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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

Contains fulltext : 282508.pdf (Publisher’s version ) (Open Access) OBJECTIVES: The complement component 5 (C5) inhibitor ravulizumab demonstrated non-inferiority to eculizumab following 26 weeks of treatment in complement inhibitor-naïve and complement inhibitor-experienced patients with paroxysmal nocturnal hemoglobinuria (PNH; studies 301 and 302, respectively). This study aims to describe the results of both studies from 27 weeks to 2 years. METHODS: Patients (N = 441) continued to receive ravulizumab throughout the extension period. Efficacy endpoints included lactate dehydrogenase (LDH) normalization, transfusion avoidance and fatigue score (FACIT-F). Safety analyses were also performed. RESULTS: From 27 weeks to 2 years, improvements in LDH levels were maintained in both study populations. Transfusion avoidance was maintained in 81.9% (study 301) and 85.6% (study 302) of patients, and FACIT-F scores remained stable. Ravulizumab was well tolerated, and the incidence of adverse events (AEs) were similar between patients of both studies. Incidence of serious AEs deemed related to ravulizumab treatment was low (

What is this summary about? Eculizumab and ravulizumab are approved treatments for paroxysmal nocturnal hemoglobinuria (PNH), a rare blood disease which can cause potentially fatal complications if left untreated. Long-term ravulizumab treatment in patients with PNH is under investigation in two ongoing studies (‘301’ and ‘302’). This article describes the results at 2 years for both studies. What were the results? Ravulizumab continued to manage most patients' symptoms and less than 3% of patients experienced serious side effects related to treatment during this time. What do the results mean? This article highlights why eculizumab and ravulizumab are the usual treatments for PNH, where available. Long-term, ravulizumab controlled patients' PNH disease activity with few side-effects related to treatment. Clinical Trial Registration: Study 301: NCT02946463 Study 302: NCT03056040

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder, characterized by complement-mediated intravascular hemolysis and thrombosis. The increased incidence of PNH-driven thrombosis is still poorly understood, but unlike other thrombotic disorders, is thought to largely occur through complement-mediated mechanisms. Treatment with a C5 inhibitor, eculizumab, has been shown to significantly reduce the number of thromboembolic events in these patients. Based on previously described links between changes in fibrin clot structure and thrombosis in other disorders, our aim was to investigate clot structure as a possible mechanism of thrombosis in patients with PNH and the anti-thrombotic effects of eculizumab treatment on clot structure. Clot structure, fibrinogen levels and thrombin generation were examined in plasma samples from 82 patients from the National PNH Service in Leeds, UK. Untreated PNH patients were found to have increased levels of fibrinogen and thrombin generation, with subsequent prothrombotic changes in clot structure. No link was found between increasing disease severity and fibrinogen levels, thrombin generation, clot formation or structure. However, eculizumab treated patients showed decreased fibrinogen levels, thrombin generation and clot density, with increasing time spent on treatment augmenting these antithrombotic effects. These data suggest that PNH patients have a prothrombotic clot phenotype due to increased fibrinogen levels and thrombin generation, and that the antithrombotic effects of eculizumab are, in-part, due to reductions in fibrinogen and thrombin generation with downstream effects on clot structure.

Objectives A retrospective population-based study to determine the incidence and prevalence of patients with the rare blood disease paroxysmal nocturnal haemoglobinuria (PNH). Methods All patients were identified by flow cytometric detection of blood cells deficient in glycosylphosphatidylinositol (GPI) linked proteins at a single diagnostic reference laboratory that serves the Yorkshire based, Haematological Malignancy Research Network (HMRN) with a population of 3.8 million. Results One hundred and ninety-seven patients with detectable PNH clones at a level of >0.01% in at least two lineages of cells (neutrophils, monocytes and/or red cells) were identified over a 15-year period (2004-2018). Of these, 88% had aplastic anaemia (AA), 8% classical PNH and 3% myelodysplastic syndrome. The overall incidence rate was estimated at 0.35 cases per 100 000 people per year. This equates to 220 cases newly diagnosed in the United Kingdom each year. The overall prevalence rate was 3.81 per 100 000, this equates to an estimated 2400 prevalent cases in the UK. The overall and relative 5-year survival rates were 72% and 82.7%, respectively. Conclusions This study showed that classical haemolytic PNH is a rare disease and represents only a small proportion overall of patients with detectable PNH cells, the majority of which have aplastic anaemia.

