Non-clotting factor therapies for preventing bleeds in people with congenital hemophilia A or B.

BACKGROUND: Management of congenital hemophilia A and B is by prophylactic or on-demand replacement therapy with clotting factor concentrates. The effects of newer non-clotting factor therapies such as emicizumab, concizumab, marstacimab, and fitusiran compared with existing standards of care are yet to be systematically reviewed. OBJECTIVES: To assess the effects (clinical, economic, patient-reported, and adverse outcomes) of non-clotting factor therapies for preventing bleeding and bleeding-related complications in people with congenital hemophilia A or B compared with prophylaxis with clotting factor therapies, bypassing agents, placebo, or no prophylaxis. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, electronic databases, conference proceedings, and reference lists of relevant articles and reviews. The date of the last search was 16 August 2023. SELECTION CRITERIA: Randomized controlled trials (RCTs) evaluating people with congenital hemophilia A or B with and without inhibitors, who were treated with non-clotting factor therapies to prevent bleeds. DATA COLLECTION AND ANALYSIS: Two review authors independently reviewed studies for eligibility, assessed risk of bias, and extracted data for the primary outcomes (bleeding rates, health-related quality of life (HRQoL), adverse events) and secondary outcomes (joint health, pain scores, and economic outcomes). We assessed the mean difference (MD), risk ratio (RR), 95% confidence interval (CI) of effect estimates, and evaluated the certainty of the evidence using GRADE. MAIN RESULTS: Six RCTs (including 397 males aged 12 to 75 years) were eligible for inclusion. Prophylaxis versus on-demand therapy in people with inhibitors Four trials (189 participants) compared emicizumab, fitusiran, and concizumab with on-demand therapy in people with inhibitors. Prophylaxis using emicizumab likely reduced annualized bleeding rates (ABR) for all bleeds (MD -22.80, 95% CI -37.39 to -8.21), treated bleeds (MD -20.40, 95% CI -35.19 to -5.61), and annualized spontaneous bleeds (MD -15.50, 95% CI -24.06 to -6.94), but did not significantly reduce annualized joint and target joint bleeding rates (AjBR and AtjBR) (1 trial; 53 participants; moderate-certainty evidence). Fitusiran also likely reduced ABR for all bleeds (MD -28.80, 95% CI -40.07 to -17.53), treated bleeds (MD -16.80, 95% CI -25.80 to -7.80), joint bleeds (MD -12.50, 95% CI -19.91 to -5.09), and spontaneous bleeds (MD -14.80, 95% CI -24.90 to -4.71; 1 trial; 57 participants; moderate-certainty evidence). No evidence was available on the effect of bleed prophylaxis using fitusiran versus on-demand therapy on AtjBR. Concizumab may reduce ABR for all bleeds (MD -12.31, 95% CI -19.17 to -5.45), treated bleeds (MD -10.10, 95% CI -17.74 to -2.46), joint bleeds (MD -9.55, 95% CI -13.55 to -5.55), and spontaneous bleeds (MD -11.96, 95% CI -19.89 to -4.03; 2 trials; 78 participants; very low-certainty evidence), but not target joint bleeds (MD -1.00, 95% CI -3.26 to 1.26). Emicizumab prophylaxis resulted in an 11.31-fold increase, fitusiran in a 12.5-fold increase, and concizumab in a 1.59-fold increase in the proportion of participants with no bleeds. HRQoL measured using the Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QoL) physical and total health scores was improved with emicizumab, fitusiran, and concizumab prophylaxis (low-certainty evidence). Non-serious adverse events were higher with non-clotting factor therapies versus on-demand therapy, with injection site reactions being the most frequently reported adverse events. Transient antidrug antibodies were reported for fitusiran and concizumab. Prophylaxis versus on-demand therapy in people without inhibitors Two trials (208 participants) compared emicizumab and fitusiran with on-demand therapy in people without inhibitors. One trial assessed two doses of emicizumab (1.5 mg/kg weekly and 3.0 mg/kg bi-weekly). Fitusiran 80 mg monthly, emicizumab 1.5 mg/kg/week, and emicizumab 3.0 mg/kg bi-weekly all likely resulted in a large reduction in ABR for all bleeds, all treated bleeds, and joint bleeds. AtjBR was not reduced with either of the emicizumab dosing regimens. The effect of fitusiran prophylaxis on target joint bleeds was not assessed. Spontaneous bleeds were likely reduced with fitusiran (MD -20.21, 95% CI -32.12 to -8.30) and emicizumab 3.0 mg/kg bi-weekly (MD -15.30, 95% CI -30.46 to -0.14), but not with emicizumab 1.5 mg/kg/week (MD -14.60, 95% CI -29.78 to 0.58). The percentage of participants with zero bleeds was higher following emicizumab 1.5 mg/kg/week (50% versus 0%), emicizumab 3.0 mg/kg bi-weekly (40% versus 0%), and fitusiran prophylaxis (40% versus 5%) compared with on-demand therapy. Emicizumab 1.5 mg/kg/week did not improve Haem-A-QoL physical and total health scores, EQ-5D-5L VAS, or utility index scores (low-certainty evidence) when compared with on-demand therapy at 25 weeks. Emicizumab 3.0 mg/kg bi-weekly may improve HRQoL measured by the Haem-A-QoL physical health score (MD -15.97, 95% CI -29.14 to -2.80) and EQ-5D-5L VAS (MD 9.15, 95% CI 2.05 to 16.25; 1 trial; 43 participants; low-certainty evidence). Fitusiran may result in improved HRQoL shown as a reduction in Haem-A-QoL total score (MD -7.06, 95% CI -11.50 to -2.62) and physical health score (MD -19.75, 95% CI -25.76 to -11.94; 1 trial; 103 participants; low-certainty evidence). The risk of serious adverse events in participants without inhibitors also likely did not differ following prophylaxis with either emicizumab or fitusiran versus on-demand therapy (moderate-certainty evidence). Transient antidrug antibodies were reported in 4% (3/80) participants to fitusiran, with no observed effect on antithrombin lowering. A comparison of the different dosing regimens of emicizumab identified no differences in bleeding, safety, or patient-reported outcomes. No case of treatment-related cancer or mortality was reported in any study group. None of the included studies assessed our secondary outcomes of joint health, clinical joint function, and economic outcomes. None of the included studies evaluated marstacimab. AUTHORS' CONCLUSIONS: Evidence from RCTs shows that prophylaxis using non-clotting factor therapies compared with on-demand treatment may reduce bleeding events, increase the percentage of individuals with zero bleeds, increase the incidence of non-serious adverse events, and improve HRQoL. Comparative assessments with other prophylaxis regimens, assessment of long-term joint outcomes, and assessment of economic outcomes will improve evidence-based decision-making for the use of these therapies in bleed prevention.

