Pyruvate Kinase Deficiency Research Articles

Relative Bioavailability Studies With Mitapivat: Formulation and Food Effect Assessments in Healthy Subjects.

Pyruvate kinase (PK) deficiency is a rare, hereditary, hemolytic anemia caused by mutations in the PKLR gene encoding the PK enzyme. Mitapivat (previously designated AG-348) is a first-in-class, oral, allosteric activator of PK. We report results from 5 Phase 1 trials in healthy adults to characterize and compare mitapivat pharmacokinetics across different formulations and analyze food effects on mitapivat bioavailability (Studies 1-5). Pharmacokinetic assessments were peak exposure, total exposure, time to maximum plasma concentration of mitapivat, and relative bioavailability (where appropriate). Plasma total exposure of mitapivat was similar in the fasted and fed (high-fat meal or different soft foods) states after capsule, tablet, and pediatric granule formulations. Although mitapivat administration with food reduced the rate of mitapivat absorption (delay in time to maximum plasma concentration; reduction in maximum concentration) versus dosing under fasted conditions, this was not considered clinically relevant, given the lack of effect on total mitapivat exposure. Consequently, the administration instructions for mitapivat relating to food state that "patients may take mitapivat tablets with or without food." These findings will continue to inform clinical studies and development of mitapivat in adult and pediatric patients with hemolytic anemias and may help inform healthcare professionals on mitapivat dosing/administration recommendations in clinical practice.

Evaluation of Glucose 6-Phosphate Dehydrogenase, Pyruvate Kinase, and New Generation Inflammation Biomarkers in Prolonged Neonatal Jaundice.

Background and Objectives: To evaluate the clinical findings of glucose 6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK) deficiency in prolonged jaundice and to determine whether the systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) can be used in the diagnosis of neonatal prolonged jaundice. Materials and Methods: Among full-term neonates with hyperbilirubinemia who were admitted to Medicine Hospital between January 2019 and January 2024 with the complaint of jaundice, 167 infants with a serum bilirubin level above 10 mg/dL, whose jaundice persisted after the 10th day, were included in this study. Results: G6PD activity was negatively correlated with NLR, SII, age, and hematocrit (Hct). There was a weak negative correlation between G6PD and NLR and a moderate negative correlation between G6PD activity and SII when adjusted for age and Hct. PK activity showed no significant correlation with G6PD, NLR, PLR, SII, age, and Hct. A linear relationship was observed between G6PD activity and SII and NLR. Conclusions: NLR and SII can be easily calculated in the evaluation of prolonged jaundice in G6PD deficiency has a considerable advantage. NLR and SII levels may contribute by preventing further tests for prolonged jaundice and regulating its treatment. It may be useful to form an opinion in emergencies and in early diagnostic period.

Response to Mitapivat: A Quinolone Sulfonamide to Manage Hemolytic Anemia in Adults With Pyruvate Kinase Deficiency.

Response to Mitapivat: A Quinolone Sulfonamide to Manage Hemolytic Anemia in Adults With Pyruvate Kinase Deficiency.

Efficacy and Safety of Mitapivat in Pyruvate Kinase Deficiency: A Systematic Review and Meta-analysis of Clinical Trials

Efficacy and Safety of Mitapivat in Pyruvate Kinase Deficiency: A Systematic Review and Meta-analysis of Clinical Trials

Designing a single-arm phase 2 clinical trial of mitapivat for adult patients with erythrocyte membranopathies (SATISFY): a framework for interventional trials in rare anaemias – pilot study protocol

IntroductionMembranopathies encompass haemolytic disorders arising from genetic variants in erythrocyte membrane proteins, including hereditary spherocytosis and stomatocytosis. Congenital dyserythropoietic anaemia type II (CDA II) is associated with the SEC23B gene...

Flawed Value Assessment of Mitapivat to Manage Hemolytic Anemia in Adults With Pyruvate Kinase Deficiency.

Flawed Value Assessment of Mitapivat to Manage Hemolytic Anemia in Adults With Pyruvate Kinase Deficiency.

Pyruvate kinase deficiency in 29 Turkish patients with two novel intronic variants.

Pyruvate kinase (PK) is a key enzyme of anaerobic glycolysis. The genetic heterogeneity of PK deficiency (PKD) is high, and over 400 unique variants have been identified. Twenty-nine patients who had been diagnosed as PKD genetically in seven distinct paediatric haematology departments were evaluated. Fifteen of 23 patients (65.2%) had low PK levels. The PK:hexokinase ratio had 100% sensitivity for PKD diagnosis, superior to PK enzyme assay. Two novel intronic variants (c.695-1G>A and c.694+43C>T) have been described. PKD should be suspected in patients with chronic non-spherocytic haemolytic anaemia, even if enzyme levels are falsely normal. Total PKLR gene sequencing is necessary for the characterization of patients with PKD and for genetic counselling.

