Anti-complement Treatment for Paroxysmal Nocturnal Hemoglobinuria: Time for Proximal Complement Inhibition? A Position Paper From the SAAWP of the EBMT

Phase 3 randomized COMMODORE 2 trial: Crovalimab versus eculizumab in patients with paroxysmal nocturnal hemoglobinuria naive to complement inhibition

Crovalimab is a novel C5 complement inhibitor that enables rapid and sustained C5 inhibition with subcutaneous, low-volume self-administration every 4 weeks. COMMODORE 2 (NCT04434092) is a global, randomized, open-label, multicenter, phase 3 trial evaluating the non-inferiority of crovalimab versus eculizumab in patients with paroxysmal nocturnal hemoglobinuria not previously treated with C5 inhibition. C5 inhibitor-naive patients with lactate dehydrogenase (LDH) ≥2 × upper limit of normal (ULN) were randomized 2:1 to crovalimab or eculizumab. Co-primary efficacy endpoints were proportion of patients with hemolysis control (centrally assessed LDH ≤1.5 × ULN) and proportion with transfusion avoidance. Secondary efficacy endpoints were proportions of patients with breakthrough hemolysis, stabilized hemoglobin, and change in FACIT-Fatigue score. The primary treatment period was 24 weeks. Two hundred and four patients were randomized (135 crovalimab; 69 eculizumab). Crovalimab was non-inferior to eculizumab in the co-primary endpoints of hemolysis control (79.3% vs. 79.0%; odds ratio, 1.0 [95% CI, 0.6, 1.8]) and transfusion avoidance (65.7% vs. 68.1%; weighted difference, -2.8 [-15.7, 11.1]), and in the secondary efficacy endpoints of breakthrough hemolysis (10.4% vs. 14.5%; weighted difference, -3.9 [-14.8, 5.3]) and hemoglobin stabilization (63.4% vs. 60.9%; weighted difference, 2.2 [-11.4, 16.3]). A clinically meaningful improvement in FACIT-Fatigue score occurred in both arms. Complete terminal complement activity inhibition was generally maintained with crovalimab. The safety profiles of crovalimab and eculizumab were similar with no meningococcal infections. Most patients who switched from eculizumab to crovalimab after the primary treatment period preferred crovalimab. These data demonstrate the positive benefit-risk profile of crovalimab.

The complement model disease paroxysmal nocturnal hemoglobinuria

We describe initial, current, and future aspects of complement activation and inhibition in the rare hematological disease paroxysmal nocturnal hemoglobinuria (PNH). PNH is a rare but severe hematological disorder characterized by complement-mediated intravascular hemolysis resulting in anemia and severe thrombosis. Insights into the complement-mediated pathophysiology ultimately led to regulatory approval of the first-in-class complement inhibitor, eculizumab, in 2007. This anti-complement C5 therapy resulted in the stabilization of many hematologic parameters and dramatically reduced the often fatal, coagulant-resistant thrombotic events. Despite the remarkable clinical success, a substantial proportion of PNH patients experience suboptimal clinical responses during anti-C5 therapy. We describe the identification and mechanistic dissection of four unexpected processes responsible for such suboptimal clinical responses: (1) pharmacokinetic and (2) pharmacodynamic intravascular breakthrough hemolysis, (3) continuing low-level residual intravascular hemolysis, and (4) extravascular hemolysis. Novel complement therapeutics mainly targeting different complement proteins proximal in the cascade attempt to address these remaining problems. With five approved complement inhibitors in the clinic and many more being evaluated in clinical trials, PNH remains one of the complement diseases with the highest intensity of clinical research. Mechanistically unexpected breakthrough events occur not only with C5 inhibitors but also with proximal pathway inhibitors, which require further mechanistic elaboration.

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).

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.

Complement inhibition in paroxysmal nocturnal hemoglobinuria: From biology to therapy

Complement inhibitors are the mainstay of paroxysmal nocturnal hemoglobinuria (PNH) treatment. The anti-C5 monoclonal antibody eculizumab was the first treatment to improve hemolysis, thrombotic risk, and survival in PNH although at the price of a life-long intravenous fortnightly drug. Additionally, suboptimal response may occur in up to 2/3 of patients with persistent anemia due to incomplete control of intravascular hemolysis, development of upstream C3-mediated extravascular hemolysis (EVH), or concomitant bone marrow failure. Ravulizumab, a longer half-life anti-C5 developed from eculizumab, administered every 8 weeks, improved patient convenience, and reduced pharmacokinetic breakthrough hemolysis (BTH) by establishing more stable anti-C5 concentrations. More recently, several other anti-C5 compounds (crovalimab, pozelimab, tesidolumab, cemdisiran, zilucoplan, and coversin) are on study in clinical trials. Upstream inhibition of complement cascade was also explored with the anti-C3 pegcetacoplan, and with the alternative pathway inhibitors iptacopan (anti-factor B) and danicopan (anti-factor D). These drugs efficiently target EVH and are able to improve anemia and transfusion need in suboptimal responders to anti-C5. The route and schedule of administration (twice weekly subcutaneously for pegcetacoplan and twice or thrice oral daily dosing for iptacopan and danicopan, respectively) are very convenient but pose novel issues regarding adherence. Additionally, both anti-C5 and upstream inhibitors do not resolve the unmet need of pharmacodynamic BTH events due to complement amplifying conditions such as infections, traumas, and surgery. In this review, we will recapitulate PNH physiopathology, clinical presentation, and diagnosis and describe available and developing drugs that will lead to a precision medicine approach for this rare though heterogenous disease.

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.

Evaluation of the impact of two C5 genetic variants on C5-eculizumab complex stability at the molecular level

Complement C5 is the target of the monoclonal antibody eculizumab, used in complement dysregulating disorders, like the rare disease Paroxysmal Nocturnal Hemoglobinuria (PNH). PNH is an acquired hematopoietic stem cell condition characterized by aberrant destruction of erythrocytes, chronic hemolytic anemia, and thromboembolism propensity. C5 is a protein component of the complement system which is part of the immune system of the body and plays a prominent role in the destruction of red blood cells, misidentifying them as a threat. This work describes the application of molecular dynamics simulations to the study of the underlying interactions between complement C5 and eculizumab. This study also reveals the importance of single nucleotide polymorphisms on C5 protein concerning the effective inhibition of the mAB, involving the mechanistic events taking place at the interface spots of the complex. The predicted conformational change in the C5 Arg885/His/Cys mutation has implications on the protein's interaction with eculizumab, compromising their compatibility. The acquired insights into the conformational changes, dynamics, flexibility, and interactions shed light on the knowledge of the function of this biomolecule providing answers about the poor response to the treatment in PNH patient carriers of the mutations. By investigating the intricate dynamics, significant connections between C5 and eculizumab can be uncovered. Such insights may aid in the creation of novel compounds or lead to the enhancement of eculizumab's efficacy.Communicated by Ramaswamy H. Sarma.

Oral Iptacopan Monotherapy in Paroxysmal Nocturnal Hemoglobinuria

BACKGROUND

Persistent hemolytic anemia and a lack of oral treatments are challenges for patients with paroxysmal nocturnal hemoglobinuria who have received anti-C5 therapy or have not received complement inhibitors. Iptacopan, a first-in-class oral factor B inhibitor, has been shown to improve hemoglobin levels in these patients.

