Natural history of paroxysmal nocturnal hemoglobinuria

Classical Paroxysmal Nocturnal Hemoglobinuria Presenting With Severe Anemia and Pigmented Acute Kidney Injury

Paroxysmal nocturnal hemoglobinuria is a rare form of intravascular hemolysis caused by an acquired deficiency of complement regulatory glycoproteins. In our case, a 53-year-old male presented with fatigue, discoloration of urine, and reduced urine output. Preliminary investigations showed severe anemia (3.7 g/dl) and hyperkalemia (7.6 mmol/L) in the setting of acute kidney injury, requiring urgent dialysis. Four units of packed cell volumes were transfused for the correction of anaemia. Following initial stabilization, flow cytometry and a fluorescein-labeled proaerolysin (FLAER) study showed a total deficiency of CD59 in 95.92% of granulocytes and a 97.14% deficiency in monocytes. A bone marrow biopsy showed erythroblast hyperplasia confirming the diagnosis of classical paroxysmal nocturnal hemoglobinuria. The patient was treated with steroids, androgens, and iron supplementation and made a complete recovery with a near-total resolution of his acute kidney injury. This paper aims to review the clinical features and investigations in order to focus on acute kidney injury as an outcome of paroxysmal nocturnal hemoglobinuria.

Portal vein thrombosis as the first presentation of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired clonal hematopoietic stem cell disorder, characterized by hemolytic anemia, bone marrow failure and thrombosis. Portal vein thrombosis (PVT) is relatively rare in patients with PNH. In this paper, we reported PVT as the first clinical presentation of PNH in a female patient. PVT related symptoms resolved after anticoagulation therapy.

Low Rate of Clinically Evident Extravascular Hemolysis in Patients with Paroxysmal Nocturnal Hemoglobinuria Treated with a Complement C5 Inhibitor: Results from a Large, Multicenter, US Real-World Study

Purpose

Most patients with paroxysmal nocturnal hemoglobinuria (PNH) treated with a complement protein 5 (C5) inhibitor achieve full control of terminal complement activity and intravascular hemolysis. The minority remains anemic and transfusion dependent despite this control. Etiology for ongoing anemia is multifactorial and includes bone marrow failure, breakthrough hemolysis, extravascular hemolysis (EVH) and nutritional deficiencies.

Patients and Methods

To evaluate the potential etiologies of hemoglobin levels <10 g/dL despite receiving C5 inhibitor therapy, we performed a retrospective US chart review of adult patients with PNH and treated for at least 12 months with eculizumab (n=53), ravulizumab (n=32), or eculizumab followed by ravulizumab (n=15). Clinically evident EVH was defined as at least one transfusion, reticulocyte count ≥120×10⁹/L and hemoglobin level ≤9.5 g/dL. Safety data were not collected. Mean treatment duration was 26.5±17.2 months.

Results

Treatment with C5 inhibitors significantly improved hemoglobin, lactate dehydrogenase, and number of transfusions versus baseline. Among the patients with hemoglobin <10 g/dL during the last 6 months of treatment (n=38), one patient (eculizumab) had clinically evident EVH, and 10 patients had active concomitant bone marrow failure. Bone marrow failure was a major contributor to hemoglobin <10 g/dL and transfusion dependence; clinically evident EVH was uncommon.

Conclusion

A range of hematologic causes need to be considered when evaluating anemia in the presence of treatment with a C5 inhibitor.

The role of the alternative pathway in paroxysmal nocturnal hemoglobinuria and emerging treatments

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by uncontrolled activation of the terminal complement pathway, leading to intravascular hemolysis (IVH) and a prothrombotic state. Treatment with terminal complement (C5) inhibitors, the current standard of care, suppresses IVH and reduces the risk of thrombosis and the associated morbidity and mortality. Opportunities exist to further improve care by alternative modes of administration and the reduction of clinically significant anemia and transfusion dependence caused by extravascular hemolysis in some patients.

AREAS COVERED

This review describes the pathophysiology of PNH, provides an overview of the current standard of care, and discusses potential avenues for enhancing patient care, with a focus on the literature describing new and emerging treatments that target the alternative pathway. Emerging treatments include biosimilars and novel C5 inhibitors as well as agents with novel mechanisms of action that target the proximal complement pathways (C3 inhibitors, factor B inhibitors, and factor D inhibitors).

EXPERT OPINION

Alternative complement pathway inhibitors may offer further benefit as long as terminal complement is completely inhibited to reduce IVH and disease activity. This may lead to improvements in adherence and health-related quality of life for patients with PNH.

Generalized pulp canal obliteration in a patient on long-term glucocorticoids: a case report and literature review

BACKGROUND

The calcification of the tooth pulp is a pathological condition that occurs in response to various factors. A uncommon haematological condition known as paroxysmal nocturnal haemoglobinuria (PNH) is characterized by bouts of haemolysis, and it requires long-term use of glucocorticoids (GCs).

CASE PRESENTATION

A female patient who was diagnosed with PNH and had a history of long-term use of GCs came to our department for root canal therapy (RCT) for teeth 25, 26, and 27. The radiographs showed generalized pulp canal obliteration (PCO) in most of the patients. None of these teeth (25, 26, or 27) were sensitive to percussion, and they did not respond to thermal or electrical sensitivity tests. A diagnose of pulp necrosis was made for these teeth. RCT was carried out with the help of an oral microscope, and then a prosthodontic procedure was created for the teeth.

CONCLUSIONS

Based on the patient's long history use of GCs and a series of related studies, we conclude that the long-term usage of GCs contributes significantly to the onset of PCO.

