Publications by authors named "Janet L Kwiatkowski"

87 Publications

Lentiviral vector ALS20 yields high hemoglobin levels with low genomic integrations for treatment of beta-globinopathies.

Mol Ther 2021 Jan 19. Epub 2021 Jan 19.

Division of Hematology, Children's Hospital of Philadelphia (CHOP), Philadelphia, PA, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Cell and Molecular Biology Affinity Group (CAMB), University of Pennsylvania, Philadelphia, PA, USA; Raymond G. Perelman Center for Cellular and Molecular Therapeutics, CHOP, Philadelphia, PA, USA; Penn Center for Musculoskeletal Disorders, CHOP, Philadelphia, PA, USA. Electronic address:

Ongoing clinical trials for treatment of beta-globinopathies by gene therapy involve the transfer of the beta-globin gene, which requires integration of three to four copies per genome in most target cells. This high proviral load may increase genome toxicity, potentially limiting the safety of this therapy and relegating its use to total body myeloablation. We hypothesized that introducing an additional hypersensitive site from the locus control region, the complete sequence of the second intron of the beta-globin gene, and the ankyrin insulator may enhance beta-globin expression. We identified a construct, ALS20, that synthesized significantly higher adult hemoglobin levels than those of other constructs currently used in clinical trials. These findings were confirmed in erythroblastic cell lines and in primary cells isolated from sickle cell disease patients. Bone marrow transplantation studies in beta-thalassemia mice revealed that ALS20 was curative at less than one copy per genome. Injection of human CD34 cells transduced with ALS20 led to safe, long-term, and high polyclonal engraftment in xenograft experiments. Successful treatment of beta-globinopathies with ALS20 could potentially be achieved at less than two copies per genome, minimizing the risk of cytotoxic events and lowering the intensity of myeloablation.
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http://dx.doi.org/10.1016/j.ymthe.2020.12.036DOI Listing
January 2021

The pyruvate kinase (PK) to hexokinase enzyme activity ratio and erythrocyte PK protein level in the diagnosis and phenotype of PK deficiency.

Br J Haematol 2020 May 28. Epub 2020 May 28.

Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, MA, USA.

Diagnosis of pyruvate kinase deficiency (PKD), the most common cause of hereditary non-spherocytic haemolytic anaemia, remains challenging in routine practice and no biomarkers for clinical severity have been characterised. This prospective study enrolled 41 patients with molecularly confirmed PKD from nine North American centres to evaluate the diagnostic sensitivity of pyruvate kinase (PK) enzyme activity and PK:hexokinase (HK) enzyme activity ratio, and evaluate the erythrocyte PK (PK-R) protein level and erythrocyte metabolites as biomarkers for clinical severity. In this population not transfused for ≥90 days before sampling, the diagnostic sensitivity of the PK enzyme assay was 90% [95% confidence interval (CI) 77-97%], whereas the PK:HK ratio sensitivity was 98% (95% CI 87-100%). There was no correlation between PK enzyme activity and clinical severity. Transfusion requirements correlated with normalised erythrocyte ATP levels (r = 0·527, P = 0·0016) and PK-R protein levels (r = -0·527, P = 0·0028). PK-R protein levels were significantly higher in the never transfused [median (range) 40·1 (9·8-73·9)%] versus ever transfused [median (range) 7·7 (0·4-15·1)%] patients (P = 0·0014). The PK:HK ratio had excellent sensitivity for PK diagnosis, superior to PKLR exon sequencing. Given that the number of PKLR variants and genotype combinations limits prognostication based on molecular findings, PK-R protein level may be a useful prognostic biomarker of disease severity and merits further study.
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http://dx.doi.org/10.1111/bjh.16724DOI Listing
May 2020

Genotype-phenotype correlation and molecular heterogeneity in pyruvate kinase deficiency.

Am J Hematol 2020 05 6;95(5):472-482. Epub 2020 Mar 6.

Department of Pediatrics, University of Würzburg, Würzburg, Germany.

Pyruvate kinase (PK) deficiency is a rare recessive congenital hemolytic anemia caused by mutations in the PKLR gene. This study reports the molecular features of 257 patients enrolled in the PKD Natural History Study. Of the 127 different pathogenic variants detected, 84 were missense and 43 non-missense, including 20 stop-gain, 11 affecting splicing, five large deletions, four in-frame indels, and three promoter variants. Within the 177 unrelated patients, 35 were homozygous and 142 compound heterozygous (77 for two missense, 48 for one missense and one non-missense, and 17 for two non-missense variants); the two most frequent mutations were p.R510Q in 23% and p.R486W in 9% of mutated alleles. Fifty-five (21%) patients were found to have at least one previously unreported variant with 45 newly described mutations. Patients with two non-missense mutations had lower hemoglobin levels, higher numbers of lifetime transfusions, and higher rates of complications including iron overload, extramedullary hematopoiesis, and pulmonary hypertension. Rare severe complications, including lower extremity ulcerations and hepatic failure, were seen more frequently in patients with non-missense mutations or with missense mutations characterized by severe protein instability. The PKLR genotype did not correlate with the frequency of complications in utero or in the newborn period. With ICCs ranging from 0.4 to 0.61, about the same degree of clinical similarity exists within siblings as it does between siblings, in terms of hemoglobin, total bilirubin, splenectomy status, and cholecystectomy status. Pregnancy outcomes were similar across genotypes in PK deficient women. This report confirms the wide genetic heterogeneity of PK deficiency.
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http://dx.doi.org/10.1002/ajh.25753DOI Listing
May 2020

American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support.

