Effect of eculizumab on hemolysis and transfusion requirements in patients with paroxysmal nocturnal hemoglobinuria

Upregulation of Checkpoint Ligand Programmed Death-Ligand 1 in Patients with Paroxysmal Nocturnal Hemoglobinuria Explained by Proximal Complement Activation

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hemolytic disease driven by impaired complement regulation. Mutations in genes encoding the enzymes that build the GPI anchors are causative, with somatic mutations in the PIG-A gene occurring most frequently. As a result, the important membrane-bound complement regulators CD55 and CD59 are missing on the affected hematopoietic stem cells and their progeny, rendering those cells vulnerable to complement attack. Immune escape mechanisms sparing affected PNH stem cells from removal are suspected in the PNH pathogenesis, but molecular mechanisms have not been elucidated. We hypothesized that exuberant complement activity in PNH results in enhanced immune checkpoint interactions, providing a molecular basis for the potential immune escape in PNH. In a series of PNH patients, we found increased expression levels of the checkpoint ligand programmed death-ligand 1 (PD-L1) on granulocytes and monocytes, as well as in the plasma of PNH patients. Mechanistically, we demonstrate that complement activation leading to the decoration of particles/cells with C3- and/or C4-opsonins increased PD-L1 expression on neutrophils and monocytes as shown for different in vitro models of classical or alternative pathway activation. We further establish in vitro that complement inhibition at the level of C3, but not C5, inhibits the alternative pathway-mediated upregulation of PD-L1 and show by means of soluble PD-L1 that this observation translates into the clinical situation when PNH patients are treated with either C3 or C5 inhibitors. Together, the presented data show that the checkpoint ligand PD-L1 is increased in PNH patients, which correlates with proximal complement activation.

Long-term follow-up of patients with paroxysmal nocturnal hemoglobinuria treated with eculizumab: post-marketing surveillance in Japan

All Japanese patients with paroxysmal nocturnal hemoglobinuria (PNH) treated with eculizumab were enrolled in post-marketing surveillance (PMS) between June 2010 and August 2019 to assess the long-term effectiveness and safety of eculizumab. The reduction in intravascular hemolysis, the change in hemoglobin (Hb) level, and the change in renal function were assessed to determine the effectiveness of eculizumab. The types and frequencies of adverse events (AEs) were assessed to determine its safety. A total of 632 patients were enrolled and the median treatment duration was 3.6 years. Treatment with eculizumab significantly reduced lactate dehydrogenase (LDH) levels and significantly increased Hb levels. These changes were maintained for up to 5 years of treatment. An estimated glomerular filtration rate ≥ 60 ml/min/1.73 m² and higher LDH level at baseline were associated with increases in Hb levels during eculizumab treatment. The overall incidence of any AE was 69.92/100 patient-years. Hemolysis was the most common AE (6.43/100 patient-years). The incidence of infection-related AEs was 20.57/100 patient-years, and included meningococcal infection in three patients (0.12/100 patient-years). This long-term follow-up of patients with PNH demonstrated the sustained effectiveness of eculizumab and supports its well-established safety profile.

Treating Rare Diseases in Africa: The Drugs Exist but the Need Is Unmet

Rare diseases (RD) pose serious challenges in terms of both diagnosis and treatment. Legislation was passed in the US (1983) and in EU (2000) aimed to reverse the previous neglect of RD, by providing incentives for development of “orphan drugs” (OD) for their management. Here we analyse the current situation in Africa with respect to (1) sickle cell disease (SCD), that qualifies as rare in the US and in EU, but is not at all rare in African countries (frequencies up to 1–2%); (2) paroxysmal nocturnal haemoglobinuria (PNH), that is ultra-rare in Africa as everywhere else (estimated <10 per million). SCD can be cured by bone marrow transplantation and recently by gene therapy, but very few African patients have access to these expensive procedures; on the other hand, the disease-ameliorating agent hydroxyurea is not expensive, but still the majority of patients in Africa are not receiving it. For PNH, currently most patients In high income countries are treated with a highly effective OD that costs about $400,000 per year per patient: this is not available in Africa. Thus, the impact of OD legislation has been practically nil in this continent. As members of the medical profession and of the human family, we must aim to remove barriers that are essentially financial: especially since countries with rich economies share a history of having exploited African countries. We call on the Global Fund to supply hydroxyurea for all SCD patients; and we call on companies who produce ODs to donate, for every patient who receives an expensive OD in a high income country, enough of the same drug, at a symbolic price, to treat one patient in Africa.

Emerging drugs for the treatment of paroxysmal nocturnal hemoglobinuria

INTRODUCTION

Eculizumab, the first anti-C5 monoclonal antibody approved for patients with paroxysmal nocturnal hemoglobinuria (PNH), has revolutionized the natural history of this disease, blocking intravascular hemolysis, reducing the risk of thrombo-embolic events, resulting in a significant improvement in survival and quality of life. However, the hematological response to eculizumab is extremely heterogeneous, with only one-third of PNH patients reaching normal hemoglobin levels.

AREAS COVERED

This article reviews the current new drugs being investigated in phase II and III trials for adult PNH patients. Literature search was performed using Medline and Clinicaltrials.org databases.

EXPERT OPINION

The new molecules have been classified according to the target of the complement system on which they act; we have novel terminal complement inhibitors, which target C5, and proximal complement inhibitors, which interfere with C3 or even further upstream (factor B and D). Ravulizumab is the first next-generation C5 inhibitor, approved by FDA and EMA, which reproduced the excellent results achieved with eculizumab, trying to improve the convenience of patients. However, unresolved issues remain, such as C3-mediated extravascular hemolysis, on which novel proximal complement inhibitors are showing their efficacy. Pegcetacoplan is the first C3-inihibitor approved by FDA. Long-term safety data for novel complement inhibitors are needed.

Aptamers: Potential Diagnostic and Therapeutic Agents for Blood Diseases

Aptamers are RNA/DNA oligonucleotide molecules that specifically bind to a targeted complementary molecule. As potential recognition elements with promising diagnostic and therapeutic applications, aptamers, such as monoclonal antibodies, could provide many treatment and diagnostic options for blood diseases. Aptamers present several superior features over antibodies, including a simple in vitro selection and production, ease of modification and conjugation, high stability, and low immunogenicity. Emerging as promising alternatives to antibodies, aptamers could overcome the present limitations of monoclonal antibody therapy to provide novel diagnostic, therapeutic, and preventive treatments for blood diseases. Researchers in several biomedical areas, such as biomarker detection, diagnosis, imaging, and targeted therapy, have widely investigated aptamers, and several aptamers have been developed over the past two decades. One of these is the pegaptanib sodium injection, an aptamer-based therapeutic that functions as an anti-angiogenic medicine, and it is the first aptamer approved by the U.S. Food and Drug Administration (FDA) for therapeutic use. Several other aptamers are now in clinical trials. In this review, we highlight the current state of aptamers in the clinical trial program and introduce some promising aptamers currently in pre-clinical development for blood diseases.

