A survey of pediatric hematology/oncology specialists regarding management of central line associated venous thrombosis

Central venous catheters (CVCs) account for the largest proportion of thrombotic events in pediatric patients. Questions remain regarding adequate treatment and prevention methods. We surveyed pediatric hematology/oncology specialists, using hypothetical cases to assess management strategies for acute CVC thrombosis and secondary prevention. Survey respondents varied in the use of the thrombophilia evaluation (33.3%, 41/123) and duration of treatment (6 weeks: 54.1%, 66/122). Secondary CVC prophylaxis was utilized by 36.6% (45/123) of respondents and by 24.4% (30/123) but only if there was a documented thrombophilia. This heterogeneity highlights the need for clinical studies to address these important clinical questions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137422/1/pbc26383_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137422/2/pbc26383.pd

Apixaban overdose in children:case report and proposed management. A brief communication from the Pediatric and Neonatal Thrombosis and Hemostasis SSC of ISTH

Background: Direct oral anticoagulants are commonly prescribed for adults and increasingly also for children requiring anticoagulation therapy. While household medications should not be accessible to children, accidental, and intentional overdoses occur. Key Clinical Question: How should apixaban overdose in children be managed?. Clinical Approach: We present a case of an accidental overdose with the factor Xa antagonist apixaban in a young child and propose an approach to the management of cases of apixaban overdose in children. Conclusion: Given the increasing use of direct oral anticoagulants, it is important to have an approach to the management of overdose of these medications.</p

Apixaban overdose in children:case report and proposed management. A brief communication from the Pediatric and Neonatal Thrombosis and Hemostasis SSC of ISTH

Background: Direct oral anticoagulants are commonly prescribed for adults and increasingly also for children requiring anticoagulation therapy. While household medications should not be accessible to children, accidental, and intentional overdoses occur. Key Clinical Question: How should apixaban overdose in children be managed?. Clinical Approach: We present a case of an accidental overdose with the factor Xa antagonist apixaban in a young child and propose an approach to the management of cases of apixaban overdose in children. Conclusion: Given the increasing use of direct oral anticoagulants, it is important to have an approach to the management of overdose of these medications.</p

A Prospective Observational Study of Antihemophilic Factor (Recombinant) Prophylaxis Related to Physical Activity Levels in Patients with Hemophilia A in the United States (SPACE)

Introduction: High collision-risk physical activity can increase bleeding risk in people with hemophilia A, as can increasing the time between factor VIII (FVIII) administration and physical activity. FVIII prophylaxis may be tailored to planned activities to prevent activity-related bleeding. Aim: To explore the relationship between physical activity levels, FVIII infusion timing, and occurrence of bleeding in patients with severe/moderately severe hemophilia A without FVIII inhibitors receiving antihemophilic factor (recombinant) (rAHF; ADVATE®; Baxalta US Inc., a Takeda company, Lexington, MA, USA). Methods: SPACE was a 6-month, prospective, multicenter, observational outcomes study (NCT02190149). Enrolled patients received an eDiary application and a wearable activity tracker, which recorded physical activity, rAHF infusion, and occurrence of bleeding. Physical activity risks were ranked using National Hemophilia Foundation criteria. Results: Fifty-four patients aged 11– 58 years (n = 47 prophylaxis, n = 7 on-demand) were included in the analysis. Patients had a mean (SD) 8.14 (10.94) annualized bleeding rate, and recorded 4980 intervals between an rAHF infusion and physical activity; 1759 (35.3%) of these intervals were ≤ 24 hours. Analysis of recorded eDiary data showed that the risk of activity-related bleeding did not significantly increase with time between last infusion and activity, but did increase with higher-risk physical activities. Analysis of activity tracker recorded data showed that the risk of bleeding reported by patients as spontaneous increased with prolonging time (≤ 24 to \u3e 24 hours) from last infusion to physical activity start (odds ratio 2.65, p \u3c 0.05). Joint health data collected at baseline were not included in the regression analysis because of small sample size; therefore the study could not assess whether patients with more joint disease at baseline were at higher risk of injury-related and reported spontaneous occurrence of bleeding. Conclusion: These results show that activities with a high risk of collision lead to an increased risk of bleeding. Further investigation is warranted to explore potential benefits of FVIII infusion timing to reduce the risks of activity-related occurrence of bleeding

