How do we optimally utilize factor concentrates in persons with hemophilia?

The current mainstay of therapy for hemophilia is to replace the deficient clotting factor with the intravenous administration of exogenous clotting factor concentrates. Prophylaxis factor replacement therapy is now considered the standard of care in both pediatric and adult patients with hemophilia with a severe phenotype to protect musculoskeletal health and improve quality of life. Heterogeneity in bleeding presentation among patients with hemophilia due to genetic, environmental, and treatment-related factors has been well described. Accordingly, the World Federation of Hemophilia recommends an individualized prophylaxis regimen that considers the factors mentioned above to meet the clinical needs of the patient, which can vary over time. This review focuses on the practical points of choosing the type of factor concentrate, dose, and interval while evaluating appropriate target trough factor levels and bleeding triggers such as level of physical activity and joint status. We also discuss the use of a pharmacokinetics assessment and its incorporation in the clinic for a tailored approach toward individualized management. Overall, adopting an individualized prophylaxis regimen leads to an optimal utilization of factor concentrates with maximum efficacy and minimum waste.

Hemophilia Natural History Study (ATHN 7): Safety of Current Therapies for People with Hemophilia A or B

INTRODUCTION: The recent introduction of new therapies for people with hemophilia A and B (HA and HB) mandates careful monitoring of the safety of these treatments. The primary aim of ATHN 7: A Natural History Study of the Safety, Effectiveness, and Practice of Treatment for People with Hemophilia (NCT03619863) is to monitor the safety of current hemophilia therapies. METHODS: ATHN 7 is a longitudinal, prospective cohort study being conducted at 26 American Thrombosis and Hemostasis Network (ATHN)-affiliated sites. The study is approved by central and local institutional review boards. Any person with a diagnosis of congenital hemophilia A or B (factor VIII or IX activity < 50%) who receives care at a participating site is eligible for inclusion. Participants and/or a parent/guardian sign informed consent and assent prior to participation. Adverse events, including those events designated by the European Haemophilia Safety Surveillance group as well as other adverse events of special interest, are recorded and monitored. Demographic and clinical information are collected at baseline and at least quarterly through participant interview and medical record review. Descriptive statistics of medical history and demographic data as well as longitudinal data are used to characterize the study population. RESULTS: As of June 2021, a total of 391 participants had enrolled in ATHN 7. The median age of participants was 22.5 ± 17.8 years. Males represented 97.7% (382/391) of participants. Eighty-five percent (333/391) were not Hispanic. White participants comprised 82.6% (323/391) of the study population, while 7.9% (31/391) were Black/African American, 3.8% (15/391) were Asian, 1.8% (7/391) were of mixed race, and 3.8% (15/391) were of other or unknown race. The primary diagnosis of participants included 70.1% (274/391) with severe HA, 15.3% (60/391) with moderate HA, 7.2% (28/391) with mild HA, 4.1% (16/391) with severe HB, 2.0% (8/391) with moderate HB, and 1.0% (4/391) with mild HB. Nineteen percent (71/391) of participants had a documented history of an inhibitor at the time of enrollment with a mean peak inhibitor titer of 96.7 ± 214.3 Bethesda Units. Substitution therapy with a non-factor molecule was the primary medication for 43.4% (162/391) participants, while 4.3% (16/391) utilized a plasma-derived clotting factor concentrate, 28.4% (196/391) utilized a standard half-life, recombinant factor concentrate, 18.3% (126/391) utilized an extended half-life recombinant factor concentrate, 4.1% (28/391) utilized a bypassing agent, and 19.3% (133/391) utilized some other hemostatic agent. Continuous prophylaxis was the primary regimen for 79.1% (295/391) participants. The remaining 19.6% (73/391) of participants were on episodic therapy. Within the cohort of 391 participants, a total of 14 adverse events have been reported in 8 participants. No adverse events of special interest were reported. Redness or rash at injection site accounted for 64.2% (9/14) of the reported adverse events, all in participants receiving emicizumab. Two participants experienced bruising or bleeding while on emicizumab. Two participants on emicizumab were diagnosed with malignancy, neither found to be attributed to their therapy. One participant developed an allergic reaction to their standard half-life recombinant factor concentrate. DISCUSSION: Open to enrollment in January 2019, ATHN 7 has now collected 18 months of longitudinal safety data for therapies used to treat HA and HB in 391 participants, an addition of 12 months and 24 participants since our last report. As the study was designed to enhance representation of those utilizing substitution therapy, almost half of the participants were on emicizumab for prophylaxis of bleeding. Adverse events attributable to hemophilia therapy was limited to minor skin reactions. As previously reported, a single participant experienced delayed bleeding after closed head trauma (despite factor replacement and normal intracranial imaging at the time of the event), providing potentially important information on the risk of delayed bleeding from significant trauma in those receiving emicizumab. Over the coming year, participants in ATHN 7 will be transitioned to ATHN's new longitudinal natural history study, ATHN TRANSCENDS (NCT04398628). Disclosures Buckner: Pfizer: Honoraria; Takeda: Honoraria; Bayer: Honoraria; Sanofi: Honoraria; Spark: Honoraria; Genetech: Honoraria; CSL Behring: Honoraria; Novo Nordisk: Honoraria; Tremeau Pharmaceuticals: Consultancy, Honoraria; BioMarin: Consultancy, Honoraria; uniQure: Consultancy, Honoraria; American Thrombosis: Membership on an entity's Board of Directors or advisory committees; Hemostasis Network: Membership on an entity's Board of Directors or advisory committees. Carpenter: Hemophilia and Thrombosis Research Society: Membership on an entity's Board of Directors or advisory committees; Kedrion Pharmaceuticals: Honoraria; Genentech: Honoraria; Novo Nordisk: Honoraria. Raffini: Genentech: Consultancy; CSL Behring: Consultancy; HEMA Biologics: Consultancy; XaTek: Consultancy; Bayer: Consultancy. Zia: Takeda: Consultancy; Hemophilia and Thrombosis Research Society: Membership on an entity's Board of Directors or advisory committees. Recht: Hema Biologics: Consultancy; Kedrion: Consultancy; Novo Nordisk: Consultancy; Octapharma: Consultancy; Pfizer: Consultancy; Sanofi: Consultancy; Takeda: Consultancy; uniQure: Consultancy; Foundation for Women and Girls with Blood Disorders, Partners in Bleeding Disorders: Speakers Bureau; American Thrombosis and Hemostasis Network: Current Employment; Oregon Health & Science University: Current Employment; Genentech: Consultancy; CSL Behring: Consultancy; Catalyst Biosciences: Consultancy.