Discovering C3 targeting therapies for paroxysmal nocturnal hemoglobinuria: Achievements and pitfalls

The treatment of paroxysmal nocturnal hemoglobinuria (PNH) was revolutionized by the introduction of the anti-C5 agent eculizumab, which resulted in sustained control of intravascular hemolysis, leading to transfusion avoidance and hemoglobin stabilization in at least half of all patients. Nevertheless, extravascular hemolysis mediated by C3 has emerged as inescapable phenomenon in PNH patients on anti-C5 treatment, frequently limiting its hematological benefit. More than 10 years ago we postulated that therapeutic interception of the complement cascade at the level of C3 should improve the clinical response in PNH. Compstatin is a 13-residue disulfide-bridged peptide binding to both human C3 and C3b, eventually disabling the formation of C3 convertases and thereby preventing complement activation via all three of its activating pathways. Several generations of compstatin analogs have been tested in vitro, and their clinical evaluation has begun in PNH and other complement-mediated diseases. Pegcetacoplan, a pegylated form of the compstatin analog POT-4, has been investigated in two phase I/II and one phase III study in PNH patients. In the phase III study, PNH patients with residual anemia already on eculizumab were randomized to receive either pegcetacoplan or eculizumab in a head-to-head comparison. At week 16, pegcetacoplan was superior to eculizumab in terms of hemoglobin change from baseline (the primary endpoint), as well as in other secondary endpoints tracking intravascular and extravascular hemolysis. Pegcetacoplan showed a good safety profile, even though breakthrough hemolysis emerged as a possible risk requiring additional attention. Here we review all the available data regarding this innovative treatment that has recently been approved for the treatment of PNH.

Predictors of prolonged hospitalisation and mortality among children admitted with blackwater fever in eastern Uganda

Our study aimed at determining clinical factors associated with prolonged hospitalisation and death among children admitted with blackwater fever (BWF). We analysed 920 eligible records for the period January - December 2018 from Mbale and Soroti Regional Referral Hospitals in Eastern Uganda. The median hospitalisation was 3 (IQR: 2-5 days) days. Prolonged hospitalisation was in 251/920 (27.3%). Clinical features independently associated with prolonged hospitalisation included abdominal tenderness, body pain and mild fever. 29/920 (3.2%) died, of these 20 (69.0%) within 48 h of admission. Features of severity associated with mortality were noisy or interrupted breathing, tachypnoea, chest pain, convulsions, delayed capillary refill time (≥3 s), severe pallor, high fever (>38.5°C), altered level of consciousness, prostration and acidotic breathing.

Toward a pathophysiology inspired treatment of VEXAS syndrome

VEXAS syndrome has an unmet need for therapeutic interventions. Even if few data exist regarding the treatment of this newly described syndrome, different options can be proposed given the unique pathophysiological consequences of the clonal dominance of UBA1 mutated hematopoietic stem cells. To date, allogeneic transplantation is the only curative option, but many questions remain regarding the selection of eligible patients, the conditioning regimen or management of toxicities that may be unique to VEXAS patients. Alternatively, drugs used in myelodysplastic syndrome such as hypomethylating agents or lenalidomide are interesting candidates, which could theoretically have also an effect on the clone. Another strategy is to target the inflammatory cascade, by inhibiting proinflammatory cytokines (such as TNFα, IL1, IL6) or effector cells, for example with JAK inhibitors. Whatever the choice of treatment for VEXAS patients, supportive care is always needed to be considered to manage frequent complications such as cytopenia, thrombosis and infections. Finally, we discuss the challenges of the design of clinical trials for VEXAS patients, from inclusion criteria to clinical and biological endpoints of activity.

A Diagnostic Dilemma: Catastrophic or Seronegative Antiphospholipid Syndrome

Catastrophic antiphospholipid syndrome (CAPS) and seronegative APS (SN-APS) are rare and severe variants of antiphospholipid syndrome (APS). Due to the significant morbidity and mortality associated with these variants, early recognition and adequate treatment with immunomodulatory agents and anticoagulation are crucial. Here, we report a rare presentation of seronegative CAPS in a young adult with systemic lupus erythematosus (SLE) who presented with seizures, encephalopathy, and quadriplegia. Brain imaging revealed intracranial hemorrhage and attenuated vessels in the Circle of Willis suggestive of vasculitis. Imaging also revealed bilateral pulmonary emboli involving the main pulmonary, segmental, and subsegmental arteries; lower extremity deep vein thrombosis in the right common femoral vein; and superficial venous thrombi in the left cephalic and basilic veins. Due to the absence of APS seropositivity and the catastrophic nature of her presentation, namely the widespread thrombi formation and multiorgan involvement, there was high suspicion for a diagnosis of seronegative CAPS. After two weeks of high doses of immunomodulatory agents, plasmapheresis, and intravenous immune globulin (IVIG) treatment, the patient showed clinical improvement and a reduced burden of venous thrombi. The predicament of not being able to use anticoagulation in this patient due to cerebral hemorrhage added to the complexity and uniqueness of this case.

Novel Selection Approaches to Identify Antibodies Targeting Neoepitopes on the C5b6 Intermediate Complex to Inhibit Membrane Attack Complex Formation

The terminal pathway of complement is implicated in the pathology of multiple diseases and its inhibition is, therefore, an attractive therapeutic proposition. The practicalities of inhibiting this pathway, however, are challenging, as highlighted by the very few molecules in the clinic. The proteins are highly abundant, and assembly is mediated by high-affinity protein-protein interactions. One strategy is to target neoepitopes that are present transiently and only exist on active or intermediate complexes but not on the abundant native proteins. Here, we describe an antibody discovery campaign that generated neoepitope-specific mAbs against the C5b6 complex, a stable intermediate complex in terminal complement complex assembly. We used a highly diverse yeast-based antibody library of fully human IgGs to screen against soluble C5b6 antigen and successfully identified C5b6 neoepitope-specific antibodies. These antibodies were diverse, showed good binding to C5b6, and inhibited membrane attack complex (MAC) formation in a solution-based assay. However, when tested in a more physiologically relevant membrane-based assay these antibodies failed to inhibit MAC formation. Our data highlight the feasibility of identifying neoepitope binding mAbs, but also the technical challenges associated with the identification of functionally relevant, neoepitope-specific inhibitors of the terminal pathway.

Advancing therapeutic complement inhibition in hematologic diseases: PNH and beyond

Complement is an elaborate system of the innate immunity. Genetic variants and autoantibodies leading to excessive complement activation are implicated in a variety of human diseases. Among them, the hematologic disease paroxysmal nocturnal hemoglobinuria (PNH) remains the prototype model of complement activation and inhibition. Eculizumab, the first-in-class complement inhibitor, was approved for PNH in 2007. Addressing some of the unmet needs, a long-acting C5 inhibitor, ravulizumab, and a C3 inhibitor, pegcetacoplan have been also now approved with PNH. Novel agents, such as factor B and factor D inhibitors, are under study with very promising results. In this era of several approved targeted complement therapeutics, selection of the proper drug needs to be based on a personalized approach. Beyond PNH, complement inhibition has also shown efficacy and safety in cold agglutinin disease (CAD), primarily with the C1s inhibitor of the classical complement pathway, sutimlimab, but also with pegcetacoplan. Furthermore, C5 inhibition with eculizumab and ravulizumab, as well as inhibition of the lectin pathway with narsoplimab, are investigated in transplant-associated thrombotic microangiopathy (TA-TMA). With this revolution of next-generation complement therapeutics, additional hematologic entities, such as delayed hemolytic transfusion reaction (DHTR) or immune thrombocytopenia (ITP), might also benefit from complement inhibitors. Therefore, this review aims to describe state-of-the-art knowledge of targeting complement in hematologic diseases focusing on: a) complement biology for the clinician, b) complement activation and therapeutic inhibition in prototypical complement-mediated hematologic diseases, c) hematologic entities under investigation for complement inhibition, and d) other complement-related disorders of potential interest to hematologists.