Blood Adv 2020 Jan;4(2):327-355

Department of Internal Medicine, American University of Beirut, Beirut, Lebanon.

Background: Red cell transfusions remain a mainstay of therapy for patients with sickle cell disease (SCD), but pose significant clinical challenges. Guidance for specific indications and administration of transfusion, as well as screening, prevention, and management of alloimmunization, delayed hemolytic transfusion reactions (DHTRs), and iron overload may improve outcomes.

Objective: Our objective was to develop evidence-based guidelines to support patients, clinicians, and other healthcare professionals in their decisions about transfusion support for SCD and the management of transfusion-related complications.

Methods: The American Society of Hematology formed a multidisciplinary panel that was balanced to minimize bias from conflicts of interest and that included a patient representative. The panel prioritized clinical questions and outcomes. The Mayo Clinic Evidence-Based Practice Research Program supported the guideline development process. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to form recommendations, which were subject to public comment.

Results: The panel developed 10 recommendations focused on red cell antigen typing and matching, indications, and mode of administration (simple vs red cell exchange), as well as screening, prevention, and management of alloimmunization, DHTRs, and iron overload.

Conclusions: The majority of panel recommendations were conditional due to the paucity of direct, high-certainty evidence for outcomes of interest. Research priorities were identified, including prospective studies to understand the role of serologic vs genotypic red cell matching, the mechanism of HTRs resulting from specific alloantigens to inform therapy, the role and timing of regular transfusions during pregnancy for women, and the optimal treatment of transfusional iron overload in SCD.
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http://dx.doi.org/10.1182/bloodadvances.2019001143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988392PMC
January 2020

Corrigendum: The Spectrum of -Associated Hereditary Spherocytosis.

Front Physiol 2019;10:1331. Epub 2019 Oct 18.

Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.

[This corrects the article DOI: 10.3389/fphys.2019.00815.].
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http://dx.doi.org/10.3389/fphys.2019.01331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6843059PMC
October 2019

Ischemic stroke in children and young adults with sickle cell disease in the post-STOP era.

Am J Hematol 2019 12 1;94(12):1335-1343. Epub 2019 Nov 1.

Department of Neurology, Medical University of South Carolina, Charleston, South Carolina.

The Stroke Prevention Trial in Sickle Cell Anemia (STOP) and Optimizing Primary Stroke Prevention in Sickle Cell Anemia (STOP 2) trials established routine transcranial Doppler ultrasound (TCD) screening, with indefinite chronic red cell transfusions (CRCT) for children with abnormal TCD as standard of care. Implementation failures and limitations to the STOP protocol may contribute to continued ischemic stroke occurrence. In the "Post-STOP" study, we sought to assess the impact of the STOP protocol on the incidence of ischemic stroke in a multicenter cohort of former STOP and/or STOP 2 trial participants. A central team abstracted data for 2851 (74%) of the 3835 children who took part in STOP and/or STOP 2. Data included TCD and neuroimaging results, treatment, laboratory data, and detailed clinical information pertaining to the stroke. Two stroke neurologists independently confirmed each stroke using pre-specified imaging and clinical criteria and came to consensus. Among the 2808 patients who were stroke-free at the start of Post-STOP with available follow-up, the incidence of first ischemic stroke was 0.24 per 100 patient-years (95% CI, 0.18, 0.31), with a mean (SD) duration of follow-up of 9.1 (3.4) [median 10.3, range (0-15.4)] years. Most (63%) strokes occurred in patients in whom the STOP protocol had not been properly implemented, either failure to screen appropriately with TCD (38%) or failure to transfuse adequately patients with abnormal TCD (25%). This study shows that substantial opportunities for ischemic stroke prevention remain by more complete implementation of the STOP Protocol.
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http://dx.doi.org/10.1002/ajh.25635DOI Listing
December 2019

Safety and Efficacy of Mitapivat in Pyruvate Kinase Deficiency.

N Engl J Med 2019 09;381(10):933-944

From the Dana-Farber/Boston Children's Cancer and Blood Disorders Center and Harvard Medical School, Boston (R.F.G.), and Agios Pharmaceuticals, Cambridge (A.J.B., S.B., L.H., C.K., P.H., M.-H.J., C.B.) - all in Massachusetts; Hôpital Saint Vincent de Paul, Lille (C.R.), and Unité des Maladies Génétiques du Globule Rouge, Centre Hospitalier Universitaire Henri Mondor, Créteil (F.G.) - both in France; Hammersmith Hospital, Imperial College Healthcare NHS Trust, London (D.M.L.); Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan (W.B.); Central Pennsylvania Clinic, Belleville (D.H.M.), and Children's Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia (J.L.K.); Van Creveldkliniek, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands (E.J.B.); University of Utah, Salt Lake City (H.Y.); Wayne State University School of Medicine, Children's Hospital of Michigan, Detroit (Y.R.); University of Toronto, Toronto (K.H.M.K.); Weill Cornell Medical College, New York (S.S.); Bruce A. Silver Clinical Science and Development, Dunkirk, MD (B.S.); and Stanford University School of Medicine, Palo Alto, CA (B.G.).

Background: Pyruvate kinase deficiency is caused by mutations in and leads to congenital hemolytic anemia. Mitapivat is an oral, small-molecule allosteric activator of pyruvate kinase in red cells.

