Laboratory testing in hemophilia: Impact of factor and non‐factor replacement therapy on coagulation assays

The advent of extended half‐life (EHL) recombinant clotting factors and innovative non‐factor replacement therapeutics, such as emicizumab, offers several advantages over existing products for the prophylactic treatment of people living with hemophilia (PwH). These include low annual bleeding rates with less frequent dosing, higher trough plasma concentrations, and a more convenient route of administration. However, increasing use of these therapies poses challenges to clinicians and coagulation laboratories due to the lack of standardized assays for monitoring of hemostatic parameters, and the potential for misinterpretation of test results, which may jeopardize patient safety. Definitive diagnosis of hemophilia and treatment monitoring is reliant on demonstrating factor VIII (FVIII; hemophilia A) or factor IX (FIX; hemophilia B) deficiency using a functional coagulation assay. The most frequently used assays are based on activated partial thromboplastin time, using a one‐stage or two‐stage process. While one‐stage and chromogenic assays have performed well with human‐derived FVIII and FIX and full‐length recombinant products, EHL recombinant factors are heterogeneous in structure and mode of action and therefore show wide variation in activity levels between different one‐stage assays, and between one‐stage and chromogenic assays. In the context of the recommended stepwise approach for laboratory diagnosis of hemophilia, we examine the diagnostic challenges associated with the use of EHL factors and novel non‐factor therapeutics and consider the optimal diagnostic approach in PwH who are receiving these treatments. Ultimately, accurate diagnostic solutions are a prerequisite for personalized therapy to minimize treatment burden and improve quality of life in PwH

Influence of factor 5 rs6025 and factor 2 rs1799963 mutation on inhibitor development in patients with hemophilia A - an Israeli-German multicenter database study

AbstractObjectiveThe present cohort study was performed to investigate the impact of the factor 5 rs6025 [F5] and the factor 2 rs1799963 [F2] mutations on high-titer inhibitor development [HRI] in patients with severe/moderate-severe hemophilia A [HA].Patients and Methods216 patients with F8<2% born between 1980 and 2011 were followed after initial HA diagnosis over the first 200 exposure days. The first HA patient per family who presented for diagnosis was included in the present study.Results32 of 216 children [14.8%] tested for F5/F2 carried either the F5 or the F2 variant. HRI occurred in 14 out of 32F5/F2-carriers compared with 40 of 184 without F5/F2. Multivariate analysis adjusted for F8 genotype, treatment intensity, first-line use of plasma derived FVIII versus recombinant FVIII concentrates revealed that the presence of F5/F2 independently increases the risk of HRI development to odds [OR] of 3.4. Large deletions in the F8 gene [OR: 5.10], patients from Israel [OR: 4.0], the increase of FVIII per one IU/kgbw [OR: 1.05] and birth year [OR: 1.12] were significantly associated with the risk to develop HRI.ConclusionData presented here suggest that HRI development is of multifactorial origin and that F5 and F2 mutations may contribute to this risk

Mode of delivery in hemophilia : vaginal delivery and Cesarean section carry similar risks for intracranial hemorrhages and other major bleeds

The optimal mode of delivery for a pregnant hemophilia carrier is still a matter of debate. The aim of the study was to determine the incidence of intracranial hemorrhage and other major bleeds in neonates with moderate and severe hemophilia in relationship to mode of delivery and known family history. A total of 926 neonates, 786 with severe and 140 with moderate hemophilia were included in this PedNet multicenter study. Vaginal delivery was performed in 68.3% (n=633) and Cesarean section in 31.6% (n=293). Twenty intracranial hemorrhages (2.2%) and 44 other major bleeds (4.8%) occurred. Intracranial hemorrhages occurred in 2.4% of neonates following vaginal delivery compared to 1.7% after Cesarean section (P=not significant); other major bleeds occurred in 4.2% born by vaginal delivery and in 5.8% after Cesarean section (P=not significant). Further analysis of subgroups (n=813) identified vaginal delivery with instruments being a significant risk factor for both intracranial hemorrhages and major bleeds (Relative Risk: 4.78-7.39; PPeer reviewe

Anticoagulation in pediatric cancer–associated venous thromboembolism:a subgroup analysis of EINSTEIN-Jr