Complement and the prothrombotic state

In 2007 and 2009 the regulatory approval of the first-in-class complement inhibitor Eculizumab has revolutionized the clinical management of two rare, life-threatening clinical conditions: paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS). While being completely distinct diseases affecting blood cells and the glomerulus, PNH and aHUS remarkably share several features in their etiology and clinical presentation. An imbalance between complement activation and regulation at host surfaces underlies both diseases precipitating in severe thrombotic events that are largely resistant to anti-coagulant and/or anti-platelet therapies. Inhibition of the common terminal complement pathway by Eculizumab prevents the frequently occurring thrombotic events responsible for the high mortality and morbidity observed in patients not treated with anti-complement therapy. While many in vitro and ex vivo studies elaborate numerous different molecular interactions between complement activation products and hemostasis, this review focuses on the clinical evidence that links these two fields in humans. Several non-infectious conditions with known complement involvement are scrutinized for common patterns concerning a prothrombotic statues and the occurrence of certain complement activation levels. Next to PNH and aHUS, germline encoded CD59 or CD55 deficiency (the latter causing the disease Complement Hyperactivation, Angiopathic thrombosis, and Protein-Losing Enteropathy; CHAPLE), autoimmune hemolytic anemia (AIHA), (catastrophic) anti-phospholipid syndrome (APS, CAPS) and C3 glomerulopathy are considered. Parallels and distinct features among these conditions are discussed against the background of thrombosis, complement activation, and potential complement diagnostic and therapeutic avenues.

Randomized multicenter noninferiority phase III clinical trial of the first biosimilar of eculizumab

Currently, eculizumab is the main effective treatment for paroxysmal nocturnal hemoglobinuria (PNH). The aim of this randomized multicenter noninferiority study was to evaluate the efficacy and safety of the Biosimilar (Elizaria) in comparison with the Originator (Soliris) in patients with PNH. Biosimilar and Originator were administered at a dose of 600 mg weekly for 4 weeks at the initial stage in naive patients, as well as for maintenance therapy at a dose of 900 mg every 2 weeks in all patients. The primary endpoint was a comparative assessment of hemolytic activity based on the area under the lactate dehydrogenase (LDH) concentration–time curve during the maintenance therapy. Thirty-two (32) patients were randomized for therapy with Biosimilar (n = 16) or Originator (n = 16). The mean values of LDH concentration–time curve were similar in both treatment groups without statistically significant differences (p > 0.05). Evaluation of secondary endpoints has shown no statistically significant differences between the groups. Safety values were comparable in both treatment groups. The data obtained confirm that the Biosimilar is not inferior to the Originator in terms of the main efficacy parameter, and is also comparable with it in terms of safety and additional efficacy parameters. Clinicaltrials.gov identifier: NCT04463056

How we('ll) treat paroxysmal nocturnal haemoglobinuria: diving into the future

Paroxysmal nocturnal haemoglobinuria (PNH) is characterized by complement-mediated intravascular haemolysis, severe thrombophilia and bone marrow failure. While for patients with bone marrow failure the treatment follows that of immune-mediated aplastic anaemia, that of classic, haemolytic PNH is based on anti-complement medication. The anti-C5 monoclonal antibody eculizumab has revolutionized treatment, resulting in control of intravascular haemolysis and thromboembolic risk, with improved long-term survival. Novel strategies of complement inhibition are emerging. New anti-C5 agents reproduce the safety and efficacy of eculizumab, with improved patient convenience. Proximal complement inhibitors have been developed to address C3-mediated extra-vascular haemolysis and seem to improve haematological response.

Efficacy and Safety of Eculizumab for Paroxysmal Nocturnal Hemoglobinuria: A Systematic Review and Meta-Analysis

BACKGROUND

Eculizumab is indicated for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). This study aimed to evaluate the efficacy and safety of eculizumab in patients with PNH.

METHODS

PubMed, EMBASE, The Cochrane Library, and ClinicalTrials.gov were searched for prospective interventional studies treating PNH with eculizumab. The primary outcome was the change in lactate dehydrogenase (LDH) levels, whereas secondary outcomes included the change in hemoglobin (Hb) levels, transfusion rates, and adverse drug events.

RESULTS

Patients (n=235) from 6 studies were included in this meta-analysis. LDH and Hb levels and transfusion rates decreased significantly at 12, 26 weeks, 12, 15, and >15 months. The most frequent adverse events included nasopharyngitis (effect size [ES]: 0.53; 95% confidence intervals [CI]: 0.47 to 0.60; P=0.00), headache (ES: 0.47; 95% CI: 0.25 to 0.69; P=0.00), upper respiratory tract infection (ES: 0.37; 95% CI: 0.27 to 0.46; P=0.00), nausea (ES: 0.31; 95% CI: 0.24 to 0.38; P=0.00), fatigue, diarrhea, cough, pyrexia, abdominal pain, pain in extremities, and contusion.

CONCLUSION

Eculizumab is an effective and well-tolerated treatment for patients with PNH. It is effective at decreasing LDH levels and transfusion rates while increasing Hb levels. Further studies are needed to explore the safety of eculizumab.

Phase 2 Study of Danicopan in Paroxysmal Nocturnal Hemoglobinuria Patients with an Inadequate Response to Eculizumab

Danicopan, a first-in-class oral factor D inhibitor showed clinical benefit when given in addition to eculizumab in patients with PNH.

Addition of danicopan reduced extravascular hemolysis and improved anemia in patients with PNH with suboptimal eculizumab response.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by uncontrolled terminal complement activation and subsequent intravascular hemolysis (IVH). C5 inhibitors prevent membrane attack complex formation, but patients may experience extravascular hemolysis (EVH) and continue to require blood transfusions. Danicopan, an oral proximal complement inhibitor of alternative pathway factor D (FD), is designed to control IVH and EVH. In a phase 2 dose-finding trial, eculizumab-treated transfusion-dependent patients with PNH (n = 12) received danicopan, 100 to 200 mg thrice daily, in addition to their eculizumab regimen for 24 weeks. End points included hemoglobin (Hgb) change vs baseline at week 24 (primary), reduction in blood transfusions, and patient-reported outcomes. Safety, tolerability, and pharmacokinetics/pharmacodynamics were measured. Twelve patients received ≥1 danicopan dose; 1 patients discontinued from a serious adverse event deemed unlikely related to danicopan. Eleven patients completed the 24-week treatment period. Addition of danicopan resulted in a mean Hgb increase of 2.4 g/dL at week 24. In the 24 weeks prior to danicopan, 10 patients received 31 transfusions (50 units) compared with 1 transfusion (2 units) in 1 patient during the 24-week treatment period. Mean Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue score increased by 11 points from baseline to week 24. The most common adverse events were headache, cough, and nasopharyngitis. Addition of danicopan, a first-in-class FD inhibitor, led to a meaningful improvement in Hgb and reduced transfusion requirements in patients with PNH who were transfusion-dependent on eculizumab. These benefits were associated with improvement of FACIT-Fatigue. This trial was registered at www.clinicaltrials.gov as #NCT03472885.