Rituximab for treatment of inhibitors in haemophilia A: A Phase II Study

The development of antibodies against infused factor VIII (FVIII) in patients with haemophilia A is a serious complication leading to poorly controlled bleeding and increased morbidity. No treatment has been proven to reduce high titre antibodies in patients who fail immune tolerance induction or are not candidates for it. The Rituximab for the Treatment of Inhibitors in Congenital Hemophilia A (RICH) study was a phase II trial to assess whether rituximab can reduce anamnestic FVIII antibody (inhibitor) titres. Male subjects with severe congenital haemophilia A and an inhibitor titre ≥5 Bethesda Units/ml (BU) following a FVIII challenge infusion received rituximab 375 mg/m2 weekly for weeks 1 through 4. Post-rituximab inhibitor titres were measured monthly from week 6 through week 22 to assess treatment response. Of 16 subjects who received at least one dose of rituximab, three (18.8%) met the criteria for a major response, defined as a fall in inhibitor titre to <5 BU, persisting after FVIII re-challenge. One subject had a minor response, defined as a fall in inhibitor titre to <5 BU, increasing to 5–10 BU after FVIII re-challenge, but <50% of the original peak inhibitor titre. Rituximab is useful in lowering inhibitor levels in patients, but its effect as a solo treatment strategy is modest. Future studies are indicated to determine the role of rituximab as an adjunctive therapy in immune tolerisation strategies

Direct oral anticoagulants in pediatric venous thromboembolism: Experience in specialized pediatric hemostasis centers in the United States

BACKGROUND: Before the official US Food and Drug Administration approval in 2021, pediatric hematologists across the United States have used direct oral anticoagulants (DOACs) off-label and based on extrapolation from labeling for adults with venous thromboembolism (VTE) and interim results of pediatric-specific DOAC clinical studies. OBJECTIVES: The American Thrombosis and Hemostasis Network 15 (ATHN 15) study aimed to characterize the use of DOACs from 2015 to 2021 at 15 specialized pediatric hemostasis centers in the United States, with emphasis on safety and effectiveness. METHODS: Eligible participants were those aged 0 to 21 years who had a DOAC included as part of their anticoagulation regimen for the treatment of acute VTE or secondary prevention of VTE. Data were collected for up to 6 months after initiation of the DOAC. RESULTS: A total of 233 participants were enrolled, with a mean age of 16.5 years. Rivaroxaban was the most commonly prescribed DOAC (59.1%) followed by apixaban (38.8%). Thirty-one (13.8%) participants reported bleeding complications while on a DOAC. Major or clinically relevant nonmajor bleeding events occurred in 1 (0.4%) and 5 (2.2%) participants, respectively. Worsening menstrual bleeding was reported in 35.7% of females aged >12 years and occurred more frequently in those using rivaroxaban (45.6%) compared with apixaban (18.9%). The recurrent thrombosis rate was 4%. CONCLUSION: Pediatric hematologists at specialized hemostasis centers in the United States have been using DOACs for the treatment and prevention of VTEs, primarily in adolescents and young adults. Reported DOAC use showed adequate safety and effectiveness rates

Characterizing the Use of Direct Oral Anticoagulants in Children Using the American Thrombosis and Hemostasis Network Dataset (ATHNdataset)

