[Expert consensus on clonal screening and monitoring of complement inhibitor therapy in paroxysmal nocturnal hemoglobinuria (2024)].

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal disease with abnormal hematopoietic stem cells that causes intravascular hemolytic anemia, thrombosis, and peripheral blood cytopenia. It has a chronic progressive course and can be fatal in severe cases if not treated aggressively. Complement inhibitors are the first-line recommended treatment for hemolysis-related symptoms of PNH. With the rapid development of new complement inhibitors, it is critical to quickly screen and confirm the diagnosis, identify patients with complement inhibitor indications, and monitor breakthrough hemolysis and extravascular hemolysis during complement inhibitor therapy. Drawing on the most recent guidelines, works of literature, and meta-reviews from around the world, as well as combining with experience from the experts, this consensus focused on PNH screening principles, the significance of PNH cloning detection, and post-treatment monitoring of terminal complement inhibitors, which may contribute to a better understanding of diagnosis and treatment monitoring in the era of complement inhibitors.

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.).

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

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

Patient acceptability of intravitreal complement inhibitors in geographic atrophy (GA): protocol for a UK-based cross-sectional study.

INTRODUCTION: Geographic atrophy (GA) is the advanced form of the non-neovascular ('dry') type of age-related macular degeneration (AMD). Previously untreatable, complement inhibitors delivered by regular intravitreal injections have recently been demonstrated to slow down the progression of GA lesions in phase 3 trials. One such treatment, Syfovre (pegcetacoplan), was approved by the US Food and Drug Administration in February 2023. These therapies slow down, but do not stop or reverse, the progression of GA; they may also increase the risk of developing the neovascular ('wet') type of AMD. In light of these developments, this study aims to quantify the acceptability of these new intravitreal injection treatments to patients with GA in the UK and explore factors that may influence the acceptability of these treatments. METHODS AND ANALYSIS: In this cross-sectional, non-interventional study, the primary objective is to determine the proportion of patients with GA that find regular intravitreal therapy acceptable for slowing the progression of GA. We will use a validated acceptability questionnaire in order to quantify the acceptability of new treatments among patients with GA. The correlation between acceptability and functional and structural biomarkers of GA will be established. We will also explore demographic, general health and ocular factors that may influence acceptability. 180 individuals with a diagnosis of GA will be recruited from 7 to 8 participating National Health Service trusts across the UK. Multiple regression analysis will be conducted to determine the simultaneous effects of multiple factors on patient acceptability. ETHICS AND DISSEMINATION: The study received ethical approval from the Health Research Authority on 14 March 2023 (IRAS Project ID: 324854). Findings will be disseminated through peer-reviewed publications and conference presentations to the medical retina community, as well as through dialogue with patients and macular disease charities.

Novel uses of complement inhibitors in myasthenia gravis-Two case reports.

INTRODUCTION/AIMS: Myasthenia gravis (MG) is a rare, life-threatening immune-related adverse effect (irAE) of immune checkpoint inhibitor (ICI) treatment. C5-complement inhibitors are effective treatments for acetylcholine receptor antibody (AChR ab) positive generalized MG. We describe the use of eculizumab/ravulizumab in two patients with MG receiving concomitant pembrolizumab. METHODS: This was a retrospective review of two medical records. RESULTS: Patient 1: An 80-year-old male with recurrent, non-muscle invasive transitional cell carcinoma of the bladder developed ICI-induced AChR ab positive MG (ICI-MG), myositis, and myocarditis 2 weeks after the first dose of pembrolizumab. Myositis responded to corticosteroids. MG responded to eculizumab, followed by ravulizumab. He died of metastatic cancer 8 months later. Patient 2: A 58-year-old male had refractory thymoma-associated AChR ab-positive MG, which responded to eculizumab. He developed metastatic Merkel cell cancer necessitating pembrolizumab. MG remained stable on eculizumab. He had no irAEs for 22 months, with positron emission tomographic resolution of cancer. He then developed mild, indolent retinal vasculitis, which responded to prednisone. Discontinuation of pembrolizumab for 5 months resulted in cancer recurrence; pembrolizumab was resumed with peri-infusion pulse prednisone. MG remained stable and he continues eculizumab. DISCUSSION: In the first patient, eculizumab, followed by ravulizumab, improved ICI-MG. In the second patient, eculizumab treatment may have had a prophylactic effect on the development of ICI-induced irAEs. The effect of complement inhibition on cancer outcomes of ICI therapy is unknown. A possible biologic basis for complement inhibitors in reducing irAEs of ICI, especially in the presence of underlying autoimmune disease, merits evaluation.