Complement inhibition for prevention of antibody-mediated rejection in immunologically high-risk heart allograft recipients

Allosensitization represents a major barrier to heart transplantation (HTx). We assessed the efficacy and safety of complement inhibition at transplant in highly sensitized heart transplant recipients. We performed a single-center, single-arm, open-label trial (NCT02013037). Patients with panel reactive antibodies (PRA) ≥70% and pre-formed donor-specific antibodies (DSA) were eligible. In addition to standard of care, patients received nine infusions of eculizumab during the first 2 months posttransplant. The primary composite endpoint was antibody-mediated rejection (AMR) ≥pAMR2 and/or left ventricular dysfunction during the first year. Secondary endpoints included hemodynamic compromise, allograft rejection, and patient survival. Twenty patients were included. Median cPRA and mean fluorescence intensity of immunodominant DSA were 95% (90%-97%) and 6250 (5000-10 000), respectively. Retrospective B cell and T cell flow crossmatches were positive in 14 and 11 patients, respectively. The primary endpoint occurred in four patients (20%). Survival at 1 year was 90% with no deaths resulting from AMR. In a prespecified analysis comparing treated patients to matched control patients, we observed a dramatic reduction in the risk of biopsy-proven AMR in patients treated with eculizumab (HR = 0.36, 95% CI = 0.14-0.95, p = .032). Our findings support the prophylactic use of complement inhibition for heart transplantation at high immunological risk. ClinincalTrials.gov, NCT02013037.

The Benefits of Complement Measurements for the Clinical Practice

The complement cascade is an evolutionary ancient innate immune defense system, playing a major role in the defense against infections. Its function in maintaining host homeostasis on activated cells has been emphasized by the crucial role of its overactivation in ever growing number of diseases, such as atypical hemolytic uremic syndrome (aHUS), autoimmune diseases as systemic lupus erythematosus (SLE), C3 glomerulopathies (C3GN), age-related macular degeneration (AMD), graft rejection, Alzheimer disease, and cancer, to name just a few. The last decade of research on complement has extended its implication in many pathological processes, offering new insights to potential therapeutic targets and asserting the necessity of reliable, sensitive, specific, accurate, and reproducible biomarkers to decipher complement role in pathology. We need to evaluate accurately which pathway or role should be targeted pharmacologically, and optimize treatment efficacy versus toxicity. This chapter is an introduction to the role of complement in human diseases and the use of complement-related biomarkers in the clinical practice. It is a part of a book intending to give reliable and standardized methods to evaluate complement according to nowadays needs and knowledge.

New Insights Regarding Diagnosis and Medication for Schizophrenia Based on Neuronal Synapse-Microglia Interaction

Schizophrenia is a common psychiatric disorder that usually develops during adolescence and young adulthood. Since genetic and environmental factors are involved in the disease, the molecular status of the pathology of schizophrenia differs across patients. Recent genetic studies have focused on the association between schizophrenia and the immune system, especially microglia–synapse interactions. Microglia physiologically eliminate unnecessary synapses during the developmental period. The overactivation of synaptic pruning by microglia is involved in the pathology of brain disease. This paper focuses on the synaptic pruning function and its molecular machinery and introduces the hypothesis that excessive synaptic pruning plays a role in the development of schizophrenia. Finally, we suggest a strategy for diagnosis and medication based on modulation of the interaction between microglia and synapses. This review provides updated information on the involvement of the immune system in schizophrenia and proposes novel insights regarding diagnostic and therapeutic strategies for this disease.

Komplementinhibitoren: neue Therapeutika – neue Indikationen

Das Komplementsystem, ein klassisch transfusionsmedizinisches Thema, hat in den letzten Jahren in allen Bereichen der Medizin an Bedeutung gewonnen. Komplementinhibitoren werden aufgrund eines besseren Verständnisses der Pathophysiologie unterschiedlicher Erkrankungen in einem sich stetig erweiternden Krankheitsspektrum eingesetzt. Dieses reicht von typisch komplementassoziierten Erkrankungen wie der PNH (paroxysmale nächtliche Hämoglobinurie) bis hin zu akuten Krankheitsbildern mit einer Fehlregulation des Komplementsystems, wie COVID-19.

A Safety Management Case of Laparoscopic Colectomy in a Patient With Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria is a rare and life-threatening disorder of acquired hemolytic anemia. Surgery is one of the major clinical situations that trigger hemolytic attack. Eculizumab is a humanized monoclonal antibody that binds the complement protein C5 and prevents complement-mediated hemolysis via inhibition of the terminal complement cascade. A 76-year-old woman received a diagnosis of ascending colon cancer during the search for the cause of right lower abdominal pain. She had received a diagnosis of paroxysmal nocturnal hemoglobinuria and been followed for 26 years at our hospital. We planned to start eculizumab for perioperative management in order to reduce the risk of the patient developing hemolytic crisis as a result of surgery. We administered 600 mg of eculizumab on the 15th, 8th, and 1st preoperative days. The levels of serum complement and lactate dehydrogenase decreased with the first administration of eculizumab. Laparoscopic right hemicolectomy was performed successfully. The patient had good postoperative progress. We administered 600 mg of eculizumab on the 6th postoperative day and 900 mg of eculizumab on the 13th postoperative day. She was discharged from hospital on the 16th postoperative day. We started use of eculizumab before surgery for safety in the management of the operation and during the perioperative period. When we enforce the elective operation for patients with paroxysmal nocturnal hemoglobinuria who do not start treatment of eculizumab, we recommend the use of eculizumab for perioperative management of patients with paroxysmal nocturnal hemoglobinuria.

Difficult Cases of Paroxysmal Nocturnal Hemoglobinuria: Diagnosis and Therapeutic Novelties

Paroxysmal nocturnal hemoglobinuria (PNH) is an intriguing disease that can pose many difficulties to physicians, as well as to hematologists, who are unfamiliar with it. Research regarding its pathophysiologic, diagnostic, and therapeutic aspects is still ongoing. In the last ten years, new flow cytometry techniques with high sensitivity enabled us to detect PNH clones as small as <1% of a patient's hematopoiesis, resulting in increasing incidence but more difficult data interpretation. Particularly, the clinical significance of small PNH clones in patients with bone marrow failures, including aplastic anemia and myelodysplastic syndromes, as well as in uncommon associations, such as myeloproliferative disorders, is still largely unknown. Besides current treatment with the anti-C5 eculizumab, which reduced PNH-related morbidity and mortality, new complement inhibitors will likely fulfill unmet clinical needs in terms of patients' quality of life and better response rates (i.e., responses in subjects with C5 polymorphisms; reduction of extravascular hemolysis and breakthrough hemolysis episodes). Still, unanswered questions remain for these agents regarding their use in mono- or combination therapy, when to treat, and which drug is the best for which patient. Lastly, long-term safety needs to be assessed in real-life studies. In this review, we describe some clinical vignettes illustrating practical aspects of PNH diagnosis and management; moreover, we discuss recent advances in PNH diagnostic and therapeutic approaches.

Second-Generation C5 Inhibitors for Paroxysmal Nocturnal Hemoglobinuria

The C5 targeting monoclonal antibody eculizumab has changed the natural history of paroxysmal nocturnal hemoglobinuria (PNH) in the last 10 years. However, some unmet clinical needs persist, including persistent anemia with some patients requiring transfusions, incomplete C5 inhibition with breakthrough hemolysis (because of pharmacokinetic or pharmacodynamic issues such as infections, as well as conditions increasing complement activity), the underlying bone marrow failure, and the significant burden on patient quality of life (intravenous route of administration and frequency of infusions). Moreover, a subclass of patients carries C5 polymorphisms resistant to eculizumab inhibition. Several second-generation C5 inhibitors are under active study to overcome unmet clinical needs with eculizumab. Current strategies encompass increasing drug half-life, developing small molecule inhibitors of C5, and exploring new routes of administration (including subcutaneous and oral agents). In this review, we summarize available data on second-generation C5 inhibitors in PNH, including novel monoclonal antibodies, a small interfering RNA, and small molecules.