METHODS

In two phase 3 trials, we assessed iptacopan monotherapy over a 24-week period in patients with hemoglobin levels of less than 10 g per deciliter. In the first, anti-C5-treated patients were randomly assigned to switch to iptacopan or to continue anti-C5 therapy. In the second, single-group trial, patients who had not received complement inhibitors and who had lactate dehydrogenase (LDH) levels more than 1.5 times the upper limit of the normal range received iptacopan. The two primary end points in the first trial were an increase in the hemoglobin level of at least 2 g per deciliter from baseline and a hemoglobin level of at least 12 g per deciliter, each without red-cell transfusion; the primary end point for the second trial was an increase in hemoglobin level of at least 2 g per deciliter from baseline without red-cell transfusion.

RESULTS

In the first trial, 51 of the 60 patients who received iptacopan had an increase in the hemoglobin level of at least 2 g per deciliter from baseline, and 42 had a hemoglobin level of at least 12 g per deciliter, each without transfusion; none of the 35 anti-C5-treated patients attained the end-point levels. In the second trial, 31 of 33 patients had an increase in the hemoglobin level of at least 2 g per deciliter from baseline without red-cell transfusion. In the first trial, 59 of the 62 patients who received iptacopan and 14 of the 35 anti-C5-treated patients did not require or receive transfusion; in the second trial, no patients required or received transfusion. Treatment with iptacopan increased hemoglobin levels, reduced fatigue, reduced reticulocyte and bilirubin levels, and resulted in mean LDH levels that were less than 1.5 times the upper limit of the normal range. Headache was the most frequent adverse event with iptacopan.

CONCLUSIONS

Iptacopan treatment improved hematologic and clinical outcomes in anti-C5-treated patients with persistent anemia - in whom iptacopan showed superiority to anti-C5 therapy - and in patients who had not received complement inhibitors. (Funded by Novartis; APPLY-PNH ClinicalTrials.gov number, NCT04558918; APPOINT-PNH ClinicalTrials.gov number, NCT04820530.).

The disease burden of paroxysmal nocturnal hemoglobinuria in Denmark: Epidemiology, survival, healthcare resource utilization, costs, treatment gaps, and labor market attachment

OBJECTIVES

To establish epidemiology, healthcare costs, and labor market attachment in patients with paroxysmal nocturnal hemoglobinuria (Pt-PNH) in Denmark.

METHODS

Data were from Statistics Denmark and the Danish Health Data Authority national population registers (2005-2021). Descriptive baseline statistics characterized the Pt-PNH analytic population; ordinary least squares and adjusted Cox proportional hazards regressions measured outcomes in the Pt-PNH versus Danish general population matched comparators.

RESULTS

Overall PNH incidence in Denmark was n = 11 during 2007-2009, n = 25 during 2016-2018 and n = 7 during 2019-2020; prevalence increased from n = 13 in 2006 to n = 62 in 2021. Of the overall n = 85 Pt-PNH; n = 24 were treated with complement-5 inhibitors (Pt-C5i) and n = 61 not treated with C5i (Pt-nC5i). Versus respective comparators, all patients had significantly greater annual per-patient costs (from inpatient hospital admissions, outpatient contacts, PNH treatments; indirect costs from lost earnings + transfer payments; post-diagnosis for Pt-PNH and Pt-nC5i, post-treatment initiation for Pt-C5i). The Pt-C5i incurred the greatest healthcare and indirect cost differences (€709 119; €152 832, respectively) followed by the Pt-PNH (€189 323; €29 159, respectively) and Pt-nC5i (€95 548; €4713, respectively). The Pt-PNH versus comparators also had an increased hazard of death (2.71 [95% CI, 1.63 - 4.51]).

CONCLUSION

Although a rare disease, PNH is associated with significant patient, healthcare system, and societal burdens in Denmark.

Burden of illness in Japanese patients with paroxysmal nocturnal hemoglobinuria receiving C5 inhibitors

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening blood disorder characterized by hemolysis and resulting in anemia and fatigue. Current therapies for PNH in Japan rely on complement inhibitors targeting the C5 component of the complement. However, the disease burden of Japanese patients with PNH treated with C5 inhibitors (C5i) remains unclear. To investigate this topic, we conducted a cross-sectional survey study that included 59 Japanese patients with PNH treated with C5i. Although many participants received C5i for 1 year or longer, the mean hemoglobin (Hb) level was 10.2 g/dL. Fatigue and shortness of breath were the most common symptoms at the time of diagnosis and survey. In addition, patients with Hb levels ≥ 10.5 g/dL also reported fatigue, depression and reduced quality of life, albeit to a lesser extent. These results suggest that a substantial burden of illness remains in patients with C5i-treated PNH, likely resulting in low quality of life and effects of symptoms on daily life. This study contributes to understanding the unmet needs of the current therapies for PNH, highlighting the need for novel therapeutics.

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.

Understanding pharmacological complement inhibition in paroxysmal nocturnal hemoglobinuria

Not available.

COVID-19 vaccination prevents a more severe course and treatment with complement inhibitors reduce worsening hemolysis during the Omicron pandemic in patients with PNH: a single-center study

OBJECTIVE

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired disease characterized by chronic complement-mediated hemolysis. The concentrated outbreak of coronavirus disease 2019 (COVID-19) in China after 6 December 2022, provided an opportunity to observe the disease course of PNH during an active Omicron infection epidemic.

PATIENTS AND METHOD

Patients diagnosed with PNH at Peking Union Medical College Hospital (PUMCH) before 6 December 2022, were followed up until 10 April 2023. Clinical data related to coronavirus infection and hemolysis were recorded. Factors influencing the infection and severity rate of Omicron, as well as hemolysis provocation, were analyzed.

RESULTS

In total, 131 patients with PNH were included in this retrospective analysis; 87.8% were infected with Omicron. Among them, 15.7% met the criteria for severity, and 1 patient died (0.87%). No protective factors were identified against Omicron infections. However, patients with severe Omicron infection (n = 18) had a lower vaccination rate than those with non-severe infection (n = 97; p = 0.015). Among those infected (n = 115) with Omicron, there was a significant increase in lactate dehydrogenase (LDH) levels compared with those in the uninfected group (n = 16, p = 0.000). Patients with severe infections (n = 18) had even higher LDH increase rates than those without severe infections (n = 97; p = 0.002). 10 (37.0%) patients treated with complement inhibitors developed breakthrough hemolysis (BTH). Patients treated with complement inhibitors (n = 27) exhibited less severe hemolysis than treatment-naïve patients (n = 104; p = 0.003).

CONCLUSIONS

Omicron infection exacerbates hemolytic attacks in patients with PNH. Vaccination helps mitigate the severity of Omicron infection, and using complement inhibitors reduces hemolysis exacerbation.

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.

Addition of danicopan to ravulizumab or eculizumab in patients with paroxysmal nocturnal haemoglobinuria and clinically significant extravascular haemolysis (ALPHA): a double-blind, randomised, phase 3 trial

BACKGROUND

Symptoms of anaemia due to clinically significant extravascular haemolysis can affect patients with paroxysmal nocturnal haemoglobinuria (PNH) treated with C5 inhibitors (ravulizumab or eculizumab). The aim of this study was to assess the efficacy and safety of danicopan (ALXN2040), an investigational, first-in-class, oral complement factor D inhibitor, as add-on therapy to ravulizumab or eculizumab in patients with PNH and clinically significant extravascular haemolysis.