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

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

Predictors for improvement in patient-reported outcomes: post hoc analysis of a phase 3 randomized, open-label study of eculizumab and ravulizumab in complement inhibitor-naive patients with paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by uncontrolled terminal complement activation leading to intravascular hemolysis (IVH), thrombosis, and impairments in quality of life (QoL). The aim of this study was to identify the clinical drivers of improvement in patient-reported outcomes (PROs) in patients with PNH receiving the complement component 5 (C5) inhibitors eculizumab and ravulizumab.This post hoc analysis assessed clinical outcomes and PROs from 246 complement inhibitor-naive patients with PNH enrolled in a phase 3 randomized non-inferiority study that compared the C5 inhibitors ravulizumab and eculizumab (study 301; NCT02946463). The variables of interest were lactate dehydrogenase (LDH) levels, a surrogate measure of IVH, and hemoglobin (Hb) levels. PROs were collected using Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) to assess fatigue and QoL, respectively.Improvements in absolute mean LDH levels were significantly associated with improvements in mean FACIT-F score (p = 0.0024) and EORTC QLQ-C30 global health (GH) score (p < 0.0001) from baseline to day 183. Improvements in scores were achieved despite a non-significant increase in Hb levels. To understand the interaction between LDH and Hb, a regression analysis was performed: LDH response with Hb improvements was a significant predictor of improvement in fatigue. The independent effect of improved Hb did not significantly affect FACIT-F or EORTC QLQ-C30 GH scores.These findings suggest that LDH levels are an important determinant of fatigue and QoL outcomes in patients with PNH. CTR: NCT02946463, October 27, 2016.

Dosing Patterns of Patients with Paroxysmal Nocturnal Hemoglobinuria Treated with Ravulizumab in the United States: A Retrospective Claims-Based Analysis.