Anticoagulant treatment of pediatric cancer–associated venous thromboembolism (VTE) has not been prospectively evaluated. Management of anticoagulation for cancer-associated VTE is often challenged by drug interactions and treatment interruptions. A total of 56 of the 500 children (11.2%) with VTE who participated in the recent EINSTEIN-Jr randomized study had cancer (hematologic malignancy, 64.3%, solid malignant tumor, 35.7%). Children were allocated to either therapeutic-dose bodyweight-adjusted oral rivaroxaban (n=40) or standard anticoagulation with heparins, with or without vitamin K antagonists (n=16) and received a median of 30 concomitant medications. Based on sparse blood sampling at steady-state, pharmacokinetic (PK) parameters of rivaroxaban were derived using population PK modeling. During the 3 months of treatment, no recurrent VTE or major bleeding occurred (95% confidence interval, 0.0%-6.4%), and 3-month repeat imaging showed complete or partial vein recanalization in 20 and 24 of 52 evaluable children (38.5% and 46.2%, respectively). Anticoagulant treatment was interrupted 70 times in 26 (46.4%) children because of thrombocytopenia, invasive procedures, or adverse events, for a mean individual period of 5.8 days. Anticoagulant therapy was resumed in therapeutic doses and was not associated with thrombotic or bleeding complications. Rivaroxaban exposures were within the adult exposure range and similar to those observed in children with VTE who did not have cancer-associated VTE. Rivaroxaban and standard anticoagulants appeared safe and efficacious and were associated with reduced clot burden in most children with cancer-associated VTE, including those who had anticoagulant treatment interruptions. Rivaroxaban exposures were within the adult exposure range despite significant polypharmacy use. This trial was registered at www.clinicaltrials.gov as #NCT02234843

Dilemmas on emicizumab in children with haemophilia A: A survey of strategies from PedNet centres.

INTRODUCTION Haemophilia A care has changed with the introduction of emicizumab. Experience on the youngest children is still scarce and clinical practice varies between haemophilia treatment centres. AIM We aimed to assess the current clinical practice on emicizumab prophylaxis within PedNet, a collaborative research platform for paediatricians treating children with haemophilia. METHODS An electronic survey was sent to all PedNet members (n = 32) between October 2022 and February 2023. The survey included questions on the availability of emicizumab, on the practice of initiating prophylaxis in previously untreated or minimally treated patients (PUPs or MTPs) and emicizumab use in patients with or without inhibitors. RESULTS All but four centres (28/32; 88%) responded. Emicizumab was available in clinical practice in 25/28 centres (89%), and in 3/28 for selected patients only (e.g. with inhibitors). Emicizumab was the preferred choice for prophylaxis in PUPs or MTPs in 20/25 centres; most (85%) started emicizumab prophylaxis before 1 year of age (30% before 6 months of age) and without concomitant FVIII (16/20; 80%). After the loading dose, 13/28 centres administered the recommended dosing, while the others adjusted the interval of injections to give whole vials. In inhibitor patients, the use of emicizumab during ITI was common, with low-dose ITI being the preferred protocol. CONCLUSION Most centres choose to initiate prophylaxis with emicizumab before 12 months of age and without concomitant FVIII. In inhibitor patients, ITI is mostly given in addition to emicizumab, but there was no common practice on how to proceed after successful ITI

Emicizumab prophylaxis in infants with hemophilia A (HAVEN 7): primary analysis of a phase 3b, open-label trial

Subcutaneous emicizumab enables prophylaxis for people with hemophilia A (HA) from birth, potentially reducing risk of bleeding and intracranial hemorrhage (ICH). HAVEN 7 (NCT04431726) is the first clinical trial of emicizumab dedicated to infants, designed to investigate the efficacy, safety, pharmacokinetics, and pharmacodynamics of emicizumab in those aged ≤12 months with severe HA without factor VIII (FVIII) inhibitors. Participants in this phase 3b trial received emicizumab 3 mg/kg maintenance dose every 2 weeks for 52 weeks and are continuing emicizumab during the 7-year long-term follow-up. Efficacy end points included annualized bleed rate (ABR): treated, all, treated spontaneous, and treated joint bleeds. Safety end points included adverse events (AEs), thromboembolic events (TEs), thrombotic microangiopathies (TMAs), and immunogenicity (anti-emicizumab antibodies [ADAs] and FVIII inhibitors). At primary analysis, 55 male participants had received emicizumab (median treatment duration: 100.3; range, 52-118 weeks). Median age at informed consent was 4.0 months (range, 9 days to 11 months 30 days). Model-based ABR for treated bleeds was 0.4 (95% confidence interval, 0.30–0.63), with 54.5% of participants (n = 30) having zero treated bleeds. No ICH occurred. All 42 treated bleeds in 25 participants (45.5%) were traumatic. Nine participants (16.4%) had ≥1 emicizumab-related AE (all grade 1 injection-site reactions). No AE led to treatment changes. No deaths, TEs, or TMAs occurred. No participant tested positive for ADAs. Two participants were confirmed positive for FVIII inhibitors. This primary analysis of HAVEN 7 indicates that emicizumab is efficacious and well tolerated in infants with severe HA without FVIII inhibitors