Childhood nephrotic syndrome and the clinical profile of thromboembolism: a systematic review and meta-analysis.

Nephrotic syndrome (NS) is a common kidney disease of childhood, affecting 2-7 children per 100,000. A potentially life-threatening complication affecting children with NS is thromboembolism (TE). However, there remains a paucity of information regarding the burden of TE and its associated risk factors in this population. A systematic review was performed on observational studies examining TE events in children with NS, published in Medline, Embase, CINAHL, and CENTRAL, until May 2021. Meta-analyses were separately conducted on the prevalence of TE within articles exclusively studying children with congenital NS and among articles including all forms of NS. Out of 13,626 articles, 22 were included (14,290 children). The pooled prevalence of symptomatic TE among articles including patients with all forms of NS was 3.60% (95% CI 1.95-5.63), which increased to 8.70% (95% CI 5.11-12.96) in articles with exclusively congenital NS patients. Children with steroid-resistant NS were at a higher risk of TE compared to steroid-sensitive children (OR 4.40, 95% CI 1.34-15.59, p = 0.013). Focal segmental glomerulosclerosis was the most common histology present in patients with TE (51.2%). Children diagnosed with NS have a significant risk of TE, particularly in patients with congenital NS and steroid resistance. IMPACT: The prevalence of symptomatic thromboembolic (TE) events in children with nephrotic syndrome (NS) was 3.60% (95% CI 1.95-5.63), which increased more than two-fold in children with congenital NS to 8.70% (95% CI 5.11-12.96). Potential risk factors for TE events in this population include congenital forms of NS and steroid resistance. This review provides a better estimate of the prevalence of TE in children with NS, while identifying potentially higher-risk populations who may benefit from TE screening and thromboprophylaxis.

Risk factors for neonatal thrombosis: A retrospective study conducted in a single Canadian intensive care unit.

Among children, neonates have the highest incidence of thrombosis. We conducted a retrospective review of neonatal thrombosis, in a single intensive care unit (ICU) over 4.5 years. Among 4860 ICU admissions to our center, identified through the Canadian Neonatal Network database, 186 were associated with arterial and venous thrombosis involving 195 thrombotic sites. The neonatal thrombosis incidence was 38 per 1000 neonatal ICU admissions. We assessed patient characteristics and compared the association between risk factors and thrombosis. In the multivariate analysis, central venous catheters, sepsis, and respiratory distress syndrome were significant predictors of neonatal thrombosis.