INTRODUCTION: Complement factor 5 inhibitors eculizumab and, recently, ravulizumab are standard therapies for paroxysmal nocturnal hemoglobinuria (PNH). However, some patients experience suboptimal response and may benefit from dosage adjustments. Ravulizumab is administered less frequently than eculizumab on the basis of patient's body weight. This retrospective analysis of insurance claims investigated ravulizumab dosing patterns among patients with PNH from the USA. METHODS: Patients aged ≥ 12 years with ≥ 2 ravulizumab infusions between June 21, 2019 and May 6, 2021, and ≥ 6 months of continuous clinical activity prior to first ravulizumab infusion (index date) were identified from the Symphony Health Integrated Dataverse (IDV®) database. Observed mean (standard deviation, SD) ravulizumab doses administered were reported and stratified by previous eculizumab use. Scenarios adjusting for patients' body weights (unavailable in Symphony Health IDV) based on the US general population distribution were performed to estimate percentages of patients receiving label-recommended doses. RESULTS: Among 433 patients (mean [SD] age 47 [17] years), the mean (SD) loading dose was 3316.3 (2931.7) mg, greater than the maximal label-recommended loading dose (3000 mg for patients ≥ 100 kg). The mean (SD) loading doses were 3581.3 (3673.7) mg for eculizumab-naive versus 3093.1 (2096.8) mg for eculizumab-experienced patients. Over a mean (SD) treatment period of 11.8 (6.9) months, the mean (SD) average maintenance dose was 3403.7 (1024.4) mg, falling between label-recommended maintenance dose categories (3300 mg for ≥ 60 to < 100 kg; 3600 mg for ≥ 100 kg). Estimated percentages of patients receiving label-recommended loading and maintenance doses were 23.1% and 39.2%, respectively; 59.1% and 28.4% were estimated to receive above label-recommended loading and average maintenance doses, respectively. CONCLUSION: Although limited by missing clinical characteristics including body weight, this study of ravulizumab dosing patterns in patients with PNH identified potential deviations from label-recommended dosing, warranting further investigations of treatment response to complement inhibitors in PNH.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disease. Complement factor 5 (C5) inhibitors can help treat PNH symptoms; health care providers administer C5 inhibitors to patients during clinic or office visits. Eculizumab was the first C5 inhibitor approved for PNH. Some patients still experience symptoms with approved eculizumab doses and may need to receive larger or more frequent doses than recommended. The new C5 inhibitor ravulizumab offers reduced dosing frequency and is dosed on the basis of patients' body weights. This study assessed ravulizumab doses administered to patients with PNH in the USA using insurance claim records. Studied patients were 12 years or older and received two or more ravulizumab doses between June 21, 2019 and May 6, 2021. Researchers assessed ravulizumab doses administered to patients on the basis of body weight distribution of the US general population. The average first (loading) ravulizumab dose administered to 433 patients was 3316 mg. This was above the largest recommended loading dose of 3300 mg for patients weighing 100 kg (220 pounds) or more. Over nearly 12 months on average, the average maintenance dose administered was 3403 mg. Researchers estimated that larger loading doses than recommended were administered to almost 6 out of 10 patients and larger maintenance doses than recommended were administered to almost 3 out of 10 patients. This study found that larger than recommended ravulizumab doses may have been administered to some patients with PNH. More studies are needed to evaluate treatment response to complement inhibitors in patients with PNH.

Compassionate Use Narsoplimab for Severe Refractory Transplantation-Associated Thrombotic Microangiopathy in Children.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a common and potentially severe complication of hematopoietic cell transplantation. TA-TMA-directed therapy with eculizumab, a complement C5 inhibitor, has resulted in a survival benefit in some studies. However, children with TA-TMA refractory to C5 inhibition with eculizumab (rTA-TMA) have mortality rates exceeding 80%, and there are no other known therapies. Narsoplimab, an inhibitor of the MASP-2 effector enzyme of the lectin pathway, has been studied in adults with TA-TMA as first-line therapy with a response rate of 61%. Although there are limited data on narsoplimab use as a second-line agent in children, we hypothesized, that complement pathways proximal to C5 are activated in rTA-TMA, and that narsoplimab may ameliorate rTA-TMA in children. In this single-center study, children were enrolled on single-patient, Institutional Review Board-approved compassionate use protocols for narsoplimab treatment. Clinical complement lab tests were obtained at the discretion of the treating physician, although all patients were also offered participation in a companion biomarker study. Research blood samples were obtained at the time of TA-TMA diagnosis, prior to eculizumab treatment, at the time of refractory TA-TMA diagnosis prior to the first narsoplimab dose, and 2 weeks after the first narsoplimab dose. Single ELISA kits were used to measure markers of complement activation according to the manufacture's instructions. Five children with rTA-TMA received narsoplimab; 3 were in multiorgan failure and 2 had worsening multiorgan dysfunction at the time of treatment. Additional comorbidities at the time of treatment included sinusoidal obstructive syndrome (SOS; n = 3), viral infection (n = 3), and steroid-refractory stage 4 lower gut grade IV acute graft-versus-host disease (aGVHD, n = 3). Two infants with concurrent SOS and no aGVHD had resolution of organ dysfunction; 1 also developed transfusion-independence (complete response), and the other's hematologic response was not assessable in the setting of leukemia and chemotherapy (partial response). One additional patient achieved transfusion independence but had no improvement in organ manifestations (partial response), and 2 patients treated late in the course of disease had no response. Narsoplimab was well tolerated without any attributed adverse effects. Three patients consented to provide additional research blood samples. One patient with resolution of organ failure demonstrated evidence of proximal pathway activation prior to narsoplimab treatment with subsequent declines in Ba, Bb, C3a, and C5a and increases in C3 in both clinical and research lab tests. Otherwise, there was no clear pattern of other complement markers, including MASP-2 levels, after therapy. In this cohort of ill children with rTA-TMA and multiple comorbidities, 3 patients benefited from narsoplimab. Notably, the 2 patients with resolution of organ involvement did not have steroid-refractory aGVHD, which is thought to be a critical driver of TA-TMA. Additional studies are needed to determine which patients are most likely to benefit from narsoplimab and which markers may be most helpful for monitoring lectin pathway activation and inhibition.

