Current hemophilia treatment involves frequent intravenous infusions of clotting factors, which is associated with variable hemostatic protection, a high treatment burden, and a risk of the ...development of inhibitory alloantibodies. Fitusiran, an investigational RNA interference (RNAi) therapy that targets antithrombin (encoded by SERPINC1), is in development to address these and other limitations.
In this phase 1 dose-escalation study, we enrolled 4 healthy volunteers and 25 participants with moderate or severe hemophilia A or B who did not have inhibitory alloantibodies. Healthy volunteers received a single subcutaneous injection of fitusiran (at a dose of 0.03 mg per kilogram of body weight) or placebo. The participants with hemophilia received three injections of fitusiran administered either once weekly (at a dose of 0.015, 0.045, or 0.075 mg per kilogram) or once monthly (at a dose of 0.225, 0.45, 0.9, or 1.8 mg per kilogram or a fixed dose of 80 mg). The study objectives were to assess the pharmacokinetic and pharmacodynamic characteristics and safety of fitusiran.
No thromboembolic events were observed during the study. The most common adverse events were mild injection-site reactions. Plasma levels of fitusiran increased in a dose-dependent manner and showed no accumulation with repeated administration. The monthly regimen induced a dose-dependent mean maximum antithrombin reduction of 70 to 89% from baseline. A reduction in the antithrombin level of more than 75% from baseline resulted in median peak thrombin values at the lower end of the range observed in healthy participants.
Once-monthly subcutaneous administration of fitusiran resulted in dose-dependent lowering of the antithrombin level and increased thrombin generation in participants with hemophilia A or B who did not have inhibitory alloantibodies. (Funded by Alnylam Pharmaceuticals; ClinicalTrials.gov number, NCT02035605 .).
Background Acute chest syndrome (ACS) is the leading cause of mortality in sickle cell disease (SCD). The pathogenesis of ACS is complex and not entirely understood with multiple etiologies likely ...contributing simultaneously. One particular etiology is pulmonary vascular occlusion due to thrombosis. Thus, anticoagulation is an attractive therapeutic modality. Methods This was a single-center, randomized controlled, open-label, pilot study to determine the feasibility of performing a larger multicenter phase III trial to assess the effects of unfractionated heparin (UFH) in ACS. Subjects were randomized within 24 h of diagnosis of ACS to one of two treatment arms, UFH, and standard of care (SOC), or no UFH and SOC. UFH was given intravenously for 7 days, or until discharge, if discharge was shorter than 7 days. SOC consisted of intravenous fluids, antibiotics, supplemental oxygen, analgesia, red blood cell transfusion, and exchange transfusion. Results From July 2014 to June 2018, a total of 7 patients underwent randomization (four patients received UFH in addition to SOC and 3 patients received SOC only). Two of the prespecified feasibility criteria were not met: the capacity to consent eligible individuals and the timely notification of hospitalized patients with ACS necessary to permit randomization within 24 h of diagnosis; thus, as a result of poor enrollment, the study was terminated early. The duration of hospitalization was 279.43 (SD 267.98) and 127.31 (SD 137.70) h in the UFH and SOC arms, respectively. The duration of hypoxemia, leukocytosis, fever, and moderate to severe pain was 117.52 (SD 60.52), 24.90 (SD 29.69), 117.52 (SD 60.52), and 117.52 (SD 60.52) h, respectively, in the UFH group, and 51.49 (SD 44.79), 0, 53.11 (SD 25.06), and 88.68 (SD 72.77) h, respectively, in the SOC group. No major bleeding was noted in either group. Conclusions Our study did not achieve prespecified feasibility criteria, resulting in poor enrollment and early termination, and serves to highlight some of the pitfalls experienced in clinical research in SCD. It did show the use of UFH without any major adverse events in 7 subjects. No future large-scale study is planned. Trials registration Registered at ClinicalTrials.gov (NCT #02098993) on March 28, 2014. Keywords: Acute chest syndrome, Heparin, Sickle cell disease, Thrombosis
Introduction
Emicizumab is a bispecific monoclonal antibody that mimics factor VIII (FVIII) by binding to factors IXa and X to promote hemostasis in haemophilia A (HA) and HA with inhibitors (HA‐I). ...As emicizumab differs biochemically from FVIII, there is interest in its real‐world haemostatic efficacy.