Pregnancy in paroxysmal nocturnal hemoglobinuria: from survival to life

Background. Pregnancy in paroxysmal nocturnal hemoglobinuria (PNH) patients has historically been a high-risk situation. The combination of chronic complement-mediated hemolysis caused by the disease and physiological activation of the complement system during pregnancy, significantly worsened the prognosis for the life. For a long time, there were no effective methods for the PNH treatment, and pregnancy in patients seemed to be extremely risky, as it significantly increased the risk of life-threatening complications. The advent of targeted therapy with eculizumab turned the prognosis of this disease upside down: patients began not only to survive, but also to live comparable to healthy people. A comparative analysis of the course and outcomes of pregnancy in patients with PNH treated with eculizumab and in patients without targeted therapy was carried out. Aim. The study was to evaluate the course and outcomes of pregnancy in patients with PNH, depending on the therapeutic approach. Materials and methods. We analyzed data from 57 pregnancies in 49 women (31 used eculizumab, 26 with supportive care only) observed at the Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology or with remote consultation (23 clinics from 19 cities of Russia). Results. The high probability of pregnancy complications and its adverse outcomes outside of targeted therapy indicates the vital need for its use: all observations were accompanied by complications of varying severity. The course of pregnancy with the eculizumab is generally more favorable: an apparently higher rate of live births and a lower likelihood of complications are registered. Without increasing the incidence of complications, eculizumab significantly improves pregnancy outcomes for both mother and fetus, and does not adversely affect the health of newborns. Conclusion. Thus, eculizumab allows not only to increase the survival rate of patients with PNH, but also to comprehensively improve their quality of life, including the possibility of safe childbirth.

Safety and efficacy of pegcetacoplan in paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, hematologic disease characterized by complement-mediated hemolysis, thrombosis, and various degrees of bone marrow dysfunction. Until recently, C5 inhibition with eculizumab or ravulizumab represented the only therapies approved for patients with PNH by the United States Food and Drug Administration (US FDA). Although C5-inhibitors reduce PNH-related signs and symptoms, many patients continue to exhibit persistent anemia and require frequent blood transfusions. In May 2021, pegcetacoplan became the third US FDA-approved treatment for adults with PNH, and the first to target C3, a complement component upstream of C5. The novel strategy of inhibiting proximal complement activity with pegcetacoplan controls C5-mediated intravascular hemolysis and prevents C3-mediated extravascular hemolysis. Here, we review the results from multiple pegcetacoplan clinical studies on the efficacy and safety of pegcetacoplan treatment in adults with PNH. This review summarizes findings from three studies in complement-inhibitor-naïve patients with PNH (PADDOCK [phase Ib], PALOMINO [phase IIa], PRINCE [phase III; pegcetacoplan versus standard treatment excluding complement-inhibitors]), and one phase III study (PEGASUS) that compared eculizumab to pegcetacoplan in patients who remained anemic (hemoglobin levels < 10.5 g/dL) despite stable eculizumab treatment (⩾3 months). These studies found that pegcetacoplan contributed to superior improvements in primary and secondary endpoints related to hemoglobin levels and other hematologic parameters and provided effective management of anemia and anemia-related complications (i.e. transfusion burden, reticulocyte production, and fatigue). Furthermore, we summarize results from the 32-week open-label period from the PEGASUS trial, which confirmed the long-term safety and durable efficacy of pegcetacoplan as demonstrated by sustained improvements in clinical and hematologic outcomes in pegcetacoplan-treated patients. Pegcetacoplan is approved for the treatment of adults with PNH in the United States (Empaveli™) and for adult patients who remain anemic after at least 3 months of stable C5-inhibitor therapy in the European Union (Aspaveli®) and Australia (Empaveli; also approved for patients intolerant to C5-inhibitors).

The cost-effectiveness, of pegcetacoplan compared with ravulizumab for the treatment of paroxysmal nocturnal hemoglobinuria, in a UK setting

Aim: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder characterized by hemolytic anemia, bone marrow failure and thrombosis. We evaluated, the cost-effectiveness of pegcetacoplan, a novel proximal C3 inhibitor, versus ravulizumab in patients with PNH and hemoglobin levels <10.5 g/dl despite eculizumab treatment in the UK healthcare and social services setting. Materials & methods: A Markov cohort framework model, based on the data from the pivotal trial of pegcetacoplan (PEGASUS/NCT03500549), evaluated lifetime costs and outcomes. Patients transitioned through 3 PNH hemoglobin level/red blood cell transfusion health states. Results: Pegcetacoplan provides lower lifetime costs/greater quality-adjusted life years (£6,409,166/14.694QALYs, respectively) versus ravulizumab (£6,660,676/12.942QALYs). Conclusion: Pegcetacoplan is associated with enhanced anemia control, greater QALYs and reduced healthcare costs versus ravulizumab in the UK healthcare and social services setting.

Clinicopathological Profile of Paroxysmal Nocturnal Hemoglobinuria among Omani Patients: A Case Series

We aimed to estimate the nature and prevalence of paroxysmal nocturnal hemoglobinuria (PNH) among Omani patients. We performed a retrospective review of all patients who were tested for PNH by flow cytometry at the Sultan Qaboos University Hospital, Muscat, between 2012 and 2019. Manifestations, treatment modalities, and outcomes were assessed. A total of 10 patients were diagnosed or were on follow-up for PNH (median age 22.5 years). Clinical manifestations included fatigue (80%) and anemia (70%). Six patients had classical PNH with hemolysis, three had PNH in the context of aplastic anemia, and one patient had subclinical PNH. The median total clone size (type II + III) for neutrophils was 95.5 (range: 1.5-97) (FLAER/CD24) and for monocytes was 91.6 (range = 0.04-99) (FLAER/CD14). Four patients had clone sizes > 50% at the time of diagnosis. The median follow-up period of the patients was 62 months (range = 8-204 months). One patient suffered thrombosis. Three patients were on immunosuppressant agents, five were initiated on eculizumab, and four had a bone marrow transplant. No deaths were reported in the cohort. The estimated average incidence of PNH among Omani patients was 1.5 per 5 000 000. PNH is rare in the Omani population. The predominant presentation is hemolytic anemia.

