ISTH bleeding assessment tool and platelet function analyzer in children with mild inherited platelet function disorders.

OBJECTIVES: To evaluate the diagnostic performance of platelet function analyzer (PFA) and The International Society on Thrombosis and Hemostasis bleeding-assessment-tool (ISTH-BAT) in detecting mild inherited platelet function disorders (IPFDs) in children with suspected bleeding disorders. METHODS: Prospective single-center diagnostic study including consecutive patients <18 years with suspected bleeding disorder and performing a standardized workup for platelet function defects including ISTH-BAT, PFA, platelet aggregation testing, blood smear-based immunofluorescence, and next-generation sequencing-based genetic screening for IPFDs. RESULTS: We studied 97 patients, of which 34 von Willebrand disease (VWD, 22 type-1, 11 type-2), 29 IPFDs (including delta-/alpha-storage pool disease, Glanzmann thrombasthenia, Hermansky-Pudlak syndrome) and 34 with no diagnosis. In a model combining PFA-adenosine diphosphate (ADP), PFA-epinephrine (EPI), and ISTH-BAT overall performance to diagnose IPFDs was low with area under the curves of 0.56 (95% CI 0.44, 0.69) compared with 0.84 (95% CI 0.76, 0.92) for VWD. Correlation of PFA-EPI/-ADP and ISTH-BAT was low with 0.25/0.39 Spearman's correlation coefficients. PFA were significantly prolonged in patients with VWD and Glanzmann thrombasthenia. ISTH-BAT-scores were only positive in severe bleeding disorders, but not in children with mild IPFDs or VWD. CONCLUSION: Neither ISTH-BAT nor PFA or the combination of both help diagnosing mild IPFDs in children. PFA is suited to exclude severe IPFDs or VWD and is in this regard superior to ISTH-BAT in children.

Clinically meaningful improvements in patient-reported outcomes in mitapivat-treated patients with pyruvate kinase deficiency.

Clinically meaningful benefits in the signs, symptoms, and impacts of #PKDeficiency as assessed by disease-specific patient-reported outcome measures were observed in mitapivat-treated adult patients in two phase 3 clinical trials.

Adolescents and young adults with newly diagnosed primary immune thrombocytopenia.

Current immune thrombocytopenia (ITP) guidelines target children and adults, leading to oversimplification. Adolescents and young adults (AYAS) comprise a separate group with distinct health and psychosocial issues. This study aimed to describe the clinical presentation and therapeutic strategies of ITP among AYAS. We analyzed data from two large ITP registries (PARC-ITP; CARMEN-France) and included newly diagnosed ITP patients (aged 12-25 years) with an initial platelet counts of <100×109/L. Patients with secondary ITP or non-immune thrombocytopenia (n=57) and pregnant women (n=10) were excluded. Of the 656 cases of AYAS with primary ITP registered from 2004 up to 2021, 12-month follow-up data were available for 72%. The initial median platelet count was 12×109/L. In 109 patients (17%), the diagnosis was incidental, without documented bleeding. Apart from gynecological bleeding, the clinical and therapeutical characteristics of females and males were similar. Platelet-enhancing drugs were reported in 66%, 45%, and 30% of patients at diagnosis, 1-6 months, and 6-12 months after diagnosis, respectively. Corticosteroids were the preferred treatment at all time points. At 12 months, 50% of all patients developed chronic ITP. In the subgroup of patients with initial severe thrombocytopenia (<20×109/L), those receiving frontline treatment had a higher remission rate at 1 year than those who followed an initial watch-and-wait strategy (53% and 32%; P<0.05). Our analysis indicates that the remission rate at 1 year may be associated with the initial treatment strategy. This hypothesis must be confirmed in prospective studies.

[Updated AWMF Guideline on the Diagnosis and Treatment of Langerhans cell Histiocytosis in Children and Adolescents]. / Aktualisierte AWMF Leitlinie zur Diagnostik und Therapie der Langerhanszell Histiozytose (LCH) im Kindes- und Jugendalter.

