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Introduction: In recent years, there has been increased focus on individualizing treatment for persons with hemophilia including pharmacokinetic‐guided (PK) dosing. Aims: In this retrospective study clinical outcomes before and after PK‐guided prophylaxis were examined. Materials and methods: Eight Haemophilia Treatment Centres from the United States participated in the study and included 132 patients classified into two cohorts: those undergoing a PK‐assessment for product switch (switchers) or to optimize treatment (non‐switchers). Subset analyses for the two most common products and patients with dosing per prescription label were included for annual bleeding rates (ABR), mean weekly consumption outcomes, and annualized cost of prophylaxis. Results: The most common products before and after index date were octocog alfa, rurioctocog alfa pegol, and efmoroctocog alfa. Seventy‐four (56%) patients were identified as switchers and 58 (44%) patients were classified as non‐switchers. The majority of patients (78.0%) experienced either a decrease in ABR post‐index or maintained 0 ABR during pre‐ and post‐index time periods, with similar proportions identified in both switchers (77.0%) and non‐switchers (79.3%) populations. Non‐switchers were identified as having no significant change in cost of therapy, while switchers experienced increased cost of therapy driven by higher price of extended half‐life products. Within subset analyses, patients receiving rurioctocog alfa pegol and efmoroctocog alfa had mean ABR under 1 after index date. Conclusion: PK‐guided prophylaxis has the potential to improve clinical outcomes without increase in cost of therapy for patients maintaining product and can aid in maintaining effective protection against bleeds in those switching product. [ABSTRACT FROM AUTHOR]

Fitusiran, a subcutaneous investigational small interfering RNA therapeutic, targets antithrombin to rebalance haemostasis in people with haemophilia A or haemophilia B, irrespective of inhibitor status. We evaluated the efficacy and safety of fitusiran prophylaxis in people with haemophilia A or haemophilia B with inhibitors. This multicentre, randomised, open-label phase 3 study was done at 26 sites (primarily secondary or tertiary centres) in 12 countries. Men, boys, and young adults aged 12 years or older with severe haemophilia A or haemophilia B with inhibitors previously treated with on-demand bypassing agents were randomly assigned (2:1) to receive once-a-month 80 mg subcutaneous fitusiran prophylaxis (fitusiran prophylaxis group) or to continue with bypassing agents on-demand (bypassing agents on-demand group) for 9 months. The primary endpoint was mean annualised bleeding rate during the efficacy period in the intention-to-treat population estimated by negative binomial model. Safety was assessed as a secondary endpoint in the safety population. This trial is complete and is registered with ClinicalTrials.gov , NCT03417102. Between Feb 14, 2018, and June 23, 2021, 85 participants were screened for inclusion, of whom 57 (67%; 57 [100%] men; median age 27·0 years [IQR 19·5–33·5]) were randomly assigned: 19 (33%) participants to the bypassing agent on-demand group and 38 (67%) participants to the fitusiran prophylaxis. Negative binomial model-based mean annualised bleeding rate was significantly lower in the fitusiran prophylaxis group (1·7 [95% CI 1·0–2·7]) than in the bypassing agents on-demand group (18·1 [10·6–30·8]), corresponding to a 90·8% (95% CI 80·8–95·6) reduction in annualised bleeding rate in favour of fitusiran prophylaxis (p<0·0001). 25 (66%) participants had zero treated bleeds in the fitusiran prophylaxis group versus one (5%) in the bypassing agents on-demand group. The most frequent treatment-emergent adverse event in the fitusiran prophylaxis group was increased alanine aminotransferase in 13 (32%) of 41 participants in the safety population; there were no increased alanine aminotransferase treatment-emergent adverse events in the bypassing agents on-demand group. Suspected or confirmed thromboembolic events were reported in two (5%) participants in the fitusiran prophylaxis group. No deaths were reported. Subcutaneous fitusiran prophylaxis resulted in statistically significant reductions in annualised bleeding rate in participants with haemophilia A or haemophilia B with inhibitors, with two-thirds of participants having zero bleeds. Fitusiran prophylaxis might show haemostatic efficacy in participants with haemophilia A or haemophilia B with inhibitors; therefore, the therapeutic might have the potential to improve the management of people with haemophilia. Sanofi. [ABSTRACT FROM AUTHOR]