METHODS

ALPHA is an ongoing, international, phase 3, randomised, double-blind, placebo-controlled trial evaluating danicopan as add-on therapy to ravulizumab or eculizumab. Eligible patients were adults (age ≥18 years) with PNH and clinically significant extravascular haemolysis (haemoglobin ≤9·5 g/dL; absolute reticulocyte count ≥120 × 109/L) on ravulizumab or eculizumab for at least 6 months. Patients were randomly assigned (2:1) to danicopan or placebo added to ravulizumab or eculizumab for 12 weeks using an interactive response technology system. Randomisation was stratified based on transfusion history, haemoglobin, and patients enrolled from Japan. The initial oral danicopan dose was 150 mg three times a day; escalation to 200 mg three times a day was permitted based on clinical response. The infusion dose level of eculizumab (every 2 weeks) ranged from 900 mg to 1500 mg, and for ravulizumab (monthly or every 8 weeks) ranged from 3000 mg to 3600 mg. The primary endpoint was change in haemoglobin concentration from baseline to week 12. Here we present the protocol-prespecified interim analysis, planned when approximately 75% of participants were randomly assigned to treatment and completed or discontinued at 12 weeks. This trial is registered with ClinicalTrials.gov (NCT04469465).

FINDINGS

Individuals were randomly assigned between Dec 16, 2020, and Aug 29, 2022. At data cutoff (June 28, 2022), 73 individuals were randomly assigned, received treatment, and were analysed for safety (danicopan, n=49; placebo, n=24). The protocol-prespecified interim efficacy analysis set included the first 63 participants (danicopan, n=42; placebo, n=21). At week 12, danicopan plus ravulizumab or eculizumab increased haemoglobin versus placebo plus ravulizumab or eculizumab (least squares mean [LSM] change from baseline: danicopan, 2·94 g/dL [95% CI 2·52 to 3·36]; placebo, 0·50 g/dL [-0·13 to 1·12]; LSM difference, 2·44 g/dL [1·69 to 3·20]; p<0·0001). Grade 3 adverse events in the danicopan group were increased alanine aminotransferase (two [4%] of 49 patients), leukopenia (one [2%]), neutropenia (two [4%]), cholecystitis (one [2%]), COVID-19 (one [2%]), increased aspartate aminotransferase (one [2%]), and increased blood pressure (one [2%]), and in the placebo group were anaemia (one [4%] of 24 patients), thrombocytopenia (one [4%]), and asthenia (one [4%]). The serious adverse events reported in the danicopan group were cholecystitis (one [2%] patient) and COVID-19 (one [2%]) and in the placebo group were anaemia and abdominal pain, both in one (4%) patient. There were no serious adverse events related to study drug or deaths reported in the study.

INTERPRETATION

These primary efficacy and safety results show that danicopan as add-on treatment to ravulizumab or eculizumab significantly improved haemoglobin concentrations at week 12 with no new safety concerns, suggesting an improved benefit-risk profile in patients with PNH and clinically significant extravascular haemolysis.

FUNDING

Alexion, AstraZeneca Rare Disease.

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).

Complement and platelets: prothrombotic cell activation requires membrane attack complex-induced release of danger signals

Complement activation in the diseases paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS) results in cytolysis and fatal thrombotic events, which are largely refractory to anticoagulation and/or antiplatelet therapy. Anticomplement therapy, however, efficiently prevents thrombotic events in PNH and aHUS, but the underlying mechanisms remain unresolved. We show that complement-mediated hemolysis in whole blood induces platelet activation similarly to activation by adenosine 5'-diphosphate (ADP). Blockage of C3 or C5 abolished platelet activation. We found that human platelets failed to respond functionally to the anaphylatoxins C3a and C5a. Instead, complement activation did lead to prothrombotic cell activation in the whole blood when membrane attack complex (MAC)-mediated cytolysis occurred. Consequently, we demonstrate that ADP receptor antagonists efficiently inhibited platelet activation, although full complement activation, which causes hemolysis, occurred. By using an established model of mismatched erythrocyte transfusions in rats, we crossvalidated these findings in vivo using the complement inhibitor OmCI and cobra venom factor. Consumptive complement activation in this animal model only led to a thrombotic phenotype when MAC-mediated cytolysis occurred. In conclusion, complement activation only induces substantial prothrombotic cell activation if terminal pathway activation culminates in MAC-mediated release of intracellular ADP. These results explain why anticomplement therapy efficiently prevents thromboembolisms without interfering negatively with hemostasis.

Long-Term Efficacy and Safety of Eculizumab in Patients With Paroxysmal Nocturnal Hemoglobinuria and High Disease Burden: Real-World Data From Korea

BACKGROUND

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disorder characterized by uncontrolled terminal complement activation. Eculizumab, a monoclonal antibody C5 inhibitor was introduced in Korea in 2009 and has been the standard treatment option for PNH.

METHODS

This study assessed the long-term efficacy/safety of eculizumab in PNH using real-world data from the Korean Health Insurance Review and Assessment Service. Eighty patients who initiated eculizumab from 2009-2020 were enrolled.

RESULTS

At eculizumab initiation, the median age was 51.5 years, lactate dehydrogenase (LDH) 6.8 × upper limit of normal, and granulocyte clone size 93.0%. All patients had at least one PNH-related complication before eculizumab initiation, including renal failure (n = 36), smooth muscle spasm (n = 24), thromboembolism (n = 20), and pulmonary hypertension (n = 15). The median (range) duration of eculizumab treatment was 52.7 (1.0, 127.3) months (338.6 total treated patient-years). Despite high disease activity in the study population before treatment initiation, overall survival was 96.2% and LDH levels were stabilized in most patients during treatment. PNH-related complications at treatment initiation were resolved in 44.4% of patients with renal failure, 95.8% with smooth muscle spasm, 70.0% with thromboembolism, and 26.7% with pulmonary hypertension. Extravascular hemolysis occurred in 28.8% of patients (n = 23; 0.09 per patient-year) and breakthrough hemolysis in 18.8% (n = 15; 0.06 per patient-year). No treatment discontinuation cases related to eculizumab were observed.

CONCLUSION

These data provided evidence for the long-term efficacy and safety of eculizumab in Korean PNH patients with high disease burdens.

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.

The cost-effectiveness of pegcetacoplan in complement treatment-naïve adults with paroxysmal nocturnal hemoglobinuria in the USA

Aim: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder characterized by hemolytic anemia, bone marrow failure and thrombosis, and is associated with high healthcare burden. We evaluated the cost-effectiveness of pegcetacoplan, a proximal complement-3 inhibitor (C3i), compared with the C5i, eculizumab and ravulizumab, in complement treatment-naive adults with PNH, from the US healthcare payer perspective. Materials & methods: A de novo cost-effectiveness model based on a Markov cohort structure evaluated lifetime (55-year) PNH costs and outcomes. The 6-month cycles of the model reflected the follow-up period of PRINCE (NCT04085601), an open-label trial of pegcetacoplan compared with eculizumab in C5i-naive patients. Data from PRINCE informed the clinical, safety and health-related quality of life outcomes in the model. Results: Pegcetacoplan was associated with lifetime cost savings of USD1,176,808 and USD213,062 relative to eculizumab and ravulizumab, respectively (largely attributed to reduced drug costs and blood transfusions), and additional quality-adjusted life years (QALYs) of 0.25 and 0.24. Conclusion: In patients with PNH who are treatment-naive, the base-case cost-effectiveness analysis, scenario analysis and sensitivity analysis showed both lifetime cost savings and increased QALYs associated with pegcetacoplan compared with eculizumab or ravulizumab in the USA.

