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

Necrotizing Fasciitis in Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, progressive, and life-threatening hematopoietic stem cell disorder characterized by complement-mediated intravascular hemolysis and a prothrombotic state. Patients with PNH might have slightly increased risk of infections due to complement-associated defects subsequent to CD59 deficiency. Here, we report a rare case of a 65-year-old male patient with necrotic ulcers on both legs, where the recognition of pancytopenia and microthrombi led to the diagnosis of PNH based on FLAER (FLuorescent AERolysin) flow cytometric analysis. He was subsequently started on eculizumab therapy, with starting and maintenance doses set as per drug labelling. Progression of the patient's leg ulcers during follow-up, with fulminant tissue destruction, purulent discharge, and necrotic patches, led to a later diagnosis of necrotizing fasciitis due to Pseudomonas aeruginosa and Klebsiella pneumonia infection. Courses of broad-spectrum antibiotics, surgical debridement, and superficial skin grafting were applied with successful effect during ongoing eculizumab therapy. This case highlights the point that it is important to maintain treatment of underlying disorders such as PNH in the presence of life-threatening infections like NF.

Improvement of Renal Function by Long-Term Sustained Eculizumab Treatment in a Patient with Paroxysmal Nocturnal Hemoglobinuria

Chronic kidney disease (CKD) is one of the major manifestations of paroxysmal nocturnal hemoglobinuria (PNH). CKD in PNH is induced mainly by intravascular hemolysis of PNH-affected red blood cells (RBC) missing the glycosylphosphatidylinositol-anchored proteins with complement-regulatory activities, CD55 and CD59. CKD develops by heme absorption in the proximal tubules resulting in the interstitial deposition of iron in the kidneys. We administered eculizumab to a patient with PNH, who was one of 29 patients enrolled in the AEGIS clinical trial, an open-label study of eculizumab in Japan. The patient was complicated by stage 3 CKD with impaired estimated glomerular filtration rate (eGFR), at grade G3b, and had obvious proteinuria (2-3+, 1-2 g/day). In a two-year extension to the 12-week AEGIS study, eGFR improved significantly, and the eGFR has since been maintained at grade G2 without proteinuria by sustained eculizumab treatment (>6 years). Renal function improved and maintained by long-term sustained eculizumab treatment, presumably by clearance of iron from the kidney as well as inhibition of the production of anaphylatoxin C5a, even in advanced stages of CKD, is one of the benefits of eculizumab treatment in PNH.

Paroxysmal nocturnal haemoglobinuria at Oslo University Hospital 2000-2010

BACKGROUND

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare haematological disease characterised by chronic haemolysis, pancytopenia and venous thrombosis. The condition is attributable to a lack of control of complement attack on erythrocytes, thrombocytes and leukocytes, and can be diagnosed by means of flow cytometry. In this quality assurance study, we have reviewed information from the medical records of all patients tested for PNH using flow cytometry at our laboratory over a ten-year period.

MATERIAL AND METHOD

In the period 2000-2010 a total of 28 patients were tested for PNH using flow cytometry at the Department of Immunology and Transfusion Medicine, Oslo University Hospital. We have reviewed the results of these examinations retrospectively together with information from medical records and transfusion data for the patients concerned.

RESULTS

Flow cytometry identified 22 patients with PNH: four with classic disease and 18 with PNH secondary to another bone marrow disease. Five patients had atypical thrombosis. Seventeen patients received antithymocyte globulin or drug treatment; of these, six recovered from their bone marrow disease, while six died and five had a need for long-term transfusion. Five patients with life-threatening bone marrow disease underwent allogeneic stem cell transplantation, three of whom died. Six of 22 patients received eculizumab; the need for transfusion has been reduced or eliminated in three patients treated with eculizumab over a longer period.

INTERPRETATION

Flow cytometry identified PNH in a majority of patients from whom we obtained samples. Most patients had a PNH clone secondary to bone marrow failure. Atypical thrombosis should be borne in mind as an indication for the test. Treatment with eculizumab is relevant for selected patients with PNH.

Alterations in markers of coagulation and fibrinolysis in patients with Paroxysmal Nocturnal Hemoglobinuria before and during treatment with eculizumab

BACKGROUND

Paroxysmal Nocturnal Hemoglobinuria is characterized by complement-mediated hemolysis and an increased thrombosis risk. Eculizumab, an antibody to complement factor C5, reduces thrombotic risk via unknown mechanisms. Clinical observations suggest that eculizumab has an immediate effect.

OBJECTIVES

A better understanding of the mechanism via which eculizumab reduces thrombotic risk by studying its pharmacodynamic effect on coagulation and fibrinolysis.

METHODS

We measured microparticles (MP), tissue factor (TF) activity, prothrombin fragment 1+2 (F1+2), D-dimer and simultaneously thrombin and plasmin generation in 55 PNH patients. In 20 patients, parameters were compared before and during eculizumab treatment (at 1 and 2hours, 1, 4 and≥12weeks after commencement).

RESULTS

Patients with a history of thrombosis had elevated D-dimers (p=0.02) but not MP. Among patients on anticoagulants, those with thrombosis had higher F1+2 concentrations (p=0.003). TF activity was undetectable in plasma MP. Unexpectedly, thrombin peak height and thrombin potential were significantly lower in PNH patients than in healthy controls. Fibrinolysis parameters were normal. During eculizumab treatment D-dimer levels significantly decreased after 1hour (p=0.008) and remained decreased at≥12weeks (p=0.03). F1+2 (p=0.03) and thrombin peak height (p=0.02) in patients not on anticoagulants significantly decreased at≥week 12. MP remained unchanged.