Complement as a Therapeutic Target in Systemic Autoimmune Diseases

The complement system (CS) includes more than 50 proteins and its main function is to recognize and protect against foreign or damaged molecular components. Other homeostatic functions of CS are the elimination of apoptotic debris, neurological development, and the control of adaptive immune responses. Pathological activation plays prominent roles in the pathogenesis of most autoimmune diseases such as systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, dermatomyositis, and ANCA-associated vasculitis. In this review, we will review the main rheumatologic autoimmune processes in which complement plays a pathogenic role and its potential relevance as a therapeutic target.

One-year outcomes from a phase 3 randomized trial of ravulizumab in adults with paroxysmal nocturnal hemoglobinuria who received prior eculizumab

Ravulizumab every 8 weeks showed non‐inferiority to eculizumab every 2 weeks in a 26‐week, phase 3, randomized controlled trial in adults with paroxysmal nocturnal hemoglobinuria (PNH) who were clinically stable on eculizumab (NCT03056040). We report results from the first 26 weeks of the extension period in which patients continued ravulizumab (n = 96) or switched from eculizumab to ravulizumab (n = 95). At week 52, mean (SD) lactate dehydrogenase levels increased 8.8% (29%) with ravulizumab‐ravulizumab and 5.8% (27%) with eculizumab‐ravulizumab from primary evaluation period baseline. During the extension period, four patients (ravulizumab‐ravulizumab, n = 3; eculizumab‐ravulizumab, n = 1) experienced breakthrough hemolysis, but none associated with serum free C5 ≥ 0.5 μg/mL. Mean Functional Assessment of Chronic Illness Therapy (FACIT)‐Fatigue scores remained stable through week 52. During the extension period, proportions of patients avoiding transfusion remained stable (ravulizumab‐ravulizumab, 86.5%; eculizumab‐ravulizumab, 83.2%); 81.2% and 81.1%, respectively, had stabilized hemoglobin. All patients maintained serum free C5 levels < 0.5 μg/mL. Adverse events were generally similar between groups, and rates were lower in the extension period. Adults with PNH on stable eculizumab therapy who received ravulizumab over 52 weeks experienced durable efficacy, with consistent efficacy in patients who received eculizumab during the primary evaluation period and then switched to ravulizumab. Ravulizumab was well tolerated.

Eculizumab for pediatric dense deposit disease: A case report and literature review

Dense deposit disease (DDD), a subtype of complement component 3 (C3) glomerulopathy (C3G), results from alternative complement pathway hyperactivity leading to membrane attack complex formation. DDD treatment strategies are limited. We report a case of a 13-year-old girl diagnosed with DDD at 9 years of age, with nephritic and nephrotic syndrome and C3 nephritic factor-negative alternative complement pathway activation. Initial treatment with prednisolone, methylprednisolone pulses (MPs), and mizoribines was effective for 3 years, after which she relapsed. Despite MP treatment followed by prednisolone and mycophenolate mofetil (MMF), her kidney function and proteinuria deteriorated with a high soluble (s)C5b-9 level; she also developed dyspnea and pleural effusion (PE). Three days after the first eculizumab (ECZ) infusion, urine volume increased, respiratory condition improved, PE resolved, and proteinuria decreased in 1 month. Serum creatinine level decreased, and kidney function completely normalized within 7 weeks. The sC5b-9 level normalized, and although proteinuria decreased, nephrotic range proteinuria persisted during ECZ treatment with MMF for 53 weeks, even with increased treatment interval. Thus, complement activation pathway-targeted therapy may be useful for rapidly progressing DDD. Our data support the role of complement pathway abnormalities in C3G with DDD.

Safety of current treatments for paroxysmal nocturnal hemoglobinuria

Introduction: Eculizumab, which is indicated to treat patients with paroxysmal nocturnal hemoglobinuria (PNH), is proven to decrease intravascular hemolysis and thrombosis and improve survival. Ravulizumab is a long-acting, second-generation complement component 5 (C5) inhibitor designed to alleviate the burden of the eculizumab treatment schedule and reduce the frequency of breakthrough hemolysis. As the clinical benefits of these treatments have been emphasized, their safety also should be considered. Areas covered: This article reviews safety data for the current approved PNH treatments from published articles about eculizumab and ravulizumab in patients with PNH. Special settings (pregnancy, pediatrics, long-term safety of continued eculizumab treatment, and extravascular hemolysis) are also discussed. Expert opinion: In phase 3 trials, eculizumab and ravulizumab were found to be safe and well tolerated. In addition, 10 years of experience with eculizumab provided evidence that mitigates initial concerns about infectious events. However, to minimize meningococcal infections, vaccination and close monitoring remain essential. Because extravascular hemolysis limits eculizumab efficacy in some patients, continued investigation of proximal complement inhibitors is warranted to obviate this mechanism. Long-term safety data for ravulizumab treatment are needed.

Paroxysmal nocturnal hemoglobinuria: current treatments and unmet needs

The current standard of care for paroxysmal nocturnal hemoglobinuria (PNH) are the C5 inhibitors eculizumab and ravulizumab, both monoclonal antibodies designed to target the complement protein C5, thereby preventing its cleavage and the formation of the terminal attack complex. C5 inhibitors have yielded substantial improvements in the treatment of PNH and changed the mortality and morbidity, as well as health-related quality of life of patients with the disease. These treatments target underlying intravascular hemolysis; however, they do not address extravascular hemolysis, resulting in incomplete response and remaining symptoms in some patients. Therefore, despite treatment with a C5 inhibitor, some patients still experience anemia with associated fatigue, transfusion needs, and impaired health-related quality of life. DISCLOSURES: This research was developed under a research contract between RTI Health Solutions and Apellis Pharmaceuticals and was funded by Apellis Pharmaceuticals. Bektas, Copley-Merriman, and Khan are employees of RTI Health Solutions. Sarda is an employee of Apellis Pharmaceuticals. Shammo consults for Apellis Pharmaceuticals.

One-year efficacy and safety of ravulizumab in adults with paroxysmal nocturnal hemoglobinuria naïve to complement inhibitor therapy: open-label extension of a randomized study

Background:

Ravulizumab, the only long-acting complement C5 inhibitor for adults with paroxysmal nocturnal hemoglobinuria (PNH), demonstrated non-inferiority to eculizumab after 26 weeks of treatment in complement inhibitor-naïve patients during a phase III randomized controlled trial. We present open-label extension results with up to 52 weeks of treatment.

Methods:

Patients assigned to ravulizumab every 8 weeks (q8w) or eculizumab every 2 weeks during the randomized primary evaluation period received ravulizumab q8w during the 26-week extension. Efficacy endpoints were lactate dehydrogenase (LDH) normalization, transfusion avoidance, breakthrough hemolysis (BTH), LDH levels, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scale, and stabilized hemoglobin. Serum free C5 levels and safety were assessed. Outcomes as of the data cut-off (4 September 2018) were summarized using descriptive statistics.

Results:

Overall, 124 patients continued ravulizumab, and 119 switched from eculizumab to ravulizumab. During the extension, 43.5% and 40.3% of patients in the ravulizumab–ravulizumab and eculizumab–ravulizumab arms, respectively, achieved LDH normalization; 76.6% and 67.2% avoided transfusion. BTH decreased in the eculizumab–ravulizumab arm; no events were associated with free C5 ⩾0.5 μg/mL while receiving ravulizumab. Overall, 73.4% and 65.5% of patients in the ravulizumab–ravulizumab and eculizumab–ravulizumab arms, respectively, achieved stabilized hemoglobin. Similar proportions of patients achieved ⩾3-point improvement in FACIT-Fatigue at week 52 (ravulizumab–ravulizumab, 64.5%; eculizumab–ravulizumab, 57.1%). All patients maintained free C5 <0.5 μg/mL during the ravulizumab extension, including those who experienced C5 excursions ⩾0.5 μg/mL while receiving eculizumab during the primary evaluation period. Adverse events were comparable between groups and decreased over time.