Background: The incidence of venous thromboembolism (VTE) in children has risen significantly. (Raffini, Huang et al. 2009) There are currently four direct oral anticoagulants (DOACs) - apixaban, dabigatran, edoxaban, and rivaroxaban - approved for the acute treatment and prevention of VTE in adults. Advantages of these medications over the traditionally used anticoagulants, enoxaparin and warfarin, include fixed dosing, no need for routine laboratory monitoring, few drug interactions and no dietary restrictions. Despite lack of information on the safety and efficacy of these agents in children, pediatric hematologists across the United States are using DOACs in their patients based on extrapolated data from adult studies. The American Thrombosis and Hemostasis Network (ATHN) is a nonprofit network of over 140 federally funded Hemophilia Treatment Centers (HTCs) which provides the infrastructure for clinical and surveillance-based research. ATHN maintains the ATHNdataset (ADS), a "limited dataset" free of protected health information, with data collected on patients with bleeding and clotting disorders at participating HTCs within the Human Resources and Services Administration (HRSA)-supported regional hemophilia networks across the US. The authors acknowledge ATHN, the ATHN-affiliated U. S. Hemophilia Treatment Centers and their 39,000+ patients who have contributed their demographic, clinical, and genetic information to the ATHNdataset. Methods: The objective of this study was to describe the characteristics of pediatric patients diagnosed with VTE in the ADS, focusing on those patients who received a DOAC. Data were abstracted for patients in the ADS who had acute VTE at age <21 years from January 2010 to March 2019. Data extraction included basic demographics and information about VTE and treatment. Results : A total of 1,094 pediatric VTE cases were captured in the ADS. 577 (52.7%) were male. Caucasians were the most prevalent racial group (n = 809; 74%), followed by African-Americans (n = 203; 18.6%).14.9% (n = 163) were Hispanic. Deep venous thrombosis (DVT) was the most prevalent pediatric VTE reported in the ADS (n=889, 81.3%), followed by pulmonary embolism and cerebral venous thrombosis (n=130, 11.9% and n=40, 3.7% respectively). VTE location by age group is listed in Table 1. The most common DVT location was the lower extremities or pelvis, comprising 37.5% (n = 333) of all reported DVTs. Upper extremities or upper thorax DVT occurred less often (n = 211; 23.8 %). 345 (38.8 %) cases were reported only as "DVT" without a specific thrombus location. We reviewed 1,051 anticoagulant prescriptions for 650 VTE patients (mean 1.6 prescriptions per person). Enoxaparin was the most commonly prescribed anticoagulant (n = 676 prescriptions; 64.3%) followed by warfarin (n = 178 prescriptions, 16.9%). Interestingly, 116 (11%) patients, from 21 HTCs, had a DOAC prescribed as their anticoagulant regimen. Anticoagulant prescription by anticoagulant starting age is shown in Table 2. Further analysis of the DOAC subgroup showed that rivaroxaban was the most prescribed DOAC with 77.6% (n = 90/116) of the patients using this agent. Apixaban and dabigatran use was also reported (n= 23, 19.8% and n= 3, 2.6% respectively). The majority of DOACs were prescribed for patients older than 13 years of (111/116, 95.7 %). In children between 3 to 6 years of age (n = 3), rivaroxaban was the only DOAC prescribed. DOACs were primarily used to treat DVT of the extremities (84/116 patients). Other scenarios in which DOACs were also prescribed were PE and abdominal venous thrombosis patients (26, and 4 patients, respectively). Anticoagulant prescription by anticoagulant starting age is shown in Table 2. Conclusion: DVT of the lower extremities and pelvis is the most prevalent pediatric VTE in the ADS. Enoxaparin and warfarin remain the main anticoagulant agents used for pediatric VTE treatment. Despite lack of an FDA-approved pediatric indication, hematologists in US-based HTCs are already using DOACs in pediatric patients with VTE. As further characterization of DOAC use in children is needed, the authors, in collaboration with ATHN, are currently building a multi-institutional retrospective and prospective registry, ATHN 15. This registry will serve as a resource for pediatric hematologists to collect real-world use of DOACs in children, as we await the results of prospective clinical trials. Disclosures Davila: Octapharma: Other: Grant to attend VWD meeting ; Genentech: Other: Advisory board; Spire Learning: Speakers Bureau. Raffini:Bayer: Other: Advisory Board; CSL Behring: Other: Advisory Board; Roche: Other: Advisory Board. Thornburg:Sanofi Genzyme: Research Funding; Bluebird bio: Other: Data Safety Monitoring Board; Genentech: Speakers Bureau; NovoNordisk: Research Funding; Ironwood: Other: Data Safety Monitoring Board; Sanofi Genzyme: Other: Data Safety Monitoring Board. Corrales-Medina:Octapharma: Membership on an entity's Board of Directors or advisory committees; Kedrion: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding

Athn 15: Characterizing the Real-World Use of Direct Oral Anticoagulants in Pediatric Patients - Interim Analysis

