Consenso español para el diagnóstico y tratamiento de la hemoglobinuria paroxística nocturna

Consensus recommendations for optimising the diagnosis and treatment of paroxysmal nocturnal haemoglobinuria in Singapore

Introduction

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare haematologic disease characterised by intravascular haemolysis, thrombophilia and bone marrow failure. There is a lack of established clinical guidance on the screening, diagnosis and manage-ment of PNH in Singapore. A relatively low level of awareness among healthcare professionals regarding PNH manifestations further contributes to diagnostic delays. Additionally, limited access to complement inhibitors, like eculizumab, may delay treatment and impact patient outcomes.

Method

Nine haematologists from different institu-tions in Singapore convened to formulate evidence-based consensus recommendations for optimising the diagnosis and management of patients with PNH and improving access to novel treatments. The experts reviewed the existing literature and international guidelines published from January 2010 to July 2023, focusing on 7 clinical questions spanning PNH screening, diagnostic criteria, investigations, treatment and monitoring of subclinical and classic disease, PNH with underlying bone marrow disorders, and PNH in pregnancy. A total of 181 papers were reviewed to formulate the statements. All experts voted on the statements via 2 rounds of Delphi and convened for an expert panel discussion to finetune the recommendations.

Results

Sixteen statements have been formulated for optimising the screening, diagnosis and management of PNH. Upon confirmation of PNH diagnosis, individuals with active haemolysis and/or thrombosis should be considered for anti-complement therapy, with eculizumab being the only approved drug in Singapore.

Conclusion

The current recommendations aim to guide the clinicians in optimising the screening, diagnosis and management of PNH in Singapore.

Complement Inhibition in Paroxysmal Nocturnal Hemoglobinuria (PNH): A Systematic Review and Expert Opinion from Central Europe on Special Patient Populations

INTRODUCTION

Hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) is complement-mediated due to the lack of complement inhibitors in the hemopoietic cell membranes, making complement inhibition the best approach to manage PNH. Three complement inhibitors are approved by the European Medicines Agency as targeted therapy for PNH: eculizumab and ravulizumab, two humanized monoclonal antibodies targeting the same complement 5 (C5) epitope, approved in 2007 and 2019, respectively, and the more recently approved cyclic peptide, the complement 3 (C3) inhibitor pegcetacoplan. Although national and international PNH treatment guidelines exist, they do not take into consideration the latest clinical trial evidence. Given the lack of evidence-based data for some clinical situations encountered in real life, we identified specific populations of patients who may benefit from switching to proximal C3 from terminal C5 inhibition.

METHODS

The expert recommendations presented here were created using a Delphi-like process by a group of expert PNH specialists across Central Europe. Based on an initial advisory board meeting discussion, recommendations were prepared and reviewed as part of a Delphi survey to test agreement.

RESULTS

Using a systematic approach, literature databases were searched for relevant studies, and 50 articles were reviewed by the experts and included as supporting evidence.

CONCLUSION

Implementation of these recommendations uniformly across healthcare institutions will promote the best use of complement inhibition in managing PNH, and has the potential to positively impact patient outcomes in Central Europe and worldwide.

Paroxysmal nocturnal hemoglobinuria and liver transplantation, a new paradigm

Paroxysmal nocturnal hemoglobinuria (PNH) is a type of hemolytic anemia acquired by the PIG-A gene mutation. This causes a deficiency of a complement regulatory protein, CD59, which results in hemolysis, hemoglobinuria and thrombosis (due to the release of procoagulant factors). Budd-Chiari syndrome is characteristic in these patients and has classically been considered as a contraindication for liver transplantation (LT) due to post-transplant recurrence. Since the approval of eculizumab for the treatment of PHN, disease control is possible and therefore the post-transplant recurrence of thrombotic phenomena involving the liver is avoided.

[Results of phase Ib open multicenter clinical trial of the safety, pharmacokinetics and pharmacodynamics of first biosimilar of eculizumab in untreated patients with paroxysmal nocturnal hemoglobinuria during induction of therapy]

Currently, the main pathogenetic method for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) is the treatment with recombinant monoclonal antibodies that block the C5 component of the complement system. Eculizumab is the first biotechnological drug, which is a monoclonal antibody, with proven clinical efficacy and safety for the treatment of patients with PNH, which is used in world clinical practice. In Russia, in the framework of the state program Development of the pharmaceutical and medical industry for 20132020 was developed Elizaria (JSC GENERIUM) the first biosimilar of the original drug eculizumab.

