Challenges of antithrombotic therapy in the management of cardiovascular disease in patients with inherited bleeding disorders: A single-centre experience.

INTRODUCTION: Cardiovascular events in patients with inherited bleeding disorders are challenging to manage. The risk of bleeding secondary to antithrombotic treatment must be balanced against the risk of thrombosis secondary to haemostatic therapy. METHODS: Patients with inherited bleeding disorders with coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI) or atrial fibrillation (AF) from a single centre (2010-2018) are included. RESULTS: A total of 11 patients undergoing CABG (n = 3), PCI (n = 5) or with AF (n = 3) and a diagnosis of haemophilia A (n = 8), haemophilia B (n = 1), factor XI deficiency (n = 1) and von Willebrand disease (n = 1) managed by a multidisciplinary team are reported. In patients undergoing CABG, factor levels were normalized for 7-10 days with trough levels of 70-80% with severe patients continuing high-dose factor prophylaxis (trough 20-30%) three weeks post-operatively with daily aspirin. In a patient with mild haemophilia A and an inhibitor, recombinant factor VIIa dosing was monitored with thromboelastometry. For PCI, a 3rd-generation drug-eluting stent with one month of dual antiplatelet therapy in addition to high-dose prophylaxis as needed was preferred. Patients with AF and severe haemophilia did not receive antithrombotic treatment, and a thrombin generation assay was used to guide heparin dosing in mild haemophilia. CONCLUSION: Our experience demonstrates the importance of interdisciplinary communication to identify strategies that decrease the risk of bleeding and thrombosis. The use of extended, increased intensity prophylaxis facilitated antiplatelet therapy. Global assays may help balance the intensity of haemostatic and antithrombotic treatment.

Treatment burden, haemostatic strategies and real world inhibitor screening practice in non-severe haemophilia A.

Inhibitor formation in non-severe haemophilia A is a life-long risk and associated with morbidity and mortality. There is a paucity of data to understand real-world inhibitor screening practice. We evaluated the treatment burden, haemostatic strategies, F8 genotyping and inhibitor screening practices in non-severe haemophilia A in seven London haemophilia centres. In the 2-year study period, 44% (377/853) patients received at least one haemostatic treatment. Seventy-nine percent of those treated (296/377) received factor VIII (FVIII) concentrate. F8 genotype was known in 88% (331/377) of individuals. Eighteen per cent (58/331) had 'high-risk' F8 genotypes. In patients with 'standard-risk' F8 genotypes treated on-demand with FVIII concentrate, 51·3% episodes (243/474) were screened within 1 year. However, poor screening compliance was observed after 'high-risk' treatment episodes. In patients with 'standard-risk' F8 genotypes, 12·3% (28/227) of treatment episodes were screened in the subsequent 6 weeks after surgery or a bleed requiring ≥5 exposure days. Similarly, in the context of 'high-risk' F8 genotypes after any FVIII exposure, only 13·6% (12/88) of episodes were screened within 6 weeks. Further study is required to assess optimal practice of inhibitor screening in non-severe haemophilia A to inform subsequent clinical decisions and provide more robust prevalence data to further understand the underlying immunological mechanism.

A genome-wide association study of resistance to HIV infection in highly exposed uninfected individuals with hemophilia A.

Human genetic variation contributes to differences in susceptibility to HIV-1 infection. To search for novel host resistance factors, we performed a genome-wide association study (GWAS) in hemophilia patients highly exposed to potentially contaminated factor VIII infusions. Individuals with hemophilia A and a documented history of factor VIII infusions before the introduction of viral inactivation procedures (1979-1984) were recruited from 36 hemophilia treatment centers (HTCs), and their genome-wide genetic variants were compared with those from matched HIV-infected individuals. Homozygous carriers of known CCR5 resistance mutations were excluded. Single nucleotide polymorphisms (SNPs) and inferred copy number variants (CNVs) were tested using logistic regression. In addition, we performed a pathway enrichment analysis, a heritability analysis, and a search for epistatic interactions with CCR5 Δ32 heterozygosity. A total of 560 HIV-uninfected cases were recruited: 36 (6.4%) were homozygous for CCR5 Δ32 or m303. After quality control and SNP imputation, we tested 1 081 435 SNPs and 3686 CNVs for association with HIV-1 serostatus in 431 cases and 765 HIV-infected controls. No SNP or CNV reached genome-wide significance. The additional analyses did not reveal any strong genetic effect. Highly exposed, yet uninfected hemophiliacs form an ideal study group to investigate host resistance factors. Using a genome-wide approach, we did not detect any significant associations between SNPs and HIV-1 susceptibility, indicating that common genetic variants of major effect are unlikely to explain the observed resistance phenotype in this population.

Pharmacokinetics and safety of a novel recombinant human von Willebrand factor manufactured with a plasma-free method: a prospective clinical trial.