Efficacy and safety of the C5 inhibitor crovalimab in complement inhibitor-naive patients with PNH (COMMODORE 3): A multicenter, Phase 3, single-arm study

The Phase 3 single-arm COMMODORE 3 study (ClinicalTrials.gov, NCT04654468) evaluated efficacy and safety of crovalimab (novel C5 inhibitor) in complement inhibitor-naive patients with paroxysmal nocturnal hemoglobinuria (PNH). COMMODORE 3 enrolled patients from five China centers. Eligible complement inhibitor-naive patients with PNH were ≥12 years old, had lactate dehydrogenase (LDH) ≥2 × upper limit of normal (ULN), and had ≥4 transfusions of packed red blood cells within the prior 12 months. Patients received crovalimab loading doses (one intravenous, four subcutaneous) and subsequent every-4-weeks subcutaneous maintenance doses per weight-based tiered-dosing schedule. Co-primary efficacy endpoints were mean proportion of patients with hemolysis control (LDH ≤1.5 × ULN) from Week (W)5 through W25 and difference in proportion of patients with transfusion avoidance from baseline through W25 versus within 24 weeks of prescreening in patients who had ≥1 crovalimab dose and ≥1 central LDH assessment after first dose. Between March 17 and August 24, 2021, 51 patients (15-58 years old) were enrolled; all received treatment. At primary analysis, both co-primary efficacy endpoints were met. Estimated mean proportion of patients with hemolysis control was 78.7% (95% CI: 67.8-86.6). Difference between proportion of patients with transfusion avoidance from baseline through W25 (51.0%; n = 26) versus within 24 weeks of prescreening (0%) was statistically significant (p < .0001). No adverse events led to treatment discontinuation. One treatment-unrelated death (subdural hematoma following a fall) occurred. In conclusion, crovalimab, with every-4-weeks subcutaneous dosing is efficacious and well tolerated in complement inhibitor-naive patients with PNH.

The Features of COVID-19's Course and the Efficacy of the Gam-COVID-Vac Vaccine in Patients with Paroxysmal Nocturnal Hemoglobinuria

COVID-19 and other infectious diseases can exacerbate the course of paroxysmal nocturnal hemoglobinuria (PNH). The efficacy and safety of the Gam-COVID-Vac vaccine in patients with PNH has not been adequately studied. A retrospective, observational, cohort, non-comparative study was performed to assess the course of COVID-19 as well as the safety and efficacy of the Gam-COVID-Vac (Sputnik V) vaccine in patients with paroxysmal nocturnal hemoglobinuria (PNH). The study included data from 52 patients with PNH aged 18 to 75 years, 38 of whom received background therapy with eculizumab (Elizaria®) between March 2020 and January 2022. COVID-19 was diagnosed according to the results of PCR testing. The patients were divided into two groups for comparison of the incidence of COVID-19. Group 1 included non-vaccinated patients with PNH, and Group 2 included patients vaccinated prior to the onset of COVID-19. According to vaccination, patients were subdivided into non-vaccinated and vaccinated groups without signs of previous COVID-19 at the beginning of the analyzed period, and patients vaccinated half a year or more after recovery from COVID-19. Testing for anti-SARS-CoV-2 IgG levels was carried out in patients with PNH in the year after their COVID-19. Tests for anti-SARS-CoV-2 RBD IgG levels were performed on vaccinated patients. In total, 28 (53.8%) of the enrolled patients had COVID-19, including asymptomatic forms in 7 (25%) and mild forms in 16 (57%) patients. A total of 22 (42.3%) patients were fully vaccinated with Gam-COVID-Vac, of which 13 (25%) patients were vaccinated without the signs of previous SARS-CoV-2infection, and 9 (17.3%) patients were vaccinated after COVID-19. The number of patients who had COVID-19 was about two times higher in Group 1 (non-vaccinated; 24) (61.5%), whereas in Group 2 (vaccinated), the number of patients with COVID-19 was only 4 (30.8%). The proportion and number of patients who did not have COVID-19 was higher in the group of vaccinated patients (9; 69.2%) than in the group of non-vaccinated patients (15; 38.5%) (p = 0.054). In patients who had been infected with COVID-19, maximum concentrations of anti-SARS-CoV-2 IgG were observed 2-3 months after the acute infection phase, followed by a gradual decline by month 9-10. The mean RBD IgG concentration was higher in the group of patients who had been infected by COVID-19 than in the group of patients without COVID-19 (p = 0.047). Therapy type, including eculizumab, did not have a significant impact on RBD IgG titers (p > 0.05). Hospitalization was required in five (18%) patients, all of whom had breakthrough hemolysis and severe lung damage on CT scans. After the first dose, adverse events (AEs) were reported in 41% of the patients (body temperature increased in 18%; headache in 13.6%; and pain in joints in 4.5%; colitis exacerbation was observed in 4.5%). After the second dose, no AEs were reported. The performed study suggests the possible efficacy and demonstrates the safety of Gam-COVID-Vac (Sputnik V) for the prophylaxis of COVID-19 in patients with PNH who experience immunosuppression due to target therapy.

Normalisation of haemoglobin and control of breakthrough haemolysis with increased frequency pegcetacoplan dosing in treated paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal haemoglobinura is an acquired life-threatening haemolytic condition, which is generally well controlled with terminal complement blockade with eculizumab. Whilst almost all patients treated with terminal complement inhibitors develop extravascular haemolysis, only a small proportion of these results in symptomatic anaemia limiting their activities and requiring red cell transfusion. This case highlights the potential role for the C3 inhibitor, pegcetacoplan, in controlling both intravascular and extravascular haemolysis, and is the first case to report on the use of additional doses of pegcetacoplan to control breakthrough haemolysis.

Clonal evolution in aplastic anemia: failed tumor surveillance or maladaptive recovery?

Clonal evolution to secondary paroxysmal nocturnal hemoglobinuria (PNH) or myeloid neoplasia (MN) represents one of the long-term complications of patients with aplastic anemia (AA). The recent evidence in the field of immunology and the application of next-generation sequencing have shed light on the molecular underpinnings of these clonal complications, revealing clinical and molecular risk factors as well as potential immunological players. Particularly, whether MN evolution represents a failed tumor surveillance or a maladaptive recovery is still a matter of controversy in the field of bone marrow failure syndromes. However, recent studies have explored the precise dynamics of the immune-molecular forces governing such processes over time, generating knowledge useful for potential early therapeutic strategies. In this review, we will discuss the immune pathophysiology of AA and the emergence of clonal hematopoiesis with regard to the adaptive and maladaptive mechanisms at the basis of secondary evolution trajectories operating under the immune pressure.

Crovalimab treatment in patients with paroxysmal nocturnal haemoglobinuria: Long-term results from the phase I/II COMPOSER trial

OBJECTIVES

This study reports long-term outcomes from the open-label extension (OLE) period of the Phase I/II COMPOSER trial (NCT03157635) that evaluated crovalimab in patients with paroxysmal nocturnal haemoglobinuria, who were treatment-naive or switched from eculizumab at enrolment.

METHODS

COMPOSER consists of four sequential parts followed by the OLE. The primary OLE objective was to assess long-term crovalimab safety, with a secondary objective to assess crovalimab pharmacokinetics and pharmacodynamics. Exploratory efficacy endpoints included change in lactate dehydrogenase (LDH), transfusion avoidance, haemoglobin stabilisation and breakthrough haemolysis (BTH).

RESULTS

A total 43 of 44 patients entered the OLE after completing the primary treatment period. Overall, 14 of 44 (32%) experienced treatment-related adverse events. Steady state exposure levels of crovalimab and terminal complement inhibition were maintained over the OLE. During the OLE, mean normalised LDH was generally maintained at ≤1.5× upper limit of normal, transfusion avoidance was achieved in 83%-92% of patients and haemoglobin stabilisation was reached in 79%-88% of patients across each 24-week interval. Five BTH events occurred with none leading to withdrawal.