A Case of a Pediatric Patient With Protein S Heerlen Polymorphism and Deep Venous Thrombosis.

Hereditary protein S (PS) deficiency is a rare autosomal dominant disorder with increased risk of venous thromboembolism. The PS Heerlen polymorphism at codon 501 of the PROS1 gene is considered a variant of uncertain significance. It has since been shown that PS Heerlen has a reduced half-life, resulting in reduced levels of free PS. We report a case of an adolescent female with May Thurner syndrome and heterozygous PS Heerlen mutation resulting in a mild PS deficiency and venous thromboembolism. With this nonmodifiable risk factor, the patient received prolonged anticoagulation with strong consideration for lifelong prophylaxis.

Successful Use of Thrombolysis in an Extremely Low Birth Weight, Premature Infant With Aortic Thrombosis.

BACKGROUND: Severe neonatal aortic thrombosis is rare but can lead to significant morbidity or death if inadequately treated. Thrombolytic therapy is indicated for thrombi which are life-threatening, organ-threatening, or limb-threatening, but dosing consensus has not been established. OBSERVATION: We report a case of a 700 g preterm neonate with spontaneous intestinal perforation who developed an occlusive aortic thrombus with signs of limb ischemia. He was treated successfully with tissue plasminogen activator without hemorrhagic complications. He was started at a dose of 0.06 mg/kg/h and received a maximum dose of 0.3 mg/kg/h. Long-term follow-up at 3 years and 3 months showed no negative sequelae. CONCLUSION: Alteplase may be considered in premature, extremely low-birth weight infants with careful assessment of risk and benefits, along with frequent surveillance and supportive care.

Oral Corticosteroid Therapy as an Adjuvant Treatment for Acute Bleeding in Hemophilia Patients With High Titer Inhibitors.

Treatment options exist for patients with severe hemophilia and high titer factor VIII inhibitors but is often inadequate. Few studies have been conducted to evaluate the utility of short-term corticosteroid therapy for improvement in bleeding complications and temporary or sustained resolution of inhibitors in these patients. We describe 2 patients with acute muscular hematomas successfully treated with 4 to 5 days of oral adjuvant corticosteroid therapy resulting in improvement in their acute bleeds and temporary reduction of inhibitors. Thus, the addition of corticosteroids to traditional therapy of hemophilia with inhibitors may be beneficial in some patients. In those with impending compartment syndrome steroids may improve edema and bleeding symptoms preventing the need for surgical interventions.

Management of Anticoagulation Therapy in Patients With Thromboembolism in the Context of Renal Dysfunction: Challenging Cases and Practical Algorithms.

BACKGROUND: Low-molecular-weight heparin is cleared through the kidneys and is commonly used for anticoagulation in the pediatric population. OBSERVATION: We present 3 challenging cases of children requiring anticoagulation in the context of acute kidney injury, nephrotic syndrome, and hemodialysis. CONCLUSIONS: A significant change in anti-factor Xa (anti-Xa) levels-used for drug monitoring-should prompt an assessment of renal function. In nephrotic syndrome, anti-Xa levels should be closely monitored when there is a change in the status of nephrotic disease activity. In hemodialysis patients, enoxaparin at once daily reduced dosing should be considered with trough and peak anti-Xa levels monitoring.

Central venous catheters are an important factor in paediatric thrombosis.

AIM: To establish the incidence and characteristics of paediatric thrombosis (PT) in a Canadian tertiary care centre during the era of low molecular weight heparin (LMWH). METHODS: A retrospective observational case study of all patients <18 years of age evaluated for arterial and venous thrombosis from May 2008 to July 2018 at McMaster Children's Hospital was conducted through the electronic medical record. RESULTS: The incidence of PT was 52.2 per 10 000 hospital admissions (n = 477/91 462). Provoked thrombosis was more prevalent (88.9%, n = 424/477) than unprovoked (2.9%, n = 14/477) or idiopathic thrombosis (4%, n = 19/477). Half of PT were in children <2 years (51.2%, n = 244/477). Central vascular catheterisation was a contributory factor in more than half of thrombotic events (56.2%, n = 268/477), while trauma (1.1%, n = 5/477), oral contraceptives (4%, n = 19/477), infection (4%, n = 19/477), surgery (6.9%, n = 33/477) and malignancy (8.4%, n = 40/477) were also risk factors. Arterial ischaemic stroke was diagnosed in 11.1% of cases (n = 53/477), while pulmonary embolism was identified in 7.1% (n = 34/477) and 1.7% of cases were fatal (n = 8/477). LMWH was the first-line therapeutic of choice (47.8%, n = 228/477), with 28.1% (n = 134/477) requiring no intervention. CONCLUSION: These data reiterate the elevated thrombosis risk to which infants and children with central vascular access are exposed.