AIM

To evaluate the pharmacokinetic and pharmacodynamic parameters, as well as safety and immunogenicity parameters of the drug Elizara in the induction phase of therapy in previously untreated patients with PNH.

MATERIALS AND METHODS

The study included 11 patients with PNH aged 26 to 75 years who had not previously received eculizumab. Each of the study participants was injected with the studied drug Elizaria at a dose of 600 mg intravenously once a week for 4 weeks.

RESULTS

During the clinical study, it was noted that the concentration of the studied drug significantly increased by the time the infusion was completed and then gradually decreased to a minimum at the end of the dosing interval. The average concentration of eculizumab 5 minutes before the administration of the study drug at all visits exceeded 35 g/ml, the minimum concentration sufficient to completely inhibit intravascular hemolysis in patients with PNH. The pharmacodynamic efficacy of the drug Elizaria was confirmed by a decrease in the concentration of the membrane-attack complex (MAC) after the first infusion of the drug was maintained at stable levels until visit 5. A persistent decrease in the level of MAC and a four-fold decrease in the average values of lactate dehydrogenase to visit 5 from 1286.4 to 280.9 U/l demonstrated a marked decrease in activity and stabilization of the hemolytic process against the background of the induction of therapy with Elizaria at a dose of 600 mg once a week and confirmed the effecacy of the study drug. Among the 9 adverse events, only 5 had a relationship with the studied drug, including one serious adverse event in the form of an allergic reaction, which, according to the researcher, had a possible cause-effect relationship with the infusion of the studied drug. In 2 patients, low-titer binding anti-drug antibodies were detected without neutralizing activity during treatment with the studied drug, which may indicate its low immunogenicity.

CONCLUSION

The study evaluated the pharmacokinetic and pharmacodynamic properties of the drug Elizaria in the regimen of induction therapy in previously untreated patients with PNH, confirming its efficacy. The study demonstrated the safety and low immunogenicity of the study drug.

Consensus statement for diagnosis and treatment of paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal hemoglobinuria is a chronic, multi-systemic, progressive and life-threatening disease characterized by intravascular hemolysis, thrombotic events, serious infections and bone marrow failure. Paroxysmal nocturnal hemoglobinuria results from the expansion of a clone of hematopoietic cells that due to an inactivating mutation of the X-linked gene PIG-A are deficient in glycosylphosphatidylinositol-linked proteins. Early diagnosis, using flow cytometry performed on peripheral blood, the gold standard test to confirm the diagnosis of paroxysmal nocturnal hemoglobinuria, is essential for improved patient management and prognosis. The traditional therapy for paroxysmal nocturnal hemoglobinuria includes blood transfusion, anti-thrombosis prophylaxis or allogeneic bone marrow transplantation. The treatment that has recently become available is the complement blockade by the anti-C5 monoclonal antibody eculizumab. In this consensus, we are aiming to review the diagnosis and treatment of the paroxysmal nocturnal hemoglobinuria patients, as well as the early recognition of its systemic complications. These procedures express the opinions of experts and have been based on the best available evidence and international guidelines, with the purpose of increasing benefits and reducing harm to patients.

Paroxysmal nocturnal hemoglobinuria: Test to monitor the action of eculizumab treatment

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a somatic mutation in the PIG-A gene, which encodes for glycosylphosphatidylinositol, a phospholipid membrane that anchors proteins like CD55 and CD59. These proteins are inhibitors of the complement-mediated lysis. PNH is diagnosed by flow cytometry, and treatment with eculizumab improves the life quality of patients with severe clinical compromise. The aim of this work was to evaluate a hemolytic test that allows monitoring the blockade of the alternative complement pathway caused by eculizumab (herein MET test).

METHODS

There were analyzed a total of 163 serum samples from nine patients with PNH under treatment with eculizumab and ten healthy volunteers like controls. The patients were evaluated for 6 months. The MET test consisted in incubating red blood cells from patients (RBC_PNH ) with either acidified serum from healthy volunteers and from patients with PNH. The results can be (a) Positive, (b) Blockade profile, or (c) Negative.

RESULTS

Seven patients responded favorably to the eculizumab, and the test evidenced the blockade profile. The two remaining patients were nonresponders to the treatment, with a positive MET test. In these patients, the dose was increased. One responded favorably with a blockade profile, and the other continued to be nonresponder.

CONCLUSIONS

The MET test proved to be a useful tool to monitor the blockade of complement by eculizumab.