Comorbidities and complications in adult and paediatric patients with pyruvate kinase deficiency: Analysis from the Peak Registry.

Pyruvate kinase (PK) deficiency, a rare, congenital haemolytic anaemia caused by mutations in the PKLR gene, is associated with many clinical manifestations, but the full disease burden has yet to be characterised. The Peak Registry (NCT03481738) is an observational, longitudinal registry of adult and paediatric patients with PK deficiency. Here, we described comorbidities and complications in these patients by age at most recent visit and PKLR genotype. As of 13 May 2022, 241 patients were included in the analysis. In total, 48.3% had undergone splenectomy and 50.5% had received chelation therapy. History of iron overload (before enrolment/during follow-up) was common (52.5%), even in never-transfused patients (20.7%). Neonatal complications and symptoms included jaundice, splenomegaly and hepatomegaly, with treatment interventions required in 41.5%. Among adults, osteopenia/osteoporosis occurred in 19.0% and pulmonary hypertension in 6.7%, with median onset ages of 37, 33 and 22 years, respectively. Biliary events and bone health problems were common across PKLR genotypes. Among 11 patients who had thromboembolic events, eight had undergone prior splenectomy. Patients with PK deficiency may have many complications, which can occur early in and throughout life. Awareness of their high disease burden may help clinicians better provide appropriate monitoring and management of these patients.

Updates on clinical and laboratory aspects of hereditary dyserythropoietic anemias.

Hereditary dyserythropoietic anemias, or congenital dyserythropoietic anemias (CDAs), are rare disorders disrupting normal erythroid lineage development, resulting in ineffective erythropoiesis and monolinear cytopenia. CDAs include three main types (I, II, III), transcription-factor-related forms, and syndromic forms. The widespread use of next-generation sequencing in the last decade has unveiled novel causative genes and unexpected genotype-phenotype correlations. The discovery of the genetic defects underlying the CDAs not only facilitates accurate diagnosis but also enhances understanding of CDA pathophysiology. Notable advancements include identifying a hepatic-specific role of the SEC23B loss-of-function in iron metabolism dysregulation in CDA II, deepening CDIN1 dysfunction during erythroid differentiation, and uncovering a recessive CDA III form associated with RACGAP1 variants. Current treatments primarily rely on supportive measures tailored to disease severity and clinical features. Comparative studies with pyruvate kinase deficiency have illuminated new therapeutic avenues by elucidating iron dyshomeostasis and dyserythropoiesis mechanisms. We herein discuss recent progress in diagnostic methodologies, novel gene discoveries, and enhanced comprehension of CDA pathogenesis and molecular genetics.

Clinical and Demographic Characteristics of Pyruvate Kinase Deficiency Patients: A Comprehensive Case Series Analysis.

Introduction Pyruvate kinase deficiency (PKD) is a rare autosomal recessive disorder characterized by mutations in the PKLR gene, causing impaired glycolysis in red blood cells and leading to diverse clinical manifestations. The prevalence of PKD in Saudi Arabia remains understudied, particularly in the context of consanguinity and non-specialized medical facilities. Methods We conducted a retrospective analysis of seven PKD patients of Arab ethnicity, focusing on demographics, medical history, clinical features, laboratory results, treatments, and outcomes. Results Our patient cohort comprised five males and two females, aged 10 to 38 years, of Arab ethnicity. Consanguinity was prevalent, and hereditary connections were identified in five patients. PKD exhibited varying clinical presentations, with early-onset symptoms including neonatal jaundice and symptomatic anemia. One patient experienced severe hepatic disease progression leading to multiorgan failure. Blood transfusions were universally required, indicating the severity of the disorder. Anemia severity varied among patients, with diverse hematological irregularities. Splenectomy was performed for most patients, improving hemoglobin levels and transfusion needs in some cases. Iron chelation was administered, although iron overload persisted. Thrombocytosis and venous thromboembolism were observed post splenectomy. Jaundice and gallstones were common, leading to cholecystectomy. Laboratory findings remained consistent, with heightened reticulocyte counts and altered enzyme levels. Discussion PKD is a rare disorder characterized by diverse clinical manifestations. Prevalence estimation is complex due to various factors, and its diagnosis is challenged by clinical similarities with other disorders. Our cohort exhibited a spectrum of complications, highlighting the necessity for tailored interventions. Iron overload remained a concern, necessitating continuous monitoring. Although endocrine disorders and osteoporosis were absent in our cohort, vigilance is essential due to the disease's progressive nature. Genetic factors were prominent, supporting the genetic basis of PKD. Splenectomy improved anemia but had a limited impact on gallstones. Iron overload management and bone health remain crucial considerations. Conclusion This study offers comprehensive insights into the clinical and demographic characteristics of PKD patients, illustrating the complex nature of the disorder. The findings underscore the need for personalized management strategies and vigilant monitoring to address the diverse clinical manifestations and challenges associated with PKD.