Non-capsulated Neisseria meningitidis sepsis in a paroxysmal nocturnal hemoglobinuria patient treated with ravulizumab: case report and review of the literature.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired haematopoietic stem cell disease characterized by complement-mediated intravascular hemolysis, thrombosis, and bone marrow failure. Eculizumab and ravulizumab are anti-C5 monoclonal antibodies that reduce hemolysis, anaemia and thrombotic risk, but are associated with increased risk of infection with encapsulated bacteria, including Neisseria meningitidis. We report a case of life-threatening infection by non-groupable Neisseria meningitidis in a young PNH patient treated with ravulizumab. Despite prompt admission to the intensive care unit, microbe isolation was delayed due to the negativity of capsular antigens, and the patient required intubation, dialysis, and transfusion support for pancytopenia. Notably, PNH disease activity remained controlled and no additional anti-C5 doses were administered. Increasing awareness regarding septic risk in PNH patients on complement inhibitors despite vaccinations is pivotal. A warning about serotypes generally not pathogenetic and not covered by vaccination, such as non-capsulated forms, is emerging.

Antibody based therapeutics for autoimmune hemolytic anemia.

INTRODUCTION: Autoimmune hemolytic anemia (AIHA) treatment has been revolutionized by the introduction of target therapies, mainly monoclonal antibodies (MoAbs). AREAS COVERED: The anti-CD20 rituximab, which targets Ab production by B-cells, induces 80% of response in warm-type AIHA (wAIHA) and 50-60% in cold agglutinin disease (CAD). Other B-cell targeting MoAbs including ianalumab, povetacicept, and obexelimab are under active study. The anti-CD38 MoAb daratumumab has been used in several reports to target long-lived plasma-cells responsible for AIHA relapse, being effective even in multi-refractory cases. Anti-complement MoAbs will soon change the treatment paradigm in CAD; the anti-C1s sutimlimab rapidly increased Hb in more than 80% of the cases. Finally, MoAbs inhibiting the neonatal Fc receptor (FcRn), such as nipocalimab, can reduce the half-life of the pathogenic autoAbs, representing a promising treatment for wAIHA. EXPERT OPINION: MoAbs offer the potential to improve efficacy by reducing toxicity. However, there is a huge need for clinical trials exploring response duration rather than short-term efficacy. Complement inhibitors and anti-FcRns do not abrogate autoAb production and are being developed as long-term therapies. Thus, the combination of B-cell/plasma cell targeting drugs deserves to be explored. On the other hand, their rapid efficacy should be exploited for the acute AIHA phase.

Prevalence of geographic atrophy in Nordic countries and number of patients potentially eligible for intravitreal complement inhibitor treatment: A systematic review with meta-analyses and forecasting study.