ENNOBLE-ATE trial: an open-label, randomised, multi-centre, observational study of edoxaban for children with cardiac diseases at risk of thromboembolism.

Children with cardiac diseases suffer from significant morbidity and mortality secondary to thromboembolic complications. Anticoagulant agents currently used for thromboprophylaxis have many limitations, including subcutaneous administration (low molecular weight heparins) and requirement for frequent monitoring via venipuncture (vitamin K antagonists). Edoxaban is an oral direct factor Xa inhibitor without need of monitoring. In the treatment of venous thromboembolism in adults, edoxaban has shown to be effective and safe.This manuscript summarises the rationale and design of a phase 3, open-label, randomised controlled trial to evaluate and compare the safety and efficacy of edoxaban against standard of care (namely, vitamin K antagonist and low molecular weight heparin) in children with cardiac diseases.A goal of 150 children with cardiac diseases at risk of thromboembolic complications who need primary or secondary anticoagulant prophylaxis will be recruited. Eligible children between 6 months and <18 years of age will be randomised in a ratio of 2 to 1 for edoxaban versus standard of care. Randomisation will be stratified based on underlying cardiac disease and concomitant use of aspirin for patients other than Kawasaki disease. The primary outcome will be safety, comprised of major and clinically relevant non-major bleeding in first 3 months of treatment. Bleeding beyond 3 months, symptomatic and asymptomatic thromboembolic events, and pharmacokinetic and pharmacodynamic parameters will be evaluated as secondary outcomes.Randomised controlled anticoagulation trials are challenging in children. This study will evaluate a potentially valuable alternative of oral anticoagulant prophylactic use in children with cardiac diseases.

Inferior vena cava syndrome in neonates: An evidence-based systematic review of the literature.

Neonatal inferior vena cava syndrome (IVCS), though uncommon, is associated with significant morbidity and mortality. Information on risk factors, diagnosis, treatment, and outcomes is limited. This review comprised 61 neonates across 33 reports. Thrombosis occurred in 98% and 42% involved a central venous catheter. Diagnosis was mainly established by ultrasound in 82%. Therapeutically, heparin was employed in 36% and thrombolysis in 18% of the cases. The overall mortality was 23%. An algorithm of clinical signs, investigation, and management is presented. Well-designed prospective studies are needed to establish a concrete investigational approach to neonatal IVCS and institute safe, evidence-based treatment.

Feasibility and safety of delivering full-dose anticoagulation therapy in children treated according to Dana-Farber Cancer Institute acute lymphoblastic leukemia consortium therapy protocols.

BACKGROUND: The literature is void of an evidence-based anticoagulation therapy (ACT) management strategy in the context of thrombocytopenia. We examined the impact of thrombocytopenia on low-molecular-weight heparin (LMWH) dosing and incidence of bleeding in children with acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) who developed thromboembolism (TE) during therapy according to DFCI ALL protocols. PROCEDURE: Patient records from our tertiary care center were reviewed for demographics, details of diagnoses and therapy of ALL/LL and TE diagnoses, platelet counts during ACT, LMWH dosing, and bleeding episodes. RESULTS: Thirty-nine TEs were diagnosed in 33 patients [mean age 9 years (range, 2.5-18); 16 males and 31 with ALL] during the study period. A majority (85%) of patients were diagnosed with TE in the consolidation phase with mean time to TE 5.75 months from ALL/LL diagnosis. All patients received LMWH, and the median duration of ACT was 5.9 months (range, 1-11 months). Platelets were measured weekly. On 29 occasions, platelet nadir was <50 × 109 /L, and twice it was < 20 × 109 /L. One (3%) patient had major bleeding episode while on ACT. Platelet count at the time of bleeding was 222 × 109 /L. Ninety-two procedures [83 lumbar punctures (LPs), 9 central venous line (CVL) insertion/revision] were completed without bleeding complications. Asparaginase was held temporarily with TE diagnosis in 48% of patients; most (88%) patients completed all scheduled doses as per protocol. CONCLUSIONS: Ability to administer full-dose LMWH, expected bleeding rate, and completion of asparaginase doses while on ACT suggest full-dose ACT is feasible and safe in children with ALL/LL who develop TE during DFCI ALL consortium therapy protocols.

Outcomes following neonatal portal vein thrombosis: A descriptive, single-center study and review of anticoagulant therapy.