Pyruvate kinase deficiency: A case series of congenital non-spherocytic hemolytic anemia

BackgroundPyruvate kinase deficiency (PKD) is a common cause of congenital non-spherocytic hemolytic anemia (CNSHA). The heterogeneity of clinical presentation complicates the diagnosis and management of this disease. The objective was to describe the clinical, laboratory, and genetic profile of pediatric patients with PKD. Material and methodsIt was a retrospective, observational study. Children and their family members presenting to the Department of Pediatric Hematology and Oncology, St John's Medical College Hospital Bangalore, India, and diagnosed with PKD during 2011–2023 were enrolled. ResultsEight patients were identified through retrospective chart reviews. Four cases were clustered in one family and affected twins in the second family. All patients had a history of neonatal jaundice; however, they varied in their severity and the requirement for transfusion support. Some patients underwent splenectomy and one had hematopoietic stem cell transplant. ConclusionPKD is a known cause of congenital non-spherocytic hemolytic anemia with heterogeneous presentation. A high index of suspicion, enzyme assay, and genetic studies are required for diagnosis.

Unveiling the genetic landscape of suspected congenital dyserythropoietic anemia type I: A retrospective cohort study of 36 patients.

Congenital Dyserythropoietic Anemia type I (CDA I) is a rare hereditary condition characterized by macrocytic/normocytic anemia, splenomegaly, iron overload, and distinct abnormalities during late erythropoiesis, particularly internuclear bridges between erythroblasts. Diagnosis of CDA I remains challenging due to its rarity, clinical heterogeneity, and overlapping phenotype with other rare hereditary anemias. In this case series, we present 36 patients with suspected CDA I. A molecular diagnosis was successfully established in 89% of cases, identifying 16 patients with CDA I through the presence of 18 causative variants in the CDAN1 or CDIN1 genes. Transcriptomic analysis of CDIN1 variants revealed impaired erythroid differentiation and disruptions in transcription, cell proliferation, and histone regulation. Conversely, 16 individuals received a different diagnosis, primarily pyruvate kinase deficiency. Comparisons between CDA I and non-CDA I patients revealed no significant differences in erythroblast morphological features. However, hemoglobin levels and red blood cell count differed between the two groups, with non-CDA I subjects being more severely affected. Notably, most patients with severe anemia belonged to the non-CDA I group (82% non-CDA I vs. 18% CDA I), with a subsequent absolute prevalence of transfusion dependency among non-CDA I patients (100% vs. 41.7%). All patients exhibited reduced bone marrow responsiveness to anemia, with a more pronounced effect observed in non-CDA I patients. Erythropoietin levels were significantly higher in non-CDA I patients compared to CDA I patients. However, evaluations of erythroferrone, soluble transferrin receptor, and hepcidin revealed no significant differences in plasma concentration between the two groups.

Mitapivat: New dawn in pyruvate kinase deficiency and beyond

Mitapivat is the first in class oral allosteric activator of pyruvate kinase enzyme, leading to increased ATP production. Since red blood cells (RBC) rely on anaerobic metabolism, converting phosphoenolpyruvate to pyruvate in Embden– Meyerhof glycolytic pathway is the most important step for ATP production. Deficiency of ATP in patients with pyruvate kinase deficiency (PKD) leads to the destruction of RBCs. In hemoglobinopathies, including thalassemia and sickle cell disease, increased stress and utilization leads to rapid depletion of ATP resources.Phase II DRIVE PK study was the first randomized controlled trial that showed benefits in adult patients without regular transfusion requirement in regards to a rise in hemoglobin ≥1.0 g/dl and improvement in other parameters of hemolysis even with a low 50 mg twice daily dose. Minor adverse effects, including headache, insomnia, and nausea were reported.Subsequent adult studies like ACTIVATE III (non-transfusion-dependent) and ACTIVATE III – T (transfusion-dependent) in patients with PKD showed sustained hemoglobin response in 16/40 (40%) patients. It was tolerated well, and the adverse effect profile was similar to the previous study except for hypertriglyceridemia and hypertension in two patients.Phase I/II trials on patients with thalassemia and sickle cell anemia have also shown promising results in reducing transfusion burden and other disease-related co-morbidities, paving the way for further studies.Mitapivat appears to be a safe, well-tolerated, and effective drug for PKD and other RBC pathologies in adults. Results of ongoing pediatric studies in these settings are awaited to reveal its safety profile in children.