CONCLUSIONS

Over a 3-year median treatment duration, crovalimab was well tolerated and sustained C5 inhibition was achieved. Intravascular haemolysis control, haemoglobin stabilisation and transfusion avoidance were maintained, signifying long-term crovalimab efficacy.

Pegcetacoplan controls hemolysis in complement inhibitor-naive patients with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterized by complement-mediated hemolysis. Pegcetacoplan is the first C3-targeted therapy approved for adults with PNH (United States), adults with PNH with inadequate response or intolerance to a C5 inhibitor (Australia), and adults with anemia despite C5-targeted therapy for ≥3 months (European Union). PRINCE was a phase 3, randomized, multicenter, open-label, controlled study to evaluate the efficacy and safety of pegcetacoplan vs control (supportive care only; eg, blood transfusions, corticosteroids, and supplements) in complement inhibitor-naive patients with PNH. Eligible adults receiving supportive care only for PNH were randomly assigned and stratified based on their number of transfusions (<4 or ≥4) 12 months before screening. Patients received pegcetacoplan 1080 mg subcutaneously twice weekly or continued supportive care (control) for 26 weeks. Coprimary end points were hemoglobin stabilization (avoidance of >1-g/dL decrease in hemoglobin levels without transfusions) from baseline through week 26 and lactate dehydrogenase (LDH) change at week 26. Overall, 53 patients received pegcetacoplan (n = 35) or control (n = 18). Pegcetacoplan was superior to control for hemoglobin stabilization (pegcetacoplan, 85.7%; control, 0; difference, 73.1%; 95% confidence interval [CI], 57.2-89.0; P < .0001) and change from baseline in LDH (least square mean change: pegcetacoplan, -1870.5 U/L; control, -400.1 U/L; difference, -1470.4 U/L; 95% CI, -2113.4 to -827.3; P < .0001). Pegcetacoplan was well tolerated. No pegcetacoplan-related adverse events were serious, and no new safety signals were observed. Pegcetacoplan rapidly and significantly stabilized hemoglobin and reduced LDH in complement inhibitor-naive patients and had a favorable safety profile. This trial was registered at www.clinicaltrials.gov as NCT04085601.

Molecular pharmacology in complement-mediated hemolytic disorders

In the last decade, a deeper understanding of the pathogenesis of complement mediated hemolytic disorders, such as paroxysmal nocturnal hemoglobinuria (PNH), cold agglutinin disease (CAD), warm type autoimmune hemolytic anemia (AIHA) with complement activation (wAIHA), and atypical hemolytic uremic syndrome (aHUS), paved the way to the therapeutic shift from purely supportive approaches to complement-targeted therapies. This resulted in a significant improvement in disease management, survival, and quality of life. In this review, we will provide a snapshot of novel therapies for complement-mediated hemolytic anemias with a focus on those ready to use in clinical practice. C5 inhibitors eculizumab and the long-acting ravulizumab, are the established gold standard for untreated PNH patients, whilst the C3 inhibitor pegcetacoplan should be considered for suboptimal responders to anti-C5 drugs. Several additional compounds targeting the complement cascade at different levels (other C5 inhibitors, factor B and D inhibitors) are under active investigation with promising results. In CAD, immunosuppression with rituximab remains the first-line. However, recently FDA and EMA approved the anti-C1s monoclonal antibody, sutimlimab, that showed dramatic responses and whose regulatory approval is soon awaited in many countries. Other drugs under investigation in AIHA include the C3 inhibitor pegcetacoplan, and the anti-C1q ANX005 for warm AIHA with complement activation. Finally, aHUS is an indication for complement inhibitors. Eculizumab and ravulizumab have been approved, whilst other C5 inhibitors, and novel lectin pathway inhibitors are under active investigation in this disease.

Atypical haemolytic uremic syndrome with refractory multiorgan involvement and heterozygous CFHR1/CFHR3 gene deletion

BACKGROUND

We present this challenging case report of Atypical Haemolytic Uremic Syndrome (aHUS) presenting with multi-organ involvement in a patient and heterozygous CFHR1/CFHR3 gene variant, which was refractory to initial eculizumab therapy.

CASE PRESENTATION

A forty-three year old female presented with aHUS and had heterozygous disease-associated deletions in the complement genes CFHR1/CFHR3. She had progressive kidney failure and severe extra-renal manifestations including cardiomyopathy and haemorrhagic cystitis; as well as pulmonary, gastrointestinal and neurological involvement. The initial kidney biopsy revealed thrombotic microangiopathy (TMA) changes involving all glomeruli. Clinical improvement was initially seen during eculizumab initiation with suppressed CH50 level, but a new rhinovirus/enterovirus upper respiratory tract infection triggered further severe multi-organ disease activity. The extra-renal manifestations stabilised, then ultimately improved after a period of eculizumab dose intensification. However, the impact on dose intensification on this improvement is unclear. Despite the extra-renal clinical improvement, she ultimately progressed to end-stage kidney disease (ESKD), commencing peritoneal dialysis for three years before undergoing a successful uncomplicated cadaveric kidney transplant without prophylactic eculizumab. Two years after transplant, she has excellent transplant graft function without any further disease recurrence.

CONCLUSIONS

This case highlights the concept of extra-renal manifestations in aHUS initially resistant to eculizumab, which potentially responded to dose intensification. Whilst organ injuries are potentially reversible with timely targeted treatment, it appears that the kidneys are most vulnerable to injury.

Changes in Hematologic Lab Measures Observed in Patients with Paroxysmal Nocturnal Hemoglobinuria Treated with C5 Inhibitors, Ravulizumab and Eculizumab: Real-World Evidence from a US Based EMR Network

Paroxysmal nocturnal hemoglobinuria (PNH), a rare acquired hematologic disorder, can be treated with C5 inhibitors (C5i) such as eculizumab or ravulizumab. This retrospective study is the first to describe real-world treatment patterns and changes in hematologic PNH-monitoring laboratory tests among C5i-treated US patients. Data were extracted from TriNetX Dataworks Network and included patients with a PNH diagnosis between 1 January 2010, and 20 August 2021. Patients were stratified into three cohorts based on their C5i usage: eculizumab, ravulizumab (prior eculizumab), and ravulizumab (eculizumab naïve). Hematological markers (hemoglobin [Hb], lactate dehydrogenase [LDH], and absolute reticulocyte count [ARC]) and relevant clinical events (e.g., breakthrough hemolysis [BTH], complement-amplifying conditions [CAC], thrombosis, infection, and all-cause mortality) were captured any time within 12 months post-index treatment. Of the 143 (eculizumab), 43 (ravulizumab, prior eculizumab), and 33 (ravulizumab, eculizumab naïve) patients, mean age across cohorts was 42-51 years, 55-61% were female, 63-73% were White, and 33-40% had aplastic anemia. Among all cohorts 12 months post-C5i treatment, 50-82% remained anemic, 8-32% required ≥1 transfusion, and 13-59% had BTH, of which 33%-54% had CACs. Additionally, thrombosis was seen in 7-15% of patients, infection in 20-25%, and mortality in 1-7%. These findings suggest many C5i-treated patients experience suboptimal disease control.