The importance of terminal complement inhibition in paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic hematologic disorder associated with inappropriate terminal complement activity on blood cells that can result in intravascular hemolysis (IVH), thromboembolic events (TEs), and organ damage. Untreated individuals with PNH have an increased risk of morbidity and mortality. Patients with PNH experiencing IVH often present with an elevated lactate dehydrogenase (LDH; ⩾ 1.5 × the upper limit of normal) level which is associated with a significantly higher risk of TEs, one of the leading causes of death in PNH. LDH is therefore used as a biomarker for IVH in PNH. The main objective of PNH treatment should therefore be prevention of morbidity and mortality due to terminal complement activation, with the aim of improving patient outcomes. Approval of the first terminal complement inhibitor, eculizumab, greatly changed the treatment landscape of PNH by giving patients an effective therapy and demonstrated the critical role of terminal complement and the possibility of modulating it therapeutically. The current mainstays of treatment for PNH are the terminal complement component 5 (C5) inhibitors, eculizumab and ravulizumab, which have shown efficacy in controlling terminal complement-mediated IVH, reducing TEs and organ damage, and improving health-related quality of life in patients with PNH since their approval by the United States Food and Drug Administration in 2007 and 2018, respectively. Moreover, the use of eculizumab has been shown to reduce mortality due to PNH. More recently, interest has arisen in developing additional complement inhibitors with different modes of administration and therapeutics targeting other components of the complement cascade. This review focuses on the pathophysiology of clinical complications in PNH and explores why sustained inhibition of terminal complement activity through the use of complement inhibitors is essential for the management of patients with this chronic and debilitating disease.

Long-term safety and efficacy of ravulizumab in patients with paroxysmal nocturnal hemoglobinuria: 2-year results from two pivotal phase 3 studies

OBJECTIVES

The complement component 5 (C5) inhibitor ravulizumab demonstrated non-inferiority to eculizumab following 26 weeks of treatment in complement inhibitor-naïve and complement inhibitor-experienced patients with paroxysmal nocturnal hemoglobinuria (PNH; studies 301 and 302, respectively). This study aims to describe the results of both studies from 27 weeks to 2 years.

METHODS

Patients (N = 441) continued to receive ravulizumab throughout the extension period. Efficacy endpoints included lactate dehydrogenase (LDH) normalization, transfusion avoidance and fatigue score (FACIT-F). Safety analyses were also performed.

RESULTS

From 27 weeks to 2 years, improvements in LDH levels were maintained in both study populations. Transfusion avoidance was maintained in 81.9% (study 301) and 85.6% (study 302) of patients, and FACIT-F scores remained stable. Ravulizumab was well tolerated, and the incidence of adverse events (AEs) were similar between patients of both studies. Incidence of serious AEs deemed related to ravulizumab treatment was low (<3%).

CONCLUSIONS

This study reports, to date, the longest period of follow-up in over 400 patients with PNH treated with ravulizumab (662 patient-years). Long-term, ravulizumab demonstrated durable efficacy and was well tolerated, highlighting the importance of C5 inhibitors as the mainstay of PNH treatment.

Composite endpoint to evaluate complement inhibition therapy in patients with paroxysmal nocturnal hemoglobinuria

This study developed and explored a novel composite endpoint to assess the overall impact that treatment can have on patients living with paroxysmal nocturnal hemoglobinuria (PNH). Candidate composite endpoint variables were selected by a group of experts and included: lactate dehydrogenase levels as a measure of intravascular hemolysis; complete terminal complement inhibition; absence of major adverse vascular events, including thrombosis; absence of any adverse events leading to death or discontinuation of study treatment; transfusion avoidance; and improvements in fatigue‐related quality of life as determined by the Functional Assessment of Chronic Illness Therapy (FACIT)‐Fatigue score. From these variables, a novel composite endpoint was constructed and explored using data collected in the ravulizumab PNH Study 301 (NCT02946463). Thresholds were defined and reported for each candidate variable. Five of the six candidate variables were included in the final composite endpoint; the FACIT‐Fatigue score was excluded. Composite endpoint criterion was defined as patients meeting all five selected individual component thresholds. All patients in the ravulizumab arm achieved complete terminal complement inhibition and a reduction in lactate dehydrogenase levels; 51.2% and 41.3% of patients in the ravulizumab arm and eculizumab arm, respectively, achieved all composite endpoint component thresholds (treatment difference: 9.4%; 95% confidence interval: −3.0, 21.5). The composite endpoint provided a single and simultaneous measurement of overall benefit for patients receiving treatment for PNH. Use of the composite endpoint in future PNH research is recommended to determine clinical benefit, and its use in health technology assessments should be evaluated.