Conclusion:

In adult, complement inhibitor–naïve patients with PNH, ravulizumab q8w for up to 52 weeks demonstrated durable efficacy and was well tolerated, with complete and sustained free C5 inhibition and a decreased incidence of BTH with no events associated with loss of free C5 control.

Trial registration:

ClinicalTrials.gov identifier, NCT02946463

Pharmacokinetic and Pharmacodynamic Properties of Cemdisiran, an RNAi Therapeutic Targeting Complement Component 5, in Healthy Subjects and Patients with Paroxysmal Nocturnal Hemoglobinuria

BACKGROUND

Cemdisiran, an N-acetylgalactosamine (GalNAc) conjugated RNA interference (RNAi) therapeutic, is currently under development for the treatment of complement-mediated diseases by suppressing liver production of complement 5 (C5) protein. This study was designed to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of cemdisiran in healthy subjects and in patients with paroxysmal nocturnal hemoglobinuria (PNH) in order to support dose selection for late-stage clinical trials.

METHODS

Healthy volunteers (HVs; n = 32, including 12 Japanese subjects) were randomized (3:1) to receive single doses of subcutaneous cemdisiran (50-900 mg) or placebo, or repeat doses of subcutaneous cemdisiran (100-600 mg) or placebo weekly, biweekly, weekly/biweekly, or weekly/monthly for 5, 8, or 13 weeks (n = 24). Cemdisiran 200 or 400 mg was administered weekly in an open-label manner, for varying durations, as monotherapy in three eculizumab-naïve PNH patients or in combination with eculizumab in three PNH patients who were receiving stable label doses of eculizumab (900 or 1200 mg biweekly) before the start of the study. After the last dose of cemdisiran, patients were followed for safety and ongoing pharmacologic effects with the eculizumab regimen (600 or 900 mg every month).

RESULTS

In HVs, cemdisiran was rapidly converted to a major active metabolite, AS(N-2)3'-cemdisiran, both declining below the lower limit of quantification (LLOQ) in plasma within 48 h, and showing minimal renal excretion. AS(N-2)3'-cemdisiran exhibited more than dose-proportional PK. The C5 protein reductions were dose-dependent, with > 90% reduction of C5 protein beginning on days 21-28 and maintained for 10-13 months following single and biweekly doses of 600 mg. The dose-response relationship, described by an inhibitory sigmoid maximum effect (E_max) model, estimated half-maximal effective dose (ED₅₀) of 14.0 mg and maximum C5 reduction of 99% at 600 mg. The PK and PD were similar between Japanese and non-Japanese subjects, and PNH patients and HVs. One of 48 subjects tested transiently positive for antidrug antibody with low titer, with no impact on PK or PD. In PNH patients, C5 suppression by cemdisiran enabled effective inhibition of residual C5 levels with lower dose and/or dosing frequency of eculizumab, which was maintained for 6-10 months after the last dose of cemdisiran.

CONCLUSIONS

Consistent with the PK/PD properties of liver targeting GalNac conjugates, cemdisiran and AS(N-2)3'-cemdisiran plasma concentrations declined rapidly while showing rapid and robust C5 suppression maintained up to 13 months following single and multiple doses, which indicates long residence times of cemdisiran within hepatocytes. The long PD duration of action in liver, low immunogenicity and acceptable safety profiles enables low, infrequent SC dosing and support further evaluation of cemdisiran in complement-mediated diseases as monotherapy or in combination with a C5 inhibitor antibody.

CLINICAL TRIAL REGISTRATION NO

NCT02352493.

16th International Congress on Antiphospholipid Antibodies Task Force Report on Antiphospholipid Syndrome Treatment Trends

Antiphospholipid syndrome (APS), an acquired autoimmune thrombophilia, is characterised by thrombosis and/or pregnancy morbidity in association with persistent antiphospholipid antibodies. The 16th International Congress on Antiphospholipid Antibodies Task Force on APS Treatment Trends reviewed the current status with regard to existing and novel treatment trends for APS, which is the focus of this Task Force report. The report addresses current treatments and developments since the last report, on the use of direct oral anticoagulants in patients with APS, antiplatelet agents, adjunctive therapies (hydroxychloroquine, statins and vitamin D), targeted treatment including rituximab, belimumab, and anti-TNF agents, complement inhibition and drugs based on peptides of beta-2-glycoprotein I. In addition, the report summarises potential new players, including coenzyme Q10, adenosine receptor agonists and adenosine potentiation. In each case, the report provides recommendations for clinicians, based on the current state of the art, and suggests a clinical research agenda. The initiation and development of appropriate clinical studies requires a focus on devising suitable outcome measures, including a disease activity index, an optimal damage index, and a specific quality of life index.

Monoclonal Antibody-Based Therapies for Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune, neuromuscular disorder that produces disabling weakness through a compromise of neuromuscular transmission. The disease fulfills strict criteria of an antibody-mediated disease. Close to 90% of patients have antibodies directed towards the nicotinic acetylcholine receptor (AChR) on the post-synaptic surface of skeletal muscle and another 5% to the muscle-specific kinase, which is involved in concentrating the AChR to the muscle surface of the neuromuscular junction. Conventional treatments of intravenous immunoglobulin and plasma exchange reduce autoantibody levels to produce their therapeutic effect, while prednisone and immunosuppressives do so by moderating autoantibody production. None of these treatments were specifically developed for MG and have a range of adverse effects. The extensive advances in monoclonal antibody technology allowing specific modulation of biological pathways has led to a tremendous increase in the potential treatment options. For MG, monoclonal antibody therapeutics target the effector mechanism of complement inhibition and the reduction of antibody levels by FcRn inhibition. Antibodies directed against CD20 and signaling pathways, which support lymphocyte activity, have been used to reduce autoantibody production. Thus far, only eculizumab, an antibody against C5, has reached the clinic. We review the present status of monoclonal antibody-based treatments for MG that have entered human testing and offer the promise to transform treatment of MG.

Pregnancy in Classical Paroxysmal Nocturnal Hemoglobinuria and Aplastic Anemia-Paroxysmal Nocturnal Hemoglobinuria: A High-Risk Constellation

Pregnancies in paroxysmal nocturnal hemoglobinuria (PNH) are associated with increased morbidity and mortality. Retrospective studies suggest that outcome has improved with the advent of the complement inhibitor eculizumab. To substantiate this assumption we analyzed the data from patients treated in our department since 2009. All patients were included in the International PNH registry and followed prospectively. We identified 16 pregnancies in 9 patients with classical PNH, and two pregnancies in two patients with aplastic anemia (AA)-PNH. In classical PNH, 13 pregnancies were supported by eculizumab. Breakthrough hemolysis occurred in six pregnancies, necessitating an increase in the biweekly eculizumab dose from 900 mg to 1,200–1,800 mg. Red blood cell transfusions were given in six and platelet transfusions in two pregnancies. A Budd-Chiari syndrome and cholecystitis complicated the course of two pregnancies. Four of 13 pregnancies supported by eculizumab ended in spontaneous abortion or stillbirth, and one was prematurely terminated because of fetal trisomy 21. None of the three pregnancies not supported by eculizumab had a successful outcome. Half the deliveries were preterm. None of the patients died, and, in all but one patient, the post-partum period was uneventful. Both pregnancies in patients with AA-PNH took a favorable course. Our results confirm low maternal mortality and frequent breakthrough hemolysis in pregnant PNH patients receiving eculizumab. Fetal mortality and the rate of preterm delivery were higher than reported previously, possibly related to the use of registry data that are likely to reduce the risk of publication and recall biases.

