drug costs per patient were USD 11,651 and USD 11,082, respectively. Average drug costs per good-to-complete responder with pegcetacoplan were similar across complement inhibitor-naïve populations and were consistently lower than with eculizumab. Switching from eculizumab to pegcetacoplan allowed more patients with a suboptimal response to attain a good-to-complete response at lower costs. These results apply to patients with a suboptimal response to prior eculizumab treatment only.

Complement Inhibition in Paroxysmal Nocturnal Hemoglobinuria (PNH): A Systematic Review and Expert Opinion from Central Europe on Special Patient Populations

INTRODUCTION

Hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) is complement-mediated due to the lack of complement inhibitors in the hemopoietic cell membranes, making complement inhibition the best approach to manage PNH. Three complement inhibitors are approved by the European Medicines Agency as targeted therapy for PNH: eculizumab and ravulizumab, two humanized monoclonal antibodies targeting the same complement 5 (C5) epitope, approved in 2007 and 2019, respectively, and the more recently approved cyclic peptide, the complement 3 (C3) inhibitor pegcetacoplan. Although national and international PNH treatment guidelines exist, they do not take into consideration the latest clinical trial evidence. Given the lack of evidence-based data for some clinical situations encountered in real life, we identified specific populations of patients who may benefit from switching to proximal C3 from terminal C5 inhibition.

METHODS

The expert recommendations presented here were created using a Delphi-like process by a group of expert PNH specialists across Central Europe. Based on an initial advisory board meeting discussion, recommendations were prepared and reviewed as part of a Delphi survey to test agreement.

RESULTS

Using a systematic approach, literature databases were searched for relevant studies, and 50 articles were reviewed by the experts and included as supporting evidence.

CONCLUSION

Implementation of these recommendations uniformly across healthcare institutions will promote the best use of complement inhibition in managing PNH, and has the potential to positively impact patient outcomes in Central Europe and worldwide.

Pegcetacoplan: A New Opportunity for Complement Inhibition in PNH

Pegcetacoplan is the newest inhibitor of the complement system to be approved by the FDA and EMA for the treatment of Paroxysmal Nocturnal Hemoglobinuria (PNH). The cyclic peptide inhibitor of C3 was evaluated in several clinical trials in PHN leading to its approval. The focus of this paper will review the efficacy and safety of Pegcetacoplan (PEG), and considerations for use in patients with PNH.

Paroxysmal nocturnal hemoglobinuria: Where we stand

For the last 20 years, therapy of paroxysmal nocturnal hemoglobinuria (PNH) relied-up until recently-on antibody based terminal complement inhibitionon. PNH pathophysiology-a mutational defect leading to partial or complete absence of complement-regulatory proteins on blood cells-leads to intravascular hemolysis and consequences such as thrombosis and other sequelae. A plethora of new drugs interfering with the proximal and terminal complement cascade are under recent development and the first "proof-of-pinciple" proximal complement inhibitor targeting C3 has been approved in 2021. "PNH: where we stand" will try to give a brief account on where we came from and where we stand focusing on approved therapeutic options. The associated improvements as well as potential consequences of actual and future treatments as well as their impact on the disease will continue to necessitate academic and scientific focus on improving treatment options as well as on side effects and outcomes relevant to individual patient lives and circumstances in order to develop effective, safe, and available treatment for all hemolytic PNH patients globally.

Pegcetacoplan: A Review in Paroxysmal Nocturnal Haemoglobinuria

Subcutaneous pegcetacoplan (EMPAVELI® in the USA and ASPAVELI® in the EU) is the first complement component 3 (C3) inhibitor approved for the treatment of adults with paroxysmal nocturnal haemoglobinuria (PNH) in the USA, and in adults with PNH who are anaemic after ≥ 3 months of treatment with a C5 inhibitor in the EU. In the phase III PRINCE trial in adults with PNH who were anaemic and naïve to a complement inhibitor therapy, pegcetacoplan was superior to the control group (supportive care, excluding complement inhibitors) in achieving haemoglobin stabilization and reducing lactate dehydrogenase levels. Similarly, in the phase III PEGASUS trial in adults with PNH who had a haemoglobin level < 10.5 g/dL despite eculizumab therapy, pegcetacoplan was superior to eculizumab in improving haemoglobin levels. In both trials, pegcetacoplan also improved other clinical and haematological parameters of haemolysis, as well as quality of life (QOL) outcomes. Clinical benefits of pegcetacoplan were sustained for up to 48 weeks of treatment. Pegcetacoplan was generally well tolerated in patients with PNH, with its tolerability profile being similar in patients previously treated with eculizumab and in complement inhibitor-naïve patients. Long-term data would be beneficial to further support the safety profile of pegcetacoplan. Current evidence indicates that pegcetacoplan is a valuable treatment option for adults with PNH.