Langerhans cell Histiocytosis is a rare neoplastic disease, which occurs mainly in children and adolescents. The disease may affect any organ, and therefore, the clinical symptoms vary widely. Some patients have a spontaneous remission of the disease, whereas others experience a rapid and potentially lethal clinical course. The therapeutic approach depends on the extent of the disease, and reaches from a watch-and-wait strategy to chemotherapy with the standard drugs vinblastine and prednisone. The identification of mutations in the MAPK-pathway resulted in growing interest in targeted therapy using compounds such as the BRAF inhibitors. Chronic relapses and permanent sequelae are important problems of LCH and are the focus of current research.

Electronic diaries in the management of haemophilia gene therapy: Perspective of an expert group from the German, Austrian and Swiss Society on Thrombosis and Haemostasis (GTH).

INTRODUCTION: Gene therapy (GT) is becoming a realistic treatment option for patients with haemophilia. Outside clinical trials, the complexity and potential complications of GT will pose unprecedented challenges to haemophilia care centres. AIM: To explore the potential use of electronic tools to improve the delivery of GT under real-world conditions. METHODS: Considering the hub-and-spoke model, the GTH working group on GT considered the entire patient pathway and reached consensus on requirements for an integrative software tool to secure documenting and sharing information between treaters, pharmacies and patients. RESULTS: Six steps of the gene therapy process were identified, each requiring completion of the previous step as a prerequisite for entry. The responsibilities of GT dosing and follow-up treatment centres, read/write access rules, and the minimum data set were outlined. Data contributed by patients through mobile devices was also considered. CONCLUSION: Important information needs to be shared between patients and treatment centres in a real-world GT hub-and-spoke model. Collecting and sharing this information in well-organised electronic applications will not only improve patient care but also enable national and international data collection in clinical registries.

Hemostatic Management in an Infant With Neuroblastoma and Severe Hemophilia B With Extended Half-life Recombinant Factor IX Fusion Protein.

In the rare co-occurrence of childhood cancer and severe hemophilia, hemostatic management is of paramount therapeutic importance. We present the case of an 11-month-old boy with severe congenital hemophilia B, who was diagnosed with metastatic high-risk neuroblastoma. He consequently developed paraneoplastic coagulopathy with life-threatening tumor hemorrhage and intracranial hemorrhage, showing central nervous system relapse. Management consisted of factor IX replacement with extended half-life factor IX fusion protein, adjusted to bleeding risk. Additional interventions included factor XIII, fibrinogen, fresh frozen plasma, tranexamic acid, and platelet transfusions. The half-life of factor IX products was markedly reduced requiring close factor IX monitoring and adequate replacement. This intensified treatment allowed chemotherapy, autologous stem cell transplantation, and GD2 antibody immune therapy without bleeding or thrombosis.

Pyruvate kinase deficiency in children.

BACKGROUND: Pyruvate kinase deficiency (PKD) is a rare, autosomal recessive red blood cell enzyme disorder, which leads to lifelong hemolytic anemia and associated complications from the disease and its management. METHODS: An international, multicenter registry enrolled 124 individuals younger than 18 years old with molecularly confirmed PKD from 29 centers. Retrospective and prospective clinical data were collected. RESULTS: There was a wide range in the age at diagnosis from 0 to 16 years. Presentation in the newborn period ranged from asymptomatic to neonatal jaundice to fulminant presentations of fetal distress, myocardial depression, and/or liver failure. Children <5 years old were significantly more likely to be transfused than children >12 to <18 years (53% vs. 14%, p = .0006), which correlated with the timing of splenectomy. Regular transfusions were most common in children with two severe PKLR variants. In regularly transfused children, the nadir hemoglobin goal varied considerably. Impact on quality of life was a common reason for treatment with regular blood transfusions and splenectomy. Splenectomy increased the hemoglobin and decreased transfusion burden in most children but was associated with infection or sepsis (12%) and thrombosis (1.3%) even during childhood. Complication rates were high, including iron overload (48%), perinatal complications (31%), and gallstones (20%). CONCLUSIONS: There is a high burden of disease in children with PKD, with wide practice variation in monitoring and treatment. Clinicians must recognize the spectrum of the manifestations of PKD for early diagnostic testing, close monitoring, and management to avoid serious complications in childhood.

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

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 (P = .007), lower indirect bilirubin (P = .005), and missense PKLR mutations (P = .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.

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

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.

Arteriopathy Influences Pediatric Ischemic Stroke Presentation, but Sickle Cell Disease Influences Stroke Management.