Paroxysmal nocturnal haemoglobinuria, diagnosis and haematological findings, first report from Iran, model for developing countries

Since paroxysmal nocturnal haemoglobinuria (PNH) was first described in 1881, the diagnosis and follow-up patients diagnosed with the illness has remained an area of concern, with several different techniques of varying sensitivity having been described in the literature for both the diagnosis and monitoring treatment of the disease. PNH is a rare and life-threatening disease that manifests symptoms of haemolytic anaemia. Hence, a quick and reliable technique for precise diagnosis would be crucial. PNH patients who have previously been diagnosed with aplastic anaemia or myelodysplastic syndrome carry small PNH clones and for more than a century traditional method with low sensitivity was used for such patients. In 2010, the International Clinical Cytometry Society described a highly sensitive method for detection and quantification of different types of PNH clones using multi-colour flow cytometry. In this method, a three-colour flow cytometer is essential to detect PNH affected cells amongst monocytes and granulocytes. This started a new era in the diagnosis of patients who carry small clones of PNH cells. Before this, flow cytometric analysis was used only for detection of PNH cells amongst erythrocytes. By using flow cytometry instruments with more light sources, the sensitivity of detection and quantification of PNH clones would be augmented. However, standardisation and crosstalk compensation would be the most concerning issue. For the first time in Iran, we set up and standardised multi-colour flow cytometry technique to detect PNH cells in erythrocytes and leukocytes at Payvand medical laboratory.

Difficulties in diagnosing paroxysmal nocturnal hemoglobinuria in a municipal internal disease hospital

Background: The purpose of this work is to present a case of paroxysmal nocturnal hemoglobinuria in the clinical practice of an internist for the purpose of differential diagnosis with other diseases with the jaundice syndrome in a city hospital. Clinical case description: Patient H., 51-year-old, was seen at the emergency department of the city hospital due to the periodic appearance of jaundice with dark-colored urine and fever. The physical and laboratory examination methods revealed an enlargement of the spleen, signs of mild hemolytic anemia, severe thrombocytopenia, a significant increase in the markers of cytolysis and cholestasis. Proteinuria and cylindruria were noted in the urine analysis. In terms of a differential diagnosis, Gilberts syndrome, viral hepatitis, hemorrhagic fever were considered. Conclusion: Based on the data obtained, hemolytic and uremic syndromes were suspected. A therapy with iron preparations, vitamin B12, infusions of glucose and saline was applied with the positive clinical and laboratory dynamics. GPI-linked glycoproteins were determined on the surface of red blood cells (CD59), neutrophils (CD 24/FLAER), and monocytes by FLAER-/CD14 flow cytometry, which confirmed the diagnosis of paroxysmal nocturnal hemoglobinuria.

Effect of eculizumab treatment in patients with paroxysmal nocturnal hemoglobinuria with or without high disease activity: Real-world findings from the International Paroxysmal Nocturnal Hemoglobinuria Registry

BACKGROUND

The effects of eculizumab treatment in paroxysmal nocturnal hemoglobinuria (PNH) patients with or without high-disease activity (HDA), defined by LDH ≥ 1.5 × ULN and history of major adverse vascular events (MAVEs; including thrombotic events [TEs]); anemia; and/or physician-reported abdominal pain, dyspnea, dysphagia, erectile dysfunction, fatigue, and/or hemoglobinuria, in the International PNH Registry were evaluated.

METHODS

Registry patients were stratified by baseline HDA and eculizumab-treatment status. Longitudinal changes in laboratory and clinical PNH-related endpoints were evaluated using linear mixed models (continuous variables) or Poisson regression (incidence rates).

RESULTS

As of May 1, 2017, 3009 patients (HDA/eculizumab-treated, n = 913; HDA/never-treated, n = 651; no-HDA/eculizumab-treated, n = 173; no-HDA/never-treated, n = 1272) were analyzed. Higher proportions of eculizumab-treated patients had HDA and history of MAVEs. In patients with and without HDA, respectively, eculizumab treatment resulted in reductions from baseline for (1) LDH ratio (mean [SD]: -5.3 [4.0] and -2.3 [3.8]); (2) incidence rate ratio (IRR) for MAVEs (-80% and -70%); (3) IRR for TEs (-80% for both); and (4) units of red blood cell transfusions per year (from 6.8 to 2.8 and 3.6 to 2.5 units).

CONCLUSIONS

Eculizumab treatment in a real-world setting improved outcomes, including substantial decreases in hemolysis, MAVE rates, TEs, and transfusions in PNH patients regardless of HDA.

Pegcetacoplan for Paroxysmal Nocturnal Hemoglobinuria

Approximately a third of patients with paroxysmal nocturnal hemoglobinuria (PNH) remain transfusion dependent or have symptomatic anemia despite treatment with a C5 inhibitor. Pegcetacoplan inhibits complement proximally at the level of C3 and is highly effective in treating persistent anemia resulting from C3-mediated extravascular hemolysis. We describe the rationale for C3 inhibition in the treatment of PNH and discuss preclinical and clinical studies using pegcetacoplan and other compstatin derivatives. We propose an approach for sequencing complement inhibitors in PNH.

The spectrum of paroxysmal nocturnal hemoglobinuria clinical presentation in a Brazilian single referral center

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder caused by the expansion of a hematopoietic clone harboring a somatic genetic variant in the PIG-A gene translating into a wide spectrum of clinical and laboratory changes, from intravascular hemolysis, thrombosis, and bone marrow failure to subclinical presentation. In this study, we retrospectively analyzed 87 consecutive cases (39 women; median follow-up, 18 months; range, 0–151 months) in whom a PNH clone was detected by flow cytometry between 2006 and 2019 seen at a single Brazilian referral center. The median age at diagnosis was 29 years (range, 8 to 83 years); 29 patients (33%) were initially classified as PNH/bone marrow failure, 13 (15%) as classic PNH, and 45 (52%) as subclinical PNH. The median overall survival (OS) of the entire cohort was not reached during follow-up, without significant differences between groups. At diagnosis, the median PNH clone size was 2.8% (range, 0 to 65%) in erythrocytes and 5.4% (range, 0 to 80%) in neutrophils. Fourteen patients experienced clone expansion during follow-up; in other 14 patients the clone disappeared, and in 18 patients it remained stable throughout the follow-up. A subclinical PNH clone was detected in three telomeropathy patients at diagnosis, but it was persistent and confirmed by DNA sequencing in only one case. In conclusion, PNH presentation was variable, and most patients had subclinical disease or associated with marrow failure and did not require specific anticomplement therapy. Clone size was stable or even disappeared in most cases.