Methods: In this uncontrolled, phase 2 study, we evaluated the safety and efficacy of mitapivat in 52 adults with pyruvate kinase deficiency who were not receiving red-cell transfusions. The patients were randomly assigned to receive either 50 mg or 300 mg of mitapivat twice daily for a 24-week core period; eligible patients could continue treatment in an ongoing extension phase.

Results: Common adverse events, including headache and insomnia, occurred at the time of drug initiation and were transient; 92% of the episodes of headache and 47% of the episodes of insomnia resolved within 7 days. The most common serious adverse events, hemolytic anemia and pharyngitis, each occurred in 2 patients (4%). A total of 26 patients (50%) had an increase of more than 1.0 g per deciliter in the hemoglobin level. Among these patients, the mean maximum increase was 3.4 g per deciliter (range, 1.1 to 5.8), and the median time until the first increase of more than 1.0 g per deciliter was 10 days (range, 7 to 187); 20 patients (77%) had an increase of more than 1.0 g per deciliter in the hemoglobin level at more than 50% of visits during the core study period, with improvement in markers of hemolysis. The response was sustained in all 19 patients remaining in the extension phase, with a median follow-up of 29 months (range, 22 to 35). Hemoglobin responses were observed only in patients who had at least one missense mutation and were associated with the red-cell pyruvate kinase protein level at baseline.

Conclusions: The administration of mitapivat was associated with a rapid increase in the hemoglobin level in 50% of adults with pyruvate kinase deficiency, with a sustained response during a median follow-up of 29 months during the extension phase. Adverse effects were mainly low-grade and transient. (Funded by Agios Pharmaceuticals; ClinicalTrials.gov number, NCT02476916.).
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http://dx.doi.org/10.1056/NEJMoa1902678DOI Listing
September 2019

The Spectrum of -Associated Hereditary Spherocytosis.

Front Physiol 2019 3;10:815. Epub 2019 Jul 3.

Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.

Hereditary spherocytosis (HS) is the most common red blood cell (RBC) membrane disorder causing hereditary hemolytic anemia. Patients with HS have defects in the genes coding for ankyrin (), band 3 (), protein 4.2 (), and α () or β-spectrin (). Severe recessive HS is most commonly due to biallelic mutations. α-spectrin is produced in excess in normal erythroid cells, therefore -associated HS ensues with mutations causing significant decrease of normal protein expression from both alleles. In this study, we systematically compared genetic, rheological, and protein expression data to the varying clinical presentation in eleven patients with -associated HS. The phenotype of HS in this group of patients ranged from moderately severe to severe transfusion-dependent anemia and up to which is typically fatal if transfusions are not initiated before term delivery. The pathogenicity of the mutations could be corroborated by reduced mRNA expression in the patients' reticulocytes. The disease severity correlated to the level of α-spectrin protein in their RBC cytoskeleton but was also affected by other factors. Patients carrying the low expression α allele to a null mutation were not all transfusion dependent and their anemia improved or resolved with partial or total splenectomy, respectively. In contrast, patients with near-complete or complete α-spectrin deficiency have a history of having been salvaged from fatal , either because they were born prematurely and started transfusions early or because they had intrauterine transfusions. They have suboptimal reticulocytosis or reticulocytopenia and remain transfusion dependent even after splenectomy; these patients require either lifetime transfusions and iron chelation or stem cell transplant. Comprehensive genetic and phenotypic evaluation is critical to provide accurate diagnosis in patients with -associated HS and guide toward appropriate management.
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http://dx.doi.org/10.3389/fphys.2019.00815DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6617536PMC
July 2019

Gene therapy of hemoglobinopathies: progress and future challenges.

Hum Mol Genet 2019 10;28(R1):R24-R30

Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France.

Recently, gene therapy clinical trials have been successfully applied to hemoglobinopathies, such as sickle cell disease (SCD) and β-thalassemia. Among the great discoveries that led to the design of genetic approaches to cure these disorders is the discovery of the β-globin locus control region and several associated transcription factors, which determine hemoglobin switching as well as high-level, erythroid-specific expression of genes at the ß-globin locus. Moreover, increasing evidence shows that lentiviral vectors are efficient tools to insert large DNA elements into nondividing hematopoietic stem cells, showing reassuring safe integration profiles. Alternatively, genome editing could restore expression of fetal hemoglobin or target specific mutations to restore expression of the wild-type β-globin gene. The most recent clinical trials for β-thalassemia and SCD are showing promising outcomes: patients were able to discontinue transfusions or had reduced transfusion requirements. However, toxic myeloablation and the high cost of current ex vivo hematopoietic stem cell gene therapy platforms represent a barrier to a widespread application of these approaches. In this review, we summarize these gene therapy strategies and ongoing clinical trials. Finally, we discuss possible strategies to improve outcomes, reduce myeloablative regimens and future challenges to reduce the cost of gene therapy platform.
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http://dx.doi.org/10.1093/hmg/ddz172DOI Listing
October 2019

Beta Thalassemia: Monitoring and New Treatment Approaches.

Hematol Oncol Clin North Am 2019 06 2;33(3):339-353. Epub 2019 Apr 2.

Division of Hematology, Children's Hospital of Philadelphia, 3401 Civic Center Boulevard, Colket Translational Research Building, Room 11024, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA, USA. Electronic address:

Beta thalassemias are a significant global health problem. Globin chain imbalance leads to a complex physiologic cascade of hemolytic anemia, ineffective erythropoiesis, and iron overload. Management of the broad spectrum of phenotypes requires the careful use of red blood transfusions, supportive care, monitoring, and management of iron overload. In this article, the authors discuss recommendations for monitoring of individuals with thalassemia, as well as ongoing preclinical and clinical trials of therapies targeting different aspects of thalassemia pathophysiology.
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http://dx.doi.org/10.1016/j.hoc.2019.01.003DOI Listing
June 2019

Matched Sibling Donor Hematopoietic Stem Cell Transplantation to Prevent Stroke in Children With Sickle Cell Anemia.

