Paroxysmal nocturnal hemoglobinuria: current treatments and unmet needs

Health-related quality of life and influencing factors of patients with paroxysmal nocturnal hemoglobinuria in China

BACKGROUND

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder, leading to various complications and impairments in patients' health-related quality of life (HRQOL). Limited research has been conducted to evaluate the HRQOL of Chinese patients with PNH. Understanding the HRQOL in this specific population is crucial for providing effective healthcare interventions and improving patient' health outcomes. This study aimed to assess HRQOL of Chinese patients with PNH, and identify key determinants.

METHODS

A cross-sectional study was conducted during 2022 to recruit patients with PNH in China. The study population was recruited from PNH China, one of the largest public welfare PNH patient mutual aid organization in China. Data were collected via an online questionnaire including the EQ-5D-5L (5L), and social-demographic and clinical characteristics. Descriptive statistics were employed to summarize the characteristics of the participants and their HRQOL. Multiple linear and logistic regression analyses were adopted to explore key factors affecting HRQOL.

RESULTS

A total of 329 valid questionnaires were collected. The mean (SD) age of the patients was 35.3 (10.0) years, with 52.3% of them being male. The patients reported more problems in Anxiety/Depression (81.5%) and Pain/Discomfort (69.9%) dimensions compared to the other three 5L dimensions. The mean (SD) of 5L health utility score (HUS) and EQ-VAS score were 0.76 (0.21) and 62.61 (19.20), respectively. According to multiple linear regression, initial symptoms (i.e., Anemia [fatigue, tachycardia, shortness of breath, headache] and back pain) and complication of thrombosis were significant influencing factors affecting 5L HUS. Total personal income of the past year, initial symptom of hemoglobinuria and complication of thrombosis were significantly influencing factors of VAS score. Social-demographic and clinical characteristics, such as gender, income, and thrombosis, were also found to be significantly related to certain 5L health problems as well.

CONCLUSION

Our study manifested the HRQOL of PNH patients in China was markedly compromised, especially in two mental-health related dimensions, and revealed several socio-demographic and clinical factors of their HRQOL. These findings could be used as empirical evidence for enhancing the HRQOL of PNH patients in China.

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

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

Pegcetacoplan controls hemolysis in complement inhibitor-naive patients with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterized by complement-mediated hemolysis. Pegcetacoplan is the first C3-targeted therapy approved for adults with PNH (United States), adults with PNH with inadequate response or intolerance to a C5 inhibitor (Australia), and adults with anemia despite C5-targeted therapy for ≥3 months (European Union). PRINCE was a phase 3, randomized, multicenter, open-label, controlled study to evaluate the efficacy and safety of pegcetacoplan vs control (supportive care only; eg, blood transfusions, corticosteroids, and supplements) in complement inhibitor-naive patients with PNH. Eligible adults receiving supportive care only for PNH were randomly assigned and stratified based on their number of transfusions (<4 or ≥4) 12 months before screening. Patients received pegcetacoplan 1080 mg subcutaneously twice weekly or continued supportive care (control) for 26 weeks. Coprimary end points were hemoglobin stabilization (avoidance of >1-g/dL decrease in hemoglobin levels without transfusions) from baseline through week 26 and lactate dehydrogenase (LDH) change at week 26. Overall, 53 patients received pegcetacoplan (n = 35) or control (n = 18). Pegcetacoplan was superior to control for hemoglobin stabilization (pegcetacoplan, 85.7%; control, 0; difference, 73.1%; 95% confidence interval [CI], 57.2-89.0; P < .0001) and change from baseline in LDH (least square mean change: pegcetacoplan, -1870.5 U/L; control, -400.1 U/L; difference, -1470.4 U/L; 95% CI, -2113.4 to -827.3; P < .0001). Pegcetacoplan was well tolerated. No pegcetacoplan-related adverse events were serious, and no new safety signals were observed. Pegcetacoplan rapidly and significantly stabilized hemoglobin and reduced LDH in complement inhibitor-naive patients and had a favorable safety profile. This trial was registered at www.clinicaltrials.gov as NCT04085601.

