Novel PKLR missense mutation (A300P) causing pyruvate kinase deficiency in an Omani Kindred - PK deficiency masquerading as Congenital Dyserythropoietic Anemia.

A 15 year child is presented with transfusion dependent chronic anemia. The clinical and laboratory features suggested a chronic nonspherocytic hemolytic anemia (CNSHA) with bone marrow suggestive of congenital dyserythropoietic anemia (CDA). DNA studies revealed the underlying novel mutation in the PKLR gene responsible for pyruvate kinase deficiency.

Lentiviral Mediated Gene Therapy for Pyruvate Kinase Deficiency: Interim Results of a Global Phase 1 Study for Adult and Pediatric Patients

Background: Pyruvate kinase deficiency (PKD) is a rare inherited hemolytic anemia caused by mutations in the PKLR gene resulting in decreased red cell pyruvate kinase activity and impaired erythrocyte metabolism. Manifestations include anemia, reticulocytosis, splenomegaly and iron overload, and may be life-threatening in severely affected individuals. PKD represents a significant unmet medical need as current treatments are palliative and limited to blood transfusions, chelation therapy, and splenectomy which are associated with significant side effects. Preclinical studies in a clinically relevant PKD murine model have demonstrated that infusion of gene-modified Lin− bone marrow (BM) cells may ameliorate PKD phenotype. Based on compelling preclinical data, a global Phase 1 clinical trial RP-L301-0119 (NCT04105166) is underway to evaluate the feasibility and safety of lentiviral mediated gene therapy in adult and pediatric subjects with severe PKD. Methods: Six adult and pediatric patients with severe PKD (defined as severe and/or transfusion-dependent anemia despite prior splenectomy) will be enrolled. Peripheral blood (PB) hematopoietic stem cells (HSCs) are collected on 2 consecutive days via apheresis after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor. HSCs are enriched, transduced with PGK-coRPK-WPRE lentiviral vector (LV), and cryopreserved. Following release testing of the investigational product (IP), RP-L301, myeloablative therapeutic drug monitoring (TDM) busulfan is administered over 4 days. RP-L301 is then thawed and infused. Patients are followed for safety assessments, including replication competent lentivirus (RCL) and insertion site analysis (ISA), and for efficacy parameters including PB and BM genetic correction, decrease in transfusion requirements, clinically significant improvement in anemia, and reduction of hemolysis for 2 years post-infusion. Results: As of May 2021, 2 adult patients with severe anemia have received RP-L301. Patient 1 (age 31 years) received 3.9x106 CD34+ cells/kg with mean vector copy number (VCN) of 2.73. Patient 2 (age 47 years) received 2.4x106 CD34+ cells/kg with mean VCN of 2.08. Despite baseline hemoglobin (Hb) levels in the 7.0-7.5 g/dL range, both patients displayed normal-range hemoglobin (Hb), improved hemolysis markers, and have required no red blood cell transfusions post-engraftment at 9- and 6- months follow-up. Both report improved quality of life. PB mononuclear cell VCNs for both patients were >2.0 at last evaluated timepoint (6- and 3-months post-treatment, respectively). No serious adverse events have been attributed to RP-L301. Updated safety and efficacy data will be presented. Conclusions: Hematopoietic stem cell mobilization using G-CSF and plerixafor is feasible and effective in adult PKD patients. RP-L301 was successfully manufactured to meet the required specifications for the Phase 1 clinical study and administered without short-term infusion related complications. Efficacy was demonstrated by normalized Hb associated with engraftment confirmed by PB and BM VCN. Disclosures Shah: OrchardTherapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Dr. Shah currently serves on the medical advisory board for Orchard Therapeutics . Navarro: Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: Dr. Navarro has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Sevilla: Miltenyi: Consultancy; Novartis: Consultancy; Amgen: Consultancy; Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Sevilla is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, and may be entitled to receive financial benefits from the licensing of such patents.; SOBI: Consultancy. Glader: Agios: Consultancy. Quintana Bustamante: Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company. Beard: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Rao: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Bueren: Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Bueren is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, may be entitled to receive financial benefits from the licensing of such patents and receives funding for research., Patents & Royalties, Research Funding. Schwartz: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Segovia: Rocket Pharmaceuticals, Inc.: Consultancy, Research Funding.