JAMA 2019 01;321(3):251-252

Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

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http://dx.doi.org/10.1001/jama.2018.20390DOI Listing
January 2019

Combination Oral Chelation in Adult Patients With Transfusion-dependent Thalassemia and High Iron Burden.

J Pediatr Hematol Oncol 2019 01;41(1):e47-e50

Division of Hematology.

An open-label, pilot study was conducted to evaluate deferasirox/deferiprone combination chelation therapy in adult patients with transfusion-dependent thalassemia and severe iron overload. Enrollment proved difficult. Nine patients (median age, 27.4 y; ferritin, 4965 ng/mL; liver iron concentration, 28.5 mg/g dry weight; cardiac T2*, 13.3 ms) received treatment. Two were withdrawn for treatment-related adverse effects. Arthralgia (4 patients) and gastrointestinal symptoms (5 patients) were common; no episodes of neutropenia/agranulocytosis occurred. Adherence difficulties were common. Of 6 patients with 12 to 18 months follow-up, 3 showed improvement in cardiac T2* and 2 in liver iron. Combination oral chelation may be effective but adverse effects and adherence challenges may limit efficacy.
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http://dx.doi.org/10.1097/MPH.0000000000001269DOI Listing
January 2019

The phenotypic spectrum of germline variants: from isolated sideroblastic anemia to mitochondrial myopathy, lactic acidosis and sideroblastic anemia 2.

Haematologica 2018 12 19;103(12):2008-2015. Epub 2018 Jul 19.

Dana Farber-Boston Children's Center for Cancer and Blood Disorders, Boston, MA, USA.

variants have previously been described in patients with myopathy, lactic acidosis and sideroblastic anemia 2 (MLASA2). encodes the mitochondrial tyrosyl-tRNA synthetase, which is responsible for conjugating tyrosine to its cognate mt-tRNA for mitochondrial protein synthesis. Here we describe 14 individuals from 11 families presenting with sideroblastic anemia and variants that we identified using a sideroblastic anemia gene panel or exome sequencing. The phenotype of these patients ranged from MLASA to isolated congenital sideroblastic anemia. As in previous cases, inter- and intra-familial phenotypic variability was observed, however, this report includes the first cases with isolated sideroblastic anemia and patients with biallelic variants that have no clinically ascertainable phenotype. We identified ten novel variants and three previously reported variants. amino-acylation assays of five novel missense variants showed that three had less effect on the catalytic activity of YARS2 than the most commonly reported variant, p.(Phe52Leu), associated with MLASA2, which may explain the milder phenotypes in patients with these variants. However, the other two missense variants had a more severe effect on YARS2 catalytic efficiency. Several patients carried the common c.572 G>T, p.(Gly191Val) variant (minor allele frequency =0.1259) in with a rare deleterious variant. We have previously shown that the p.(Gly191Val) variant reduces YARS2 catalytic activity. Consequently, we suggest that biallelic variants, including severe loss-of-function alleles in of the common p.(Gly191Val) variant, should be considered as a cause of isolated congenital sideroblastic anemia, as well as the MLASA syndromic phenotype.
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http://dx.doi.org/10.3324/haematol.2017.182659DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6269294PMC
December 2018

Epidemiologic and clinical characteristics of nontransfusion-dependent thalassemia in the United States.

Pediatr Blood Cancer 2018 07 10;65(7):e27067. Epub 2018 Apr 10.

Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

Background: Nontransfusion-dependent thalassemia (NTDT) refers to a diverse group of thalassemia mutations and clinical phenotypes that do not require chronic transfusions. It is increasingly prevalent in the United States.

Procedure: This study reviews the epidemiology and clinical characteristics of 138 patients with NTDT treated at four US thalassemia centers from 1997 to 2014. Data on laboratory results, transfusions, and clinical complications were collected from patient charts.

Results: Overall, 84 patients with α-thalassemia (62 deletional hemoglobin H; 22 nondeletional hemoglobin H), 39 with β-thalassemia (26 with homozygous or double heterozygous β mutations; 13 with single β mutations with or without α triplication), and 15 with E/β-thalassemia (12 E/β ; three E/β ) were identified. At study entry, the median age for patients with α-thalassemia was 2.3 years; 9.2 years for patients with β-thalassemia and 2.2 years for patients with E/β-thalassemia. Most patients with α-thalassemia were Asian. Patients with β-thalassemia were predominantly Caucasian (46%) or of African descent (36%). Twenty percent of patients were born outside the United States and 5% were transfused before immigration. Complications varied by genotype and age. Individuals with nondeletional hemoglobin H were severely affected and, despite their young age, had many complications. Iron overload increased with age and was more common in patients who received transfusions.

Conclusions: NTDT in the United States is a multi-ethnic disease with different genotypic mutations and phenotypic manifestations. A higher than expected proportion of patients was Black/African American. NTDT-related complications are common and increase with age, supporting a need for early diagnosis.
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http://dx.doi.org/10.1002/pbc.27067DOI Listing
July 2018

Clinical spectrum of pyruvate kinase deficiency: data from the Pyruvate Kinase Deficiency Natural History Study.