Aim
To describe real‐world patient experience with emicizumab by retrospective chart review.
Methods
We reviewed medical records of patients cared for at the Hemophilia Center of Western PA, who initiated emicizumab following its licensure, and on whom bleeding events and factor use were available. Comparisons between groups were done by Student's t test for continuous data and by chi‐square or Fisher's exact test for discrete data.
Results
A total of 42 patients whose charts were reviewed included 18 (42.9%) with HA and 24 (52.1%) with HA‐I. Groups were similar in age, 17 (40.5%) <18 years, race, and haemophilia severity, and initiated weekly subcutaneous emicizumab 1.5 mg/kg, following 4‐week induction. Fourteen (33.3%) experienced at least one breakthrough bleed, of which 11 (44.0%) were joint bleeds, with an annualized bleed rate (ABR), 0.9 ± 0.3, not different between groups, P = .251. Surgical procedures were performed in 10 (23.8%), of whom 4 (40.0%) had postoperative bleeding and one developed postoperative thrombosis in association with FEIBA despite emicizumab discontinuation 1 month preoperatively. Local skin reactions occurred in three and headache in one. Overall, 85.0% of those who rated their health indicated it was improved.
Discussion
Despite breakthrough bleeds and postoperative thrombosis associated with emicizumab, most HA and HA‐I experienced improved health.
Background
Hepatocellular carcinoma (HCC) is a major complication of chronic hepatitis C virus (HCV) infection. Among haemophilic (H) men, HCV is the leading cause of liver disease. Direct‐acting ...antiviral agents (DAA) reduce HCV viral load, but impact on HCC is unknown.
Methods
This was a retrospective study of adult H and nonhaemophilic (NH) male discharges, with and without HCC, identified by ICD‐10 codes in the National Inpatient Sample (NIS) database, 2016–2018, with DAA availability. Analyses included discharge‐level weights to reflect national estimates. Categorical variables were assessed by Rao‐Scott chi‐square and continuous variables by weighted simple linear regression. HCC correlates were determined by weighted multivariable logistic regression.
Results
Among 7,674,969 adult male discharges, 3730 H (.04%) were identified in 2016–2018, of whom 10.06% had HCV and 1.07% had HCC, significantly higher than NH (1.22% and .27%, respectively) all P < .001. Annual HCC rates were similar during the 3‐year period (2016–2018) in H and NH. Among H, HCC is associated with older age and higher rates of HCV, HBV, NASH, end‐stage liver disease, and Charlson comorbidity (CCI), each P < .001. Among HCC, H were younger and more likely HIV+, each P < .001, but less likely alcoholic (P = .018) or hyperlipidaemic (P = .008) compared to NH. In multivariable regression, risk factors for HCC among H included NASH (OR 21.6), HCV (OR 3.96), CCI (OR1.54), all P < .001, while HIV and hyperlipidaemia were protective.
Conclusion
From 2016 to 2018, HCC rates did not change significantly in haemophilia discharges. NASH, HCV, and CCI are significant risks for HCC in haemophilia during the DAA‐era.
Inhibitor formation is among the most severe complications of hemophilia treatment. With a cumulative incidence of ∼30% in those with severe hemophilia A and ∼3% in those with severe hemophilia B, ...inhibitors are caused by a T-cell response directed against infused coagulation factor; these inhibitors neutralize factor VIII or IX activity and disrupt normal hemostasis. Inhibitor patients become unresponsive to standard factor treatment and, as an alternative, use bypass treatment (eg, recombinant factor VIIa or factor VIII inhibitor bypass activity). However, response to bypass agents is poorer and the burden of disease is higher, with greater morbidity, hospitalization, cost, and mortality, than in noninhibitor patients. Furthermore, inhibitor formation interferes with prophylaxis to prevent bleeding episodes and is a contraindication to gene therapy. Thus, more effective therapies for inhibitor patients are greatly needed. In the last several years, there has been an explosion of novel alternative hemostatic agents for hemophilia patients with and without inhibitors. These agents take advantage of technologic manipulation of coagulation factors and natural anticoagulants to promote hemostasis. The approaches include the following: (1) mutants or mimics of coagulation factors, rendering them resistant to natural anticoagulants; or (2) knock-down or disruption of natural anticoagulants, preventing degradation of coagulation factors. The purpose of this article was to review these novel alternative hemostatic agents and their mechanisms of action, as well as the preliminary pharmacokinetic, safety, and efficacy data available from early-phase clinical trials.