Comparative Effectiveness of Pegcetacoplan Versus Ravulizumab and Eculizumab in Complement Inhibitor-Naïve Patients with Paroxysmal Nocturnal Hemoglobinuria: A Matching-Adjusted Indirect Comparison

INTRODUCTION

In the absence of head-to-head trials, this study compared treatment outcomes with the C3 complement inhibitor pegcetacoplan versus the C5 complement inhibitor eculizumab or ravulizumab in complement inhibitor-naïve patients with paroxysmal nocturnal hemoglobinuria (PNH).

METHODS

A matching-adjusted indirect comparison was conducted using individual patient data from the pegcetacoplan arm of the PRINCE trial (NCT04085601; n = 34) and aggregate data from the ravulizumab (n = 125) and eculizumab (n = 121) arms of the ALXN1210-PNH-301 trial (NCT03056040). Clinical and quality of life endpoints were evaluated after matching patients in the two trials on baseline characteristics. The weighted Wald test with 95% confidence interval was used to compare categorical and continuous variables (i.e., weighted chi-squared and z tests, respectively). Bias factor analysis was performed to quantify the extent of residual bias from unmeasured confounders.

RESULTS

After weighting, treatment with pegcetacoplan was associated with statistically significant improvements in most clinical endpoints compared with ravulizumab or eculizumab treatment. These included: greater absolute and percent reductions in lactate dehydrogenase (LDH) level and increase in hemoglobin level from baseline; shorter time to first occurrence of LDH normalization; larger proportions of patients achieving hemoglobin stabilization and avoiding transfusion, with fewer packed red blood cell units transfused; and a smaller proportion of patients experiencing breakthrough hemolysis (all p < 0.05). Patients receiving pegcetacoplan also had a greater increase in general health status score from baseline compared with those receiving C5 complement inhibitors.

CONCLUSION

Pegcetacoplan provides clinical benefits as first-line treatment for complement inhibitor-naïve patients with PNH.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04085601.

Mitigating Drug-Target-Drug Complexes in Patients With Paroxysmal Nocturnal Hemoglobinuria Who Switch C5 Inhibitors

Drug-target-drug complexes (DTDCs) are phenomena newly observed in patients who switch from the complement component 5 (C5) inhibitor eculizumab to crovalimab, a novel, anti-C5 antibody in development for paroxysmal nocturnal hemoglobinuria (PNH), because these agents bind to different C5 epitopes. In Part 3 of the four-part, phase I/II COMPOSER study, 19 patients with PNH switching from eculizumab received 1,000-mg crovalimab intravenously, then subcutaneous maintenance doses from Day 8 (680 mg every 4 weeks (q4w), 340 mg every 2 weeks, or 170 mg every week). Crovalimab exposure was transiently reduced, and size-exclusion chromatography and crovalimab-specific enzyme-linked immunosorbent assays revealed DTDCs in all 19 patients' sera. Additionally, self-limiting mild to moderate symptoms suggestive of type III hypersensitivity reactions occurred in two patients. Mathematical modeling simulations of DTDC kinetics and effects of dosing on DTDC size distribution using Part 3 data predicted that increased crovalimab concentrations could reduce the proportion of large, slow-clearing DTDCs in the blood. A simulation-guided, optimized crovalimab regimen (1,000 mg intravenously; four weekly, subcutaneous 340-mg doses; then 680 mg q4w from Day 29) was evaluated in Part 4. Confirming the model's predictions, mean proportions of large DTDCs in patients who switched from eculizumab to this optimized regimen decreased by > 50% by Day 22, and target crovalimab concentrations were maintained. No type III hypersensitivity reactions occurred in Part 4. Optimizing crovalimab dosing thus reduced the proportion of large DTDCs, ensured adequate complement inhibition, and may improve safety. Model-based dosing optimization to mitigate DTDC formation offers a useful strategy for patients switching to novel antibody treatments targeting soluble epitopes.

How I diagnose and treat atypical hemolytic uremic syndrome

Our understanding and management of atypical hemolytic uremic syndrome (aHUS) have dramatically improved in the last decade. aHUS has been established as a prototypic disease resulting from a dysregulation of the complement alternative C3 convertase. Subsequently, prospective nonrandomized studies and retrospective series have shown the efficacy of C5 blockade in the treatment of this devastating disease. C5 blockade has become the cornerstone of the treatment of aHUS. This therapeutic breakthrough has been dulled by persistent difficulties in the positive diagnosis of aHUS, and the latter remains, to date, a diagnosis by exclusion. Furthermore, the precise spectrum of complement-mediated renal thrombotic microangiopathy is still a matter of debate. Nevertheless, long-term management of aHUS is increasingly individualized and lifelong C5 blockade is no longer a paradigm that applies to all patients with this disease. The potential benefit of complement blockade in other forms of HUS, notably secondary HUS, remains uncertain.

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.

Management of infection in PNH patients treated with eculizumab or other complement inhibitors: Unmet clinical needs

This article presents the results of group discussion among an ad hoc constituted panel of experts aimed at identifying and addressing unmet clinical needs (UCNs) in the management of infectious risk associated with eculizumab or new terminal complement inhibitors (CIs) in paroxysmal nocturnal hemoglobinuria (PNH). With the Delphi technique, the most clinically relevant UCNs in PNH patients candidate to or on terminal CI were selected. They resulted to be: optimizing the infection prevention measures; developing non pharmacological infectious risk-mitigation strategies; improving the management of disease exacerbation during infectious complications. For each of these issues consensus opinions were provided and, when appropriate, proposals for advancement in clinical practice were addressed. The hope is that this comprehensive overview will serve to improve the practice of CIs therapy and inform the design and implementation of new studies in the field.

Nationwide study of eculizumab in paroxysmal nocturnal hemoglobinuria: Evaluation of treatment indications and outcomes

Eculizumab is an effective treatment for paroxysmal nocturnal hemoglobinuria (PNH). However, considering the risk of life-threatening meningococcal disease, life-long duration and costs, there are strict criteria for initiation of therapy. To evaluate the application and real-world effectiveness of eculizumab in the Netherlands, a multicenter retrospective cohort study was conducted: indications and treatment outcomes were collected for 105 Dutch PNH patients. In all patients, eculizumab was initiated conforming to indications as formulated in the Dutch PNH guideline. According to recently published response criteria, 23.4% of the patients had reached a complete hematological response, 53.2% a good or partial response, and 23.4% a minor response after 12 months of therapy. In the majority of patients the response remained stable during long-term follow-up. The degree and relevance of extravascular hemolysis significantly differed between response groups (p = 0.002). Improvements of EORTC-QLQc30 and FACIT-fatigue scores were observed, however patients reported lower scores than the general population. A detailed evaluation of 18 pregnancies during eculizumab showed no maternal or fetal deaths, and no thromboembolic events during pregnancy. This study demonstrates that the majority of patients benefit from eculizumab when adhering to the indications as formulated in the Dutch PNH guideline. However, novel therapies are needed to further improve real-world outcomes, such as hematological responses and quality of life.

Biomarkers and laboratory assessments for monitoring the treatment of patients with paroxysmal nocturnal hemoglobinuria: Differences between terminal and proximal complement inhibition

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening, acquired disease in which blood cells lacking complement regulatory proteins are destroyed because of uncontrolled complement activity. Since 2007, terminal complement inhibitors have revolutionized the treatment of this disease. However, patients treated with these inhibitors can still experience anemia because of C3-mediated extravascular hemolysis and clinically relevant levels of breakthrough or residual intravascular hemolysis. Proximal complement inhibitors, which are only just beginning to emerge, have the potential to address this problem by targeting components of the pathway upstream of C5, thereby protecting patients against both intra- and extravascular hemolysis. In this review, we describe different biomarkers that can be used to monitor complement pathway blockade and discuss key laboratory assessments for evaluating treatment efficacy. We also consider how these assessments are affected by each class of inhibitor and highlight how evolving treatment goals may influence the relative importance of these assessments.