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.

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.

Unmanipulated haploidentical donor and matched unrelated donor hematopoietic stem cell transplantation in patients with paroxysmal nocturnal hemoglobinuria: a single-center study

We analyzed the outcomes of 32 patients with paroxysmal nocturnal hemoglobinuria (PNH) who underwent either a haploidentical donor (HID) or a matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT). Seventeen patients received an HSCT from an HID and 15 patients received an HSCT from an MUD. The median follow-up time of the surviving patients was 36 months (range: 12-96 months). No significant differences were observed in the 3-year overall survival (OS) between the HID and MUD cohorts (74.1%±11.4% vs. 93.3%±6.4%, respectively, p=.222) or in the 3-year failure-free survival (68.8%±11.8% vs. 86.7%±8.8%, respectively, p=.307). Treatment-related mortality occurred in five patients. A univariate analysis of risk factors revealed platelet engraftment failure negatively impacted OS and FFS. We conclude that HID and MUD-HSCT are feasible and can be effective options for those PNH patients with concomitant bone marrow failure, recurrent life-threatening thrombosis, and uncontrollable hemolysis.

Current Opinions on the Clinical Utility of Ravulizumab for the Treatment of Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder of hematopoietic stem cells genetically defined by the acquisition of somatic mutations in the X-linked phosphatidylinositol glycan anchor biosynthesis, class A (PIGA) gene. PIGA is essential for the synthesis of glycosyl phosphatidylinositol (GPI) anchor proteins and its mutations result in a deficiency of such molecules on the membrane of blood cells derived from the mutant clone. In particular, the lack of the GPI-linked complement regulatory proteins CD55 and CD59 is responsible for the increased sensitivity of PNH erythrocytes to complement-mediated destruction. Indeed, the classical clinical picture of PNH includes signs and symptoms of intravascular hemolysis along with variable degrees of cytopenia and a strong tendency to thrombosis, hallmarks of the disease. Before the introduction of anti-complement inhibitors, PNH was characterized by a high mortality primarily due to thrombotic events. The approval of the terminal anti-complement inhibitor eculizumab in 2007 introduced a paradigm shift in the treatment of the disease with improvement of the chronic hemolytic process and dramatic reduction of the thrombotic rate. However, eculizumab has a relatively short half-life when considering a life-long treatment, with obvious consequences as to the quality of life of treated patients necessitating relatively frequent drug administrations. Moreover, up to 30% of PNH patients undergoing eculizumab therapy show a suboptimal response, continuing to require red cell transfusions because of extravascular hemolysis or breakthrough hemolytic episodes. In 2019, the FDA approved the second-generation C5 inhibitor ravulizumab, a long-lasting agent with a better control of disease manifestations. Herein, we discuss the use of ravulizumab in PNH, its differences with first-generation C5 inhibitors, the research evidence supporting the safety and efficacy of this drug and its impact on costs for health systems and quality of life of PNH patients.

Phase 2 study of danicopan in patients with paroxysmal nocturnal hemoglobinuria with an inadequate response to eculizumab

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.

No impact of Asian ethnicity on EORTC QLQ-C30 scores: Group differences and differential item functioning in paroxysmal nocturnal hemoglobinuria

BACKGROUND

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening terminal-complement-mediated disease resulting in intravascular hemolysis and thrombosis with significant morbidity and premature mortality. There exists no disease-specific quality-of-life (QOL) measure for PNH. Its QOL effects resemble those of hematologic cancers, which supports the use of cancer-specific QOL measures in PNH clinical trials. The European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 has published norms for many European and North American countries, but not for Asian countries. We investigated differences by Asian ethnicity in scores and item function on the EORTC QLQ-C30.

METHODS

This secondary analysis focused on two non-inferiority PNH trials (301 and 302) comparing eculizumab and ravulizumab (n = 441). Analysis of covariance examined the main effect of Asian ethnicity on baseline EORTC QLQ-C30 scores, after adjusting for propensity scores encompassing trial, demographic and clinical factors. Mixed modeling of longitudinal data compared subscale scores in Asian vs. non-Asian patients, after propensity adjustment. Differential item function (DIF) was examined using ordinal regression models at baseline and longitudinally, to predict item score from total score, ethnicity, and their interaction to test for uniform DIF (significant main effect for Asian) and non-uniform DIF (significant Asian-by-total-score interaction).

RESULTS

Of the 15 baseline domains, Asian patients scored slightly better on role and emotional functioning and slightly worse on constipation and diarrhea (0.22 < Cohen's d < 0.36). In longitudinal models, Asians reported slightly higher appetite loss, diarrhea, and financial difficulties than non-Asians (R2 increment < 0.0005). There was negligible uniform and non-uniform DIF, i.e., R2 0 to 0.018, far below Zumbo's (1999) criterion of 0.13. On average there were larger differences from norms for Asians (mean = 0.05, sd = 0.44) than non-Asians (mean = -0.07, sd = 0.36), but the size and direction of the differences varied considerably by domain, age, and gender.

CONCLUSION

When compared to norms, Asian patients showed no systematic biases. DIF results supported this finding. We conclude that Asian ethnicity does not impact interpretation of EORTC QLQ-C30 scores.

Norm-based comparison of the quality-of-life impact of ravulizumab and eculizumab in paroxysmal nocturnal hemoglobinuria

Aims

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and life-threatening intravascular hematologic disorder with significant morbidity and premature mortality. Clinical trials (NCT02946463 and NCT03056040) comparing ravulizumab with eculizumab for PNH have supported the non-inferiority of the former and similar safety and tolerability. This secondary analysis compared PNH trial participants after 26 weeks on either treatment (n = 438) to a general-population sample (GenPop) (n = 15,386) and investigated response-shift effects.

