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Introduction: Emicizumab is a humanized bispecific monoclonal antibody licensed for patients with severe haemophilia A. Breakthrough bleeding still occurs in patients on emicizumab and can be managed with recombinant factor VIIa (rFVIIa) or activated prothrombin complex concentrate (aPCC). Thrombotic events were reported when patients on emicizumab received concomitant aPCC at relatively high doses. We studied the effect of infusing various doses of aPCC to patients on emicizumab. Material and methods: Nine patients with severe haemophilia A with inhibitors who are on emicizumab were recruited to participate. Patients were infused with varying doses of aPCC in vivo. Samples were tested with thrombin generation (TG) assay. Results: In the current in vivo arm of the study four out of nine patients reached the highest dose, 75 U/kg of aPCC and six out of nine patients were actually eligible for the highest dose. In the previous in vitro arm of the study seven out of eight patients reached the normal plasma with spiking aPCC at a very low concentration equivalent to 5 U/kg. Conclusion: The in vitro portion of the study demonstrated that clinically relevant concentrations of aPCC resulted in excessive TG, however, in vivo administration of aPCC to the same patients demonstrated that most of the patients had normal TG at the approved doses of aPCC. In the management of breakthrough bleeding clinicians should heed the boxed warning for concomitant use of emicizumab and aPCC, however, should also be aware that low doses of aPCC may not result in sufficient TG. [ABSTRACT FROM AUTHOR]

Introduction: Emicizumab is a recombinant, humanized bispecific monoclonal antibody that mimics the function of factor VIII (FVIII) which results in a significant reduction in the annualized bleeding rate in patients with haemophilia A (HA), however, the degree with which emicizumab corrects the coagulation defect remains unclear. The objective of this study was to predict the approximate FVIII level in severe haemophilia A patients with inhibitors on emicizumab using global haemostasis assays. Materials and methods: Patients with moderate and mild HA in the non‐bleeding state and healthy controls had FVIII levels and thrombin generation assessed. Linear regression was utilized to model the FVIII levels as a function of the thrombin generation assay parameters and to make a calibration curve of FVIII levels versus peak thrombin and endogenous thrombin potential. Patients with severe haemophilia A with inhibitors on emicizumab had thrombin generation performed in the same manner and their peak thrombin and endogenous thrombin potential results were placed on the calibration curve to calculate their FVIII Equivalency of Emicizumab by Thrombin Generation (F8EmT). Results: All patients with severe HA with inhibitors on emicizumab had F8EmT >10%, suggesting they had been converted to a mild haemophilia phenotype. The patient's weight was inversely correlated to their F8EmT. Conclusion: The results from this study suggest that the F8EmT in patients with severe HA on emicizumab falls within the range of mild haemophilia which is consistent with the data noted in the emicizumab clinical trials and in vivo studies in animals. [ABSTRACT FROM AUTHOR]

Introduction: Management strategies and hemostatic treatments to achieve control of bleeding are relevant across many disease areas. Identification of primary outcomes for studies assessing hemostatic intervention was the objective of a National Heart, Lung and Blood Institute (NHLBI) sponsored multidisciplinary initiative. The aim of this report is to summarize the evidence reviewed, and the outcomes identified by the subgroup tasked to assess outcomes for inherited bleeding disorders. Methods: The subgroup decided to focus on haemophilia, the prototypal congenital bleeding disorder and the one with the largest available body of evidence. MEDLINE, EMBASE and PsycINFO, The Cochrane Review, CINAHL, and Web of Science were searched for systematic and narrative reviews on outcomes used in haemophilia clinical trials. Three different clinical goals were identified as typical objectives of future research. Results: Out of 1322 unique citations, 24 reviews published in the period 2002–2019 were included. We identified 113 outcome measures, categorized in 6 domains: health‐related quality of life (HRQoL), comorbidities and mortality, overall physical functioning and participation, bleeding and hemostasis, joint health, and costs and resource use. Three different clinical goals were identified as typical objectives of future research: Episodic 'on demand' replacement therapy, prevention of bleeding (Prophylaxis), and long‐term and overall impact of bleeding. For each of these scenarios, specific outcomes were recommended. Conclusions: Primary outcomes for clinical trials assessing the efficacy of hemostatic treatment in achieving control, prevention and limiting long‐term consequences of bleeding in inherited bleeding disorders are suggested, and their strength and limitations discussed. [ABSTRACT FROM AUTHOR]