Real-World Rates of Bleeding, Factor VIII Use, and Quality of Life in Individuals with Severe Haemophilia A Receiving Prophylaxis in a Prospective, Noninterventional Study

Regular prophylaxis with exogenous factor VIII (FVIII) is recommended for individuals with severe haemophilia A (HA), but standardised data are scarce. Here, we report real-world data from a global cohort. Participants were men &ge;18 years old with severe HA (FVIII &le; 1 IU/dL) receiving regular prophylaxis with FVIII. Participants provided 6 months of retrospective data and were prospectively followed for up to 12 months. Annualised bleeding rate (ABR) and FVIII utilisation and infusion rates were calculated. Differences between geographic regions were explored. Of 294 enrolled participants, 225 (76.5%) completed &ge;6 months of prospective follow-up. Pre-baseline and on-study, the median (range) ABR values for treated bleeds were 2.00 (0&ndash;86.0) and 1.85 (0&ndash;37.8), respectively; the median (range) annualised FVIII utilisation rates were 3629.0 (1008.5&ndash;13541.7) and 3708.0 (1311.0&ndash;14633.4) IU/kg/year, respectively; and the median (range) annualised FVIII infusion rates were 120.0 (52.0&ndash;364.0) and 122.4 (38.0&ndash;363.8) infusions/year, respectively. The median (range) Haemo-QoL-A Total Score was 76.3 (9.4&ndash;100.0) (n = 289), ranging from 85.1 in Australia to 67.7 in South America. Physical Functioning was the most impacted Haemo-QoL-A domain in 4/6 geographic regions. Despite differences among sites, participants reported bleeding requiring treatment and impaired physical functioning. These real-world data illustrate shortcomings associated with FVIII prophylaxis for this global cohort of individuals with severe HA

Intracranial Hemorrhages in Neonates : Incidence, Risk Factors and Treatment

Hemostasis is a dynamic process that starts in utero. Neonates, especially those who are born preterm, are at high risk of bleeding. The coagulation system evolves with age, and the decreased levels of coagulation factors along with hypo-reactive platelets are counterbalanced with increased activity of von Willebrand factor, high hematocrit and mean corpuscular volume as well as low levels of coagulation inhibitors that promote hemostasis. Neonates with congenital bleeding disorders such as hemophilia are at even higher risk of bleeding complications. This review will focus upon one of the most devastating complications associated with neonatal bleeding: intracranial hemorrhages (ICH). While etiology may be multifactorial and impacted by maternal as well as fetal risk factors, the mode of delivery certainly plays an important role in the pathogenesis of ICH. We will address prematurity and congenital bleeding disorders such as hemophilia A and B and other rare bleeding disorders as risk factors and present an updated approach for treatment and possible prevention

Long-term safety and efficacy of N8-GP in previously treated pediatric patients with hemophilia A: Final results from pathfinder5

BACKGROUND: N8-GP (turoctocog alfa pegol; Esperoct® , Novo Nordisk A/S, Bagsvaerd, Denmark) is a glycoPEGylated, extended half-life human recombinant factor VIII (FVIII). OBJECTIVE: Here, we report end-of-trial safety and efficacy results from the completed N8-GP pathfinder5 trial. METHODS: pathfinder5 (NCT01731600) was a multi-national, open-label, single-arm, non-randomized, non-controlled trial in previously treated male patients aged <12 years old with severe hemophilia A that comprised a main and an extension phase. During the main phase, patients received twice-weekly N8-GP 60 IU/kg for 50 exposure days (~26 weeks). During the extension phase, patients received the same regimen until the end of trial (first patient in main phase, 20 February 2013; trial end, 28 September 2018). RESULTS: Sixty-eight patients were exposed to N8-GP for a median time of ~4.9 years on regimen. Of the 63 patients who started in the extension phase, 62 completed the trial. No FVIII inhibitors (≥0.6 BU) or other safety concerns were detected. The overall estimated annualized bleeding rate was 1.08 (median 0.81), and nearly 20% of patients had no bleeds during the entire trial. The proportion of patients with no annual bleeds increased with time, with 56% of patients experiencing no bleeds and 86% experiencing no spontaneous bleeds during the fourth year of exposure. All baseline target joints of patients who participated in both phases of this trial were resolved in slightly over 2 years. CONCLUSION: Overall, data from the completed pathfinder5 trial show that long-term (median 4.9 years) N8-GP treatment was efficacious and well tolerated in previously treated pediatric patients with severe hemophilia A