Methods

Multivariate analysis of covariance (MANCOVA) investigated function and symptom scores on the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 of people with PNH as compared to GenPop, after covariate adjustment. Risk-factor groups were created based on clinical indicators known to be associated with worse PNH outcomes, and separate MANCOVAs were computed for lower- and higher-risk-factor groups. Differential item functioning (DIF) analyses examined whether item response varied systematically (1) by treatment, (2) compared to GenPop, and (3) over time, the latter two suggesting and reflecting response-shift effects, respectively. DIF analyses examined 24 items from scales with at least two items. Recalibration response shift was operationalized as uniform DIF over time, reflecting the idea that, for a given group, the difficulty of endorsing an item changes over time, after adjusting for the total subscale score. Reprioritization response shift was operationalized as non-uniform DIF over time, i.e., the relative difficulty of endorsing an item over time changes across the total domain score.

Results

Across PNH risk-factor levels, people who had been on either treatment for 26 weeks reported better-than-expected functioning and lower symptom burden compared to GenPop. Ravulizumab generally showed larger effect sizes. Results were similar for lower and higher PNH risk factors, with slightly stronger effects in the former. DIF analyses revealed no treatment DIF, but did uncover group DIF (9 items with uniform DIF, and 11 with non-uniform) and DIF over time (7 items with uniform DIF, and 3 with non-uniform).

Conclusions

This study revealed that people with PNH on ravulizumab or eculizumab for 26 weeks reported QOL levels better than those of the general population. Significant effects of DIF by group and DIF over time support recalibration and reprioritization response-shift effects. These findings suggest that the treatments enabled adaptive changes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02016-8.

Analysis of baseline characteristics, disease burden and long-term follow-up of 167 patients with Paroxysmal Nocturnal Hemoglobinuria at a single center in Brazil

Paroxysmal nocturnal hemoglobinuria (PNH) can occur as a hemolytic form or small PNH clone found in a patient with bone marrow failure.

METHODS

Describe Brazilian retrospective PNH cohort and identify the impact of disease burden on long-term follow-up.

RESULTS

167 patients, mean age at diagnosis 28.4 (7.1-71.2 years), four years mean interval between onset of cytopenia/aplasia diagnosis and PNH clone detection. Patients were divided into 15 Classic PNH, 55 Hemolytic PNH with bone marrow hypoplasia (PNH/AA), and 97 Subclinical PNH (sc-PNH). Hypocellular bone marrow was found in 89.2%; 55 had hemoglobinuria and 22 thrombosis during monitoring. WBC PNH clone correlated with RBC PNH clone, LDH and cytopenia. Subclinical patients had lower median lower RBC clone (2.0% vs 24.0% vs 57.8%) and WBC clone (11.7% vs 58.8% vs 81.2%) than PNH/AA and Classic PNH, respectively. PNH granulocyte clone was 89.1% in thrombotic patients. Ten-year overall survival 80.4% and mortality in transplanted patients 9.6%. Sepsis was mortality cause in subclinical PNH (16/18, 88.8%), and thrombosis in hemolytic PNH (11/13, 84.6%).

CONCLUSION

Large PNH clones and LDH burden were associated with increased hemolysis and thrombosis risks, while young patients were associated with small PNH clones and subclinical form of the disease. Knowledge of the patient profile, the low risk associated with HSCT, and the use of long-term IST may be instrumental in the clinical management of PNH in restricted-resources countries.

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.

The incidence and prevalence of patients with paroxysmal nocturnal haemoglobinuria and aplastic anaemia PNH syndrome: A retrospective analysis of the UK's population-based haematological malignancy research network 2004-2018

OBJECTIVES

A retrospective population-based study to determine the incidence and prevalence of patients with the rare blood disease paroxysmal nocturnal haemoglobinuria (PNH).

METHODS

All patients were identified by flow cytometric detection of blood cells deficient in glycosylphosphatidylinositol (GPI) linked proteins at a single diagnostic reference laboratory that serves the Yorkshire based, Haematological Malignancy Research Network (HMRN) with a population of 3.8 million.

RESULTS

One hundred and ninety-seven patients with detectable PNH clones at a level of >0.01% in at least two lineages of cells (neutrophils, monocytes and/or red cells) were identified over a 15-year period (2004-2018). Of these, 88% had aplastic anaemia (AA), 8% classical PNH and 3% myelodysplastic syndrome. The overall incidence rate was estimated at 0.35 cases per 100 000 people per year. This equates to 220 cases newly diagnosed in the United Kingdom each year. The overall prevalence rate was 3.81 per 100 000, this equates to an estimated 2400 prevalent cases in the UK. The overall and relative 5-year survival rates were 72% and 82.7%, respectively.

CONCLUSIONS

This study showed that classical haemolytic PNH is a rare disease and represents only a small proportion overall of patients with detectable PNH cells, the majority of which have aplastic anaemia.

Cost-Utility Analysis of Eculizumab for the Treatment of Paroxysmal Nocturnal Hemoglobinuria from the Perspective of the Brazilian Public Health System

OBJECTIVE

To perform a first cost-utility analysis of eculizumab for the treatment of paroxysmal nocturnal hemoglobinuria from the perspective of the Brazilian Unified Health System.