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: Challenges with personalised prophylaxis in haemophilia remain, including designing unique dosing schedules that require continual adjustments and monitoring using complex sampling procedures. Aim: To assess long‐term efficacy and pharmacokinetic outcomes with fixed‐dose N8‐GP prophylaxis. Methods: Descriptive analyses were performed on data from the pathfinder 2 and pathfinder 5 trials of patients with severe haemophilia A. Bleed frequency and reoccurrence were assessed in relation to several clinical criteria of interest. Bleed risk relative to time since last dose was assessed using calculated annualised bleeding rate (ABR). Long‐term ABR and mean factor VIII (FVIII) trough levels were assessed in patients who received consistent N8‐GP prophylaxis every 4 days (Q4D). Results: During pathfinder 2, 117/136 patients with study‐drug exposure of ≥600 days experienced bleeding episodes; 8.6% of bleeds were reoccurring bleeds; bleed reoccurrence decreased over time. For patients who received consistent Q4D prophylaxis across the trial (n = 61), mean ABR decreased from 3.5 bleeds/year (Year 1) to 1.6 bleeds/year (Year 6); mean FVIII trough levels stabilised at approximately 5% (Year 6). Across patients who received prophylaxis at some point during pathfinder 2 (n = 177), 125/126 (99%) reoccurring bleeds were joint bleeds. For patients receiving Q4D prophylaxis, bleeding risk generally increased as the time since the last prophylaxis dose increased. A similar reduction in ABR and stabilisation of trough level was observed in pathfinder 5. Conclusion: Long‐term exposure (> 5 years) to fixed‐dose N8‐GP prophylaxis resulted in a protective haemostatic effect, with reduction in bleed frequency and reoccurrence, and stabilisation of FVIII trough level over time. [ABSTRACT FROM AUTHOR]

Introduction: Emicizumab has been shown to be safe and effective for prevention of bleeds in patients with severe haemophilia A (SHA), both with and without inhibitors. The subcutaneous administration and long half‐life make emicizumab an attractive option for prophylaxis in infants with SHA, however data to inform treatment decisions in this younger age group are almost absent. Aim: The aim of this report is to share real world experience to illustrate how the availability of emicizumab has shifted the prophylaxis paradigm in the management of infants with SHA. Method: We selected four cases from our own cohort of infants with SHA to outline the rationale for emicizumab prophylaxis in a range of scenarios familiar to paediatric haemophilia treaters. Results: In Case 1 emicizumab was commenced at 7 days following initial treatment of neonatal ICH with a FVIII infusion. In Case 2 emicizumab was commenced at 5 weeks due to parental anxiety regarding the potential for ICH during infancy. Case 3 commenced emicizumab at 15 months in lieu of standard primary prophylaxis. Case 4 switched to emicizumab prophylaxis at 14 months after a period of primary prophylaxis with FVIII concentrates to alleviate parental anxiety regarding future inhibitor development. No patient had any bleeding events after commencement of emicizumab (median follow up 12 months), and no drug‐related adverse effects were observed. Conclusion: Despite the paucity of data in infants with SHA the potential role of emicizumab prophylaxis should be discussed with families when clinically relevant, with decisions tailored to individual need. [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: 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]

Introduction: The efficacy and safety of recombinant factor VIII Fc fusion protein (rFVIIIFc) as an extended half‐life treatment for severe haemophilia A were demonstrated in the Phase 3 A‐LONG and Kids A‐LONG studies. Eligible subjects who completed A‐LONG and Kids A‐LONG could enrol in ASPIRE (NCT01454739), an open‐label extension study. Aim: To report the long‐term safety and efficacy of rFVIIIFc in subjects with severe haemophilia A who enrolled in ASPIRE. Methods: Previously treated subjects received one or more of the following regimens: individualized prophylaxis (IP), weekly prophylaxis, modified prophylaxis or episodic treatment. Subjects could switch treatment regimen at any time. The primary endpoint was inhibitor development. Results: A total of 150 subjects from A‐LONG and 61 subjects from Kids A‐LONG enrolled in ASPIRE. Most subjects received the IP regimen (A‐LONG: n = 110; Kids A‐LONG: n = 59). Median (range) treatment duration in ASPIRE for subjects from A‐LONG and Kids A‐LONG was 3.9 (0.1‐5.3) years and 3.2 (0.3‐3.9) years, respectively. No inhibitors were observed (0 per 1000 subject‐years; 95% confidence interval, 0‐5.2) and the overall rFVIIIFc safety profile was consistent with prior studies. For subjects on the IP regimen, annualized bleed rates (ABR) remained low (median overall ABR for adults and adolescents was <1.0) and extended‐dosing intervals were maintained (median of 3.5 days) for the majority of subjects in ASPIRE. Conclusion: ASPIRE results, which include up to 5 years of follow‐up data, confirm earlier reports on the consistent and well‐characterized safety and efficacy of rFVIIIFc treatment for severe haemophilia A. [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]