Blood 2018 05 16;131(20):2183-2192. Epub 2018 Mar 16.

Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.

An international, multicenter registry was established to collect retrospective and prospective clinical data on patients with pyruvate kinase (PK) deficiency, the most common glycolytic defect causing congenital nonspherocytic hemolytic anemia. Medical history and laboratory and radiologic data were retrospectively collected at enrollment for 254 patients with molecularly confirmed PK deficiency. Perinatal complications were common, including anemia that required transfusions, hyperbilirubinemia, hydrops, and prematurity. Nearly all newborns were treated with phototherapy (93%), and many were treated with exchange transfusions (46%). Children age 5 years and younger were often transfused until splenectomy. Splenectomy (150 [59%] of 254 patients) was associated with a median increase in hemoglobin of 1.6 g/dL and a decreased transfusion burden in 90% of patients. Predictors of a response to splenectomy included higher presplenectomy hemoglobin ( = .007), lower indirect bilirubin ( = .005), and missense mutations ( = .0017). Postsplenectomy thrombosis was reported in 11% of patients. The most frequent complications included iron overload (48%) and gallstones (45%), but other complications such as aplastic crises, osteopenia/bone fragility, extramedullary hematopoiesis, postsplenectomy sepsis, pulmonary hypertension, and leg ulcers were not uncommon. Overall, 87 (34%) of 254 patients had both a splenectomy and cholecystectomy. In those who had a splenectomy without simultaneous cholecystectomy, 48% later required a cholecystectomy. Although the risk of complications increases with severity of anemia and a genotype-phenotype relationship was observed, complications were common in all patients with PK deficiency. Diagnostic testing for PK deficiency should be considered in patients with apparent congenital hemolytic anemia and close monitoring for iron overload, gallstones, and other complications is needed regardless of baseline hemoglobin. This trial was registered at www.clinicaltrials.gov as #NCT02053480.
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http://dx.doi.org/10.1182/blood-2017-10-810796DOI Listing
May 2018

Unrelated Donor Transplantation in Children with Thalassemia using Reduced-Intensity Conditioning: The URTH Trial.

Biol Blood Marrow Transplant 2018 06 31;24(6):1216-1222. Epub 2018 Jan 31.

Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University, Chicago, Illinois.

Allogeneic hematopoietic stem cell transplantation (HSCT) can cure transfusion-dependent thalassemia (TDT). In a multicenter trial we investigated the efficacy of reduced-intensity conditioning (RIC) before unrelated donor (URD) HSCT in children with TDT. Thirty-three children, ages 1 to 17 years, received bone marrow (BM) or umbilical cord blood (UCB) allografts. Median time to neutrophil engraftment was 13 days (range, 10 to 25) and 24 days (range, 18 to 49) and platelet engraftment 23 days (range, 12 to 46) and 50 days (range, 31 to 234) after BM and UCB allografts, respectively. With a median follow-up of 58 months (range, 7 to 79), overall and thalassemia-free survival was 82% (95% CI, .64% to .92%) and 79% (95% CI, .6% to .9%), respectively. The cumulative incidence of grades II to IV acute graft-versus-host disease (GVHD) after BM and UCB allografts was 24% and 44%; the 2-year cumulative incidence of chronic extensive GVHD was 29% and 21%, respectively; 71% of BM and 91% of UCB recipients discontinued systemic immunosuppression by 2 years. Six patients who had Pesaro risk class 2 (n = 5) and class 3 (n = 1) died of GVHD (n = 3), viral pneumonitis (n = 2) and pulmonary hemorrhage (n = 1). Outcomes after this RIC compared favorably with URD HSCT outcomes for TDT and supported engraftment in 32 of 33 patients. Efforts to reduce GVHD and infectious complications are being pursued further.
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http://dx.doi.org/10.1016/j.bbmt.2018.01.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5993578PMC
June 2018

Safety and pharmacokinetics of the oral iron chelator SP-420 in β-thalassemia.

Am J Hematol 2017 Dec 31;92(12):1356-1361. Epub 2017 Oct 31.

Department of Pediatrics & Thalassemia Center, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.

Our phase I, open-label, multi-center, dose-escalation study evaluated the pharmacokinetics (PK) of SP-420, a tridentate oral iron chelating agent of the desferrithiocin class, in patients with transfusion dependent β-thalassemia. SP-420 was administered as a single dose of 1.5 (n = 3), 3 (n = 3), 6 (n = 3), 12 (n = 3), and 24 (n = 6) mg/kg or as a twice-daily dose of 9 mg/kg (n = 6) over 14-28 days. There was a near dose-linear increase in the mean plasma SP-420 concentrations and in the mean values for C and AUC over the dose range evaluated. The median t ranged from 0.5 to 2.25 h and was not dose dependent. The study was prematurely terminated by the sponsor due to renal adverse events (AE) including proteinuria, increase in serum creatinine, and one case of Fanconi syndrome. Other adverse effects included hypersensitivity reactions and gastrointestinal disturbances. Based on current dose administration, the renal AE observed outweighed the possible benefits from chelation therapy. However, additional studies assessing efficacy and safety of lower doses or less frequent dosing of SP-420 over longer durations with close monitoring would be necessary to better explain the findings of our study and characterize the safety of the study drug.
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http://dx.doi.org/10.1002/ajh.24914DOI Listing
December 2017

Deferiprone for the treatment of transfusional iron overload in thalassemia.