Rise of the planet of rare anemias: An update on emerging treatment strategies

Therapeutic options for rare congenital (hemoglobinopathies, membrane and enzyme defects, congenital dyserythropoietic anemia) and acquired anemias [warm autoimmune hemolytic anemia (wAIHA), cold agglutinin disease CAD, paroxysmal nocturnal hemoglobinuria (PNH), and aplastic anemia (AA)] are rapidly expanding. The use of luspatercept, mitapivat and etavopivat in beta-thalassemia and pyruvate kinase deficiency (PKD) improves transfusion dependence, alleviating iron overload and long-term complications. Voxelotor, mitapivat, and etavopivat reduce vaso-occlusive crises in sickle cell disease (SCD). Gene therapy represents a fascinating approach, although patient selection, the toxicity of the conditioning regimens, and the possible long-term safety are still open issues. For acquired forms, wAIHA and CAD will soon benefit from targeted therapies beyond rituximab, including B-cell/plasma cell targeting agents (parsaclisib, rilzabrutinib, and isatuximab for wAIHA), complement inhibitors (pegcetacoplan and sutimlimab for CAD, ANX005 for wAIHA with complement activation), and inhibitors of extravascular hemolysis in the reticuloendothelial system (fostamatinib and FcRn inhibitors in wAIHA). PNH treatment is moving from the intravenous anti-C5 eculizumab to its long-term analog ravulizumab, and to subcutaneous and oral proximal inhibitors (anti-C3 pegcetacoplan, factor D and factor B inhibitors danicopan and iptacopan). These drugs have the potential to improve patient convenience and ameliorate residual anemia, although patient compliance becomes pivotal, and long-term safety requires further investigation. Finally, the addition of eltrombopag significantly ameliorated AA outcomes, and data regarding the alternative agent romiplostim are emerging. The accelerated evolution of treatment strategies will need further effort to identify the best candidate for each treatment in the precision medicine era.

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.

The complement alternative pathway in paroxysmal nocturnal hemoglobinuria: From a pathogenic mechanism to a therapeutic target

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal, not malignant, hematological disease characterized by intravascular hemolysis, thrombophilia and bone marrow failure. While this latter presentation is due to a T-cell mediated auto-immune disorder resembling acquired aplastic anemia, the first two clinical presentations are largely driven by the complement pathway. Indeed, PNH is characterized by a broad impairment of complement regulation on affected cells, which is due to the lack of the complement regulators CD55 and CD59. The deficiency of these two proteins from PNH blood cells is due to the somatic mutation in the phosphatidylinositol N-acetylglucosaminyltransferase subunit A gene causing the disease, which impairs the surface expression of all proteins linked via the glycosylphosphatidylinositol anchor. The lack of the complement regulators CD55 and CD59 on PNH erythrocytes accounts for the hallmark of PNH, which is the chronic, complement-mediated intravascular hemolysis. This hemolysis results from the impaired regulation of the alternative pathway upstream in the complement cascade, as well as of the downstream terminal pathway. PNH represented the first indication for the development of anti-complement agents, and the therapeutic interception of the complement cascade at the level of C5 led to remarkable changes in the natural history of the disease. Nevertheless, the clinical use of an inhibitor of the terminal pathway highlighted the broader derangement of complement regulation in PNH, shedding light on the pivotal role of the complement alternative pathway. Here we review the current understanding of the role of the alternative pathway in PNH, including the emergence of C3-mediated extravascular hemolysis in PNH patients on anti-C5 therapies. These observations provide the rationale for the development of novel complement inhibitors for the treatment of PNH. Recent preclinical and clinical data on proximal complement inhibitors intercepting the alternative pathway with the aim of improving the treatment of PNH are discussed, together with their clinical implications which are animating a lively debate in the scientific community.

Protein therapeutics and their lessons: Expect the unexpected when inhibiting the multi-protein cascade of the complement system

Over a century after the discovery of the complement system, the first complement therapeutic was approved for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). It was a long-acting monoclonal antibody (aka 5G1-1, 5G1.1, h5G1.1, and now known as eculizumab) that targets C5, specifically preventing the generation of C5a, a potent anaphylatoxin, and C5b, the first step in the eventual formation of membrane attack complex. The enormous clinical and financial success of eculizumab across four diseases (PNH, atypical hemolytic uremic syndrome (aHUS), myasthenia gravis (MG), and anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD)) has fueled a surge in complement therapeutics, especially targeting diseases with an underlying complement pathophysiology for which anti-C5 therapy is ineffective. Intensive research has also uncovered challenges that arise from C5 blockade. For example, PNH patients can still face extravascular hemolysis or pharmacodynamic breakthrough of complement suppression during complement-amplifying conditions. These "side" effects of a stoichiometric inhibitor like eculizumab were unexpected and are incompatible with some of our accepted knowledge of the complement cascade. And they are not unique to C5 inhibition. Indeed, "exceptions" to the rules of complement biology abound and have led to unprecedented and surprising insights. In this review, we will describe initial, present and future aspects of protein inhibitors of the complement cascade, highlighting unexpected findings that are redefining some of the mechanistic foundations upon which the complement cascade is organized.

The burden of illness of patients with paroxysmal nocturnal haemoglobinuria receiving C5 inhibitors: clinical outcomes and medical encounters from the patient perspective

OBJECTIVES

To assess the clinical and healthcare resource burden among C5 inhibitor (C5i)-treated patients with paroxysmal nocturnal haemoglobinuria (PNH), using patient-reported data.

METHODS

This web-based, cross-sectional survey (01FEB2021-31MAR2021) of adults with PNH treated with eculizumab (France, Germany, UK) or ravulizumab (Germany) included: patient characteristics; treatment patterns/dosage; haematological outcomes (haemoglobin [Hb] levels, transfusions, thrombotic events, breakthrough haemolysis); and medical encounters. Treatment and Hb-level subgroup differences were assessed with statistical significance tests.

RESULTS

Among 71 patients, 98.6% were C5i-treated for ≥3 months. The majority (with reported Hb levels) had levels ≤12.0 g/dL (85.7%; n = 54/63). The mean Hb level was 10.2 g/dL (standard deviation [SD]: 2.0; median 10.0 g/dL). Treatment with above label-recommended doses was reported by 30.4% (eculizumab) and 5.3% (ravulizumab) of patients. Within the past 12 months among patients treated with C5i for ≥1 year: 24.1% had ≥1 transfusion; 3.2% had ≥1 thrombosis; and 28.6% had ≥1 breakthrough haemolysis. Among all patients, 26.8% and 31.0% reported emergency department/room [ER] and inpatient visits, respectively. Mean annual, per-patient all-cause medical encounters were: 0.5 (ER); 1.9 (inpatient); and overall outpatient visits ranged by setting from 2.0 to 6.4. Most encounters were PNH-related, with means of 0.4 (ER); 1.8 (inpatient); and 1.6-5.4 (outpatient). Primary haematological and medical encounter outcomes were similar between treatment as well as Hb-level subgroups, with almost no statistically significant differences.

CONCLUSIONS

Despite at least 3 months of C5i treatment, high proportions of patients with PNH reported low haemoglobin levels and required transfusions and hospitalizations, which suggests remaining unmet needs.