Thromboembolic events in patients with paroxysmal nocturnal hemoglobinuria (PNH): Real world data of a Greek nationwide multicenter retrospective study

Thrombosis is the most common and a life-threatening complication in patients with Paroxysmal Nocturnal Hemoglobinuria. One-third of patients with PNH experience at least one thromboembolic event during the course of the disease, with thrombosis being the most common cause of death in these patients. The mechanism of thrombosis in PNH is complex and continues to be of great research interest. Since the introduction of C5 complement inhibitors in the treatment of PNH, the incidence of thromboembolic events has decreased substantially. We retrospectively analyzed data concerning the thrombotic episodes of 41 patients with PNH from 14 different national hematology centers in Greece. Sixteen patients (39%) experienced at least one episode of thrombosis, including, seven (43.8%) at diagnosis, seven (43.8%) during the course of the disease and two (12.5%) patients prior to PNH diagnosis. Nearly half of these individuals (n=7, 43.8%) had multiple episodes of thrombosis during the course of their disease. The most common sites of thrombosis were intra-abdominal veins. Three out of 26 patients developed thrombosis while on eculizumab. In none of the 16 patients, the thrombotic event was fatal. Our findings, despite the small number of patients, confirmed that thrombosis continues to be a significant complication of PNH affecting more than one third of the patients.

Attack of the Clones: A Patient With Untreated Aplastic Anemia Presenting With Classical Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired X-linked, clonal hematopoietic stem cell disease. Patients with PNH may complain of vague symptomatology that contributes to the challenge of its diagnosis. This is especially true in the clinical context of a coinciding hematologic disorder. Aplastic anemia (AA) is an additional immune-mediated illness that results in the destruction of hematopoietic precursors and pancytopenia. The authors encourage screening for PNH clones in patients initially diagnosed with AA, treating underlying hematologic disease to prevent clonal expansion, and further research to investigate the effectiveness of eculizumab in an unusual "classical" PNH secondary to AA with hypercellular bone marrow.

The burden of illness of patients with paroxysmal nocturnal haemoglobinuria receiving C5 inhibitors: clinical outcomes and medical encounters from the patient perspective

OBJECTIVES

To assess the clinical and healthcare resource burden among C5 inhibitor (C5i)-treated patients with paroxysmal nocturnal haemoglobinuria (PNH), using patient-reported data.

METHODS

This web-based, cross-sectional survey (01FEB2021-31MAR2021) of adults with PNH treated with eculizumab (France, Germany, UK) or ravulizumab (Germany) included: patient characteristics; treatment patterns/dosage; haematological outcomes (haemoglobin [Hb] levels, transfusions, thrombotic events, breakthrough haemolysis); and medical encounters. Treatment and Hb-level subgroup differences were assessed with statistical significance tests.

RESULTS

Among 71 patients, 98.6% were C5i-treated for ≥3 months. The majority (with reported Hb levels) had levels ≤12.0 g/dL (85.7%; n = 54/63). The mean Hb level was 10.2 g/dL (standard deviation [SD]: 2.0; median 10.0 g/dL). Treatment with above label-recommended doses was reported by 30.4% (eculizumab) and 5.3% (ravulizumab) of patients. Within the past 12 months among patients treated with C5i for ≥1 year: 24.1% had ≥1 transfusion; 3.2% had ≥1 thrombosis; and 28.6% had ≥1 breakthrough haemolysis. Among all patients, 26.8% and 31.0% reported emergency department/room [ER] and inpatient visits, respectively. Mean annual, per-patient all-cause medical encounters were: 0.5 (ER); 1.9 (inpatient); and overall outpatient visits ranged by setting from 2.0 to 6.4. Most encounters were PNH-related, with means of 0.4 (ER); 1.8 (inpatient); and 1.6-5.4 (outpatient). Primary haematological and medical encounter outcomes were similar between treatment as well as Hb-level subgroups, with almost no statistically significant differences.

CONCLUSIONS

Despite at least 3 months of C5i treatment, high proportions of patients with PNH reported low haemoglobin levels and required transfusions and hospitalizations, which suggests remaining unmet needs.

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.

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.