METHODS

A Markov decision model was developed for 35-year-old patients with symptomatic paroxysmal nocturnal hemoglobinuria. We used a cycle length of one month and a time horizon of 20 years. The effectiveness measure was the quality-adjusted life year (QALY). Data were extracted from clinical trials, historical cohorts, and Unified Health System databases. Resource use and costs were estimated from the perspective of the Unified Health System. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

The estimated gain in effectiveness with the use of eculizumab was 1.08 QALY through the incremental cost of R$10,959,375.95. The incremental cost-effectiveness ratio was R$10,139,542.84 per QALY, being 331.92 times greater than the Brazilian gross domestic product per capita. In the deterministic sensitivity analysis, the parameters related to the utilities of health states were associated with greater impact in the model. The results of the probabilistic sensitivity analysis with 1000 simulations evidence that 100% of the simulations were not considered cost-effective with the arbitrated willingness to pay R$30,548.40 and R$91,645.20 per QALY.

CONCLUSIONS

The gain in effectiveness with the use of eculizumab was modest, associated with an unjustifiable incremental cost. Therefore, eculizumab is not a cost-effective drug compared with the current standard of care in the treatment of paroxysmal nocturnal hemoglobinuria from the Brazilian Unified Health System perspective.

Complement Decay-Accelerating Factor is a modulator of influenza A virus lung immunopathology

Clearance of viral infections, such as SARS-CoV-2 and influenza A virus (IAV), must be fine-tuned to eliminate the pathogen without causing immunopathology. As such, an aggressive initial innate immune response favors the host in contrast to a detrimental prolonged inflammation. The complement pathway bridges innate and adaptive immune system and contributes to the response by directly clearing pathogens or infected cells, as well as recruiting proinflammatory immune cells and regulating inflammation. However, the impact of modulating complement activation in viral infections is still unclear. In this work, we targeted the complement decay-accelerating factor (DAF/CD55), a surface protein that protects cells from non-specific complement attack, and analyzed its role in IAV infections. We found that DAF modulates IAV infection in vivo, via an interplay with the antigenic viral proteins hemagglutinin (HA) and neuraminidase (NA), in a strain specific manner. Our results reveal that, contrary to what could be expected, DAF potentiates complement activation, increasing the recruitment of neutrophils, monocytes and T cells. We also show that viral NA acts on the heavily sialylated DAF and propose that the NA-dependent DAF removal of sialic acids exacerbates complement activation, leading to lung immunopathology. Remarkably, this mechanism has no impact on viral loads, but rather on the host resilience to infection, and may have direct implications in zoonotic influenza transmissions.

Exacerbated complement activation and immune deregulation are at the basis of several pathologies induced by respiratory viruses. Here, we report that complement decay-accelerating factor (DAF), which inhibits complement activation in healthy cells, increases disease severity upon influenza A virus (IAV) infection. Remarkably, DAF interaction with IAV proteins, hemagglutinin (HA) and neuraminidase (NA), resulted in excessive complement activation and recruitment of innate and adaptive immune cells, without affecting viral loads. Furthermore, we observed that viral NA directly cleaves DAF and promotes complement activation, providing a possible link between IAV-DAF interaction and pathology. Therefore, our results unveil a novel pathway that could modulate disease severity, which may help to understand the increased pathogenicity of zoonotic and pandemic IAV infections.

Concept confirmation of the Treatment Administration Satisfaction Questionnaire (TASQ) in rare paroxysmal nocturnal hemoglobinuria

Background

This study was conducted to evaluate content validity of the IntraVenous and SubCutaneous Treatment Administration Satisfaction Questionnaires (TASQ-IV and TASQ-SC), for use in a clinical trial population of participants with paroxysmal nocturnal hemoglobinuria (PNH) undergoing eculizumab treatment.

Methods

Participants underwent semi-structured combined brief introduction to disease history and full cognitive debriefing interviews to establish symptoms and key impacts of PNH and to explore the clarity and relevance of both sets of instructions (TASQ-IV and TASQ-SC). The clarity, relevance, response options, and recall period of the TASQ-IV items were also explored.

Results

Ten participants with PNH were recruited. Fatigue was the most commonly reported symptom (n = 7); the most commonly reported impact of PNH was on physical activity (n = 4). Nine participants indicated understanding and relevance of the TASQ-IV instructions; three participants suggested changes. Of the 20 TASQ-IV items, ≥ 15 were considered understandable, relevant and to have suitable response options (n ≥ 8). The TASQ-SC instructions were understood by all participants; seven participants indicated relevance. While a few participants suggested minor changes for the items, these reflected the one-off completion of the measure in an interview setting and were thus not considered sufficient to justify modification of the measure for clinical trial completion.

Conclusions

Most participants understood the TASQ-IV and TASQ-SC instructions (n = 9 and 10, respectively) and the TASQ-IV items were considered clear, relevant and to have suitable response options, demonstrating face and content validity of the instruments for the clinical trial setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-021-00319-9.

Ultradeep Sequencing Analysis of Paroxysmal Nocturnal Hemoglobinuria Clones Detected by Flow Cytometry: PIG Mutation in Small PNH Clones

OBJECTIVES

We aimed to determine whether small paroxysmal nocturnal hemoglobinuria (PNH) clones detected by flow cytometry (FCM) harbor PIG gene mutations with quantitative correlation.

METHODS

We analyzed 89 specimens from 63 patients whose PNH clone size was ≥0.1% by FCM. We performed ultradeep sequencing for the PIGA, PIGM, PIGT, and PIGX genes in these specimens.

RESULTS

A strong positive correlation between PNH clone size by FCM and variant allele frequency (VAF) of PIG gene mutation was identified (RBCs: r = 0.77, P < .001; granulocytes: r = 0.68, P < .001). Granulocyte clone size of 2.5% or greater and RBCs 0.4% or greater by FCM always harbored PIG gene mutations. Meanwhile, in patients with clone sizes of less than 2.5% in granulocytes or less than 0.4% in RBCs, PIG gene mutations were present in only 15.9% and 12.2% of cases, respectively. In addition, there was not a statistically significant positive correlation between FCM clone size and VAF or the presence or absence of a PIG mutation.