CONCLUSIONS

Eculizumab induces an immediate decrease of D-dimer levels but not of other markers. The decrease in thrombin peak height and F1+2 suggests that eculizumab reduces thrombin generation. Elevated D-dimer levels in untreated PNH patients with a history of thrombosis suggest possible value in predicting thrombotic risk.

Eculizumab hepatotoxicity in pediatric aHUS

BACKGROUND

Eculizumab is a humanized anti-C5 antibody approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Its use is increasing in children following reports of its safety and efficacy.

METHODS

We reviewed biochemical and clinical data related to possible drug-induced liver injury in 11 children treated with eculizumab for aHUS in a single center.

RESULTS

Elevated aminotransferases were observed in 7 children aged 6 to 11 years following eculizumab treatment for aHUS. Internationally accepted liver enzyme thresholds for drug-induced liver injury were exceeded in 5 cases. In all cases, liver injury was classified as mixed hepatocellular and cholestatic. Infectious and other causes were excluded in each case. One patient with no pre-existing liver disease developed tender hepatomegaly and liver enzyme derangement exceeding 20 times the upper limit of normal following initiation of eculizumab. Recurrent liver injury following re-challenge with eculizumab necessitated its discontinuation and transition to plasma therapy.

CONCLUSIONS

Hepatotoxicity in association with eculizumab is a potentially important yet previously unreported adverse event. We recommend monitoring liver enzymes in all patients receiving eculizumab. Further research is required to clarify the impact of this adverse event, to characterize the mechanism of potential hepatotoxicity, and to identify which patients are most at risk.

New Insights in Abdominal Pain in Paroxysmal Nocturnal Hemoglobinuria (PNH): A MRI Study

Introduction

Abdominal pain in PNH has never been investigated by in-vivo imaging studies. With MRI, we aimed to assess mesenteric vessels flow and small bowel wall perfusion to investigate the ischemic origin of abdominal pain.

Materials and Methods

Six PNH patients with (AP) and six without (NOP) abdominal pain underwent MRI. In a blinded fashion, mean flow (MF, quantity of blood moving through a vessel within a second, in mL·s^-1) and stroke volume (SV, volume of blood pumped out at each heart contraction, in mL) of Superior Mesenteric Vein (SMV) and Artery (SMA), areas under the curve at 60 (AUC₆₀) and 90 seconds (AUC₉₀) and K^trans were assessed by two operators.

Results

Mean total perfusion and flow parameters were lower in AP than in NOP group. AUC₆₀: 84.81 ± 11.75 vs. 131.73 ± 18.89 (P < 0.001); AUC₉₀: 102.33 ± 14.16 vs. 152.58 ± 22.70 (P < 0.001); K^trans: 0.0346 min^-1 ± 0.0019 vs. 0.0521 ± 0.0015 (P = 0.093 duodenum, 0.009 jejunum/ileum). SMV: MF 4.67 ml/s ± 0.85 vs. 8.32 ± 2.14 (P = 0.002); SV 3.85 ml ± 0.76 vs. 6.55 ± 1.57 (P = 0.02). SMA: MF 6.95 ± 2.61 vs. 11.2 ± 2.32 (P = 0.07); SV 6.52 ± 2.19 vs. 8.78 ± 1.63 (P = 0.07). We found a significant correlation between MF and SV of SMV and AUC₆₀ (MF:ρ = 0.88, P < 0.001; SV: ρ = 0.644, P = 0.024), AUC₉₀ (MF: ρ = 0.874, P < 0.001; SV:ρ = 0.774, P = 0.003) and K^trans (MF:ρ = 0.734, P = 0.007; SV:ρ = 0.581, P = 0.047).

Conclusions

Perfusion and flow MRI findings suggest that the impairment of small bowel blood supply is significantly associated with abdominal pain in PNH.

Dissecting complement blockade for clinic use

In this issue of Blood, Peffault de Latour et al describe ex vivo measurements of complement activity in paroxysmal nocturnal hemoglobinuria (PNH) patients on eculizumab treatment. This is the first systematic pharmacodynamic (PD) study of eculizumab in PNH patients which shows that CH50 is a promising biomarker of therapeutic complement blockade.

Effective eculizumab therapy followed by BMT in a boy with paroxysmal nocturnal hemoglobinuria

A 9-year-old boy with paroxysmal nocturnal hemoglobinuria/aplastic anemia syndrome (PNH/AA) developed hemolytic crisis after receiving immunosuppressive therapy. Eculizumab dramatically relieved the signs and symptoms and then he safely underwent unrelated bone marrow transplantation, suggesting the feasibility and effectiveness of eculizumab before stem cell transplantation in children with PNH/AA in hemolytic crisis.

A perspective on the benefit-risk assessment for new and emerging pharmaceuticals in Japan

The universal health care system in Japan is facing a historical turning point as a result of the increasing fiscal burden, rapidly aging society, and a decreasing population. To understand the challenges and opportunities in the Japanese pharmaceutical market, which occupies one tenth of the global share, this review highlights several issues related to the benefit-risk assessment that is unique to the modern Japanese society: 1) regulatory system for new drug development; 2) health hazards related to pharmaceuticals ("Yakugai" in Japanese); 3) drug lag; 4) problems and controversies in the vaccination policy; and 5) clinical study misconduct. The regulatory process places a significant importance on Japanese data collection regardless of data accumulation from other countries. Because Yakugai has repeatedly caused tragedies and social disputes historically, the regulatory judgments generally tend to be more prudential when safety concerns are raised for new and emerging pharmaceuticals. Such a regulatory system has caused more than several years of approval delays compared to delays in other countries. The problem of drug lag still lingers on despite several regulatory system revisions, while the solution is incompatible with the elimination of Yakugai because the lag potentially reduces the risk of unpredictable adverse events. The Japanese vaccination policy has also received a lot of criticism, and needs improvements so that the decision-making process can be more transparent and scientifically based. Additionally, repeated clinical study misconduct damaged the reputation of Japanese clinical studies with unnecessary defrayment in health insurance; therefore, the medical community must change its inappropriate relationship with the industry. The problems surrounding pharmaceuticals are related to centralized, strict drug pricing control under the universal health coverage. Although the current government attempts to facilitate innovative research and development of novel therapeutics in Japan, further reforms should be explored for patients who need new and emerging pharmaceuticals.