Evaluation of the Main Regulators of Systemic Iron Homeostasis in Pyruvate Kinase Deficiency

Iron loading anemias are characterized by ineffective erythropoiesis and iron overload. This group of anemias includes thalassemia syndromes, congenital dyserythropoietic anemias (CDA), and some forms of congenital hemolytic anemias. Among them pyruvate kinase deficiency (PKD) has been shown to develop iron overload also in absence of transfusions suggesting dyserythropoietic features. Moreover, severe forms can be misdiagnosed as CDA due to bone marrow abnormalities and ineffective erythropoiesis further supporting this evidences. The hormone erythroferrone (hERFE) is produced by erythroblasts in response to erythropoietin (EPO), and acts by suppressing hepcidin, thereby increasing iron absorption and mobilisation for erythropoiesis demand. The ERFE-hepcidin axis seems to play a crucial role in the pathogenesis of these disorders; an increased erythroferrone release by immature erythroid cells results in hepcidin suppression and secondary iron overload that could finally results in ineffective erythropoiesis and anemia. To investigate the pathophysiological basis of iron overload in PKD, we analysed the levels of hERFE, EPO, hepcidin, and soluble transferrin receptor (sTFR) in a large group of 41 PKD patients equally distributed by gender, age and severity. The results were analysed in comparison with two groups of patients affected by hemolytic anemia with overt dyserythropoiesis (42 patients with CDA type II) and with congenital hemolytic anemia due to RBC membrane defects (51 patients with hereditary spherocytosis [HS]), respectively. Demographic, hematologic, and biochemical features of the three groups of patients are reported in the table. Among the PKD patients, 18/41 were <18 yrs, median Hb level at the time of the study was 9.05g/dL (range 5.5-14.5), 12 underwent splenectomy, 28 ever received at least three transfusions their life, 14 of them transfusion dependent (>6 tx/yrs). Mean ferritin levels at the time of the study were 546 ng/ml (range 59-4990), 15/41 patients requiring chelation therapy for iron overload developed also in absence of transfusions. As expected, CDAII patients showed decreased hepcidin levels (3.74 ng/mL; n.v. 17.25, P<0.001) associated with increased erythropoietin (62.7 IU/L, n.v. 6.5, P=0.01) and hERFE (24.8 ng/mL, n.v. 1, P<0.0001). On the contrary, HS showed increased hepcidin, with less marked increased of ERFE (9.9 ng/mL, P=0.02) and EPO (36.4IU/L, P=0.005). In PKD patients we observed decreased hepcidin levels (7.15 ng/mL, P=0.03)), increased hERFE (18ng/mL, P<0.0001) and EPO (75.6 IU/L, P=0.009). Instead, sTFR was equally increased in the three groups of patients (Figure). Interestingly, by comparing the three groups of patients, PKD showed dyserythropoietic features as evidenced by the observation of intermediate values between HS and CDAII of hepcidin (P=0.007 PKD v CDAII and P=0.0002 PKD vs HS), hEFRE, and sTFR. This study provides the first analysis of the main regulators of systemic iron homeostasis in PK deficiency compared either with the model of a structural RBC defect (HS) or with the typical model of dyserythropoietic anemia with ineffective erythropoiesis, such as CDAII. These data provide evidence of the dyserythropoietic features of PK deficiency, underlining the need of accurate diagnosis and paving the way of novel therapeutic approaches in PK deficiency. Zaninoni A. and Russo R. equally contributed to the study Figure 1 Figure 1. Disclosures Fattizzo: Kira: Speakers Bureau; Alexion: Speakers Bureau; Novartis: Speakers Bureau; Momenta: Honoraria, Speakers Bureau; Annexon: Consultancy; Apellis: Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Barcellini: Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria. Iolascon: Bluebird Bio: Other: Advisory Board; Celgene: Other: Advisory Board. Bianchi: Agios pharmaceutics: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Survey of 275 Patients and Caregivers Affected By Pyruvate Kinase Deficiency: Impact of Communication with Hematologists on Mental Health and Quality of Life