We systematically reviewed the literature on the prevalence of geographic atrophy (GA) in Nordic populations, conducted meta-analyses on age-stratified estimates, and calculated current and future number of patients and those potentially eligible for intravitreal complement inhibitor treatment. We followed the PRISMA guidelines, and our protocol was registered in PROSPERO. Ten databases were searched on 22 April 2023 for population-based studies of GA prevalence. Based on clinical descriptive analyses of GA and eligibility criteria of the phase III studies for intravitreal pegcetacoplan (complement C3 and C3b inhibitor), we were able to calculate the proportion of patients with GA potentially eligible for therapy. Finally, we extracted population data for Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) from Eurostat, applied prevalence statistics to the extracted census and forecasting data to estimate the number of patients with GA, and then applied the proportion eligible for intravitreal pegcetacoplan therapy. We identified six studies with a total of 10 159 individuals. Prevalence of GA was estimated to 0.4% (95% confidence intervals [CI]: 0.2%-0.8%), 1.5% (95% CI: 0.7%-2.6%), and 7.6% (95% CI: 4.6%-11.3%) for individuals aged 60-69, 70-79, and 80+ years, respectively. In Nordic countries, we estimate a total of 166 307 individuals with GA in 2023, increasing to 277 893 in 2050. Of these, 90 803 individuals in 2023, increasing to 151 730 in 2050, are potentially eligible for intravitreal complement inhibitor treatment. Considering these large numbers, our study highlights the importance of this topic in the coming years and its potential to significantly impact our clinical practice, organization, and staffing.

Role of complement in humoral immunity.

PURPOSE OF REVIEW: Antibody-mediated rejection (AMR) after solid organ transplantation remains an unsolved problem and leads to poor early and late patient outcomes. The complement system is a well recognized pathogenic mediator of AMR. Herein, we review the known molecular mechanisms of disease and results from ongoing clinical testing of complement inhibitors after solid organ transplant. RECENT FINDINGS: Activation and regulation of the complement cascade is critical not only for the terminal effector function of donor-specific antibodies, but also for the regulation of T and B cell subsets to generate the antidonor humoral response. Donor-specific antibodies (DSA) have heterogenous features, as are their interactions with the complement system. Clinical testing of complement inhibitors in transplant patients have shown good safety profiles but mixed efficacy to date. SUMMARY: The complement cascade is a critical mediator of AMR and clinical trials have shown early promising results. With the steady emergence of novel complement inhibitors and our greater understanding of the molecular mechanisms linking complement and AMR, there is greater optimism now for new prognostic and therapeutic tools to deploy in transplant patients with AMR.

Implications of Complement Imbalance in COVID-19: A Molecular Mechanistic Discussion on the Importance of Complement Balance.

Two central questions in COVID-19 treatment which should be considered are: "How does the imbalance of the complement system affect the therapeutic approaches?" and "Do we consider complement inhibitors in therapeutic protocols?". The complement system is a double-edged sword since it may either promote immune responses against COVID-19 or contribute to destructive inflammation in the host. Therefore, it is crucial to regulate this system with complement inhibitors. In this manuscript, we discuss the molecular mechanisms of complement and complement inhibitors in COVID-19 patients. We searched the terms "COVID-19", "Complement", "Complement inhibitor", "SARS-CoV-2", and all complement fragments and inhibitors from 2000 to 2022 in PubMed and google scholar and checked the pathways in "KEGG pathway database". Complement is not well-appreciated in the treatment protocols despite its multiple roles in the disease, and most of the preventive anti-inflammatory therapeutic approaches did not include a complement inhibitor in COVID-19 therapeutic protocols. In this review article, we discussed the most recent studies regarding complement components mediated interventions and the mechanism of these interventions in COVID-19 patients. Since the control of the complement system overactivation is associated with a better prognosis in the initial stages of COVID-19, heparin, anti-thrombin, C1-inhibitor, montelukast, and hydralazine can be effective in the initial stages of this viral infection. Recombinant complement activation (RCA) proteins are more effective in regulating complement compared to terminal pathway therapeutic approaches such as the C3a and C5a inhibitors.

[Novel anti-complement therapeutics for hemolytic anemia].