Background and Purpose- Sickle cell disease (SCD) and arteriopathy are pediatric stroke risk factors that are not mutually exclusive. The relative contributions of sickled red blood cells and arteriopathy to stroke risk are unknown, resulting in unclear guidelines for primary and secondary stroke prevention when both risk factors are present. We hypothesized that despite similarities in clinical presentation and radiographic appearance of arteriopathies, stroke evaluation and management differ in children with SCD compared with those without SCD. Methods- We compared presentation and management of children with and without SCD enrolled in the IPSS (International Pediatric Stroke Study) with acute arterial ischemic stroke, according to SCD and arteriopathy status. Regression modeling determined relative contribution of SCD and arteriopathy in variables with significant frequency differences. Results- Among 930 childhood arterial ischemic strokes, there were 98 children with SCD, 67 of whom had arteriopathy, and 466 without SCD, 392 of whom had arteriopathy. Arteriopathy, regardless of SCD status, increased likelihood of hemiparesis (odds ratio [OR], 1.94; 95% CI, 1.46-2.56) and speech abnormalities (OR, 1.67; 95% CI, 1.29-2.19). Arteriopathy also increased likelihood of headache but only among those without SCD (OR, 1.89; 95% CI, 1.40-2.55). Echocardiograms were less frequently obtained in children with SCD (OR, 0.58; 95% CI, 0.37-0.93), but the frequency of identified cardiac abnormalities was similar in both groups ( P=0.57). Children with SCD were less likely to receive antithrombotic therapy, even in the presence of arteriopathy (OR, 0.14; 95% CI, 0.08-0.22). Arteriopathy was associated with a significantly higher likelihood of antithrombotic therapy in children without SCD (OR, 5.36; 95% CI, 3.55-8.09). Conclusions- Arteriopathy, and not SCD status, was most influential of stroke presentation. However, SCD status influenced stroke management because children with SCD were less likely to have echocardiograms or receive antithrombotic therapy. Further work is needed to determine whether management differences are warranted.

A comparative prospective observational study of children and adults with immune thrombocytopenia: 2-year follow-up.

Comparative clinical studies of children and adults with immune thrombocytopenia (ITP) are poorly covered in the literature. However, the accepted classification of ITP-childhood ITP and adult ITP-results in considerable differences in treatment protocols and practice guidelines. The analysis of the Pediatric and Adult Registry on Chronic ITP (PARC-ITP) of patients at first presentation demonstrated fewer differences in clinical and laboratory findings at initial diagnosis between children and adults than expected. The present report of 2-year follow-up data supports the hypothesis that there are common aspects of childhood and adult ITP. Data of 3360 children and 420 adults were collected during the time of 2004 until 2015 at initial diagnosis. Follow-up information was available for 51% and 33% of children and 66% and 49% of adults at 12- and 24-months, respectively. Similarities were found in unexpected areas of ITP, such as the rate of late remission at 12 and 24 months, reported bleeding sites, platelet count in bleeders, and the frequency of treated patients with persistent or chronic ITP. Differences were confirmed for the overall rate of remission and treatment modalities. Unexpected differences were found in the percentage of nonbleeders, with more adults in the nonbleeder group. More studies are needed to investigate different age groups with the aim to optimize their management.

Impact of high-risk thrombophilia status on recurrence among children with a first non-central-venous-catheter-associated VTE: an observational multicentre cohort study.

Deficiency of antithrombin (AT), protein C (PC) or protein S (PS) constitutes a major risk factor for venous thromboembolism (VTE). Individuals at high risk for recurrence who benefit from screening need to be identified. The primary study objective was to determine the individual recurrence risk among children with a first non-central-venous-catheter-associated VTE with respect to their thrombophilia status and to evaluate if the clinical presentation at first VTE onset differs between children with AT, PC or PS deficiency versus no thrombophilia. We calculated the absolute risk of VTE recurrence and event-free-survival adjusted for thrombophilia, age, sex and positive family VTE history in 161 consecutively enrolled paediatric VTE patients. The presence of a deficiency relative to no thrombophilia was evaluated as a potential predictor of recurrence. Predictors for recurrence were AT deficiency (hazard ratio/95% CI: 6·5/2·46-17·2) and female gender (2·6/1·1-6·35). The annual recurrence rates (95% CIs) were 5·4% (2·6-10) in AT-deficient children, 1·3% (0·3-3·8) in patients with PC deficiency, 0·7% (0·08-2·4) in the PS-deficient cohort and 0·9% (0·4-1·8) in patients with no thrombophilia. Positive family VTE history or combined thrombophilias did not predict recurrence. Given the overall annual incidence rate of recurrence of 1·5% we suggest screening for AT deficiency in children with VTE.