Background Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired disease characterized by chronic complement-mediated hemolysis. C5 inhibition controls intravascular hemolysis in untreated PNH but cannot address extravascular hemolysis. Pegcetacoplan, a pegylated peptide targeting proximal complement protein C3, potentially inhibits both intravascular and extravascular hemolysis. Methods We conducted a phase 3 open-label, controlled trial to assess the efficacy and safety of pegcetacoplan as compared with eculizumab in adults with PNH and hemoglobin levels lower than 10.5 g per deciliter despite eculizumab therapy. After a 4-week run-in phase in which all patients received pegcetacoplan plus eculizumab, we randomly assigned patients to subcutaneous pegcetacoplan monotherapy (41 patients) or intravenous eculizumab (39 patients). The primary end point was the mean change in hemoglobin level from baseline to week 16. Additional clinical and hematologic markers of hemolysis and safety were assessed. Results Pegcetacoplan was superior to eculizumab with respect to the change in hemoglobin level from baseline to week 16, with an adjusted (least squares) mean difference of 3.84 g per deciliter (P Conclusions Pegcetacoplan was superior to eculizumab in improving hemoglobin and clinical and hematologic outcomes in patients with PNH by providing broad hemolysis control, including control of intravascular and extravascular hemolysis. (Funded by Apellis Pharmaceuticals; PEGASUS ClinicalTrials.gov, NCT03500549. opens in new tab.)

Context: Pegcetacoplan (PEG) is a C3 complement inhibitor recently approved by the FDA for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). PEG was superior to eculizumab (ECU; C5-inhibitor) in improving hemoglobin levels at week 16 during the phase 3 PEGASUS trial (NCT03500549) in patients with suboptimal response to prior ECU treatment. Objective: We report on efficacy and safety of PEG and results from a post hoc time-aligned analysis based on start of PEG dosing. Design: Eighty PNH patients (≥18 years, hemoglobin levels Results: PEG-to-PEG patients achieved sustained improvements in hemoglobin levels at week 16 through the OLP (week 48 mean hemoglobin level: 11.3 g/dL; CFB: 2.5 g/dL). ECU-to-PEG patients displayed improved hemoglobin levels during the OLP (week 48 mean hemoglobin level: 11.6 g/dL; CFB: 2.9 g/dL). Timepoint alignment demonstrated no significant difference (p=0.64) between improvements in hemoglobin levels at 28 and 48 weeks among PEG-to-PEG and ECU-to-PEG groups, respectively. Thirty percent of patients reported a serious AE, 6% possibly PEG-related. Common AEs for PEG-treated patients were injection site reactions (36%), hemolysis (24%), and diarrhea (21%). Twelve patients (15%) discontinued PEG due to AEs: 3 in RCP, 8 in OLP, 1 during follow-up, including one death due to COVID-19, unrelated to PEG. Conclusions: PEG-treated patients experienced sustained improvements in hemoglobin levels at week 48, and the safety profile of PEG was consistent with previously reported data. The treatment effect of PEG on hemoglobin levels over time was similar between PEG-to-PEG and ECU-to-PEG groups. Thus, PEG represents a new effective therapeutic option for PNH patients.