Paroxysmal nocturnal haemoglobinuria: to prednisone or not to prednisone?--a case report of a patient previously treated with steroids for 15 yrs and significant response on eculizumab

BACKGROUND

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired haematopoietic stem cell disorder characterised by persistent haemolysis and platelet activation, severe end-organ damage, an increased risk of thrombosis and early mortality. We present the case of a 56-year-old male with long-standing PNH and significant disease-related morbidity who underwent steroid therapy for approximately 15 yrs before treatment with eculizumab, a humanized monoclonal antibody that blocks the terminal phase of the complement cascade at the C5 level.

CASE HISTORY

The patient presented with a severely impaired quality of life in 1997 and was diagnosed with PNH 8 months later, soon after which he was commenced on steroid therapy with prednisone. During long-term steroid therapy with progressive increases in prednisone dose, the patient had frequent haemolytic episodes as well as thrombosis and renal complications. He also experienced Cushing's syndrome with arterial hypertension, insulin-dependent diabetes mellitus, osteoporosis, acne and portal fibrosis. Eculizumab therapy was started in late-2009 and led to rapid improvements in haemoglobin and lactate dehydrogenase levels with a complete cessation of haemolytic episodes. Eculizumab has been well tolerated.

CONCLUSIONS

Long-term steroid therapy was not effective in controlling PNH in this patient and was associated with significant comorbidities. Treatment with eculizumab led to major improvements, even after such a long period with relatively uncontrolled disease.

Paroxysmal nocturnal hemoglobinuria: a complement-mediated hemolytic anemia

Paroxysmal nocturnal hemoglobinuria is manifests with a chronic hemolytic anemia from uncontrolled complement activation, a propensity for thrombosis and marrow failure. The hemolysis is largely mediated by the alternative pathway of complement. Clinical manifestations result from the lack of specific cell surface proteins, CD55 and CD59, on PNH cells. Complement inhibition by eculizumab leads to dramatic clinical improvement. While this therapeutic approach is effective, there is residual complement activity resulting from specific clinical scenarios as well as from upstream complement components that can account for suboptimal responses in some patients. Complement inhibition strategies are an area of active research.

Anticomplement C5 therapy with eculizumab for the treatment of paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome

The complement inhibitor eculizumab is a humanized monoclonal antibody against C5. It was developed to specifically target cleavage of C5 thus preventing release of C5a and activation of the terminal pathway. Paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS) are 2 diseases with distinctly different underlying molecular mechanisms. In PNH, progeny of hematopoietic stem cells that harbor somatic mutations lead to a population of peripheral blood cells that are deficient in complement regulators resulting in hemolysis and thrombosis. In aHUS, germline mutations in complement proteins or their regulators fail to protect the glomerular endothelium from complement activation resulting in thrombotic microangiopathy and renal failure. Critical to the development of either disease is activation of the terminal complement pathway. Understanding this step has led to the study of eculizumab as a treatment for these diseases. In clinical trials, eculizumab is proven to be effective and safe in PNH and aHUS.

Assessing complement blockade in patients with paroxysmal nocturnal hemoglobinuria receiving eculizumab

CH50 activity reflects C5 blockade in PNH patients treated with eculizumab and is directly related to circulating free eculizumab levels. Both CH50 and free eculizumab level markers look promising for the monitoring of complement blockade in patients with PNH receiving eculizumab.

Clinical management of multiple sclerosis and neuromyelitis optica with therapeutic monoclonal antibodies: approved therapies and emerging candidates

Therapeutic monoclonal antibodies (mAbs) are a relatively novel class of drugs that has substantially advanced immunotherapy for patients with multiple sclerosis. The advantage of these agents is that they bind specifically and exclusively to predetermined proteins or cells. Natalizumab was the first mAb in neurology to obtain approval. It is also considered one of the most potent options for annualized relapse rate reduction among available therapeutic options. Alemtuzumab is currently also approved in several countries. Several mAbs have been tested in clinical studies in multiple sclerosis. Here, we review the history of drug development of therapeutic mAbs and their classification. Furthermore, we outline the putative mechanisms of action, clinical evidence and safety of approved mAbs and those in different stages of clinical development in multiple sclerosis and neuromyelitis optica.

Eculizumab effect on the hemostatic state in patients with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by a hypercoagulable state associated with acute hemolysis. Eculizumab is used to reduce the intensity of intravascular hemolysis in PNH patients. The hemostatic status of three patients with PNH was assessed during eculizumab treatment by D-dimer assay and the global assays: thromboelastography (TEG), thrombin generation test (TGТ), and thrombodynamics (TD). In the state of hemolytic crisis before the therapy D-dimer concentration was increased in two patients accompanied by hypercoagulation changes in TEG parameter angle (α). TD parameter the clot growth velocity (V) revealed hypercoagulability while TGT parameter ETP was within the normal range in all patients. The lactate dehydrogenase (LDH) activity decreased during the 8months of eculizumab therapy. The physical health was improved, the frequency of hemolytic crisis decreased. Patients periodically exhibited hypercoagulable state: the mean values α=38±11° (with normal range 20-40°), ETP=1311±442nM·min (with normal range 800-1560nM·min), V=31±4μm/min (with normal range 20-29μm/min). During the eculizumab therapy two patients had the repeated clinical manifestation of acute hemolytic crisis, the parameters of the global tests were increased compared to the previous measurement. The global hemostasis tests TEG, TGT and TD revealed hypercoagulability in patients with PNH during eculizumab therapy.