Expert Rev Hematol 2017 06;10(6):493-503

b Children's Hospital of Philadelphia, Division of Hematology and Perelman School of Medicine at the University of Pennsylvania, Department of Pediatrics , Philadelphia , PA , USA.

Introduction: Transfusional iron overload can lead to hepatic fibrosis, arrhythmias and congestive heart failure and a number of endocrinopathies. Deferiprone is an oral iron chelator approved for use in the United States as a second line agent for the treatment of transfusional iron overload in patients with thalassemia. Areas covered: This article will review the data regarding the efficacy of deferiprone for iron chelation and prevention and reversal of iron related complications, the drug's adverse effect profile, and the use of this drug in combination regimens. Expert commentary: Extensive data support that deferiprone is particularly efficacious at cardiac iron removal and therefore, a chelator regimen that contains deferiprone is generally recommended when there is significant cardiac iron loading and/or in the setting of iron-related cardiac disease. The most concerning side effects of deferiprone are agranulocytosis and milder forms of neutropenia, which require appropriate monitoring and patient/provider education.
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http://dx.doi.org/10.1080/17474086.2017.1318052DOI Listing
June 2017

Therapy induced iron deficiency in children treated with eltrombopag for immune thrombocytopenia.

Am J Hematol 2017 Jun 20;92(6):E88-E91. Epub 2017 Mar 20.

Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.

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http://dx.doi.org/10.1002/ajh.24705DOI Listing
June 2017

Transcranial doppler re-screening of subjects who participated in STOP and STOP II.

Am J Hematol 2016 12 25;91(12):1191-1194. Epub 2016 Oct 25.

Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

In children with Sickle Cell Disease, the combination of risk stratification with Transcranial Doppler Ultrasound (TCD) and selective chronic red cell transfusion (CRCT-the STOP Protocol) is one of the most effective stroke prevention strategies in medicine. How fully it is being implemented is unclear. Nineteen of 26 sites that conducted the two pivotal clinical trials (STOP and STOP II) participated in Post STOP, a comprehensive medical records review assessing protocol implementation in the 10-15 years since the trials ended. Professional abstractors identified medical records in the Post STOP era in 2851 (74%) of the 3,840 children who took part in STOP and/or STOP II, and documented TCD rescreening, maintenance of CRCT in those at risk, and stroke. Among 1,896 children eligible for TCD rescreening (target group), evidence of any rescreening was found in 1,090 (57%). There was wide site variation in TCD rescreening ranging from 18% to 91% of eligible children. Both younger age and having a conditional TCD during STOP/II were associated with a higher likelihood of having a TCD in Post STOP. Sixty eight new abnormal, high risk cases were identified. Despite clear evidence of benefit the STOP protocol is not fully implemented even at experienced sites. Site variation suggests that system improvements might remove barriers to implementation and result in even greater reduction of ischemic stroke in children with SCD. Am. J. Hematol. 91:1191-1194, 2016. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajh.24551DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5155448PMC
December 2016

Increased prevalence of potential right-to-left shunting in children with sickle cell anaemia and stroke.

Br J Haematol 2017 Jan 21;176(2):300-308. Epub 2016 Oct 21.

Departments of Clinical Science (Biostatistics) and Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA.

'Paradoxical' embolization via intracardiac or intrapulmonary right-to-left shunts (RLS) is an established cause of stroke. Hypercoagulable states and increased right heart pressure, which both occur in sickle cell anaemia (SCA), predispose to paradoxical embolization. We hypothesized that children with SCA and overt stroke (SCA + stroke) have an increased prevalence of potential RLS. We performed contrasted transthoracic echocardiograms on 147 children (aged 2-19 years) with SCA + stroke) mean age 12·7 ± 4·8 years, 54·4% male) and a control group without SCA or stroke (n = 123; mean age 12·1 ± 4·9 years, 53·3% male). RLS was defined as any potential RLS detected by any method, including intrapulmonary shunting. Echocardiograms were masked and adjudicated centrally. The prevalence of potential RLS was significantly higher in the SCA+stroke group than controls (45·6% vs. 23·6%, P < 0·001). The odds ratio for potential RLS in the SCA + stroke group was 2·7 (95% confidence interval: 1·6-4·6) vs controls. In post hoc analyses, the SCA + stroke group had a higher prevalence of intrapulmonary (23·8% vs. 5·7%, P < 0·001) but not intracardiac shunting (21·8% vs. 18·7%, P = 0·533). SCA patients with potential RLS were more likely to report headache at stroke onset than those without. Intrapulmonary and intracardiac shunting may be an overlooked, independent and potentially modifiable risk factor for stroke in SCA.
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http://dx.doi.org/10.1111/bjh.14391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5239723PMC
January 2017

Cranial epidural hematomas: A case series and literature review of this rare complication associated with sickle cell disease.

Pediatr Blood Cancer 2017 03 13;64(3). Epub 2016 Sep 13.

Division of Pediatric Hematology, Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.

Background: Patients with sickle cell disease (SCD) may experience many complications of the central nervous system (CNS) including stroke, silent cerebral infarcts, and neuropsychological deficits. Cranial epidural hematoma is a rare but potentially serious complication.

Procedure: Case series of cranial epidural hematomas in children with SCD from three different institutions is considered, along with a literature review of cranial epidural hematomas in this population.