Background Eculizumab, the first C5 inhibitor approved for paroxysmal nocturnal hemoglobinuria (PNH), transformed PNH treatment by improving survival to that of an age- and sex- matched general population. Previous analyses demonstrating the survival benefit of eculizumab in patients with PNH leveraged historical data and were limited by small patient numbers and short follow-up durations; few evaluated survival of patients receiving eculizumab compared with untreated patients. The objective of the current analysis was to describe the baseline characteristics and overall survival of a large international cohort of eculizumab-treated patients compared with a contemporaneous untreated cohort using data from the prospective, observational International PNH Registry (NCT01374360). Methods Data from patients enrolled in the Registry after March 16, 2007 with complete information for birth date, sex, enrollment date, and treatment status were included (database cut-off, April 12, 2021). Ever-treated patients were those who received eculizumab for a minimum treatment period of 35 days while enrolled in the Registry; never-treated patients did not receive eculizumab at any time before or during Registry participation. Univariate and multivariate analyses were performed using a Cox proportional hazards that incorporated the following parameters at baseline as covariates: treatment status, presence of high disease activity (HDA), age, sex, history of bone marrow failure (BMF), history of thrombotic events (TE), transfusion dependence, and estimated glomerular filtration rate ≤60 mL/min/1.73 m 2. HDA was defined as lactate dehydrogenase (LDH) ratio ≥1.5 × upper limit of normal (ULN) and ≥1 of the following: history of major adverse vascular events (including TE); anemia (hemoglobin Results Baseline characteristics of the 4627 patients included in the analysis (mean [SD] age at disease start, 40.2 [18.71] years; 53% female; 75% white) were comparable between the ever-treated and never-treated groups (n=1892 and n=2735, respectively). Compared with never-treated patients, more ever-treated patients had LDH ≥1.5 × ULN (90% vs 35%), and fewer had Conclusion In this analysis of Registry data, treatment with the C5 inhibitor eculizumab improved patient survival compared with a never-treated cohort at a comparable time point in their disease course. Covariates were assessed at baseline only and competing risks and time on treatment were not controlled for, which are potential limitations. Survival benefits conferred by eculizumab treatment were observed regardless of HDA status at baseline, were more pronounced in treated patients with HDA vs those without HDA, and were maintained through 2 decades of real-world follow-up. Figure 1 Figure 1. Disclosures Terriou: Alexion, AstraZeneca Rare Disease: Consultancy, Membership on an entity's Board of Directors or advisory committees. Patriquin: Alexion, AstraZeneca Rare Disease: Consultancy, Honoraria, Speakers Bureau; Biocryst: Honoraria; Apellis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria. Griffin: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees; BioCryst Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sobi Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Apellis: Other: Educational grant support. Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gustovic: Alexion, AstraZeneca Rare Disease: Current Employment. Patel: Alexion, AstraZeneca Rare Disease: Current Employment. Szer: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Prevail Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

INTRODUCTION Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic disease characterized by chronic complement-mediated intravascular and extravascular hemolysis. In the phase 3 PEGASUS study (NCT03500549), pegcetacoplan, a C3 inhibitor targeting the proximal complement pathway, was superior to eculizumab (ECU) on the primary endpoint of hemoglobin (Hb) change from baseline at week 16, and improved clinical and hematologic parameters. Additional analyses assessed if any groups of patients might experience further benefit from pegcetacoplan. METHODS Patients ≥18 years old with a diagnosis of PNH and persistent anemia (Hb RESULTS Pegcetacoplan treatment was associated with significantly greater increases in Hb levels than ECU at week 16, regardless of baseline age group, sex, race, prior transfusions, or platelet count (Tables 1-2). At week 16, regardless of baseline platelet count strata, mean Hb significantly increased from baseline in the pegcetacoplan group and decreased in the ECU group. The proportion of transfusion-free patients was similar in the pegcetacoplan group, regardless of age (≤65 years, 87.1%; >65 years, 80%), sex (female, 81.5%; male, 92.9%), race (Asian, 100%; black, 100%; white, 75.0%), transfusion strata (65 years, 0%), sex (female, 18.2%; male, 11.8%), race (Asian, 28.6%; black, 0%; white, 16.0%), transfusion strata ( CONCLUSIONS In this prespecified stratified analysis of the phase 3 PEGASUS study of patients with PNH and persistent anemia, mean Hb levels increased significantly more, the proportion of transfusion-free patients was significantly higher, ARC change from baseline at week 16 was significantly lower, and LDH decreases were larger with pegcetacoplan versus ECU, regardless of baseline age group, sex, race, prior transfusion numbers, and platelet count. Disclosures Peffault De Latour: Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Research Funding; Apellis: Membership on an entity's Board of Directors or advisory committees. de Castro:Alexion: Honoraria, Research Funding; Apellis: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Other: Steering committee; Biocryst: Honoraria, Other: Data monitoring committee. Szer:Apellis: Consultancy; Pfizer: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Prevail Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees. Usuki:Alexion: Research Funding, Speakers Bureau; Apellis: Research Funding; Chugai: Research Funding; Novartis: Research Funding, Speakers Bureau. Hillmen:Alexion: Consultancy, Research Funding, Speakers Bureau; Apellis: Consultancy, Research Funding, Speakers Bureau; Gilead: Other: Financial or material support, Research Funding; AstraZeneca: Consultancy, Speakers Bureau; Roche: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Pharmacyclics: Other: Financial or material support, Research Funding; Janssen: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Acerta: Other: Financial or material support. Griffin:Alexion Pharmaceuticals: Honoraria, Other: Conference Support; Biocryst: Membership on an entity's Board of Directors or advisory committees. Hamdani:Apellis Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Ajayi:Apellis Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Weitz:Alexion: Consultancy, Honoraria, Speakers Bureau; Apellis: Consultancy, Honoraria. OffLabel Disclosure: Pegcetacoplan is an investigational drug for the treatment of paroxysmal nocturnal hemoglobinuria.