Eculizumab for treating patients with paroxysmal nocturnal hemoglobinuria

BACKGROUND

Paroxysmal nocturnal hemoglobinuria (PNH) is a chronic, not malignant, disease of the hematopoietic stem cells, associated with significant morbidity and mortality. It is a rare disease with an estimated incidence of 1.3 new cases per one million individuals per year. The treatment of PNH has been largely empirical and symptomatic, with blood transfusions, anticoagulation, and supplementation with folic acid or iron. Eculizumab, a biological agent that inhibits complement cascade, was developed for preventing hemolytic anemia and severe thrombotic episodes.

OBJECTIVES

To assess the clinical benefits and harms of eculizumab for treating patients with paroxysmal nocturnal hemoglobinuria (PNH).

SEARCH METHODS

We conducted a comprehensive search strategy. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2014, Issue 5), Ovid MEDLINE (from 1946 to 15 May 2014), EMBASE (from 1980 to 25 June 2014), and LILACS (from 1982 to 25 June 2014). We did not apply any language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) irrespective of their publication status or language. No limits were applied with respect to period of follow-up. We excluded quasi-RCTs. We included trials comparing eculizumab with placebo or best available therapy. We included any patient with a confirmed diagnosis of PNH. Primary outcome was overall survival.

DATA COLLECTION AND ANALYSIS

We independently performed a duplicate selection of eligible trials, risk of bias assessment, and data extraction. We estimated risk ratios (RRs) and 95% confidence interval (CIs) for dichotomous outcomes, and mean differences (MDs) and 95% CIs for continuous outcomes. We used a random-effects model for analysis.

MAIN RESULTS

We identified one multicenter (34 sites) phase III RCT involving 87 participants. The trial compared eculizumab versus placebo, and was conducted in the US, Canada, Europe, and Australia with 26 weeks of follow-up. This small trial had high risk of bias in many domains (attrition and selective reporting). It was sponsored by a pharmaceutical company. No patients died during the study. By using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (scores can range from 0 to 100, with higher scores on the global health status and functioning scales indicating improvement), the trial showed improvement in health-related quality of life in patients treated with eculizumab (mean difference (MD) 19.4, 95% CI 8.25 to 30.55; P = 0.0007; low quality of evidence). By using the Functional Assessment of Chronic Illness Therapy Fatigue instrument (scores can range from 0 to 52, with higher scores indicating improvement in fatigue), the trial showed a reduction in fatigue (MD 10.4, 95% CI 9.97 to 10.83; P = 0.00001; moderate quality of evidence) in the eculizumab group compared with placebo. Eculizumab compared with placebo showed a greater proportion of patients with transfusion independence: 51% (22/43) versus 0% (0/44); risk ratio (RR) 46.02, 95% CI 2.88 to 735.53; P = 0.007; moderate quality of evidence; and withdrawal for any reason: 4.7% (2/43) versus 22.72% (10/44); RR 0.20, 95% CI 0.05 to 0.88; P = 0.03; moderate quality of evidence. Due to the low rate of events observed, the included trial did not show any difference between eculizumab and placebo in terms of serious adverse events: 9.3% (4/43) versus 20.4% (9/44); RR 0.15, 95% CI 0.15 to 1.37; P = 0.16; low quality of evidence. We did not observe any difference between intervention and placebo for the most frequent adverse events. One participant receiving placebo showed an episode of thrombosis. The trial did not assess overall survival, transformation to myelodysplastic syndrome and acute myelogenous leukemia, or development or recurrence of aplastic anemia on treatment.

AUTHORS' CONCLUSIONS

This review has detected an absence of evidence for eculizumab compared with placebo for treating paroxysmal nocturnal hemoglobinuria (PNH), in terms of overall survival, nonfatal thrombotic events, transformation to myelodysplastic syndrome and acute myelogenous leukemia, and development and recurrence of aplastic anemia on treatment. Current evidence indicates that compared with placebo, eculizumab increases health-related quality of life and increases transfusion independence. During the execution of the included trial, no patients died. Furthermore, the intervention seems to reduce fatigue and withdrawals for any reason. The safety profile of eculizumab is unclear. These conclusions are based on one small trial with risk of attrition and selective reporting bias.Therefore, prescription of eculizumab for treating patients with PNH can neither be supported nor rejected, unless new evidence from a large high quality trial alters this conclusion. Therefore, we urge the reader to interpret the trial results with much caution. Future trials on this issue should be conducted according to the SPIRIT statement and reported according to the CONSORT statement by independent investigators, and using the Foundation of Patient-Centered Outcomes Research recommendations.

A novel antibody against human factor B that blocks formation of the C3bB proconvertase and inhibits complement activation in disease models

The alternative pathway (AP) is critical for the efficient activation of complement regardless of the trigger. It is also a major player in pathogenesis, as illustrated by the long list of diseases in which AP activation contributes to pathology. Its relevance to human disease is further emphasized by the high prevalence of pathogenic inherited defects and acquired autoantibodies disrupting components and regulators of the AP C3-convertase. Because pharmacological downmodulation of the AP emerges as a broad-spectrum treatment alternative, there is a powerful interest in developing new molecules to block formation and/or activity of the AP C3-convertase. In this paper, we describe the generation of a novel mAb targeting human factor B (FB). mAb FB48.4.2, recognizing with high affinity an evolutionary-conserved epitope in the Ba fragment of FB, very efficiently inhibited formation of the AP C3-proconvertase by blocking the interaction between FB and C3b. In vitro assays using rabbit and sheep erythrocytes demonstrated that FB28.4.2 was a potent AP inhibitor that blocked complement-mediated hemolysis in several species. Using ex vivo models of disease we demonstrated that FB28.4.2 protected paroxysmal nocturnal hemoglobinuria erythrocytes from complement-mediated hemolysis and inhibited both C3 fragment and C5b-9 deposition on ADP-activated HMEC-1 cells, an experimental model for atypical hemolytic uremic syndrome. Moreover, i.v. injection of FB28.4.2 in rats blocked complement activation in rat serum and prevented the passive induction of experimental autoimmune Myasthenia gravis. As a whole, these data demonstrate the potential value of FB28.4.2 for the treatment of disorders associated with AP complement dysregulation in man and animal models.