Rare red cell enzymopathies in the Indian population: A comprehensive review

Red blood cell enzyme deficiencies are a rare category of hemolytic anaemia that typically present in children with varying degrees of hemolysis, indirect hyperbilirubinemia and splenomegaly. Glucose 6-phosphate dehydrogenase (G6PD) is the most common enzyme deficiency, followed by pyruvate kinase deficiency (PKD). This article aims to understand the pathophysiology of the rare enzymopathies due to deficiencies in the Embden-Meyerhoff pathway, glutathione metabolism, hexose monophosphate shunt and nucleotide metabolism pathway, and to study the incidence, clinical symptoms, diagnostic strategy, and management of enzyme deficiencies in the Indian patients. Most red blood cell (RBC) enzyme deficiencies are inherited in an autosomal recessive fashion except for G6PD, and phosphoglycerate kinase deficiency which has X-linked inheritance. Presentation depends on the representation of the enzyme on different tissues of the body, hence some enzyme deficiencies may present with neurological or muscular manifestations. In patients with suspected hemolytic anaemia, complete blood count and peripheral smear help in differentiating from hemoglobinopathies, etc. To clinch the diagnosis enzyme levels and genetic testing may be required. These tests guide antenatal diagnosis in subsequent pregnancies. Management of RBC enzymopathies depends on the predominant symptoms and severity of hemolysis. Patients with marked hemolysis require regular blood transfusions and hence appropriate chelation therapy. Hematopoeitic stem cell transplant is attempted in patients with severe spectrum with variable results. Newer drugs, including mitapivat have proven to be beneficial in adults with PKD and ongoing trials in children are showing promising results.

PKLR mutations in pyruvate kinase deficient Polish patients: Functional characteristics of c.101-1G > A and c.1058delAAG variants

Pyruvate kinase (PK) deficiency is a rare autosomal recessive disorder characterized by chronic hemolytic anemia of variable severity. Nine Polish patients with severe hemolytic anemia but normal PK activity were found to carry mutations in the PKLR gene encoding PK, five already known ones and one novel (c.178C > T). We characterized two of the known variants by molecular modeling (c.1058delAAG) and minigene splicing analysis (c.101-1G > A). The former gives a partially destabilized PK tetramer, likely of suboptimal activity, and the c.101-1G > A variant gives alternatively spliced mRNA carrying a premature stop codon, encoding a severely truncated PK and likely undergoing nonsense-mediated decay.

Pyruvate kinase deficiency and PKLR gene mutations: Insights from molecular dynamics simulation analysis

Pyruvate kinase deficiency is a rare hereditary erythrocyte enzyme disease caused by mutations in the pyruvate kinase liver and red blood cell gene. The clinical presentations of pyruvate kinase deficiency are significantly heterogeneous, ranging from just mild anemia to hemolytic crisis or even death. The proband in our study was a 2-year-old girl for severe skin and scleral icterus with progressive aggravation. We collected the family's data for further analysis. Whole exome genome sequencing of the pedigree revealed a novel compound heterozygous mutation, c.1097del (p.P366Lfs*12) and c.1493G > A (p.R498H), in the pyruvate kinase liver and red blood cell gene. Furthermore, molecular dynamics simulations were employed to uncover differences between the wild type and mutant pyruvate kinase liver and red blood cell proteins, focusing on structural stability, protein flexibility, secondary structure, and overall conformation. The combined bioinformatic tools were also utilised to assess the effects of the missense mutation on protein function. Thereafter, wild type and mutant plasmids were constructed and transfected into 293T cells, and Western blot assay was conducted to validate the impact of the mutations on the expression of pyruvate kinase liver and red blood cell protein. The data presented in our study enriches the genotype database and provides evidence for genetic counseling and molecular diagnosis of pyruvate kinase deficiency.