Eculizumab, the monoclonal antibody targeting C5, is the only licensed treatment for Paroxysmal Nocturnal Hemoglobinuria (PNH) in the UK. Inherent to the mechanism of action, C5 inhibitors increase patient susceptibility to encapsulated microorganisms, particularly Neisseria meningitidis. The PNH National service (UK), has 18 years of experience treating patients with PNH using complement inhibition. The risk of N. meningitidis is mitigated by vaccination, ciprofloxacin (500 mg bd) on days 1-13 since we moved to vaccination on day one of complement inhibitor therapy, followed by daily prophylaxis with penicillin (or erythromycin). Since a case of sepsis with penicillin-resistant meningococci was observed, patients also have a rescue course ciprofloxacin. Patient education, safety cards, prompt action in case of fever and a 24 hour on-call service for patients are equally important. Until 2010 patients were revaccinated with MenACWY every 3 years. Bexsero (MenB vaccine) vaccination (2 vaccines within first 6 months) with boosters every 5 years was added in 2015. In collaboration with the Public Health England Meningococcal Reference Unit in 2010 a program was developed to monitor antibody titers after vaccination and to revaccinate against MenACWY if titers declined to below protective levels. It is technically not possible to assay for meningoccal serogroup B antibody titers when on Eculizumab therapy. We present the outcome of this project. Methods: Antibody titers to serogroups ACWY were assayed following vaccination and then once per annum. Patients with unprotective antibody titers were revaccinated. We evaluate our practice and review the 9 meningococcal infections in 8 patients. We present disease characteristics, serogroup and outcome, vaccination history and antibody status. Results: Between May 2002 and July 2020, 324 patients commenced complement inhibitor treatment for PNH. 801 vaccinations with MenACWY were administered; median 2 vaccinations per patient (range 1 - 10). A total of 1,671 antibody titer assessments were conducted in 294 patients, median of 4 tests per patient (range 1 - 15). Every test assessed antibodies against all four serogroups. Titers were not assessed in 9% of patients (30), due to vaccination prior to change in practice or recent commencement on treatment. A protective antibody response to all serogroups after first vaccination was observed in 170 / 294 patients (57.8%) and a partial response (antibodies to 3 serotypes) in 51 /294 (17.3%). Revaccination of 51 partial responders resulted in an additional 21 patients with a full response. Revaccination of 73 non-responders (antibodies to 0-2 serotypes) resulted in 32 more partial or full responses. 287 of 324 patients received MenB vaccinations; median 2 vaccinations per patient (range 1 - 4). Eight of 324 (2%) patients with median age 22.5 years developed meningococcal sepsis (see table); patient 5 had 2 episodes. 3 of 5 cases with serogroup B infection were before serogroup B vaccination was introduced. The other 4 episodes in 3 patients were due to Y, C, W meningococci, in one the serogroup is unknown. All except patient 1 were compliant with antibiotic prophylaxis. Patient 7 died from meningococcemia, a delay in seeking medical attention may have contributed, however this was also a penicillin resistant strain. Discussion: We report the largest experience of managing meningococcal risk in patients on complement inhibitor therapy for PNH. Despite our proactive management we had 9 cases of meningococcal sepsis, with one fatal infection. Our most recently introduced practice of prompt treatment with ciprofloxacin if pyrexic on antibiotic prophylaxis will prevent cases like patient 7 with a penicillin resistant strain. Three patients had a meningococci sepsis with serogroups C, W and Y; whilst 1 patient had no check of titers due to recent commencement on treatment, the titres of the other 2 had suggested protective immunity. We demonstrated that a full antibody response can be obtained on a second vaccination in most patients if the first one failed. If no response is achieved upfront or revaccination then further MenACWY vaccination is not likely to be successful. Current practice significantly mitigates the risk of meningococcal disease, however it is essential patients remain vigilant for fever, seeking immediate medical attention stating their diagnosis of PNH on complement inhibitor therapy. Disclosures Arnold: Alexion Pharmaceuticals: Honoraria. Borrow:Pfizer: Research Funding; GlaxoSmithKline: Research Funding; Alexion pharmacueticals: Research Funding; Sanofi: Research Funding. Riley:Alexion: Honoraria. Munir:Alexion: Honoraria; F. Hoffmann-La Roche: Consultancy, Other: Medical writing support, furnished by Scott Battle, PhD, of Health Interactions, was funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland. Kelly:Alexion: Honoraria. Pike:Apellis: Research Funding. Hillmen:Acerta: Other: Financial or material support; Roche: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Pharmacyclics: Other: Financial or material support, Research Funding; Janssen: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Gilead: Other: Financial or material support, Research Funding; Alexion: Consultancy, Research Funding, Speakers Bureau; Apellis: Consultancy, Research Funding, Speakers Bureau. Griffin:Alexion Pharmaceuticals: Honoraria, Other: Conference Support; Biocryst: Membership on an entity's Board of Directors or advisory committees.