Results: Seven children with SCD with cranial epidural hematomas were identified from three different institutions. All patients were male and the age at presentation ranged from 10 to 18 years. Two patients presented with headache (28.6%), while the rest had no neurologic symptoms at presentation. Four patients required urgent neurosurgical intervention (57.1%) and one patient died (14.3%). A literature review identified 18 additional cases of cranial epidural hematomas in children with SCD. Of these, treatment ranged from supportive care to neurosurgical intervention. Twelve patients completely recovered (66.7%), one patient had long-term cognitive impairment (5.6%), and four patients died (22.2%). Combined with our data, cranial epidural hematomas have a mortality rate of 20.0%.

Conclusions: Although rare, cranial epidural hematoma can be fatal and should be considered in patients with acute neurological symptoms.
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http://dx.doi.org/10.1002/pbc.26237DOI Listing
March 2017

Current recommendations for chelation for transfusion-dependent thalassemia.

Ann N Y Acad Sci 2016 03;1368(1):107-14

Children's Hospital of Philadelphia, and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.

Regular red cell transfusions used to treat thalassemia cause iron loading that must be treated with chelation therapy. Morbidity and mortality in thalassemia major are closely linked to the adequacy of chelation. Chelation therapy removes accumulated iron and detoxifies iron, which can prevent and reverse much of the iron-mediated organ injury. Currently, three chelators are commercially available--deferoxamine, deferasirox, and deferiprone--and each can be used as monotherapy or in combination. Close monitoring of hepatic and cardiac iron burden is central to tailoring chelation. Other factors, including properties of the individual chelators, ongoing transfusional iron burden, and patient preference, must be considered. Monotherapy generally is utilized if the iron burden is in an acceptable or near-acceptable range and the dose is adjusted accordingly. Combination chelation often is employed for patients with high iron burden, iron-related organ injury, or where adverse effects of chelators preclude administration of an appropriate chelator dose. The combination of deferoxamine and deferiprone is the best studied, but increasing data are available on the safety and efficacy of newer chelator combinations, including deferasirox with deferoxamine and the oral-only combination of deferasirox with deferiprone. The expanding chelation repertoire should enable better control of iron burden and improved outcomes.
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http://dx.doi.org/10.1111/nyas.13088DOI Listing
March 2016

Transfusional Iron Overload in a Cohort of Children with Sickle Cell Disease: Impact of Magnetic Resonance Imaging, Transfusion Method, and Chelation.

Pediatr Blood Cancer 2016 08 21;63(8):1414-8. Epub 2016 Apr 21.

Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

Background: Transfusions prevent a number of complications of sickle cell disease (SCD), but cause inevitable iron loading. With magnetic resonance imaging (MRI), liver iron can be monitored noninvasively. Erythrocytapheresis can limit iron loading and oral chelation provides a more tolerable alternative to subcutaneous administration. The impact of these factors on control of iron burden in SCD has not been well studied.

Procedure: Iron monitoring practices, chelation use, and transfusion methods were assessed in our cohort of pediatric patients with SCD receiving chronic transfusion. The impact of these factors on iron burden was assessed.

Results: Among 84 subjects, the proportion that underwent appropriate liver iron concentration (LIC) assessment rose from 21% before to 81% after implementation of R2-MRI in 2006. Among subjects with at least two R2-MRI examinations, median LIC improved (13.2-7.9 mg/g dw, P = 0.027) from initial to final study. Most (67.9%) subjects initially received simple transfusions and subsequently transitioned to erythrocytapheresis. After switching, LIC improved from 13.1 to 4.3 mg/g dw (P < 0.001) after a median of 2.7 years and ferritin improved (2,471-392 ng/ml, P < 0.001) after a median of 4.2 years. Final serum ferritin and LIC correlated negatively with the proportion of transfusions administered by erythrocytapheresis and chelation adherence.

Conclusions: Routine liver R2-MRI should be performed in individuals with SCD who receive chronic red cell transfusions. Adherence with chelation should be assessed regularly and erythrocytapheresis utilized when feasible to minimize iron loading or reduce iron stores accumulated during periods of simple transfusion.
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http://dx.doi.org/10.1002/pbc.26017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5132054PMC
August 2016

Hydroxycarbamide versus chronic transfusion for maintenance of transcranial doppler flow velocities in children with sickle cell anaemia-TCD With Transfusions Changing to Hydroxyurea (TWiTCH): a multicentre, open-label, phase 3, non-inferiority trial.

Lancet 2016 Feb 6;387(10019):661-70. Epub 2015 Dec 6.

Medical University of South Carolina, Charleston, SC, USA.

Background: For children with sickle cell anaemia and high transcranial doppler (TCD) flow velocities, regular blood transfusions can effectively prevent primary stroke, but must be continued indefinitely. The efficacy of hydroxycarbamide (hydroxyurea) in this setting is unknown; we performed the TWiTCH trial to compare hydroxyurea with standard transfusions.

Methods: TWiTCH was a multicentre, phase 3, randomised, open-label, non-inferiority trial done at 26 paediatric hospitals and health centres in the USA and Canada. We enrolled children with sickle cell anaemia who were aged 4-16 years and had abnormal TCD flow velocities (≥ 200 cm/s) but no severe vasculopathy. After screening, eligible participants were randomly assigned 1:1 to continue standard transfusions (standard group) or hydroxycarbamide (alternative group). Randomisation was done at a central site, stratified by site with a block size of four, and an adaptive randomisation scheme was used to balance the covariates of baseline age and TCD velocity. The study was open-label, but TCD examinations were read centrally by observers masked to treatment assignment and previous TCD results. Participants assigned to standard treatment continued to receive monthly transfusions to maintain 30% sickle haemoglobin or lower, while those assigned to the alternative treatment started oral hydroxycarbamide at 20 mg/kg per day, which was escalated to each participant's maximum tolerated dose. The treatment period lasted 24 months from randomisation. The primary study endpoint was the 24 month TCD velocity calculated from a general linear mixed model, with the non-inferiority margin set at 15 cm/s. The primary analysis was done in the intention-to-treat population and safety was assessed in all patients who received at least one dose of assigned treatment. This study is registered with ClinicalTrials.gov, number NCT01425307.