Complement functional tests for monitoring eculizumab treatment in patients with atypical hemolytic uremic syndrome

BACKGROUND

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy characterized by hemolysis, platelet consumption, and renal injury. Eculizumab, a mAb that blocks complement activity, has been successfully used in aHUS.

OBJECTIVES

To optimize eculizumab therapy in aHUS patients by monitoring complement functional tests and markers of disease activity.

PATIENTS/METHODS

We studied 18 patients with aHUS (10 males; eight females; age range, 2-40 years) treated with eculizumab to induce and/or maintain disease remission. Patients were followed up for a cumulative observation period of 160 months, during which blood samples were obtained at various time intervals to measure complement activity (Wieslab for the classical, alternative and mannose-binding lectin complement pathways) and the parameters of disease activity (haptoglobin and lactate dehydrogenase serum levels, and platelet count). The intravenous eculizumab doses of 12-33 mg kg(-1) were initially administered every week, with the interval between doses being gradually extended to 2 weeks, 3 weeks and 4 weeks on the basis of strict laboratory and clinical control.

RESULTS

Complement activity was normal before eculizumab treatment, regardless of the state of the disease (activity or remission). It was completely suppressed 1 week, 2 weeks and 3 weeks after the last eculizumab infusion (mean values ± standard deviation: 1% ± 1% to 3% ± 5% for both the classical and alternative pathways; P = 0.0001 vs. baseline), and partially suppressed after 4 weeks (22% ± 26% and 16% ± 27%; P = 0.0001 vs. baseline). The increase in the time interval between eculizumab infusions did not change disease activity markers.

CONCLUSIONS

Monitoring complement tests can allow a safe reduction in the frequency of eculizumab administration in aHUS while keeping the disease in remission.

Efficacy and safety of eculizumab in children and adolescents with paroxysmal nocturnal hemoglobinuria

BACKGROUND

Paroxysmal nocturnal hemoglobinuria (PNH) is rare in children, but represents a similarly serious and chronic condition as in adults. Children with PNH frequently experience complications of chronic hemolysis, recurrent thrombosis, marrow failure, serious infections, abdominal pain, chronic fatigue, and decreased quality of life with reduced survival. The terminal complement inhibitor eculizumab is proven to be effective and safe in adults and approved by the FDA for treatment of PNH.

PROCEDURE

This 12-week, open-label, multi-center phase I/II study evaluated pharmacokinetics, pharmacodynamics, efficacy, and safety in seven children with PNH 11-17 years of age. Eculizumab was intravenously administered at 600 mg weekly for 4 weeks, 900 mg in week 5, and 900 mg every 2 weeks thereafter (http://clinicaltrials.gov NCT00867932).

RESULTS

Eculizumab therapy resulted in complete and sustained inhibition of hemolysis in all participants with a reduction of lactate dehydrogenase to normal levels. All hematological parameters stabilized. No definitive, study drug-related adverse events were observed. Only one severe SAE of hospitalization due to aplastic anemia occurred, which was not study drug-related.

CONCLUSION

Eculizumab appears to be a safe and effective therapy for children with PNH.

Paroxysmal nocturnal hemoglobinuria presenting as cerebral venous sinus thrombosis: a case report

Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare type of acquired hemolytic anemia that is frequently associated with thrombophilia. It may rarely present with cerebral venous sinus thrombosis, which manifests clinically with signs of raised intracranial pressure and requires lifelong anticoagulation therapy. One such rare presentation was seen in a 28 years old male who had history of recurrent episodes of passing red colored urine and this time presented with severe headache. He was diagnosed to have cerebral venous sinus thrombosis and on further workup was found to be suffering from PNH.

Whole-exome sequencing identifies rare, functional CFH variants in families with macular degeneration

We sequenced the whole exome of 35 cases and 7 controls from 9 age-related macular degeneration (AMD) families in whom known common genetic risk alleles could not explain their high disease burden and/or their early-onset advanced disease. Two families harbored novel rare mutations in CFH (R53C and D90G). R53C segregates perfectly with AMD in 11 cases (heterozygous) and 1 elderly control (reference allele) (LOD = 5.07, P = 6.7 × 10(-7)). In an independent cohort, 4 out of 1676 cases but none of the 745 examined controls or 4300 NHBLI Exome Sequencing Project (ESP) samples carried the R53C mutation (P = 0.0039). In another family of six siblings, D90G similarly segregated with AMD in five cases and one control (LOD = 1.22, P = 0.009). No other sample in our large cohort or the ESP had this mutation. Functional studies demonstrated that R53C decreased the ability of FH to perform decay accelerating activity. D90G exhibited a decrease in cofactor-mediated inactivation. Both of these changes would lead to a loss of regulatory activity, resulting in excessive alternative pathway activation. This study represents an initial application of the whole-exome strategy to families with early-onset AMD. It successfully identified high impact alleles leading to clearer functional insight into AMD etiopathogenesis.