Spontaneous pyohaemothorax in a teenager with von Willebrand disease: a case report and review of literature

An 18-year-old man with a history of type 3 von Willebrand disease (VWD) presented with a spontaneous pyohaemothorax. Type 3 VWD may present with both mucocutaneous and deep-seated bleeds, such as visceral haemorrhages, intracranial bleeds and haemarthrosis. There have been very few cases described in children of spontaneous pyohaemothorax. Management of this patient was challenging due to risks of bleeding following surgical drainage, requiring constant replacement with von Willebrand factor concentrate, while monitoring factor VIII levels to balance the risks of thrombosis.

Continuous-infusion von Willebrand factor concentrate is effective for the management of acquired von Willebrand disease

Acquired von Willebrand disease (aVWD) is a rare disorder associated with a reduction in von Willebrand factor (VWF) activity, leading to increased bleeding risk. Monoclonal gammopathy of undetermined significance (MGUS) is the most common cause of lymphoproliferative disorder-associated aVWD and is caused by accelerated clearance of circulating VWF. Standard VWF replacement protocols for congenital VWD based on intermittent bolus dosing are typically less effective for aVWD because of antibody-mediated clearance. Intermittent bolus dosing of VWF concentrates often leads to inadequate peak response and profoundly shortened VWF half-life in aVWD. Intravenous immune globulin (IVIG) has demonstrated efficacy in aVWD; however, treatment effect is delayed up to 4 days, limiting its efficacy in acutely bleeding patients. We report the successful use of continuous-infusion VWF concentrate (with or without concomitant IVIG) in 3 patients with MGUS-associated aVWD who had demonstrated an inadequate response to bolus dosing. VWF concentrate doses required in this cohort were higher than typical doses for bleeding treatment in congenital VWD. This report illustrates that continuous-infusion VWF concentrate administration with or without intravenous immunoglobulin rapidly achieves target ristocetin cofactor activity and provides adequate hemostasis in aVWD associated with immunoglobulin G MGUS.

Type 2B von Willebrand Disease in Pregnancy: A Systematic Literature Review

Our objective was to review the maternal characteristics and obstetric complications in women with type 2B von Willebrand disease (VWD). A systematic literature search was conducted using PubMed, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. We included all publications that addressed type 2B VWD in pregnancy. Our primary and secondary outcomes were incidence of postpartum hemorrhage (PPH) and incidence of thrombocytopenia in pregnancy. Two reviewers independently identified eligible studies and abstracted data including maternal characteristics, hematologic characteristics, treatment, and delivery outcomes. Twenty studies met inclusion criteria. There were 27 women (32 pregnancies) with type 2B VWD. Primary PPH was reported in 9/20 women (45%) and secondary PPH was reported in 6/13 women (46%). Thrombocytopenia in pregnancy was present in 27/28 women (96%); 23/27 women (85%) had platelet count <100 × 109/L, mean 33.7 ± 22.7 × 109/L. Factor concentrate treatment was administered before delivery (n = 16) and postpartum (n = 18), some women received both. Seventeen deliveries required blood products postpartum with 13/17 (76%) platelet transfusions and 6/17 (35%) red blood cell transfusions. No maternal mortality was reported. Women with type 2B VWD have significant morbidity in pregnancy related to high incidence of severe thrombocytopenia and primary and secondary PPH.