BACKGROUND: Neonatal portal vein thrombosis (PVT) is uncommon with potentially serious complications that may manifest in infancy and childhood. OBJECTIVE: The primary aim of our study was to describe the short-term and long-term outcomes of neonatal PVT. METHODS: A retrospective chart review was conducted from 2008 to 2016 of neonates diagnosed with PVT. A systematic review was also performed from 2000 to 2018 to evaluate anticoagulant therapy (ACT) in neonatal PVT. RESULTS: Forty-four premature and 30 term infants (mean gestational age 30.7 vs 39.1 weeks, respectively) had PVT. Sixty-eight involved the left portal vein, one involved only the main portal vein, and 5 involved ≥1 vein. PVT was catheter associated in 46 (62%); none of the 7 neonates tested had thrombophilia. Of 74 neonates, 19 (26%) received ACT and 55 (74%) were untreated. The mean follow-up duration was 16.6 months (SD = 17.62; range, 0-89.6); 59.5% were followed for ≥6 months. On last ultrasound examination, thrombus resolution was documented in treated (ACT; n = 19) and nontreated (n = 55) neonates: 12 (63%) versus 32 (58%) with complete resolution, 1 (5%) versus 6 (11%) partial, 0 versus 1 (2%) extension, and 6 (32%) versus 16 (29%) had nonprogressive lesions, respectively. Seventy-one (96%) had no complications. Seventy-one articles met inclusion criteria for the systematic review and 19 were retained for analysis after assessment. CONCLUSIONS: PVT resolution rate was similar to previous reports. Although a low complication rate was detected, longer follow-up is necessary to determine the need for early treatment and the precise incidence of outcomes such as portal hypertension.

Fanconi Syndrome Secondary to Deferasirox in Diamond-Blackfan Anemia: Case Series and Recommendations for Early Diagnosis.

Deferasirox is an oral iron chelator used to treat patients with transfusion-related iron overload. We report, from two institutions, two children with Diamond-Blackfan anemia who developed Fanconi syndrome secondary to deferasirox administration, along with a review of the literature. The current recommendation for the laboratory monitoring of patients receiving deferasirox does not include serum electrolytes or urine analysis. Thus, despite routine clinic visits and bloodwork, these two patients presented with life-threatening electrolyte abnormalities requiring hospitalization. Hence, we propose the inclusion of serum electrolytes and urine analysis as part of routine monitoring to facilitate the early diagnosis of Fanconi syndrome in the context of high doses of deferasirox therapy.

Vaginal Yolk Sac Tumor in an Infant: A Case Report and Literature Review of the Last 30 Years.

Vaginal yolk sac tumor is a rare malignant germ-cell tumor occurring most commonly in young girls. The treatment has evolved over the last 3 decades from radical surgery to conservative surgery with chemotherapy to chemotherapy alone. Here we present a case of a 6-month-old girl successfully treated with upfront surgery followed by chemotherapy. We include a literature review of studies on vaginal yolk sac tumor published in the last 30 years. We discuss the role of upfront surgery where possible followed by chemotherapy as a safe alternative to chemotherapy alone for the treatment of this rare malignancy.

Management of children with hemophilia A on emicizumab who need surgery.

The introduction of emicizumab into the treatment regime of persons with hemophilia A has dramatically reduced frequency of bleeding in patients with and without inhibitors. However, in children with Hemophilia A (CwHA) who require surgical or other invasive procedures, additional treatment with factor replacement or other hemostatic agents may still be needed to prevent intraoperative or postoperative bleeding. This review will look at the reported outcomes in CwHA on emicizumab who have had surgery and propose recommendations for the best perioperative management of major and minor procedures.

Challenges in Management of VTE in Children With Cancer: Risk Factors and Treatment Options.

Venous thromboembolism (VTE) occurs in 2.1 to up to 50% of children with cancer and contributes to long term morbidity as well as early mortality in this population. Pediatric patients with malignancy are predisposed to VTE due to the prothrombotic nature of cancer and its associated coagulopathies as well as chemotherapeutic agents, use of central venous catheters, surgery, radiotherapy, and concomitant thrombophilia. Management of thrombosis in this population is challenging due to concomitant thrombocytopenia, associated bleeding risks, concurrent co-morbidities, and toxicities of therapy. The aim of this paper is to highlight clinically relevant issues and management dilemmas using clinical vignettes. We review the clinical significance of asymptomatic and symptomatic thrombosis, examine the various options for asparaginase-associated thrombosis, address the role and controversies of direct oral anticoagulants, and describe our approach to managing anticoagulation therapy in the context of chemotherapy-induced thrombocytopenia.