Long-term outcome of fludarabine-based reduced-intensity allogeneic hematopoietic cell transplantation for debilitating paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by intravascular hemolysis, venous thrombosis, and bone marrow failure. Seventeen patients with debilitating PNH, including 8 who were HLA-alloimmunized, underwent a reduced-intensity allogeneic hematopoietic cell transplantation (HCT). All received cyclophosphamide/fludarabine +/- antithymocyte globulin followed by a granulocyte colony-stimulating factor-mobilized HCT from an HLA-matched relative. Glycosylphosphatidylinositol-negative neutrophils were detectable after engraftment but disappeared completely at a median 100 days after transplantation. With a median follow-up of nearly 6 years, 15 patients (87.8%) survived, all without any evidence of PNH, transfusion independent, and off anticoagulation. Allogeneic reduced-intensity HCT remains a curative therapeutic option for PNH patients who are not candidates for eculizumab treatment.

Baseline characteristics and disease burden in patients in the International Paroxysmal Nocturnal Hemoglobinuria Registry

Paroxysmal nocturnal hemoglobinuria is a rare, acquired disease associated with hemolytic anemia, bone marrow failure, thrombosis, and, frequently, poor quality of life. The International PNH Registry is a worldwide, observational, non-interventional study collecting safety, effectiveness, and quality-of-life data from patients with a confirmed paroxysmal nocturnal hemoglobinuria diagnosis or detectable paroxysmal nocturnal hemoglobinuria clone, irrespective of treatment. In addition to evaluating the long-term safety and effectiveness of eculizumab in a global population, the registry aims to improve diagnosis, optimize patient management and outcomes, and enhance the understanding of the natural history of paroxysmal nocturnal hemoglobinuria. Here we report the characteristics of the first 1610 patients enrolled. Median disease duration was 4.6 years. Median granulocyte paroxysmal nocturnal hemoglobinuria clone size was 68.1% (range 0.01-100%). Overall, 16% of patients had a history of thrombotic events and 14% a history of impaired renal function. Therapies included anticoagulation (31%), immunosuppression (19%), and eculizumab (25%). Frequently reported symptoms included fatigue (80%), dyspnea (64%), hemoglobinuria (62%), abdominal pain (44%), and chest pain (33%). Patients suffered from poor quality of life; 23% of patients had been hospitalized due to paroxysmal nocturnal hemoglobinuria-related complications and 17% stated that paroxysmal nocturnal hemoglobinuria was the reason they were not working or were working less. This international registry will provide an ongoing, valuable resource to further the clinical understanding of paroxysmal nocturnal hemoglobinuria.

Successful treatment of DEAP-HUS with eculizumab

BACKGROUND

Deficiency of complement factor H-related (CFHR) proteins and CFH autoantibody-positive hemolytic uremic syndrome (DEAP-HUS) represents a unique subgroup of complement-mediated atypical HUS (aHUS). Autoantibodies to the C-terminus of CFH block CFH surface recognition and mimic mutations found in the genetic form of (CFH-mediated) aHUS. CFH autoantibodies are found in 10-15 % of aHUS patients and occur--so far unexplained--almost exclusively in the background of CFHR1 or CFHR3/CFHR1 deletions.

METHODS

As a well-defined role for eculizumab in the treatment of complement-mediated aHUS is becoming established, its role in DEAP-HUS is less conspicuous, where a B-cell-depleting and immunosuppressive treatment strategy is being proposed in the literature.

RESULTS

We here show eculizumab to be safe and effective in maintaining a disease-free state, without recurrence, in a previously plasma-therapy-dependent DEAP-HUS patient, and in another patient in whom, although showing a good clinical response to plasma therapy, the therapy was hampered by allergic reactions to fresh frozen plasma and contend there is a rationale for the use of eculizumab in concert with an immunosuppressive strategy in the treatment of DEAP-HUS. Considering the high rate of early relapse, the possible coexistence and contribution of both known and unknown complement-gene mutations, the probable pathogenic role of CFHR1 as a complement alternative pathway (CAP) regulator, the experimental nature of measuring and using anti-CFH autoantibodies to guide management, and until the positive reports of immunosuppression in addition to plasma therapy are confirmed in prospective studies, we feel that a complement-directed therapy should not be neglected in DEAP-HUS. Serial CFH autoantibody titer testing may become a valuable tool to monitor treatment response, and weaning patients off eculizumab may become an option once CFH autoantibody levels are depleted.

CONCLUSIONS

A prospective study of eculizumab treatment in a larger cohort of DEAP-HUS patients is required to validate the applicability of our positive experience.

Genetic variants in C5 and poor response to eculizumab

BACKGROUND

Eculizumab is a humanized monoclonal antibody that targets complement protein C5 and inhibits terminal complement-mediated hemolysis associated with paroxysmal nocturnal hemoglobinuria (PNH). The molecular basis for the poor response to eculizumab in a small population of Japanese patients is unclear.

METHODS

We assessed the sequences of the gene encoding C5 in patients with PNH who had either a good or poor response to eculizumab. We also evaluated the functional properties of C5 as it was encoded in these patients.

RESULTS

Of 345 Japanese patients with PNH who received eculizumab, 11 patients had a poor response. All 11 had a single missense C5 heterozygous mutation, c.2654G → A, which predicts the polymorphism p.Arg885His. The prevalence of this mutation among the patients with PNH (3.2%) was similar to that among healthy Japanese persons (3.5%). This polymorphism was also identified in a Han Chinese population. A patient in Argentina of Asian ancestry who had a poor response had a very similar mutation, c.2653C → T, which predicts p.Arg885Cys. Nonmutant and mutant C5 both caused hemolysis in vitro, but only nonmutant C5 bound to and was blocked by eculizumab. In vitro hemolysis due to nonmutant and mutant C5 was completely blocked with the use of N19-8, a monoclonal antibody that binds to a different site on C5 than does eculizumab.