Development of a patient-reported outcome questionnaire for aplastic anemia and paroxysmal nocturnal hemoglobinuria (PRO-AA/PNH)

BACKGROUND

The introduction of new therapy modalities has significantly improved the outcome of aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH) patients. However, relatively little is known about the exact disease burden of AA/PNH since standardized assessments of symptoms including health-related quality of life (HRQoL) are frequently missing or inadequately designed for this rare patient group. We aimed to develop AA/PNH-specific questionnaires for self-reporting of symptoms, which could be included in electronic platforms for data collection and patient care.

METHODS

By scoping review, we extracted any reported symptoms in AA/PNH and their prevalence from the literature (Phase I). Consensus rounds with patients and medical experts were conducted to identify core symptoms reported in the literature and to add missing items (Phase II). Ultimately, AA/PNH-specific patient-reported outcome (PRO) questionnaires including the selected measures were designed (Phase III).

RESULTS

AA symptoms from 62 and PNH symptoms from 45 observational studies were extracted from the literature. Twenty-four patients and seven medical experts identified 11 core symptoms including HRQoL issues after three consensus rounds. Significant differences in the symptom ranking of patients versus medical experts could be observed. Therefore, patient- as well as expert-centered PRO questionnaires in AA and PNH were created following the concepts of validated instruments.

CONCLUSION

The development of symptom self-reporting questionnaires for AA and PNH was feasible and the disease-specific PRO questionnaires can now be validated within a web-based workflow in a subsequent feasibility study.

The Inhibition of Complement System in Formal and Emerging Indications: Results from Parallel One-Stage Pairwise and Network Meta-Analyses of Clinical Trials and Real-Life Data Studies

This manuscript presents quantitative findings on the actual effectiveness of terminal complement component 5 (C5) inhibitors and complement component 1 (C1) esterase inhibitors through their formal and common “off-label” (compassionate) indications. The results emanated from pairwise and network meta-analyses to present evidence until September 2019. Clinical trials (CT) and real-life non-randomized studies of the effects of interventions (NRSI) are consistent on the benefits of C5 inhibitors and of the absence of effects of C1 esterase inhibitors (n = 7484): Mathematically, eculizumab (surface under the cumulative ranking area (SUCRA) >0.6) and ravulizumab (SUCRA ≥ 0.7) were similar in terms of their protective effect on hemolysis in paroxysmal nocturnal hemoglobinuria (PNH), thrombotic microangiopathy (TMA) in atypical hemolytic uremic syndrome (aHUS), and acute kidney injury (AKI) in aHUS, in comparison to pre-/off-treatment state and/or placebo (SUCRA < 0.01), and eculizumab was efficacious on thrombotic events in PNH (odds ratio (OR)/95% confidence interval (95% CI) in CT and real-life NRSI, 0.07/0.03 to 0.19, 0.24/0.17 to 0.33) and chronic kidney disease (CKD) occurrence/progression in PNH (0.31/0.10 to 0.97, 0.66/0.44 to 0.98). In addition, meta-analysis on clinical trials shows that eculizumab mitigates a refractory generalized myasthenia gravis (rgMG) crisis (0.29/0.13 to 0.61) and prevents new acute antibody-mediated rejection (AMR) episodes in kidney transplant recipients (0.25/0.13 to 0.49). The update of findings from this meta-analysis will be useful to promote a better use of complement inhibitors, and to achieve personalization of treatments with this class of drugs.

The clinical spectrum of severe childhood malaria in Eastern Uganda

BACKGROUND

Few recent descriptions of severe childhood malaria have been published from high-transmission regions. In the current study, the clinical epidemiology of severe malaria in Mbale, Eastern Uganda, is described, where the entomological inoculation rate exceeds 100 infective bites per year.

METHODS

A prospective descriptive study was conducted to determine the prevalence, clinical spectrum and outcome of severe Plasmodium falciparum malaria at Mbale Regional Referral Hospital in Eastern Uganda. All children aged 2 months-12 years who presented on Mondays to Fridays between 8.00 am and 5.00 pm from 5th May 2011 until 30th April 2012 were screened for parasitaemia. Clinical and laboratory data were then collected from all P. falciparum positive children with features of WHO-defined severe malaria by use of a standardized proforma.

RESULTS

A total of 10 208 children were screened of which 6582 (64%) had a positive blood film. Of these children, 662 (10%) had clinical features of severe malaria and were consented for the current study. Respiratory distress was the most common severity feature (554; 83.7%), while 365/585 (62.4%) had hyperparasitaemia, 177/662 (26.7%) had clinical jaundice, 169 (25.5%) had severe anaemia, 134/660 (20.2%) had hyperlactataemia (lactate ≥ 5 mmol/L), 93 (14.0%) had passed dark red or black urine, 52 (7.9%) had impaired consciousness and 49/662 (7.4%) had hypoxaemia (oxygen saturations < 90%). In-hospital mortality was 63/662 (9.5%) overall but was higher in children with either cerebral malaria (33.3%) or severe anaemia (19.5%). Factors that were independently associated with mortality on multivariate analysis included severe anaemia [odds ratio (OR) 5.36; 2.16-1.32; P = 0.0002], hyperlactataemia (OR 3.66; 1.72-7.80; P = 0.001), hypoxaemia (OR) 3.64 (95% CI 1.39-9.52; P = 0.008), and hepatomegaly (OR 2.29; 1.29-4.06; P = 0.004). No independent association was found between mortality and either coma or hyperparasitaemia.

CONCLUSIONS

Severe childhood malaria remains common in Eastern Uganda where it continues to be associated with high mortality. An unusually high proportion of children with severe malaria had jaundice or gave a history of having recently passed dark red or black urine, an issue worthy of further investigation.

Pharmacology, Pharmacokinetics and Pharmacodynamics of Eculizumab, and Possibilities for an Individualized Approach to Eculizumab

Eculizumab is the first drug approved for the treatment of complement-mediated diseases, and current dosage schedules result in large interindividual drug concentrations. This review provides insight into the pharmacokinetic and pharmacodynamic properties of eculizumab, both for reported on-label (paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, generalized myasthenia gravis) and off-label (hematopoietic stem cell transplantation-associated thrombotic microangiopathy) indications. Furthermore, we discuss the potential of therapeutic drug monitoring to individualize treatment and reduce costs.