Eltrombopag for children with chronic immune thrombocytopenia (PETIT2): a randomised, multicentre, placebo-controlled trial.

BACKGROUND: The thrombopoietin receptor agonist eltrombopag has been shown to be safe, tolerable, and effective for adults with chronic immune thrombocytopenia. We aimed to investigate the safety and efficacy of eltrombopag for children with chronic immune thrombocytopenia. METHODS: PETIT2 was a two part, randomised, multicentre, placebo-controlled study done at 38 centres in 12 countries (Argentina, Czech Republic, Germany, Hong Kong, Israel, Italy, Russia, Spain, Taiwan, Thailand, UK, and USA). Paediatric patients aged 1-17 years who had chronic immune thrombocytopenia and platelet counts less than 30 × 10(9) per L were randomly assigned (2:1) to receive eltrombopag or placebo. We stratified patients by age into three cohorts (patients aged 12-17 years, 6-11 years, and 1-5 years) before randomly entering them into a 13 week, double-blind period. Randomisation was done by the GlaxoSmithKline Registration and Medication Ordering System and both patients and study personnel were masked to treatment assignments. Patients who were allocated eltrombopag received tablets (except for those aged 1-5 years who received an oral suspension formulation) once per day for 13 weeks. Starting doses for patients aged 6-17 were based on bodyweight, and ethnic origin and ranged between 50 mg/day and 25 mg/day (starting dose for patients aged 1-5 years was 1·2 mg/kg/day or 0·8 mg/kg/day for east Asian patients). Patients who completed the double-blind period entered a 24 week open-label treatment period in which all patients received eltrombopag at either the starting dose (if they were formerly on placebo) or their established dose. The primary outcome was the proportion of patients achieving platelet counts of at least 50 × 10(9) per L in the absence of rescue therapy for 6 or more weeks from weeks 5 to 12 of the double-blind period. The intention-to-treat population included in the efficacy assessment consisted of all patients who were randomly assigned to one of the treatment groups, and the safety population included all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT01520909. FINDINGS: Beginning in March 15, 2012, 92 patients were enrolled, and the trial was completed on Jan 2, 2014. 63 patients were assigned to receive eltrombopag and 29 were assigned to receive placebo. In the double-blind period, three patients discontinued treatment because of adverse events: two patients in the eltrombopag group withdrew because of increased liver aminotransferases and one in the placebo group withdrew because of abdominal haemorrhage. 25 (40%) patients who received eltrombopag compared with one (3%) patient who received placebo achieved the primary outcome of platelet counts of at least 50 × 10(9) per L for 6 of the last 8 weeks of the double-blind period (odds ratio 18·0, 95% CI, 2·3-140·9; p=0·0004). Responses were similar in all cohorts (eltrombopag vs placebo: 39% vs 10% for patients aged 12-17 years, 42% vs 0% for patients aged 6-11 years, and 36% vs 0% for patients aged 1-5 years). Proportionately fewer patients who received eltrombopag (23 [37%] of 63 patients) had WHO grades 1-4 bleeding at the end of the double-blind period than did those who received placebo (16 [55%] of 29 patients); grades 2-4 bleeding were similar (three [5%] patients who received eltrombopag vs two [7%] patients who received placebo). During the 24-week open-label treatment period, 70 [80%] of 87 patients achieved platelet counts of 50 × 10(9) per L or more at least once. Adverse events that occurred more frequently with eltrombopag than with placebo included nasopharyngitis (11 [17%] patients), rhinitis (10 [16%] patients), upper respiratory tract infection (7 [11%] patients), and cough (7 [11%] patients). Serious adverse events occurred in five (8%) patients who received eltrombopag and four (14%) who received placebo. Safety was consistent between the open-label and double-blind periods. No deaths, malignancies, or thromboses occurred during the trial. INTERPRETATION: Eltrombopag, which produced a sustained platelet response in 40% of patients with chronic immune thrombocytopenia, is a suitable therapeutic option for children with chronic symptomatic immune thrombocytopenia. We identified no new safety concerns and few patients discontinued treatment because of adverse events. FUNDING: GlaxoSmithKline.