CONCLUSIONS

Our results showed that in small PNH clones PIG gene mutations were present in only a small portion without significant correlation to VAF or the presence or absence of a PIG mutation.

Circulating Endothelial Progenitor Cells and Their Relation to Thrombosis in Paroxysmal Nocturnal Hemoglobinuria and Aplastic Anemia

Thrombosis is a leading cause of morbidity and mortality in paroxysmal nocturnal hemoglobinuria (PNH). Multiple factors are responsible for the thrombotic tendency in these patients. Endothelial progenitorcells (EPCs) originate from primitive hematopoietic stem cells. The EPC count is considered indicative of potential damage and restoration capacity in vascular disease; lower EPC counts are deemed as a risk factor in cardiovascular diseases. We aimed to investigate the count of circulating EPCs in PNH and aplastic anemia (AA) patients receiving eculizumab treatment or not receiving treatment and their relationship with thrombosis. Seventeen PNH patients, 18 AA patients, and 10 healthy volunteers were included in the study. The CD309, CD133, and CD34 antibodies were used to determine counts of circulating EPCs using flowcytometry. EPC levels were compared between the PNH, AA, and healthy control groups. Kolmogorov-Smirnov test. ANOVA, Kruskal-Wallis, and Mann-Whitney U testswereperformedto analyze the quantitative data, while χ2 testing was performed to analyze the qualitative data. Therewasnosignificantdifference in EPC levelsbetweenpatientswithandwithout a history of thrombosis (P > 0.05). Further, therewasnosignificantdifference in thelevels of EPCsbetweenthe AA and PNH groups (P  > 0.05). However, there was a significant positive correlation between levels of EPCs and lactate dehydrogenase (LDH) in multivariate analysis (P < 0.05). The study findings suggest that hemolysis promotes vascular endothelial and new blood vessel formation. Increased EPCs in PNH may indirectly indicatevascular endothelial damage in PNH.

Clinical characteristics and therapeutic outcomes of paroxysmal nocturnal hemoglobinuria patients in Turkey: a multicenter experience

The aim of this study is to collect paroxysmal nocturnal hemoglobinuria (PNH) patient data from hematology centers all over Turkey in order to identify clinical features and management of PNH patients. Patients with PNH were evaluated by a retrospective review of medical records from 19 different institutions around Turkey. Patient demographics, medical history, laboratory findings, and PNH-specific information, including symptoms at the diagnosis, complications, erythrocyte, and granulocyte clone size, treatment, and causes of death were recorded. Sixty patients (28 males, 32 females) were identified. The median age was 33 (range; 17-77) years. Forty-six patients were diagnosed as classic PNH and 14 as secondary PNH. Fatigue and abdominal pain were the most frequent presenting symptoms. After eculizumab became available in Turkey, most of the patients (n = 31/46, 67.4%) were switched to eculizumab. Three patients with classic PNH underwent stem cell transplantation. The median survival time was 42 (range; 7-183 months) months. This study is the first and most comprehensive review of PNH cases in Turkey. It provided us useful information to find out the differences between our patients and literature, which may help us understand the 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.

Markers of Thrombin Generation and Inflammation in Patients with Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) presents with intravascular hemolysis, bone marrow failure and thrombosis. Various studies have reported geographic and ethnic variation in prevalence of thrombosis in PNH. There is limited data on thrombosis in PNH from the Indian subcontinent. In this study we describe disease burden and risk factors for thrombosis in 18 Indian PNH patients. We studied markers of thrombin generation (Thrombin-antithrombin complexes; TAT and D-Dimer), endothelium and platelet activation (soluble P-selectin) and inflammation (interleukin-6; IL-6) in PNH patients and compared their levels with healthy controls. Thrombosis was identified in 17% of PNH patients. TAT, sP-selectin and D-Dimer levels were significantly elevated in PNH patients (TAT: 5.06 ± 1.08 ng/ml; sP-selectin: 80.57 ± 19.5 ng/ml; D-Dimer mean: 936 ng/ml 95% CI 559, 1310) compared to control population (TAT: 3.39 ± 0.769 ng/ml P = 0.016; sP-selectin: 44.67 ± 5.17 ng/ml P = 0.002). Using Youden's J statistic, the cut-off values for TAT and sP-selectin in our cohort of PNH patients were 2.90 ng/ml and 58.41 ng/ml respectively. TAT, sP-selectin and D-Dimer levels were elevated beyond the cut-off values in PNH patients with thrombosis compared to those without thrombosis. A positive correlation was noted between TAT, sP-selectin and D-Dimer levels. Increased TAT, sP-selectin, and D-Dimer levels may indicate impending thrombosis in PNH.

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.

How I treat paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, clonal, complement-mediated hemolytic anemia with protean manifestations. PNH can present as a hemolytic anemia, a form of bone marrow failure, a thrombophilia, or any combination of the above. Terminal complement inhibition is highly effective for treating intravascular hemolysis from PNH and virtually eliminates the risk of thrombosis, but is not effective for treating bone marrow failure. Here, I present a variety of clinical vignettes that highlight the clinical heterogeneity of PNH and the attributes and limitations of the 2 US Food and Drug Administration-approved C5 inhibitors (eculizumab and ravulizumab) to treat PNH. I review the concept of pharmacokinetic and pharmacodynamic breakthrough hemolysis and briefly discuss new complement inhibitors upstream of C5 that are in clinical development. Last, I discuss the rare indications for bone marrow transplantation in patients with PNH.