Autoimmune Pathology in Myasthenia Gravis Disease Subtypes Is Governed by Divergent Mechanisms of Immunopathology

Myasthenia gravis (MG) is a prototypical autoantibody mediated disease. The autoantibodies in MG target structures within the neuromuscular junction (NMJ), thus affecting neuromuscular transmission. The major disease subtypes of autoimmune MG are defined by their antigenic target. The most common target of pathogenic autoantibodies in MG is the nicotinic acetylcholine receptor (AChR), followed by muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4). MG patients present with similar symptoms independent of the underlying subtype of disease, while the immunopathology is remarkably distinct. Here we highlight these distinct immune mechanisms that describe both the B cell- and autoantibody-mediated pathogenesis by comparing AChR and MuSK MG subtypes. In our discussion of the AChR subtype, we focus on the role of long-lived plasma cells in the production of pathogenic autoantibodies, the IgG1 subclass mediated pathology, and contributions of complement. The similarities underlying the immunopathology of AChR MG and neuromyelitis optica (NMO) are highlighted. In contrast, MuSK MG is caused by autoantibody production by short-lived plasmablasts. MuSK MG autoantibodies are mainly of the IgG4 subclass which can undergo Fab-arm exchange (FAE), a process unique to this subclass. In FAE IgG4, molecules can dissociate into two halves and recombine with other half IgG4 molecules resulting in bispecific antibodies. Similarities between MuSK MG and other IgG4-mediated autoimmune diseases, including pemphigus vulgaris (PV) and chronic inflammatory demyelinating polyneuropathy (CIDP), are highlighted. Finally, the immunological distinctions are emphasized through presentation of biological therapeutics that provide clinical benefit depending on the MG disease subtype.

Complement, infection, and autoimmunity

PURPOSE OF REVIEW

Complement system dysfunction in terms of upregulation, downregulation, or dysregulation can create an imbalance of both host defense and inflammatory response leading to autoimmunity. In this review, we aimed at describing the role of complement system in host defense to inflection and in autoimmunity starting from the evidence from primary and secondary complement system deficiencies.

RECENT FINDINGS

Complement system has a determinant role in defense against infections: deficiencies of complement components are associated with increased susceptibility to infections. Primary complement system deficiencies are rare disorders that predispose to both infections and autoimmune diseases. Secondary complement system deficiencies are the result of the complement system activation with consumption. Complement system role in enhancing risk of infective diseases in secondary deficiencies has been demonstrated in patients affected by systemic autoimmune disorders, mainly systemic lupus erythematosus and vasculitis.

SUMMARY

The relationship between the complement system and autoimmunity appears paradoxical as both the deficiency and the activation contribute to inducing autoimmune diseases. In these conditions, the presence of complement deposition in affected tissues, decreased levels of complement proteins, and high levels of complement activation fragments in the blood and vessels have been documented.

Increasing Incidence and Prevalence of Acquired Hemolytic Anemias in Denmark, 1980-2016

Background

Acquired hemolytic disorders—autoimmune hemolytic anemia (AIHA), cold agglutinin disease (CAD), paroxysmal nocturnal hemoglobinuria (PNH), drug-induced hemolysis (DIHA), and acquired hemolysis not otherwise specified (AHNOS)—are considered rare. Despite their potentially major health implications, data regarding their incidence and prevalence are scarce.

Methods

To fill this gap we collected data regarding all patients with acquired hemolytic disorder diagnoses in 1977–2016 from the Danish National Patient Register. These data were linked with vital and migration status information from the Danish Civil Registration System. From these data combined with annual demographic data for the background population, we calculated age- and sex-specific incidence rates and prevalence proportions of acquired hemolytic disorders for specified time periods.

Results

Our analysis included 5868 patients with acquired hemolytic disorders (2715 with AIHA, 112 CAD, 397 DIHA, 116 PNH, and 2154 AHNOS). The incidence rates per 100 000 person-years in 1980–1993 and 2008–2016 were 0.81 and 1.77 for AIHA, 0.31 and 0.12 for DIHA, and 0.04 and 0.08 for PNH, respectively. The 2008–2016 CAD incidence rate was 0.18/100 000 person-years, CAD diagnosis code was not defined before 1994. All incidence rates increased with age. The prevalence proportion per 100 000 persons in 1980 and 2015 was 2.52 and 17.01 for AIHA, 0.80 and 1.50 for DIHA, and 0.18 and 1.04 for PNH. CAD prevalence in 2015 was 1.04/100 000 persons.

Conclusion

Acquired hemolytic anemia incidence rates and prevalence proportions with the exception of DIHA are markedly increasing.

Hemolytic Dynamics of Weekly Primaquine Antirelapse Therapy Among Cambodians With Acute Plasmodium vivax Malaria With or Without Glucose-6-Phosphate Dehydrogenase Deficiency

Background

Hemoglobin (Hb) data are limited in Southeast Asian glucose-6-phosphate dehydrogenase (G6PD) deficient (G6PD⁻) patients treated weekly with the World Health Organization–recommended primaquine regimen (ie, 0.75 mg/kg/week for 8 weeks [PQ _0.75]).

Methods

We treated Cambodians who had acute Plasmodium vivax infection with PQ_0.75 and a 3-day course of dihydroartemisinin/piperaquine and determined the Hb level, reticulocyte count, G6PD genotype, and Hb type.

Results

Seventy-five patients (male sex, 63) aged 5–63 years (median, 24 years) were enrolled. Eighteen were G6PD deficient (including 17 with G6PD Viangchan) and 57 were not G6PD deficient; 26 had HbE (of whom 25 were heterozygous), and 6 had α-/β-thalassemia. Mean Hb concentrations at baseline (ie, day 0) were similar between G6PD deficient and G6PD normal patients (12.9 g/dL [range, 9‒16.3 g/dL] and 13.26 g/dL [range, 9.6‒16 g/dL], respectively; P = .46). G6PD deficiency (P = <.001), higher Hb concentration at baseline (P = <.001), higher parasitemia level at baseline (P = .02), and thalassemia (P = .027) influenced the initial decrease in Hb level, calculated as the nadir level minus the baseline level (range, −5.8–0 g/dL; mean, −1.88 g/dL). By day 14, the mean difference from the day 7 level (calculated as the day 14 level minus the day 7 level) was 0.03 g/dL (range, −0.25‒0.32 g/dL). Reticulocyte counts decreased from days 1 to 3, peaking on day 7 (in the G6PD normal group) and day 14 (in the G6PD deficient group); reticulocytemia at baseline (P = .001), G6PD deficiency (P = <.001), and female sex (P = .034) correlated with higher counts. One symptomatic, G6PD-deficient, anemic male patient was transfused on day 4.

Conclusions

The first PQ_0.75 exposure was associated with the greatest decrease in Hb level and 1 blood transfusion, followed by clinically insignificant decreases in Hb levels. PQ_0.75 requires monitoring during the week after treatment. Safer antirelapse regimens are needed in Southeast Asia.

Clinical Trials Registration

ACTRN12613000003774.

Inhibition of complement pathway activation with Pozelimab, a fully human antibody to complement component C5

Complement is a key component of the innate immune system. Inappropriate complement activation underlies the pathophysiology of a variety of diseases. Complement component 5 (C5) is a validated therapeutic target for complement-mediated diseases, but the development of new therapeutics has been limited by a paucity of preclinical models to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) properties of candidate therapies. The present report describes a novel humanized C5 mouse and its utility in evaluating a panel of fully human anti-C5 antibodies. Surprisingly, humanized C5 mice revealed marked differences in clearance rates amongst a panel of anti-C5 antibodies. One antibody, pozelimab (REGN3918), bound C5 and C5 variants with high affinity and potently blocked complement-mediated hemolysis in vitro. In studies conducted in both humanized C5 mice and cynomolgus monkeys, pozelimab demonstrated prolonged PK and durable suppression of hemolytic activity ex vivo. In humanized C5 mice, a switch in dosing from in-house eculizumab to pozelimab was associated with normalization of serum C5 concentrations, sustained suppression of hemolytic activity ex vivo, and no overt toxicity. Our findings demonstrate the value of humanized C5 mice in identifying new therapeutic candidates and treatment options for complement-mediated diseases.