CONCLUSIONS

The functional capacity of C5 variants with mutations at Arg885, together with their failure to undergo blockade by eculizumab, account for the poor response to this agent in patients who carry these mutations. (Funded by Alexion Pharmaceuticals and the Ministry of Health, Labor, and Welfare of Japan.).

Complement activation in malaria: friend or foe?

Complement is activated during malaria infection, but there is little evidence that it benefits the host. On the contrary, growing evidence points to the central role of complement activation in the pathogenesis of complicated malaria. Recent evidence suggests a critical role for C5a and the membrane attack complex in the pathogenesis of cerebral malaria, and for C5a in the pathogenesis of placental malaria. In addition, erythrocytes of children with severe malarial anemia have increased deposition of C3b and decreased capacity to regulate complement activation, that probably increase their susceptibility to destruction by liver and splenic macrophages. These observations justify further investigation of the role of complement in malaria and the testing of complement inhibitors as adjunctive treatment for severe malaria.

Eculizumab prevents recurrent antiphospholipid antibody syndrome and enables successful renal transplantation

Renal transplantation in patients with antiphospholipid antibodies has historically proven challenging due to increased risk for thrombosis and allograft failure. This is especially true for patients with antiphospholipid antibody syndrome (APS) and its rare subtype, the catastrophic antiphospholipid antibody syndrome (CAPS). Since a critical mechanism of thrombosis in APS/CAPS is one mediated by complement activation, we hypothesized that preemptive treatment with the terminal complement inhibitor, eculizumab, would reduce the extent of vascular injury and thrombosis, enabling renal transplantation for patients in whom it would otherwise be contraindicated. Three patients with APS, two with a history of CAPS, were treated with continuous systemic anticoagulation together with eculizumab prior to and following live donor renal transplantation. Two patients were also sensitized to human leukocyte antigens (HLA) and required plasmapheresis for reduction of donor-specific antibodies. After follow-up ranging from 4 months to 4 years, all patients have functioning renal allografts. No systemic thrombotic events or early graft losses were observed. While the appropriate duration of treatment remains to be determined, this case series suggests that complement inhibitors such as eculizumab may prove to be effective in preventing the recurrence of APS after renal transplantation.

14th International Congress on Antiphospholipid Antibodies: task force report on antiphospholipid syndrome treatment trends

Antiphospholipid Syndrome (APS) is characterized by vascular thrombosis and/or pregnancy morbidity occurring in patients with persistent antiphospholipid antibodies (aPL). The primary objective of the APS Treatment Trends Task Force, created as part of the 14th International Congress on aPL, was to systematically review the potential future treatment strategies for aPL-positive patients. The task force chose as future clinical research directions: a) determining the necessity for controlled clinical trials in venous thromboembolism with the new oral direct thrombin or anti-factor Xa inhibitors pending the results of the ongoing rivaroxaban in APS (RAPS) trial, and designing controlled clinical trials in other forms of thrombotic APS; b) systematically analyzing the literature as well as aPL/APS registries, and creating specific registries for non-warfarin/heparin anticoagulants; c) increasing recruitment for an ongoing primary thrombosis prevention trial, and designing secondary thrombosis and pregnancy morbidity prevention trials with hydroxychloroquine; d) determining surrogate markers to select patients for statin trials; e) designing controlled studies with rituximab and other anti-B-cell agents; f) designing mechanistic and clinical studies with eculizumab and other complement inhibitors; and g) chemically modifying peptide therapy to improve the half-life and minimize immunogenicity. The report also includes recommendations for clinicians who consider using these agents in difficult-to-manage aPL-positive patients.

Effects of immunosuppressive therapy in a patient with aplastic anemia-paroxysmal nocturnal hemoglobinuria (AA-PNH) syndrome during ongoing eculizumab treatment

A 65-year-old woman experienced a hemolytic attack triggered by sepsis. She presented with markedly increased CD55(-) CD59(-) erythrocytes and the signs of bone marrow failure, which led to a diagnosis of aplastic anemia-paroxysmal nocturnal hemoglobinuria (AA-PNH) syndrome. There was a possibility of increasing hemolysis, as large PNH clones remained after immunosuppressive therapy (IST). Accordingly, eculizumab was first used to control the hemolytic attack followed by IST with antithymocyte globulin and cyclosporine A. The patient was successfully weaned from blood transfusions and has been followed up without any recurrence of hemolytic attacks.

Cross-sectional validation study of patient-reported outcomes in patients with paroxysmal nocturnal haemoglobinuria

BACKGROUND

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, acquired, clonal haemopoietic stem cell disorder that causes chronic intravascular haemolysis, increases the risk of thrombosis and results in significant patient morbidity and mortality. The symptoms of PNH may have a major impact on patient quality of life.

AIMS

To assess patient fatigue and health-related quality of life in 29 patients with PNH using the Functional Assessment of Chronic Illness Therapy Fatigue subscale version 4 (FACIT-Fatigue) and the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire-C30, version 3 (EORTC QLQ-C30).

METHODS

Following completion of the questionnaires, patients were interviewed to assess the validity, clarity, relevance and comprehensiveness of the assessments.

RESULTS

Overall, patients considered both the FACIT-Fatigue and EORTC QLQ-C30 instruments to be relevant and adequate in assessing the level of PNH-associated fatigue and other quality-of-life measures. The FACIT-Fatigue questionnaire was considered to be clear and to comprehensively cover PNH-related fatigue. The EORTC QLQ-C30 instrument was considered to be easy to understand, but of an overall lower relevance, although some differences between countries were observed. Patients suggested additional questions that could be incorporated into future EORTC QLQ-C30 versions to make it more relevant to PNH.