Impact of high risk thrombophilia status on recurrence among children and adults with VTE: An observational multicenter cohort study.

BACKGROUND: Antithrombin [AT]-, protein C [PC]- or protein S [PS]-deficiency [D] constitutes a major risk factor for venous thromboembolism [VTE]. Primary study objective was to evaluate if the clinical presentation at first VTE onset differs between children and adults and to compare the individual recurrence risk among patients with respect to age at onset and their thrombophilia status ATD, PCD or PSD. METHODS/PATIENTS/RESULTS: In 137 of 688 consecutively enrolled pediatric and adult VTE patients we calculated the absolute risk of VTE recurrence and event-free-survival adjusted for thrombophilia and positive family VTE history. At first VTE children manifested i) with a lower rate of pulmonary embolism, ii) a higher rate of cerebral vascular events or multiple VTEs, and iii) showed a higher proportion of unprovoked VTE compared to adolescents and adults. Adult patients reported more often a positive VTE history compared to younger study participants. The adjusted odds of recurrence in adults was 2.05 compared to children. CONCLUSION: At disease manifestation children and adults differ with respect to i) thrombotic locations, ii) percentage of unprovoked versus provoked VTE, and iii) different rates of positive VTE family histories. Furthermore, adults showed a two-fold increase risk of VTE recurrence compared to children.

Clinical and laboratory characteristics of children with venous thromboembolism and protein C-deficiency: an observational Israeli-German cohort study.

Venous thromboembolism [TE] is a multifactorial disease and protein C deficiency [PCD] constitutes a major risk factor. In the present study the prevalence of PCD and the clinical presentation at TE onset, including neonatal purpura fulminans, in a cohort of children are reported. In 367 unselected children (0·1-19 years) recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. Twenty-five of 338 children (7·4%) had PCD. Mean age at first TE onset was 10 years (range 0·1-18). Leading thromboembolic manifestations were neonatal purpura fulminans (n = 5), TE of cerebral veins (n = 3), stroke (n = 2) deep veinthrombosis (DVT) of the leg (n = 10), DVT & pulmonary embolism (n = 2) and DVT & pelvic veins (n = 3). Concomitant risk factors for TE were identified in 12 patients, whereas 13 children spontaneously developed TE. A positive family history of DVT was found in 10 children. In this unselected cohort of paediatric patients with symptomatic TE the overall prevalence of PCD was 7·4%; 1·5% presented with neonatal purpura fulminans. Given its clinical implication for patients and family members, thrombophilia testing should be performed and the benefit of medical or educational interventions should be evaluated in this high-risk population.

Inherited thrombophilia in children with venous thromboembolism and the familial risk of thromboembolism: an observational study.

Screening for inherited thrombophilia (IT) is controversial; persons at high risk for venous thromboembolism (VTE) who benefit from screening need to be identified. We tested 533 first- and second-degree relatives of 206 pediatric VTE patients for IT (antithrombin, protein C, protein S, factor V G1691A, factor II G20210A) and determined the incidence of symptomatic VTE relative to their IT status. The risk for VTE was significantly increased among family members with, versus without, IT (hazard ratio = 7.6; 95% confidence interval [CI], 4.0-14.5; P < .001) and highest among carriers of antithrombin, protein C, or protein S deficiency (hazard ratio = 25.7; 95% CI, 12.2-54.2; P < .001). Annual incidences of VTE were 2.82% (95% CI, 1.63%-4.80%) among family members found to be carriers of antithrombin, protein C, or protein S deficiency, 0.42% (0.12%-0.53%) for factor II G202010A, 0.25% (0.12%-0.53%) for factor V G1691A, and 0.10% (0.06%-0.17%) in relatives with no IT. Given the high absolute risk of VTE in relatives with protein C, protein S, and antithrombin deficiency, we suggest screening for these forms of hereditary thrombophilia in children with VTE and their relatives. Interventional studies are required to assess whether thromboembolism can be prevented in this high-risk population.