Mitapivat improves ineffective erythropoiesis and iron overload in adult patients with pyruvate kinase deficiency

AbstractPyruvate kinase (PK) deficiency is a rare, hereditary disease characterized by chronic hemolytic anemia. Iron overload is a common complication regardless of age, genotype, or transfusion history. Mitapivat, an oral, allosteric PK activator, improves anemia and hemolysis in adult patients with PK deficiency. Mitapivat’s impact on iron overload and ineffective erythropoiesis was evaluated in adults with PK deficiency who were not regularly transfused in the phase 3 ACTIVATE trial and long-term extension (LTE) (#NCT03548220/#NCT03853798). Patients in the LTE received mitapivat throughout ACTIVATE/LTE (baseline to week 96; mitapivat-to-mitapivat [M/M] arm) or switched from placebo (baseline to week 24) to mitapivat (week 24 to week 96; placebo-to-mitapivat [P/M] arm). Changes from baseline in markers of iron overload and erythropoiesis were assessed to week 96. Improvements in hepcidin (mean, 4770.0 ng/L; 95% confidence interval [CI], −1532.3 to 11 072.3), erythroferrone (mean, −9834.9 ng/L; 95% CI, −14 328.4 to −5341.3), soluble transferrin receptor (mean, −56.0 nmol/L; 95% CI, −84.8 to −27.2), and erythropoietin (mean, −32.85 IU/L; 95% CI, −54.65 to −11.06) were observed in the M/M arm (n = 40) from baseline to week 24, sustained to week 96. No improvements were observed in the P/M arm (n = 40) to week 24; however, upon transitioning to mitapivat, improvements similar to those observed in the M/M arm were seen. Mean changes from baseline in liver iron concentration by magnetic resonance imaging at week 96 in the M/M arm and the P/M arm were −2.0 mg Fe/g dry weight (dw; 95% CI, −4.8 to −0.8) and −1.8 mg Fe/g dw (95% CI, −4.4 to 0.80), respectively. Mitapivat is the first disease-modifying pharmacotherapy shown to have beneficial effects on iron overload and ineffective erythropoiesis in patients with PK deficiency. This trial was registered at www.ClinicalTrials.gov as #NCT03548220 (ACTIVATE) and #NCT03853798 (LTE).

Mitapivat: A Novel Treatment of Hemolytic Anemia in Adults with Pyruvate Kinase Deficiency.

Mitapivat is an orally bioavailable small molecule allosteric activator of pyruvate kinase. It was approved by the US FDA on February 17, 2022, and the European Union in November 2022 for the treatment of hemolytic anemia in adult patients with pyruvate kinase deficiency. In this short perspective, physicochemical properties, synthesis, dosage and administration, mechanism of action, pharmacodynamics, pharmacokinetics, drug interactions, and adverse reactions of mitapivat are described.

Genotype-phenotype relationship in pyruvate kinase deficiency: baseline transfusion dependence and splenectomy response

Genotype-phenotype relationship in pyruvate kinase deficiency: baseline transfusion dependence and splenectomy response

Mortality among US veterans with a physician-documented diagnosis of pyruvate kinase deficiency

ABSTRACT Real-world studies of pyruvate kinase (PK) deficiency and estimates of mortality are lacking. This retrospective observational study aimed to identify patients with PK deficiency and compare their overall survival (OS) to that of a matched cohort without PK deficiency. Patients with ≥1 diagnosis code related to PK deficiency were selected from the US Veterans Health Administration (VHA) database (01/1995–07/2019); patients with a physician-documented diagnosis were included (PK deficiency cohort; index: date of first diagnosis code related to PK deficiency). Patients in the PK deficiency cohort were matched 1:5 to patients from the general VHA population (non-PK deficiency cohort; index: random visit date during match’s index year). OS from index was compared between the two cohorts. Eighteen patients in the PK deficiency cohort were matched to 90 individuals in the non-PK deficiency cohort (both cohorts: mean age 57 years, 94% males; median follow-up 6.0 and 8.0 years, respectively). At follow-up, patients in the non-PK deficiency cohort had significantly longer OS than the PK deficiency cohort (median OS: 17.1 vs. 10.9 years; hazard ratio: 2.3; p = 0.0306). During their first-year post-index, 75% and 40% of the PK deficiency cohort had laboratory-confirmed anemia and iron overload, respectively. Among patients who died, cause of death was highly heterogeneous. These results highlight the increased risk of mortality and substantial clinical burden among patients with PK deficiency. While the intrinsic characteristics of the VHA database may limit the generalizability of the results, this is the first real-world study to characterize mortality in patients with PK deficiency.