Background: There are currently four direct oral anticoagulants (DOACs) approved for the acute treatment and prevention of venous thromboembolism (VTE) in adults. Pediatric hematologists across the United States (US) are using DOACs for their patients based on extrapolated data from adult studies and recently published phase 3 pediatric-specific studies. (Brandao LR, et al. Blood, 2019 and Male C, et al. Lancet Haematol, 2020.) Because further data regarding DOAC use in children are needed, ATHN 15: Characterizing the Real-World Use of Direct Oral Anticoagulants in Pediatric Patients, was developed and is being sponsored by the American Thrombosis and Hemostasis Network (ATHN). The study is being conducted at ATHN-affiliated sites in the US and aims to characterize the real-world use of DOACs in children diagnosed with VTE. ATHN is a nonprofit network of over 140 federally funded hemophilia treatment centers (HTCs) that provides the infrastructure for clinical research and public health surveillance. Methods: Data being captured includes demographics, clinical characteristics, anticoagulation management, and treatment outcomes (bleeding and recurrent thrombosis) of patients <21 years of age, who have received or are receiving a DOAC since January 1, 2015 for the treatment of an acute VTE episode or prevention of thrombosis recurrence. Data are collected for up to 6 months from the start of DOAC treatment. Results: As of May 31, 2020, 76 patients from 9 sites have been enrolled (see Table 1 for demographics). Deep venous thrombosis (DVT) of the lower extremities or pelvis is the most prevalent VTE (n = 23, 30.26%), followed by DVT of the upper extremity or upper thorax and pulmonary embolism plus VTE (n = 22, 28.95 and n = 13, 17.1% respectively). 82.89% of patients did not have a history of prior VTE at the time of enrollment. Of the 15 patients with a radiologically confirmed anatomic anomaly, Paget Schroetter/Thoracic Outlet Syndrome and May-Turner Syndrome are the most common (n = 6, 40% and n = 4, 26.7%, respectively). Factor V Leiden heterozygosity, reported in 8 patients, is the most prevalent inherited thrombophilia. Forty-eight patients were identified as having a medical risk factor associated with their VTEs. Sixteen (33.3%) were classified as obese and another 13 (27.1%) had a hospital admission stay greater than 7 days and within 30 days prior to the VTE. At least one specific drug or environmental risk factor was reported in 44 patients. Concomitant use of hormonal contraception (currently taking/stopped within 4 weeks prior to VTE) and the presence of a central venous catheter (present at time of VTE or within 30 days prior to VTE) were the most commonly reported (n = 18, 40.9% and n = 15, 34.09%, respectively). Rivaroxaban is the most prescribed DOAC with 59.2% (n = 45) of patients using this agent. Apixaban and dabigatran use is also reported (n = 29; 38.2% and n = 2; 2.6% respectively). Of the 76 patients, 65 received a different anticoagulant prior to starting a DOAC. Enoxaparin and unfractionated heparin are most commonly prescribed prior to the institution of a DOAC regimen (n = 52, 80% and n = 17, 26.2%). Conclusions: Despite lack of an FDA-approved pediatric indication, hematologists in the US are already using DOACs for children with VTE. Most pediatric patients treated with a DOAC are older than 13 years of age, although we anticipate this will change as providers develop more comfort with these drugs. Interestingly, most of these patients were started on a different anticoagulation regimen prior to starting a DOAC. As enrollment continues, ATHN 15 will serve as a resource for pediatric hematologists to characterize the real-world use of DOACs in children. Further analysis will evaluate DOAC-specific utilization, efficacy and adverse events, including heavy menstrual bleeding. Disclosures Davila: Spire Learning: Speakers Bureau; ATHN: Other: Grant Funding. Corrales-Medina:Bayer: Consultancy; Takeda: Consultancy; Octapharma: Consultancy, Speakers Bureau. Raffini:XaTek: Other: Advisory Board; CSL Behring: Other: Advisory Board; HemaBiologics: Other: Advisory Board; Bayer: Other: Advisory Board; Roche: Other: Advisory Board. Thornburg:Sanofi Genzyme: Consultancy, Other: Data Safety Monitoring Board, Research Funding; NovoNordisk: Research Funding; Genentech: Speakers Bureau; Biomarin: Consultancy, Speakers Bureau; Bayer Pharmaceuticals: Research Funding; American Thrombosis and Hemostasis Network: Research Funding; National Hemophilia Foundation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Ironwood Pharmaceuticals: Consultancy, Other: Data Safety Monitoring Board; Bluebird Bio: Consultancy; Spark Therapeutics: Consultancy. OffLabel Disclosure: Apixaban, Rivaroxaban, Dabigatran and Enoxaparin use in the pediatric population

Direct oral anticoagulants in pediatric venous thromboembolism: Experience in specialized pediatric hemostasis centers in the United States

Before the official US Food and Drug Administration approval in 2021, pediatric hematologists across the United States have used direct oral anticoagulants (DOACs) “off-label” and based on extrapolation from labeling for adults with venous thromboembolism (VTE) and interim results of pediatric-specific DOAC clinical studies. The American Thrombosis and Hemostasis Network 15 (ATHN 15) study aimed to characterize the use of DOACs from 2015 to 2021 at 15 specialized pediatric hemostasis centers in the United States, with emphasis on safety and effectiveness. Eligible participants were those aged 0 to 21 years who had a DOAC included as part of their anticoagulation regimen for the treatment of acute VTE or secondary prevention of VTE. Data were collected for up to 6 months after initiation of the DOAC. A total of 233 participants were enrolled, with a mean age of 16.5 years. Rivaroxaban was the most commonly prescribed DOAC (59.1%) followed by apixaban (38.8%). Thirty-one (13.8%) participants reported bleeding complications while on a DOAC. Major or clinically relevant nonmajor bleeding events occurred in 1 (0.4%) and 5 (2.2%) participants, respectively. Worsening menstrual bleeding was reported in 35.7% of females aged >12 years and occurred more frequently in those using rivaroxaban (45.6%) compared with apixaban (18.9%). The recurrent thrombosis rate was 4%. Pediatric hematologists at specialized hemostasis centers in the United States have been using DOACs for the treatment and prevention of VTEs, primarily in adolescents and young adults. Reported DOAC use showed adequate safety and effectiveness rates. •The use of direct oral anticoagulants (DOACs) in specialized pediatric centers in the United States was investigated.•DOACs were mostly used in adolescents and young adults for the treatment/prevention of blood clots.•Rivaroxaban and apixaban were the most commonly prescribed DOACs.•DOACs were found to be safe and effective