Novel Complement C5 Small-interfering RNA Lipid Nanoparticle Prolongs Graft Survival in a Hypersensitized Rat Kidney Transplant Model

BACKGROUND

Prophylaxis of antibody-mediated rejection (AMR) caused by donor-specific antibodies remains challenging. Given the critical roles of complement activity in antibody-mediated graft injury, we developed a lipid nanoparticle (LNP) formulation of small-interfering RNA against complement C5 (C5 siRNA-LNP) and investigated whether C5 siRNA-LNP could downregulate the complement activity and act as an effective treatment for AMR.

METHODS

Lewis recipient rats were sensitized by skin grafting from Brown Norway donor rats. Kidney transplantation was performed at 4 wk post-skin grafting.C5 siRNA- or control siRNA-LNP was administered intravenously, and the weekly injections were continued until the study's conclusion. Cyclosporin (CsA) and/or deoxyspergualin (DSG) were used as adjunctive immunosuppressants. Complement activity was evaluated using hemolysis assays. The deposition of C5b9 in the grafts was evaluated using immunohistochemical analysis on day 7 posttransplantation.

RESULTS

C5 siRNA-LNP completely suppressed C5 expression and complement activity (hemolytic activity ≤ 20%) 7 d postadministration. C5 siRNA-LNP in combination with CsA and DSG (median survival time: 56.0 d) prolonged graft survival compared with control siRNA-LNP in combination with CsA and DSG (median survival time: 21.0 d; P = 0.0012; log-rank test). Immunohistochemical analysis of the grafts revealed that downregulation of C5 expression was associated with a reduction in C5b9-positive area ( P = 0.0141, Steel-Dwass test).

CONCLUSIONS

C5 siRNA-LNP combined with immunosuppressants CsA and DSG downregulated C5 activity and significantly prolonged graft survival compared with control siRNA-LNP with CsA and DSG. Downregulation of C5 expression using C5 siRNA-LNP may be an effective therapeutic approach for AMR.

Aplastic anemia and paroxysmal nocturnal hemoglobinuria in children and adults in two centers of Northern Greece

Bone marrow failure (BMF) syndromes are a group of various hematological diseases with cytopenia as a main common characteristic. Given their rarity and continuous progress in the field, we aim to provide data considering the efficiency and safety of the therapeutic methods, focusing on the treatment of aplastic anemia(AA) and paroxysmal nocturnal hemoglobinuria (PNH). We enrolled consecutive patients diagnosed with BMF in two referral centers of Northern Greece from 2008 to 2020. We studied 43 patients with AA (37 adults and 6 children/adolescents) and 6 with classical PNH. Regarding classical PNH, 4 patients have received eculizumab treatment with 1/4 presenting extravascular hemolysis. Among 43 patients with aplastic anemia, PNH clones were detected in 11. Regarding patients that did not receive alloHCT (n=15), 14/15 were treated with ATG and cyclosporine as first line, with the addition of eltrombopag in patients treated after its approval (n=9). With a median follow-up of 16.7 (1.8-56.2) months from diagnosis, 12/14 (85.7%) are alive (4-year OS: 85.1%). AlloHCT was performed in 28 patients. Five patients developed TA-TMA which did not resolve in 3/5 (all with a pre-transplant PNH clone). With the follow-up among survivors reaching 86.3 (6.3-262.4) months, 10-year OS was 56.9%, independently associated with PNH clones after adjusting for age (p=0.024). In conclusion, our real-world experience confirms that novel treatments are changing the field of BMF syndromes. Nevertheless, there is still an unmet need to personalize algorithms in this field.

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

BACKGROUND

In the PEGASUS trial, the complement C3 inhibitor, pegcetacoplan, showed superiority to eculizumab in improving haematological outcomes in adult patients with paroxysmal nocturnal haemoglobinuria and suboptimal response to eculizumab at 16 weeks. The aim of the open-label period was to evaluate the long-term efficacy and safety of pegcetacoplan through to 48 weeks.

METHODS

PEGASUS was a phase 3, randomised, open-label, active-comparator controlled trial conducted in 44 centres in Australia, Belgium, Canada, France, Germany, Japan, Russia, South Korea, Spain, the UK, and the USA. Eligible participants were aged 18 years or older, had paroxysmal nocturnal haemoglobinuria, and had a haemoglobin concentration of less than 10·50 g/dL after 3 months or longer of stable eculizumab treatment. After a 4-week run-in with eculizumab plus pegcetacoplan, patients were randomly assigned (1:1) by interactive response technology to pegcetacoplan (1080 mg subcutaneously twice weekly) or eculizumab (according to their regimen at enrolment) for 16 weeks and could continue to the open-label period (32 weeks of pegcetacoplan monotherapy [pegcetacoplan-to-pegcetacoplan] or 28 weeks of pegcetacoplan monotherapy [eculizumab-to-pegcetacoplan]). Randomisation was stratified by platelet count and number of previous blood transfusions. The primary endpoint was change from baseline in haemoglobin at week 16, which has previously been reported. The outcomes of the open-label period (week 16 to week 48) are reported here. At 48 weeks, efficacy (including mean haemoglobin concentration and quality of life measured on the Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue scale) was assessed in the intention-to-treat population and safety was assessed per protocol. This trial was registered with ClinicalTrials.gov, NCT03500549, and has been completed.

FINDINGS

Between June 14, 2018, and Nov 14, 2019, 80 patients were randomly assigned to receive treatment with pegcetacoplan (41 patients) or eculizumab (39 patients). Most participants were women (49 [61%]) and 31 (39%) were men; 12 (15%) were Asian, two (3%) were Black, 49 (61%) were White, and 17 (21%) were another race or did not report their race. The open-label period had 77 participants (38 pegcetacoplan-to-pegcetacoplan, 39 eculizumab-to-pegcetacoplan). Patients in the pegcetacoplan-to-pegcetacoplan group maintained high mean haemoglobin concentrations between 16 weeks (11·54 g/dL [SD 1·96]) and 48 weeks (11·30 g/dL [1·77]; p=0·14). Patients in the eculizumab-to-pegcetacoplan group had significantly greater mean haemoglobin concentrations at 48 weeks (11·57 g/dL [2·21]) versus 16 weeks (8·58 g/dL [0·96]; p<0·0001). Clinically meaningful improvements in FACIT-Fatigue scores were observed at 48 weeks, with a mean change from baseline for all patients receiving pegcetacoplan monotherapy of 9·89 points (SD 9·63), for patients in the pegcetacoplan-to-pegcetacoplan group mean 10·14 points (9·06), and for patients in the eculizumab-to-pegcetacoplan group mean 9·62 points (10·34). During the entire study period, 13 (16%) of 80 patients discontinued treatment (three [7%] of 41 through to week 16 due to breakthrough haemolysis, and ten [13%] of 77 due to severe treatment-emergent adverse events) and 18 patients (eight pegcetacoplan-to-pegcetacoplan, ten eculizumab-to-pegcetacoplan) had at least one serious treatment-emergent adverse event during the open-label period, four were considered to be related to pegcetacoplan treatment. The most common treatment-emergent adverse events (in ≥10% patients) among both pegcetacoplan-treated groups during the open-label period were injection site reactions (in 20 [26%] of 77 patients), haemolysis (15 [19%]), nasopharyngitis (12 [16%]), and diarrhoea (ten [13%]). No treatment-related deaths occurred throughout the duration of the study.

INTERPRETATION

The durability of improved haematological outcomes and favourable safety profile over 48 weeks of treatment suggests that pegcetacoplan has the potential to improve treatment benefit and alter treatment goals in patients with paroxysmal nocturnal haemoglobinuria.

FUNDING

Apellis Pharmaceuticals.