Background. Pyruvate Kinase deficiency (PKD) is a rare congenital hemolytic anemia which affects approximately three people per million individuals worldwide. With no disease-modifying treatments currently available, management tends to focus on supportive symptom control such as blood transfusions. PKD has a profound, wide-ranging impact on quality of life (QoL). Patient advocacy and patient-reported outcomes research has been limited. The PKD Advocacy Advisory Council (AAC), a group of patients, caregivers, patient advocates and physicians, was formed in 2020, by Agios Pharmaceuticals, to improve both timely diagnosis and access to education, support and care for individuals with PKD. Objective. The AAC initiated a survey to explore communication between patients/ caregivers affected by PKD and their hematologists to inform future best practices and improve outcomes. Methods. A web-based, quantitative and qualitative survey was conducted amongst adult patients with PKD, and adult caregivers, with respondents from 11 countries including France, Germany, Italy, Spain, the UK and US. Question types included closed-ended, multiple choice, Likert scale and binary choice plus free text. The survey was carried out according to British Healthcare Business Intelligence Association Legal and Ethical Guidelines, as well as guidelines established by the UK's Market Research Society. Participants were recruited via online panels and via AAC member channels, including PKD Facebook groups. Results : The survey was completed by 200 adult patients with PKD and 75 adult caregivers (n=275). Twenty percent of patients were >50 years of age, 64% were ages 31-50 years and 17% were 18-30 years of age. Half of the patients had been diagnosed for >10 years. Although 82% of patients reported that their hematologist manages PK deficiency "well", the survey revealed gaps in hematologists' understanding. Only 56% of respondents stated their hematologist is able to answer disease management questions and only 44% say their hematologist searches for and finds solutions to optimize disease management. Less than half of respondents, 44%, reported that their hematologists demonstrate a deep knowledge of PKD. The survey revealed an unmet need regarding emotional and psychosocial support with 25% of respondents reporting feeling neither positive nor negative, or somewhat negative, after hematologist interactions and 29% reporting at least one negative emotion following interactions. After meeting with their hematologist, 21% of respondents report feeling worried, 17% anxious, and 17% depressed. Communication with the hematologist was reported to be negative most often among patients who receive 0 transfusions per year. Within this group, only 62% report that their hematologist manages their condition well compared to 82% overall (p=0.003). Only 51% state that their hematologist understands the impact of PK deficiency on their QoL (compared to 83% amongst respondents receiving one or more transfusions per year, p<0.001). Of those who are not transfused, only 44% state their hematologist takes their perspective and experiences into consideration for their disease management plan (compared to 75% amongst respondents receiving one or more transfusions per year, p<0.001). Conclusions PKD is a lifelong chronic disease that significantly impacts QoL of patients and families. The results of this largest ever survey of patients and caregivers with PKD point to a need to adapt clinical approaches to improve outcomes. Hematologists should seek to improve their understanding of the disease and its burden, particularly in non-transfused patients. Care should attend to emotional and psychosocial health aspects. Clinicians should consult with other medical specialists, including hematologists who specialize in PKD, to ensure complications are managed effectively. More research is needed to build on the survey insights, drive further awareness and understanding of the needs of those living with PKD among hematologists, and inform approaches to improve outcomes. The authors would like to acknowledge and thank members of the AAC that made this work possible. Figure 1 Figure 1. Disclosures Grace: Dova: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Agios: Research Funding; Principia: Membership on an entity's Board of Directors or advisory committees. Barcellini: Novartis: Honoraria; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria; Incyte: Membership on an entity's Board of Directors or advisory committees.

Health-Related Quality of Life and Fatigue in Children and Adults with Pyruvate Kinase Deficiency

Pyruvate kinase deficiency (PKD) is the most common cause of congenital non-spherocytic hemolytic anemia. Although recognition of the disease spectrum has recently expanded, data describing its impact on health-related quality of life (HRQoL) are limited. In this prospective international cohort of 254 patients (131 adults and 123 children) with PKD, we assessed the disease impact on HRQoL (EuroQL-5D, PedsQL, FACT-An) and fatigue (PROMIS Fatigue, PedsFACIT-F) using validated measures. Significant variability in HRQoL and fatigue was reported for both adults and children although individual scores were stable over a 2-year interval. While adults who were regularly transfused reported worse HRQoL and fatigue compared to those who were not regularly transfused (EQ-VAS 58 vs. 80, p=0.01), this difference was not seen in children. Regularly transfused adults reported lower physical, emotional, and functional well-being and more anemia symptoms. Both HRQoL and fatigue significantly differed in children by genotype with the worst scores in those with two severe PKLR mutations; this difference was not seen in adults. However, iron chelation was associated with significantly worse HRQoL scores in both children and adults. Pulmonary hypertension was also associated with significantly worse HRQoL. In PKD-specific symptom assessment, 59% of adults and 35% of children reported that their jaundice upset them, identifying this as an important symptom for consideration. While current treatments for PK deficiency are limited to supportive care, new therapies are currently in clinical trials. Understanding the impact of PKD on HRQoL is important to assess the utility of these treatments. (Clinicaltrials.gov number NCT02053480)

A Sri Lankan girl with a new genetic variant in the PKLR gene causing pyruvate kinase deficiency: a case report

Background Erythrocyte pyruvate kinase is expressed under the control of the PKLR gene located on chromosome 1q21. Pyruvate kinase catalyzes the final steps of the glycolytic pathway and creates 50% of the red cell total adenosine triphosphate. Pyruvate kinase deficiency is the commonest glycolytic defect causing congenital non-spherocytic hemolytic anemia inherited in an autosomal recessive trait in which homozygotes and compound heterozygotes are common. Over 200 mutations have been described in patients with pyruvate kinase deficiency. This case report identifies a new pathogenic variant in PKLR gene detected in a patient with severe pyruvate kinase deficiency. Case presentation A Sri Lankan Sinhalese girl who developed neonatal anemia and jaundice within 24 hours of birth with mild hepatomegaly. She was from a nonconsanguineous marriage and had two siblings who had no hematological disorders. She had repeated admissions due to similar illnesses and at the age of 8 years was found to have pyruvate kinase deficiency associated with a novel homozygous pathogenic variant c.507+1delG in the PKLR gene. Conclusions A novel genetic variant in PKLR gene, consistent with pyruvate kinase deficiency, was detected in a Sri Lankan girl. This genetic variant may be specific to the Asian population and requires further studies.