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hemolytic and thrombotic condition. Patients can experience severe anemia due to intravascular hemolysis, thrombotic events, renal impairment and pulmonary hypertension. Symptomatic patients are treated with complement inhibitors either in clinical trials or with eculizumab the only licensed treatment in the UK. Due to the mechanism of action of eculizumab, it increases susceptibility to Neisseria infection, including Neisseria meningitidis. To reduce this risk of infection, worldwide practice is for patients to be vaccinated at least 2 weeks prior to receiving eculizumab (serogroups A, C, Y, W 135 and B). It was noted within the PNH National Service at Leeds (UK) that a small number of patients deteriorated with enhanced intravascular hemolysis and thrombosis during the period between vaccination and eculizumab, leading to a review of practice. We report five of 121 patients with events in the intervening 2 weeks between vaccination and commencement of eculizumab from 2002-2012:A 44 year female presented with hemolysis and hemoglobinuria, with a granulocyte PNH clone of 99.4%. She was transfusion dependent and on anticoagulation. She consented to the PNH pilot eculizumab study, undergoing meningococcal vaccination as per protocol. Twenty two days later, she suffered an ischemic stroke with left hemiplegia and permanent weakness, resulting in exclusion from the study. Two years later she received eculizumab in the TRIUMPH study.A 37 year male presented with hemoglobinuria and fatigue with a granulocyte PNH clone of 99.58%. He had significant hemolysis, managed initially with warfarin and blood transfusions. He consented to start eculizumab and received meningococcal vaccination. 4 days later he presented with a symptomatic right hepatic vein thrombosis, promptly commenced eculizumab.A 29 year male, with abdominal pain and hemoglobinuria for 3 years developed a stroke and portal vein thrombosis leading to a diagnosis of PNH, with a granulocyte PNH clone of 84.99%. He commenced anticoagulation. Four months after the stroke he received meningococcal vaccination in preparation for scheduled commencement with eculizumab. He experienced a left central retinal vein thrombosis 15 days after its administration prior to starting eculizumab.A 47 year old male, was diagnosed with haemolytic PNH but only had mild symptoms and anaemia. Twenty four years later, he developed increasing hemolysis and symptoms; granulocyte PNH clone of 96.45%. Eculizumab was planned and he received meningococcal vaccination, but presented ten days later with acute renal failure secondary to massive intravascular haemolysis, necessitating emergency eculizumab therapy.A 35 year female, with a granulocyte PNH clone of 99.87%. Although she had active intravascular hemolysis, eculizumab was declined, and anticoagulation commenced. Four years later she consented to start eculizumab, receiving meningococcal vaccination. She was admitted 24 hours later with a stroke and commenced eculizumab the same day, but has persistent neurological impairment to date. See Table 1 Discussion: The close time proximity of these serious events to the patients' vaccinations raised concern that the complement system was being activated by administration of the vaccine, precipitating complications of PNH. It is also concerning that 4 of the 5 patients experienced thrombotic events despite therapeutic anticoagulation, confirming that anticoagulation only partially mitigates the risk of thrombosis in patients with PNH. The decision was taken to administer the vaccination immediately after the first dose of eculizumab, with therapeutic doses of antibiotic (ciprofloxacin 500mg bd) for the first 14 days post vaccination, followed by long term meningococcal prophylaxis (penicillin V or erythromycin 500mg bd) whilst receiving a complement inhibitor. Since this change in practice in 2012 we have commenced eculizumab therapy in 211 patients with no similar complications as described. Thus the change in practice appears to reduce the occurrence of these severe complications associated with vaccinations prior to initiating anti-complement therapy. Whilst it is possible these events could have been caused by the underlying condition of PNH, we would advise colleagues to also adopt a change in practice to reduce potentially significant complications. Disclosures Arnold: Alexion Pharmaceuticals: Honoraria. Kelly:Alexion: Honoraria. Munir:F. Hoffmann-La Roche: Consultancy, Other: Medical writing support, furnished by Scott Battle, PhD, of Health Interactions, was funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland; Alexion: Honoraria. Pike:Apellis: Research Funding. Riley:Alexion: Honoraria. Griffin:Alexion Pharmaceuticals: Honoraria, Other: Conference Support; Biocryst: Membership on an entity's Board of Directors or advisory committees. Hillmen:Acerta: Other: Financial or material support; Roche: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Pharmacyclics: Other: Financial or material support, Research Funding; Janssen: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Apellis: Consultancy, Research Funding, Speakers Bureau; Alexion: Consultancy, Research Funding, Speakers Bureau; Gilead: Other: Financial or material support, Research Funding.