Hepatitis C virus (HCV) is the major cause of chronic liver disease in hemophiliacs. To determine the effect of human immunodeficiency virus (HIV) on the natural history of HCV infection, we ...evaluated end-stage liver disease (ESLD) in 157 hemophiliacs (85 HIV positive and 72 HIV negative) with HCV infection for an average of 24 years. After adjusting for age at HCV infection, past or current hepatitis B surface antigen positivity, and history of alcohol abuse, we determined that the rate of ESLD was significantly greater among HIV-positive than among HIV-negative hemophiliacs (relative risk RR, 3.72; 95% confidence interval CI, 1.25–11.09), as was the adjusted RR for death due to ESLD (RR, 3.81; 95% CI, 1.19–12.16). Among HIV-positive hemophiliacs, crude RR for ESLD was lower, but not significantly so, with antiretroviral treatment (RR, 0.19; 95% CI, 0.03–1.14; P=.069) and increased with each decade of HCV infection (RR, 2.26; 95% CI, 1.42–3.59; P=.0006) and HIV infection (RR, 2.18; 95% CI, 1.36–3.49; P=.0013). These findings suggest that HIV accelerates HCV disease progression
Hemophilia A is an inherited bleeding disorder caused by defective or deficient coagulation factor VIII (FVIII) activity. Until recently, the only treatment for prevention of bleeding involved IV ...administration of FVIII. Gene therapy with adeno-associated vectors (AAVs) has shown some efficacy in patients with hemophilia A. However, limitations persist due to AAV-induced cellular stress, immunogenicity, and reduced durability of gene expression. Herein, we examined the efficacy of liver-directed gene transfer in FVIII knock-out mice by AAV8-GFP. Surprisingly, compared with control mice, FVIII knockout (F8TKO) mice showed significant delay in AAV8-GFP transfer in the liver. We found that the delay in liver-directed gene transfer in F8TKO mice was associated with absence of liver sinusoidal endothelial cell (LSEC) fenestration, which led to aberrant expression of several sinusoidal endothelial proteins, causing increased capillarization and decreased permeability of LSECs. This is the first study to link impaired liver-directed gene transfer to liver-endothelium maladaptive structural changes associated with FVIII deficiency in mice.
In this issue of Blood, Chen et al demonstrate that platelets expressing factor VIII (FVIII) shield FVIII from immune detection. In the naive FVIII null hemophilia A (HA) mouse, platelet-derived VIII ...prevents both a primary and memory anti-FVIII immune response, and together with total body irradiation, suppresses anti-FVIII immune response.
Introduction
While it has been shown that haemophilia patients receiving care at Haemophilia Treatment Centres (HTCs) experience decreased morbidity and mortality, little research has been done on ...the outcomes of patients with von Willebrand disease (VWD).
Aim
To compare the quality of periprocedural care received by patients with VWD at HTCs and non‐HTCs.
Methods
We performed a retrospective chart review on all adult VWD patients undergoing an invasive procedure from 2015 to 2017. Quality of periprocedural care was measured using the following surrogate outcomes: periprocedural VWD‐specific therapy use per 2007 National Heart, Lung, and Blood Institute (NHLBI) guidelines, procedural estimated blood loss (EBL), and post‐procedure bleeding. Comparisons were performed according to the setting of care at the time of the invasive procedure, HTC versus non‐HTC.
Results
There were 668 invasive procedures performed on 305 patients, of which 8.2% were HTC cases. Non‐type 1 VWD was more likely in HTC cases. VWD‐specific therapy was used per NHLBI guidelines in 100% of HTC cases compared with 10.6% of non‐HTC cases. Procedural EBL > = 100 ml was more likely to occur in HTC differences cases (OR = 2.34; 95% CI, 1.05 to 5.25). There was no difference in post‐procedure bleeding between the two groups (OR = 1.26, 95% CI, .20‐ 7.86).
Conclusion
Despite widespread periprocedural use of VWD‐specific therapy outside established guidelines at non‐HTCs, there was no difference in periprocedural bleeding. Possible explanations include diagnostic error, in disease severity and procedure types, and dataset limitations. Additional studies are needed to investigate this further and compare other patient care outcomes between HTCs and non‐HTCs.
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