Findings: Between Sept 20, 2011, and April 17, 2013, 159 patients consented and enrolled in TWiTCH. 121 participants passed screening and were then randomly assigned to treatment (61 to transfusions and 60 to hydroxycarbamide). At the first scheduled interim analysis, non-inferiority was shown and the sponsor terminated the study. Final model-based TCD velocities were 143 cm/s (95% CI 140-146) in children who received standard transfusions and 138 cm/s (135-142) in those who received hydroxycarbamide, with a difference of 4·54 (0·10-8·98). Non-inferiority (p=8·82 × 10(-16)) and post-hoc superiority (p=0·023) were met. Of 29 new neurological events adjudicated centrally by masked reviewers, no strokes were identified, but three transient ischaemic attacks occurred in each group. Magnetic resonance brain imaging and angiography (MRI and MRA) at exit showed no new cerebral infarcts in either treatment group, but worsened vasculopathy in one participant who received standard transfusions. 23 severe adverse events in nine (15%) patients were reported for hydroxycarbamide and ten serious adverse events in six (10%) patients were reported for standard transfusions. The most common serious adverse event in both groups was vaso-occlusive pain (11 events in five [8%] patients with hydroxycarbamide and three events in one [2%] patient for transfusions).

Interpretation: For high-risk children with sickle cell anaemia and abnormal TCD velocities who have received at least 1 year of transfusions, and have no MRA-defined severe vasculopathy, hydroxycarbamide treatment can substitute for chronic transfusions to maintain TCD velocities and help to prevent primary stroke.

Funding: National Heart, Lung, and Blood Institute, National Institutes of Health.
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http://dx.doi.org/10.1016/S0140-6736(15)01041-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5724392PMC
February 2016

Effects of hydroxyurea treatment for patients with hemoglobin SC disease.

Am J Hematol 2016 Feb;91(2):238-42

Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.

Although hemoglobin SC (HbSC) disease is usually considered less severe than sickle cell anemia (SCA), which includes HbSS and HbS/β(0) -thalassemia genotypes, many patients with HbSC experience severe disease complications, including vaso-occlusive pain, acute chest syndrome, avascular necrosis, retinopathy, and poor quality of life. Fully 20 years after the clinical and laboratory efficacy of hydroxyurea was proven in adult SCA patients, the safety and utility of hydroxyurea treatment for HbSC patients remain unclear. Recent NHLBI evidence-based guidelines highlight this as a critical knowledge gap, noting HbSC accounts for ∼30% of sickle cell patients within the United States. To date, only 5 publications have reported short-term, incomplete, or conflicting laboratory and clinical outcomes of hydroxyurea treatment in a total of 71 adults and children with HbSC. We now report on a cohort of 133 adult and pediatric HbSC patients who received hydroxyurea, typically for recurrent vaso-occlusive pain. Hydroxyurea treatment was associated with a stable hemoglobin concentration; increased fetal hemoglobin (HbF) and mean corpuscular volume (MCV); and reduced white blood cell count (WBC), absolute neutrophil count (ANC), and absolute reticulocyte count (ARC). Reversible cytopenias occurred in 22% of patients, primarily neutropenia and thrombocytopenia. Painful events were reduced with hydroxyurea, more in patients >15 years old. These multicenter data support the safety and potentially salutary effects of hydroxyurea treatment for HbSC disease; however, a multicenter, placebo-controlled, Phase 3 clinical trial is needed to determine if hydroxyurea therapy has efficacy for patients with HbSC disease.
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http://dx.doi.org/10.1002/ajh.24255DOI Listing
February 2016

Increasing prevalence of thalassemia in America: Implications for primary care.

Ann Med 2015 5;47(7):592-604. Epub 2015 Nov 5.

b Perelman School of Medicine, University of Pennsylvania , Children's Hospital of Philadelphia, Division of Hematology, Department of Pediatrics , Philadelphia , USA.

Thalassemia, once a rarity in the United States, is increasingly encountered in clinical practice due to shifts in immigration. Early carrier screening in at-risk populations can help clinicians implement genetic counseling and prevent new cases. Chronic transfusions are the mainstay of therapy for patients with severe thalassemia (beta thalassemia major), and are used intermittently in individuals with milder forms of thalassemia (Hb H/H Constant Spring disease and beta thalassemia intermedia). Iron overload is a major source of morbidity and mortality in individuals with transfusion and non-transfusion-dependent thalassemia, necessitating iron chelation therapy. Iron overload contributes to increased risk of cirrhosis, heart failure, and endocrinopathies, while ineffective erythropoiesis and hemolysis contribute to multiple complications, including splenomegaly, extramedullary hematopoiesis, pulmonary hypertension, and thrombosis. An understanding of the importance of carrier screening, complications, monitoring, and management strategies, coupled with collaboration with a hematologist with thalassemia expertise, is essential to reduce the morbidity and mortality in patients with thalassemia.
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http://dx.doi.org/10.3109/07853890.2015.1091942DOI Listing
September 2016