Introduction: Emicizumab is a humanized bispecific monoclonal antibody licensed for patients with severe haemophilia A with and without inhibitors. Management of breakthrough bleeding in patients with inhibitors on emicizumab involves episodic treatment with bypassing agents (BPA), activated prothrombin complex concentrate (aPCC) or recombinant activated factor VII (rFVIIa). Thrombotic events and thrombotic microangiopathy were reported when patients on emicizumab received concomitant aPCC at relatively high doses yet such events were not reported with rFVIIa. We studied the effect of spiking various concentrations of BPA on plasma taken from patients on emicizumab. Material and Methods: Eleven patients with severe haemophilia A with inhibitors who are on emicizumab were recruited to participate. Blood samples drawn from patients were spiked in vitro with varying concentrations of aPCC and rFVIIa. All samples were tested utilizing global haemostasis assays, thromboelastography and thrombin generation assay. Results: Thrombin generation increased with higher concentrations of spiked BPA with a normalized endogenous thrombin potential at a concentration of 0.05 IU/ml and 4 mcg/ml for aPCC and rFVIIa, respectively. Concentrations of aPCC in the range of licensed dosing led to excessive thrombin generation. Thromboelastography was not sufficiently sensitive. Conclusion: Due to the known thrombotic complications when emicizumab is used in conjunction with aPCC, there has been a large‐scale abandonment of the use of aPCC in patients on emicizumab. However, it is possible that aPCC can be used safely with emicizumab albeit with lower doses than are typically prescribed. It would be important to test this hypothesis in a clinical study. [ABSTRACT FROM AUTHOR]

Introduction: Persons with haemophilia A (PwHA) with factor (F)VIII inhibitors, including children, have impaired health‐related quality of life (HRQoL). The HAVEN 2 study (NCT027955767) of paediatric PwHA with FVIII inhibitors demonstrated that subcutaneous emicizumab prophylaxis resulted in low annualizedbleed rates. Aim: We assessed the impact of emicizumab prophylaxis on the HRQoL of children and their caregivers participating in HAVEN 2. Methods: Children aged 8‐11 years self‐reported HRQoL using the Haemophilia‐Specific Quality of Life Assessment Instrument for Children and Adolescents Short Form (Haemo‐QoL SF II). Caregivers of children aged 0‐11 years completed the Adapted Inhibitor‐Specific Quality of Life Assessment with Aspects of Caregiver Burden. All scores were transformed to a 0‐100 scale, where lower scores reflect a better HRQoL. The number of missed days from school/day care and hospitalizations was also recorded. Results: In HAVEN 2 (n = 88), the median age was 6.5 years (range: 1‐15 years); 85 participants were aged < 12 years and included in this analysis, and 34 participants were aged 8‐11 years, thereby eligible to complete the Haemo‐QoL SF II questionnaire. The mean (standard deviation, n) baseline Haemo‐QoL SF II 'Total' score was 30.2 (14.9, 30), indicating moderate impairment; with emicizumab, mean score decreased by −9.62 (7.73, 17) points to 23.0 (13.93, 20) by Week 49. The most improved domains were 'Sports & School' and 'Physical Health'. Caregivers reported similar improvements. Conclusion: Prophylactic emicizumab is accompanied by substantial and sustained improvements in HRQoL of paediatric PwHA with FVIII inhibitors and their caregivers. [ABSTRACT FROM AUTHOR]

Summary: Haemophilia is a serious inherited bleeding disorder resulting from a deficiency of coagulation factor VIII (haemophilia A) or coagulation factor IX (haemophilia B). While effective therapies have been developed to replace the missing factor and restore normal coagulation, they can lead to the development of neutralizing anti‐drug antibodies, termed inhibitors, which significantly worsen morbidity and quality of life. While advancements have been made to improve the management of patients, and particularly for this review, children with inhibitors, there remain significant unmet needs including inhibitor prevention, inhibitor eradication and, when those fail, more effective bleed prevention and a reduction in the treatment burden. This review will discuss current treatment options including the recently licensed bispecific antibody, emicizumab, and provide insights into how I treat children with inhibitors. [ABSTRACT FROM AUTHOR]

. Haemophilia is a life-long genetic disorder most often diagnosed in early childhood which results in bleeding into deep tissues and can result in arthropathy and, rarely, other serious complications. As a result of the natural physical and cognitive development in children, combined with the manner in which haemophilia is treated, there is a continuous process of changes in the approach to patient management, which collectively are called transitional issues. It is important to point out that while some traditional definitions of transition are limited to the stage when an adolescent becomes an adult and how the mode and delivery of care change during this time, a broader definition incorporating all the changes that occur from birth through adulthood will be described in this article. As such, transition should be thought of as a continuous process, though for the sake of clarity and practicality, we will divide the process into several phases. The transition issues to be discussed will be divided into medical issues and psychosocial issues, though there is clearly overlap between the two. A well-developed transition plan from birth to adulthood for patients with haemophilia facilitates the necessary change from total dependence on caregivers to complete independence by the time one reaches 18 years of age. [ABSTRACT FROM AUTHOR]

. Haemostasis management in people with haemophilia can present a range of challenges to physicians. Specific challenges that may be encountered relate to regimens for immune tolerance induction, use of central venous access devices, optimizing care of paediatric patients with inhibitors and improving outcomes in acquired haemophilia. There are also challenges related to performing surgery, and the establishment of specialist centres is valuable with regard to this. These challenges are considered in the light of available data, and with perspectives gained from the experience of experts treating patients around the world. Sharing this knowledge may help to improve patient management. [ABSTRACT FROM AUTHOR]