The development of inhibitors against factor VIII (FVIII) concentrates represents a significant treatment complication for hemophilia. Immune tolerance induction (ITI) therapy eradicates inhibitors in 60–80% of patients, resulting in a normal FVIII response. This article, based on presentations at the 6th International Coagulation Meeting, held in Barcelona, Spain, in September 2017, provides an overview of management approaches for patients with inhibitors and briefly tabulates four cases of ITI therapy (first-line or rescue ITI therapy in pediatric and adult patients) with successful outcomes. Switching FVIII product from recombinant FVIII to plasma-derived FVIII/VWF concentrate may be helpful in eradicating inhibitors. The rate of decline of inhibitor titer in the initial stages of ITI therapy is a good indicator of the success or failure of therapy, although prognostic biomarkers are needed. The development of the bispecific monoclonal antibody emicizumab, which was recently shown to reduce bleeding in inhibitor patients, offers a potential alternative therapeutic option. However, the benefits of inhibitor eradication, including a wider choice of cheaper therapeutic products for preventing and treating bleeds, suggest that at least one attempt of ITI therapy should be offered to patients who develop inhibitors. [ABSTRACT FROM AUTHOR]

Introduction: Prophylaxis with replacement factor IX (FIX) reduces bleeding frequency and improves quality of life in haemophilia B patients. With prophylaxis, the likelihood of bleeding is lowered with increasing trough levels. New products with extended half‐life (EHL) can maintain high factor activity levels over prolonged periods, compared with standard FIX products. Aim: To evaluate the safety, efficacy and pharmacokinetics of the new recombinant FIX EHL product, nonacog beta pegol (N9‐GP), using pooled data, with a focus on—but not limited to—prophylaxis at 40 IU/kg. Methods: N9‐GP has been investigated in males with congenital haemophilia B and FIX activity ≤2% in the paradigm™ clinical trial programme. This analysis includes pooled data from five completed paradigm™ trials conducted in previously treated adults, adolescents and children, focusing on results of prophylaxis with 40 IU/kg once‐weekly intravenous dosing. Results: In total, 115 previously treated patients were exposed to N9‐GP. Of 54 patients (47%) treated with N9‐GP 40 IU/kg once‐weekly prophylaxis, 72% experienced no spontaneous bleeds over 1 year. In all patients receiving 40 IU/kg once‐weekly, median overall annualized bleeding rate (ABR) was 1.03 (interquartile range 0.00; 2.89); median spontaneous ABR was 0.00 (0.00; 0.80). No patients developed inhibitors. Estimated mean steady‐state trough levels with N9‐GP 40 IU/kg once‐weekly were ≥15% overall; 27.3% in adolescents and adults. Conclusion: N9‐GP 40 IU/kg once‐weekly was well tolerated and effective in preventing bleeding, maintaining mean FIX activity levels ≥15% across all age groups. N9‐GP may provide a new treatment option for preventing bleeding in haemophilia B patients. [ABSTRACT FROM AUTHOR]

The article focuses on the importance of plasma-derived von Willebrand factor-containing FVIII concentrates for treating haemophilia. It discusses how the early pd-VWF-FVIII products had resulted in developing human immunodeficiency virus (HIV), how a level of safety had to be maintained for viral transmission.