CONCLUSIONS

This study confirms the validity of the FACIT-Fatigue and the EORTC QLQ-C30 questionnaires in this patient population and their routine use should be considered in the management of patients with PNH.

Paroxysmal nocturnal hemoglobinuria and the age of therapeutic complement inhibition

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease of hematopoietic stem cells due to a mutation in the PIG-A gene leading to a deficiency of GPI-anchored proteins. Lack of two specific GPI-anchored proteins, CD55 and CD59, leads to uncontrolled complement activation that result in both intravascular and extravascular hemolysis. Free hemoglobin leads to nitric oxide depletion that mediates the pathophysiology of some of the common clinical signs of PNH. Clinical symptoms of PNH include evidence of hemolytic anemia, bone marrow failure, smooth muscle dystonias and thromboses. Treatment options for patients with PNH include bone marrow transplantation, a therapy associated with high morbidity and mortality, or treatment with the complement inhibitor eculizumab. Eculizumab is a first-in-class anti-complement drug that in PNH has been shown to block complement-mediated hemolysis, reduce transfusion dependency, reduce thromboembolic complications and improve the quality of life (QoL) of patients.

Pulmonary hypertension associated with chronic hemolytic anemia and other blood disorders

Pulmonary hypertension (PH) has emerged as a major complication of several hematologic disorders, including hemoglobinopathies, red cell membrane disorders, chronic myeloproliferative disorders, and splenectomy. With the exception of sickle cell disease, there are a limited number of studies systematically evaluating the prevalence of PH using the gold standard right heart catheterization in these disorders. The cause of the PH in patients with hematologic disorders is multifactorial, and a thorough diagnostic evaluation is essential. More importantly, there are virtually no high-quality data on the safety and efficacy of PH-targeted therapy in this patient population.

Rapid donor T-cell engraftment increases the risk of chronic graft-versus-host disease following salvage allogeneic peripheral blood hematopoietic cell transplantation for bone marrow failure syndromes

The risk of graft-rejection after allogeneic hematopoietic cell transplantation using conventional cyclophosphamide-based conditioning is increased in patients with bone marrow failure syndromes (BMFS) who are heavily transfused and often HLA-alloimmunized. Fifty-six patients with BMFS underwent fludarabine-based reduced-intensity conditioning and allogeneic peripheral blood progenitor cell (PBPC) transplantation at a single institution. The conditioning regimen consisted of intravenous cyclophosphamide, fludarabine, and equine antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis included cyclosporine A alone or in combination with either mycophenolate mofetil or methotrexate. To reduce the risk of graft-rejection/failure, unmanipulated G-CSF mobilized PBPCs obtained from an HLA-identical or single HLA-antigen mismatched relative were transplanted rather than donor bone marrow. Despite a high prevalence of pretransplant HLA-alloimmunization (41%) and a heavy prior transfusion burden, graft-failure did not occur with all patients having sustained donor lympho-hematopoietic engraftment. The cumulative incidence of grade II-IV acute-GVHD and chronic-GVHD was 51.8% and 72%, respectively; with 87.1% surviving at a median follow-up of 4.5 years. A multivariate analysis showed pretransplant alloimmunization and rapid donor T-cell engraftment (≥95% donor by day 30) were both significantly (P < 0.05) associated with the development of chronic-GVHD (adjusted HR 2.13 and 2.99, respectively). These data show fludarabine-based PBPC transplantation overcomes the risk of graft-failure in patients with BMFS, although rapid donor T-cell engraftment associated with this approach appears to increase the risk of chronic-GVHD. (Clinicaltrials.gov identifier: NCT00003838).

Increased expression of complement regulators CD55 and CD59 on peripheral blood cells in patients with EAHEC O104:H4 infection

Background

An outbreak of Shiga Toxin 2 (Stx-2) producing enterohemorrhagic and enteroaggregative E.coli (EAHEC) O104H4 infection in May 2011 caused enterocolitis and an unprecedented high 22% rate of hemolytic uremic syndrome (HUS). The monoclonal anti-C5 antibody Eculizumab (ECU) has been used experimentally in EAHEC patients with HUS but treatment efficacy is uncertain. ECU can effectively prevent hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) caused by a lack of complement-regulating CD55 and CD59 on blood cells. We hypothesized a low expression of CD55 and CD59, as seen in PNH, might correlate with HUS development in EAHEC patients.

Methods

76 EAHEC patients (34 only gastrointestinal symptoms [GI], 23: HUS, 19: HUS and neurological symptoms [HUS/N]) and 12 healthy controls (HC) were tested for the expression of CD55 and CD59 on erythrocytes and leukocytes retrospectively. Additionally, the effect of Stx-2 on CD55 and CD59 expression on erythrocytes and leukocytes was studied ex vivo.

Results

CD55 expression on erythrocytes was similar in all patient groups and HC while CD59 showed a significantly higher expression in HUS and HUS/N patients compared to HC and the GI group. CD55 and CD59 expression on leukocytes and their subsets was significantly higher in all patient groups compared to HC regardless of treatment type. However, CD59 expression on erythrocytes was significantly higher in HUS and HUS/N patients treated combined with plasma separation (PS) and ECU compared to HC. Adding Stx-2 ex vivo had no effect on CD55 and CD59 expression on leukocytes from HC or patients.

Conclusion

HUS evolved independently from CD55 and CD59 expression on peripheral blood cells in EAHEC O104:H4 infected patients. Our data do not support a role for CD55 and CD59 in HUS development during EAHEC O104:H4 infection and point to a different mechanism within the complement system for HUS development in EAHEC patients.