Laboratory studies for paroxysmal nocturnal hemoglobinuria, with emphasis on flow cytometry

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal hematopoietic stem cell disorder caused by somatic mutations in the PIG-A gene, leading to the production of blood cells with absent or decreased expression of glycosylphosphatidylinositol-anchored proteins, including CD55 and CD59. Clinically, PNH is classified into three variants: classic (hemolytic), in the setting of another specified bone marrow disorder (such as aplastic anemia or myelodysplastic syndrome) and subclinical (asymptomatic). PNH testing is recommended for patients with intravascular hemolysis, acquired bone marrow failure syndromes and thrombosis with unusual features. Despite the availability of consensus guidelines for PNH diagnosis and monitoring, there are still discrepancies on how PNH tests are carried out, and these technical variations may lead to an incorrect diagnosis. Herein, we provide a brief historical overview of PNH, focusing on the laboratory tests available and on the current recommendations for PNH diagnosis and monitoring based in flow cytometry.

Successful whole-blood exchange transfusion in a patient with paroxysmal nocturnal hemoglobinuria: A case report and literature review

Objective

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal disorder of the hematopoietic stem cells that involves all blood cells. The primary aim of this study was to assess the role of whole-blood exchange (WBE) in treating patients with PNH.

Methods

A 32-year-old male patient was admitted our hospital because of severe anemia. His clinical test results indicated serious hemolysis, with positive anti-I on pretransfusion antibody screening tests. Because immunosuppressive therapy was ineffective and red blood cell (RBC) transfusion may aggravate hemolytic symptoms, the COBE Spectra blood cell separator was used for WBE.

Results

We performed WBE, where 1789 mL of the patient’s blood was removed and replaced with 12 U of packed RBCs, along with 150 mL of frozen plasma and 200 mL of normal saline (total volume, 1883 mL), representing an exchange of 42.5% of the patient’s total blood volume (approximately 4209 mL). The WBE treatment was considered successful. Rapid improvement in clinical signs and symptoms were observed after the WBE transfusion. The patient was discharged from the hospital on the third day after treatment.

Conclusion

Whole-blood exchange may be an applicable emergency treatment for rescuing PNH patients with severe or life-threatening hemolysis.

Renal involvement in paroxysmal nocturnal haemoglobinuria: a brief review of the literature

SUMMARY INTRODUCTION: Paroxysmal Nocturnal Haemoglobinuria (PNH) is an acquired genetic disorder characterized by complement-mediated haemolysis, thrombosis and variable cytopenias. Renal involvement may occur and causes significant morbidity to these patients. OBJECTIVE: To review the literature about pathophysiology and provide recommendations on diagnosis and management of renal involvement in PNH. METHODS: Online research in the Medline database with compilation of the most relevant 26 studies found. RESULTS: PNH may present with acute kidney injury caused by massive haemolysis, which is usually very severe. In the chronic setting, PNH may develop insidious decline in renal function caused by tubular deposits of hemosiderin, renal micro-infarcts and interstitial fibrosis. Although hematopoietic stem cell transplantation remains the only curative treatment for PNH, the drug Eculizumab, a humanized anti-C5 monoclonal antibody is capable of improving renal function, among other outcomes, by inhibiting C5 cleavage with the subsequent inhibition of the terminal complement pathway which would ultimately give rise to the assembly of the membrane attack complex. CONCLUSION: There is a lack of information in literature regarding renal involvement in PNH, albeit it is possible to state that the pathophysiological mechanisms of acute and chronic impairment differ. Despite not being a curative therapy, Eculizumab is able to ease kidney lesions in these patients.

Diagnosis and management of PNH: Review and recommendations from a Belgian expert panel

Despite its considerable morbidity and mortality, paroxysmal nocturnal haemoglobinuria (PNH) is still underdiagnosed. Patients with PNH can suffer from cardiovascular, gastrointestinal, neurological or haematological symptoms and refer to several specialists. The aim of this paper is to review the diagnosis and the management of PNH patients, with the primary focus on identifying high-risk groups. Additionally, the implementation and prognostic value of the defined high-risk groups will be commented on and the management of PNH patients is discussed from a Belgian perspective. Finally, based on the available data, recommendations are provided. Eculizumab is a potent C5 complement inhibitor and reduces intravascular haemolysis and thrombosis in PNH patients and improves their quality of life. As thrombosis is the main cause of death in PNH patients, identifying high-risk PNH patients in need of therapy is essential. Currently, novel complement inhibitors are in development and the first data seem promising. Another challenge in PNH is to identify new markers to assess the thrombotic risk to achieve a better risk-based prophylactic anti-thrombotic management. Finally, because of the low prevalence of the disease, PNH patients should be included in the prospective PNH registry, which will offer new insights on the natural course of the disease and the impact of treatment of PNH.