The anti-C5 antibody eculizumab was approved in 2007 as the first anti-complement agent for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). While eculizumab's indication has been expanded to include other diseases, the development of new anti-complement agents has been aggressively pursued for various diseases. In PNH, the anti-C5 recycling antibody ravulizumab, which is an improved version of eculizumab, has been developed, with an extended dosing interval of 2 to 8 weeks, vastly improving convenience. The treatment of PNH with terminal complement inhibitors such as eculizumab and ravulizumab presents a new challenge-extravascular hemolysis. To address this issue, the proximal complement inhibitor, a C3 inhibitor called pegcetacoplan, was approved in the United States of America. Furthermore, the amplification loop inhibitors-a factor B inhibitor iptacopan, and a factor D inhibitor danicopan-are being developed. Recently, the anti-C1s antibody sutimlimab was approved for the treatment of cold agglutinin disease, a type of autoimmune hemolytic anemia. This article discusses novel anti-complement therapies for hemolytic anemia.

Treatment preference and quality of life impact: ravulizumab vs eculizumab for atypical hemolytic uremic syndrome.

Aim: Ravulizumab and eculizumab are complement C5 inhibitors approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Ravulizumab requires less frequent infusions than eculizumab, which may reduce treatment burden. This study investigated patients' treatment preferences and the impact of both treatments on patient and caregiver quality of life. Materials & methods: Two surveys were conducted (one for adult patients with aHUS and one for caregivers of pediatric patients with aHUS) to quantitatively assess treatment preference and the patient- and caregiver-reported impact of ravulizumab and eculizumab on quality of life. Patients were required to have a diagnosis of aHUS, to be currently receiving treatment with ravulizumab and to have received prior treatment with eculizumab. Participants were recruited via various sources: the Alexion OneSource™ patient support program, the Rare Patient Voice recruitment agency, the aHUS Foundation and directly via a clinician involved in the study. Results: In total, 50 adult patients (mean age: 46.5 years) and 16 caregivers of pediatric patients (mean age: 10.1 years) completed the surveys. Most adult patients (94.0%) and all caregivers reported an overall preference for ravulizumab over eculizumab; infusion frequency was one of the main factors for patients when selecting their preferred treatment. Fewer patients reported disruption to daily life and the ability to go to work/school due to ravulizumab infusion frequency (4.0% and 5.7%, respectively) than eculizumab infusion frequency (72.0% and 60.0%), with similar results for caregivers. Conclusion: Adult patients and caregivers of pediatric patients indicated an overall preference for ravulizumab than eculizumab for the treatment of aHUS, driven primarily by infusion frequency. This study contributes to the emerging real-world evidence on the treatment impact and preference in patients with aHUS.

The Effect of Respiratory Viral Infections on Breakthrough Hemolysis in Patients with Paroxysmal Nocturnal Hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by hemolysis and thrombosis and is associated with significant morbidity and mortality. Although complement inhibitors have significantly changed the outcomes in PNH patients, breakthrough hemolysis (BTH) may still occur as a response to stress factors such as pregnancy, surgery, and infections. Despite the well-described association between bacterial infections and hemolysis in PNH patients, little is known about the effect of respiratory viruses on triggering hemolytic episodes. This is the first study, to our knowledge, addressing this question. We retrospectively analyzed 34 patients with PNH disease between 2016 and 2018, who were on eculizumab treatment and who presented with respiratory symptoms and were subsequently tested for 10 respiratory viruses (influenza A, influenza B, parainfluenza, respiratory syncytial virus, adenovirus, rhinovirus, and human metapneumovirus). NTS+ patients had higher inflammatory markers, with the majority requiring antibiotics. Acute hemolysis, along with a significant drop in hemoglobin, was noted in the NTS+ group, with three of them requiring a top-up transfusion and two requiring an extra dose of eculizumab. Furthermore, the time from the last eculizumab dose was longer in the NTS+ patients who had BTH, than those who did not. Our data indicate that respiratory virus infections pose a significant risk for BTH in PNH patients on complement inhibitor treatment, underlining the need for regular screening and close monitoring of patients with respiratory symptoms. Furthermore, it implies a higher risk for patients who are not established on complement inhibitors, suggesting the necessity for greater vigilance in these patients.