Background Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare acquired disorder characterised by intravascular hemolysis and thrombosis. Patients with symptomatic PNH are commenced on the complement inhibitor eculizumab (600mg weekly for 5 weeks then 900mg 2 weekly). This monoclonal antibody targets C5 in the complement cascade, halting terminal complement activation thus inhibiting intravascular hemolysis. In some patients intravascular hemolysis is not adequately controlled on the standard regimen. Patient symptoms, transfusion requirements and raised Lactate dehydrogenase (LDH) levels are indicators for suboptimal control of PNH and review of eculizumab dosing. The 50% hemolytic complement (CH50) test is a functional assay assessing capability of serum complement components of the classical pathway to lyse sheep red blood cells pre-coated with rabbit anti-sheep red blood cell antibody. Patients with complement inhibited PNH should demonstrate absent lysis. As the test is expensive and difficult to organise, we tested if incomplete complete blockade as determined by CH50 activity would be better to confirm under-dosing than LDH value. Methods The Leeds (UK) PNH National Service reviewed patients who underwent CH50 assay between January 2015 and March 2020. All patients were on eculizumab with clinical concerns regarding suboptimal control of PNH. Patients receive eculizumab infusions intravenously every 14 days and routine follow up from the PNH Service. Serum samples were obtained 24 hours prior to infusions for CH50 assay; LDH values were routinely collected. Complete complement blockade was defined by 1.5x upper limit of normal (ULN). Confidence intervals were set at 95% and significance set at p Results In the study period, 327 tests (median 2, range 1 - 8) were carried out in 146 patients (median age 54 years, range 16 - 89; 74 female). 81% (265) were successful; 19% (62) were unsuccessful due to processing errors. Of the successful tests, 74% (197 in 127 patients) indicated complete complement blockade and 26% (68 in 38 patients) indicated incomplete blockade. Of the patients with incomplete blockade, 68% (26) demonstrated complete blockade on repeat testing and 32% (12) had their eculizumab dose increased. Clinical symptoms of under-dosing in the 12 patients requiring a dose increase included increased transfusion requirements and/or breakthrough hemolysis (7), pregnancy (2; both returned to 900mg post pregnancy) and significant lethargy (3). Of the patients requiring a dose increase, 3 were on 1200mg before 2015; their dose was increased to 1500mg. Repeat testing was carried out in 10/12 patients after dose increase; 8 indicated complete blockade; 2 patients were incompletely blocked at 1200mg and received a further dose increase to 1500mg. Further testing indicated complete blockade in 1 patient; 1 required a 3rd dose increase to 1800mg due to incomplete blockade and ongoing transfusion requirement. Corresponding LDH values were analysed; median LDH for the complete blockade group was 1.16xULN (range 0.54 - 2.16) and 1.28xULN (range 0.76 - 2.38) for the incomplete blockade group. LDH values were not significantly higher in the incomplete blockade group compared to the complete blockade group, p=0.08. There was no significant difference in LDH values pre- and post-dose increase, p=0.38 (Figure 1); median pre-dose increase LDH 1.14xULN; median post-dose increase LDH 1.13xULN. Correlation coefficient shows that CH50 activity was positively correlated with LDH value, r(123)=0.18, p=0.04. Conclusion We report the effective utilisation of CH50 analysis where there is clinical concern of suboptimal control of PNH. All patients demonstrating hemolytic activity on CH50 assays indicated subsequent complement blockade following increase of eculizumab dose. Increasing eculizumab is costly requiring robust evidence of suboptimal complement inhibition; a positive correlation between CH50 activity and LDH values was shown however this is not sufficient to guide clinical decisions. LDH values of the incomplete blockade group were not significantly higher than those with complete blockade, suggesting the use of LDH values as an assessment of complement inhibition in patients with ongoing symptoms or transfusion requirements is not sufficient to guide eculizumab dose increases. Disclosures Munir: Alexion: Honoraria; F. Hoffmann-La Roche: Consultancy, Other: Medical writing support, furnished by Scott Battle, PhD, of Health Interactions, was funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland. Pike:Apellis: Research Funding. Arnold:Alexion Pharmaceuticals: Honoraria. Hillmen:AstraZeneca: Consultancy, Speakers Bureau; Alexion: Consultancy, Research Funding, Speakers Bureau; Acerta: Other: Financial or material support; Roche: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Pharmacyclics: Other: Financial or material support, Research Funding; Janssen: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Apellis: Consultancy, Research Funding, Speakers Bureau; Gilead: Other: Financial or material support, Research Funding. Griffin:Alexion Pharmaceuticals: Honoraria, Other: Conference Support; Biocryst: Membership on an entity's Board of Directors or advisory committees.

BACKGROUND In paroxysmal nocturnal hemoglobinuria (PNH), intravascular hemolysis (IVH) is mediated by the membrane attack complex, while extravascular hemolysis (EVH) is facilitated by C3 opsonization. Although eculizumab (ECU), a C5 inhibitor, inhibits IVH, ~70% of patients remain anemic and 36% require ≥1 transfusion per year due to C3-mediated EVH. Pegcetacoplan (APL-2), a C3 inhibitor, has the potential to control both IVH and EVH in PNH. AIMS PEGASUS, a phase 3, randomized, open-label, controlled trial (NCT03500549), assessed the efficacy and safety of pegcetacoplan compared to ECU in patients with PNH. METHODS Eighty patients aged ≥18 years with a confirmed diagnosis of PNH, hemoglobin levels 1.0 × ULN, platelets >50 × 109/L and neutrophils >0.5 × 109/L were included. All patients provided written informed consent and completed a run-in period of 4 weeks with pegcetacoplan plus ECU before 1:1 randomization to monotherapy with pegcetacoplan (41 patients, 1080 mg subcutaneously twice a week) or ECU (39 patients, continuing current dosing regimen). The primary endpoint was change in hemoglobin level from baseline (start of run-in period) to week 16. Key secondary and secondary endpoints were hemoglobin normalization (defined as hemoglobin level greater than or equal to lower limit of normal range) in the absence of transfusions, transfusion avoidance, absolute reticulocyte counts, lactate dehydrogenase (LDH), Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue score, and adverse events (AEs). Hierarchical significance testing for secondary efficacy endpoints was gated on the success of the primary efficacy endpoint. Post hoc analyses included hemoglobin stabilization (defined as avoidance of a >1 g/dL decrease from baseline) in the absence of transfusions. RESULTS Pegcetacoplan demonstrated superiority to ECU in change in hemoglobin level at week 16, with an adjusted treatment difference of 3.84 g/dL (p CONCLUSIONS In this phase 3 trial in patients with PNH, pegcetacoplan demonstrated superiority to ECU in hemoglobin level, and improved clinical outcomes at week 16 with transfusion avoidance in most patients. The safety profile of pegcetacoplan was comparable to that of ECU. The efficacy of pegcetacoplan validates the prevention of extravascular as well as intravascular hemolysis in PNH, leading to a potential new therapeutic option. Disclosures Hillmen: Acerta: Other: Financial or material support; AbbVie: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Roche: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau; Gilead: Other: Financial or material support, Research Funding; Alexion: Consultancy, Research Funding, Speakers Bureau; Apellis: Consultancy, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Speakers Bureau; Pharmacyclics: Other: Financial or material support, Research Funding; Janssen: Consultancy, Other: Financial or material support, Research Funding, Speakers Bureau. Szer:Prevail Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Apellis: Consultancy; Takeda: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Weitz:Apellis: Consultancy, Honoraria; Alexion: Consultancy, Honoraria, Speakers Bureau. Röth:Biocryst: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Apellis: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Research Funding. Hoechsmann:Alexion: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Apellis: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Panse:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Apellis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Speakers Bureau; Alexion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Membership on an entity's Board of Directors or advisory