Introduction Paradigm™4 was an international extension trial investigating the safety and efficacy of nonacog beta pegol, a recombinant glycoPEGylated factor IX (FIX) with extended half-life, in haemophilia B patients (FIX activity ≤ 2%; aged 13–70 years) who had previously participated in phase III pivotal (paradigm™2) or surgery (paradigm™3) trials. Methods Patients chose to continue treatment with nonacog beta pegol in either one of two once-weekly prophylaxis arms (10 IU/kg or 40 IU/kg), or an on-demand arm (40 IU/kg for mild/moderate bleeds; 80 IU/kg for severe bleeds). The primary objective was to evaluate immunogenicity; key secondary objectives included assessing safety and haemostatic efficacy in the treatment and prevention of bleeds. Results Seventy-one patients received prophylaxis or on-demand treatment. No patient developed an inhibitor and no safety concerns were identified. The success rate for the treatment of reported bleeds was 94.6%; most (87.9%) resolved with one injection. The median annualised bleeding rate for patients on prophylaxis was 1.36 (interquartile range [IQR] 0.00–2.23) and 1.00 (IQR 0.00–2.03) for the 10 and 40 IU/kg treatment arms, respectively. The mean FIX activity trough achieved for 10 and 40 IU once weekly was 9.8% and 21.3%, respectively. Fourteen patients on prophylaxis underwent 23 minor surgical procedures; haemostatic perioperative outcomes for all of those evaluated were ‘excellent’ or ‘good’. Conclusions Nonacog beta pegol showed a favourable tolerability profile (with no safety issues identified) with good prophylactic protection and control of bleeding in previously treated adult and adolescent haemophilia B patients. [ABSTRACT FROM AUTHOR]

The correlation between real-world clinical decisions and adherence to published treatment algorithms for problem bleeding episodes in patients with severe hemophilia and inhibitors and the resultant impact on clinical outcomes were assessed. Nine cases documenting treatment for problem bleeding episodes in patients with severe hemophilia and inhibitors were retrospectively reviewed. Adherence to treatment algorithms was rated on a scale of 1 to 5, 1 being no adherence and 5 being very high adherence. Adherence ratings >3 were assigned to 7 cases in which high adherence was associated with ≤4 days to achieve hemostatic control; hospitalization for ≤7 days was noted in 6 of these cases. In cases rated ≤3 (n = 2), time to hemostatic control ranged from 5 to 8 days and hospitalization duration ranged from 10 to 16 days. These findings suggest that adherence to treatment algorithms may be beneficial in treating problem bleeding events in patients with hemophilia and inhibitors. [ABSTRACT FROM PUBLISHER]

Abstract: Introduction: Hemophilia patients with inhibitors have frequent bleeding episodes and often develop hemophilic arthropathy which is in contradistinction to non-inhibitor patients for whom prophylaxis prevents joint disease. Recently, two prospective trials have demonstrated that secondary prophylaxis with bypassing agents in inhibitor patients offers benefit by reducing bleeding episodes. This report describes the clinical experience of secondary prophylaxis in a large population of inhibitor patients. Patients/Methods: This retrospective, observational study was performed by abstracting data from medical records of patients in whom secondary prophylaxis with rFVIIa was prescribed. Data were collected by professional medical record abstractors and included patient demographics, dosing regimens, bleeding events, and healthcare resource utilization. Data analysis was descriptive and included sensitivity analyses. Results: Data from 86 patients from 14 countries were collected. The primary outcome measure (% reduction in bleeding) was 46% (95% CI, -54.0 to −38.2) in patients with at least one bleeding episodes prior to starting prophylaxis and 52% (95% CI, -60.7 to −43.3) in patients with at least one bleeding episode per month prior to starting prophylaxis. A variety of subanalyses were performed, including among age and bleed location; the results for pediatric patients, adults, target and non-target joint bleeds categorizations were similar to the overall primary outcome. Conclusions: The results in this large observational study are similar to those from the previously reported prospective study of prophylaxis with rFVIIa in inhibitor positive patients, although this study represents a more typical inhibitor population who utilized prophylaxis in the clinical setting. As such, prophylaxis should be considered a potentially effective therapy in hemophilia patients with inhibitors. [Copyright &y& Elsevier]

. 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]