committees; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees; Grunenthal: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai: Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Blueprint Medicines: Consultancy, Membership on an entity's Board of Directors or advisory committees. Usuki:Apellis: Research Funding; Chugai: Research Funding; Novartis: Research Funding, Speakers Bureau; Alexion: Research Funding, Speakers Bureau. Griffin:Biocryst: Membership on an entity's Board of Directors or advisory committees; Alexion Pharmaceuticals: Honoraria, Other: Conference Support. Kiladjian:Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; AOP Orphan: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. de Castro:Biocryst: Honoraria, Other: Data monitoring committee; Novartis: Honoraria, Other: Steering committee; Alexion: Honoraria, Research Funding; Apellis: Consultancy, Honoraria, Research Funding. Tan:Apellis: Consultancy, Patents & Royalties. Hamdani:Apellis: Current Employment, Current equity holder in publicly-traded company. Deschatelets:Apellis: Current Employment, Current equity holder in private company, Patents & Royalties. Francois:Apellis: Current Employment, Current equity holder in private company, Patents & Royalties. Grossi:Apellis: Current Employment, Current equity holder in private company, Patents & Royalties. Risitano:Jazz: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Samsung: Membership on an entity's Board of Directors or advisory committees; Amyndas: Consultancy; RA pharma: Research Funding; Biocryst: Membership on an entity's Board of Directors or advisory committees; Apellis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Achillion: Membership on an entity's Board of Directors or advisory committees; Pfizer: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Alnylam: Research Funding; Alexion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Peffault De Latour:Apellis: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: Pegcetacoplan is an investigational drug for the treatment of paroxysmal nocturnal hemoglobinuria.

Context Anemia persists in up to 72% of patients with paroxysmal nocturnal hemoglobinuria (PNH) despite the inhibition of C5 with eculizumab. Pegcetacoplan, a C3 inhibitor, has the potential to control both intravascular (IVH) and extravascular hemolysis (EVH). Objective The phase 3, randomized, open-label, controlled PEGASUS trial ( NCT03500549 ) assessed efficacy and safety of pegcetacoplan compared to eculizumab in patients with PNH. Patients, Interventions, Main Outcome Measures Patients aged ≥18 years with PNH and hemoglobin Results Pegcetacoplan demonstrated superiority to eculizumab in change in hemoglobin at week 16, with an adjusted treatment difference of 3.84 g/dL (p Conclusions In this phase 3 trial in patients with PNH and suboptimal response to eculizumab, pegcetacoplan demonstrated superiority to eculizumab in change in hemoglobin level at week 16 with improved clinical outcomes including transfusion avoidance in most patients. The safety profile of pegcetacoplan was comparable to eculizumab.

A retrospective analysis of presentation clinical, laboratory and immunophenotypic features of 1 081 patients with paroxysmal nocturnal haemoglobinuria (PNH) clones [glycosylphosphatidylinositol (GPI)‐deficient blood cells] identified at our hospital by flow cytometry over the past 25 years was undertaken. Three distinct clusters of patients were identified and significant correlations between presentation disease type and PNH clone sizes were evident. Smaller PNH clones predominate in cytopenic and myelodysplastic subtypes; large PNH clones were associated with haemolytic, thrombotic and haemolytic/thrombotic subtypes. Rare cases with an associated chronic myeloproliferative disorder had either large or small PNH clones. Cytopenia was a frequent finding, highlighting bone marrow failure as the major underlying feature associated with the detection of PNH clones in the peripheral blood. Red cell PNH clones showed significant correlations between the presence of type II (partial GPI deficiency) red cells and thrombotic disease. Haemolytic PNH was associated with type III (complete GPI deficiency) red cell populations of >20%. Those with both haemolytic and thrombotic features had major type II and type III red cell populations. Distinct patterns of presentation age decade were evident for clinical subtypes with a peak incidence of haemolytic PNH in the 30–49 year age group and a biphasic age distribution for the cytopenia group.