The most serious current complication of factor replacement therapy for hemophilia patients is the development of neutralizing antibodies to the factor termed inhibitors. Patients with high-titer inhibitors frequently develop serious bleeding complications which do not respond to standard factor replacement therapy. Therefore, they must be treated with the so-called bypassing agents, recombinant factor VIIa and activated prothrombin complex concentrates, neither of which is as effective as standard factor replacement in patients without inhibitors. Immune tolerance therapy aimed at eradicating inhibitors is successful in a majority of patients; however, a sizable minority will have life-long inhibitors and often develop debilitating joint disease. The ultimate goal is to develop strategies aimed at preventing inhibitor development though these have not been realized yet. Until this is achieved, additional novel approaches are needed to improve the treatment of bleeding episodes and to better treat arthropathy once it develops. Finally, there is no laboratory monitoring device which can predict the clinical response of patients to bypassing agents. Thus another goal of current research is to develop such a tool which will enable the individualization of bypassing agent. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Hemophilia A (HA) is a serious inherited bleeding disorder resulting from a deficiency of coagulation factor VIII (FVIII). Replacement therapy with intravenous infusion of FVIII can be associated with treatment failure in approximately one-third of patients secondary to the development of neutralizing alloantibodies (inhibitor). Emicizumab is a recombinant, humanized, bispecific monoclonal antibody that binds factor IXa and factor X and mimics FVIII. It has been licensed in many countries for the treatment of patients with HA with and without inhibitors with a favorable efficacy and safety profile. A 7-year-old child with severe HA and FVIII inhibitors, refractory to immune tolerance therapy, developed hematuria with nephroticrange proteinuria after the first dose of emicizumab and subsequently also after a second dose 6 weeks later, which was associated with mild and transient leukopenia. Renal biopsy revealed a pattern of a full-house lupus nephritis. The patient fully and spontaneously recovered between 2 weeks after symptoms onset. In this report, we provide insights on a new and so far unreported renal complication associated to emicizumab treatment. Although emicizumab offers significant benefits for patient with HA, clinicians should be aware of this rare and potential serious renal adverse effect. [ABSTRACT FROM AUTHOR]

Background: Emicizumab (ACE910) bridges activated factor IX and factor X to restore the function of activated factor VIII, which is deficient in persons with hemophilia A. This phase 3, multicenter trial assessed once-weekly subcutaneous emicizumab prophylaxis in persons with hemophilia A with factor VIII inhibitors.Methods: We enrolled participants who were 12 years of age or older. Those who had previously received episodic treatment with bypassing agents were randomly assigned in a 2:1 ratio to emicizumab prophylaxis (group A) or no prophylaxis (group B). The primary end point was the difference in bleeding rates between group A and group B. Participants who had previously received prophylactic treatment with bypassing agents received emicizumab prophylaxis in group C.Results: A total of 109 male participants with hemophilia A with inhibitors were enrolled. The annualized bleeding rate was 2.9 events (95% confidence interval [CI], 1.7 to 5.0) among participants who were randomly assigned to emicizumab prophylaxis (group A, 35 participants) versus 23.3 events (95% CI, 12.3 to 43.9) among those assigned to no prophylaxis (group B, 18 participants), representing a significant difference of 87% in favor of emicizumab prophylaxis (P<0.001). A total of 22 participants in group A (63%) had zero bleeding events, as compared with 1 participant (6%) in group B. Among 24 participants in group C who had participated in a noninterventional study, emicizumab prophylaxis resulted in a bleeding rate that was significantly lower by 79% than the rate with previous bypassing-agent prophylaxis (P<0.001). Overall, 198 adverse events were reported in 103 participants receiving emicizumab prophylaxis; the most frequent events were injection-site reactions (in 15% of participants). Thrombotic microangiopathy and thrombosis were reported in 2 participants each (in the primary analysis) who had received multiple infusions of activated prothrombin complex concentrate for breakthrough bleeding. No antidrug antibodies were detected.Conclusions: Emicizumab prophylaxis was associated with a significantly lower rate of bleeding events than no prophylaxis among participants with hemophilia A with inhibitors. (Funded by F. Hoffmann-La Roche and Chugai Pharmaceutical; HAVEN 1 ClinicalTrials.gov number, NCT02622321 .). [ABSTRACT FROM AUTHOR]

Haemophilia A and B are hereditary haemorrhagic disorders characterised by deficiency or dysfunction of coagulation protein factors VIII and IX, respectively. Recurrent joint and muscle bleeds lead to severe and progressive musculoskeletal damage. Existing treatment relies on replacement therapy with clotting factors, either at the time of bleeding (ie, on demand) or as part of a prophylactic schedule. The major complication of such therapy is the development of neutralising antibodies (ie, inhibitors), which is most frequent in haemophilia A. Treatment might improve considerably with the availability of new modified drugs, which might overcome existing prophylaxis limitations by reducing dosing frequency and thereby rendering therapy less distressing for the patient. Subcutaneous administration of some new therapies would also simplify prophylaxis in children with poor venous access. Gene therapy has the potential for a definitive cure, and important results have been obtained in haemophilia B. Despite improvements in haemophilia care, the availability of clotting factor concentrates for all affected individuals worldwide remains the biggest challenge. [ABSTRACT FROM AUTHOR]