Safety and pharmacokinetics (PK) of recombinant von Willebrand factor (rVWF) combined at a fixed ratio with recombinant factor VIII (rFVIII) were investigated in 32 subjects with type 3 or severe type 1 von Willebrand disease (VWD) in a prospective phase 1, multicenter, randomized clinical trial. rVWF was well tolerated and no thrombotic events, inhibitors, or serious adverse events were observed. The PK of rVWF ristocetin cofactor activity, VWF antigen, and collagen-binding activity were similar to those of the comparator plasma-derived (pd) VWF-pdFVIII. In vivo cleavage of ultra-large molecular-weight rVWF multimers by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13; the endogenous VWF protease) and generation of characteristic satellite bands were demonstrated. In 2 subjects with specific nonneutralizing anti-VWF-binding antibodies already detectable before rVWF infusion, a reduction in VWF multimers and VWF activity was observed. Stabilization of endogenous FVIII was enhanced following post-rVWF-rFVIII infusion as shown by the difference in area under the plasma concentration curve compared with pdVWF-pdFVIII (AUC0-∞) (P < .01). These data support the concept of administering rVWF alone once a therapeutic level of endogenous FVIII is achieved.

Factor VIII gene (F8) mutation and risk of inhibitor development in nonsevere hemophilia A.

Neutralizing antibodies (inhibitors) toward factor VIII form a severe complication in nonsevere hemophilia A, profoundly aggravating the bleeding pattern. Identification of high-risk patients is hampered by lack of data that take exposure days to therapeutic factor VIII concentrates into account. In the INSIGHT study, we analyzed the association between F8 mutation and inhibitor development in patients with nonsevere hemophilia A (factor VIII 2-40 IU/dL). This analysis included 1112 nonsevere hemophilia A patients from 14 centers in Europe and Australia that had genotyped at least 70% of their patients. Inhibitor risk was calculated as Kaplan-Meier incidence with cumulative number of exposure days as the time variable. During 44 800 exposure days (median, 24 exposure days per patient; interquartile range [IQR], 7-90), 59 of the 1112 patients developed an inhibitor; cumulative incidence of 5.3% (95% confidence interval [CI], 4.0-6.6) after a median of 28 exposure days (IQR, 12-71). The inhibitor risk at 50 exposure days was 6.7% (95% CI, 4.5-8.9) and at 100 exposure days the risk further increased to 13.3% (95% CI, 9.6-17.0). Among a total of 214 different F8 missense mutations 19 were associated with inhibitor development. These results emphasize the importance of F8 genotyping in nonsevere hemophilia A.

Long-term follow-up of hepatitis C infection in a large cohort of patients with inherited bleeding disorders.

BACKGROUND & AIMS: Patients with inherited bleeding disorders are an interesting group to study the long-term course of chronic hepatitis C virus (HCV) infection, because of their uniform mode of infection and reliable follow-up. Our aim was to assess the long-term occurrence of adverse liver-related events in these patients. METHODS: The occurrence and determinants of end-stage liver disease (ESLD) were assessed using retrospective data of 863 HCV infected patients with inherited bleeding disorders from the Netherlands and the UK. RESULTS: Median follow-up since HCV infection was 31 years, while 30% of patients had >35 follow-up years. Nineteen percent of patients spontaneously cleared the virus and 81% developed chronic HCV infection. Of the 700 patients with chronic HCV, 90 (13%) developed ESLD. Hepatocellular carcinoma (HCC) was diagnosed in 3% of patients with chronic HCV, 41% of which occurred in the last six years. Determinants of ESLD development were age at infection (hazard ratio (HR) 1.09 per year increase), HIV co-infection (HR 10.85), history of alcohol abuse (HR 4.34) and successful antiviral treatment (HR 0.14). Of the 487 patients who were still alive at the end of follow-up, 49% did not undergo optimal conventional antiviral treatment. CONCLUSIONS: After over 30 years of HCV infection, ESLD occurred in a significant proportion of patients with inherited bleeding disorders. HCC appears to be an increasing problem. There is a significant potential for both conventional and new antiviral treatment regimens to try and limit ESLD occurrence in the future.

The incidence and treatment of bleeding episodes in non-severe haemophilia A patients with inhibitors.

The development of an inhibitory antibody in non-severe haemophilia A patients may aggravate the bleeding phenotype considerably. Effective treatment of bleeding episodes may be challenging, with ensuing severe complications. At present, evidence is scarce for optimal treatment of bleeding episodes in this patient group. The aim of this study was to describe the incidence and the treatment of bleeding episodes in inhibitor patients in a population-based unselected cohort of non-severe haemophilia A patients with clinically relevant inhibitors. Data were available for 100 of the 107 non-severe haemophilia A patients (factor VIII (FVIII) baseline, 2-40 IU/dl) from 29 centres in Europe and one centre in Australia who had developed a clinically relevant inhibitor between 1980 and 2011. The majority (89 %) of the patients were treated during the inhibitor period for bleeding episodes or a surgical intervention: 66 % needed treatment for bleeding episodes, at a median annual bleeding rate (ABR) of 1.1 (interquartile range (IQR) 0.1-2.5) and a median total of 2 (IQR 1-6) bleeding episodes. Compared to the median ABR before inhibitor development of 0.095 bleeds per year (IQR 0.02-0.42), the increase in ABR is more than a 10-fold. More than 90 % of the bleeding episodes were treated with only one type of product, most frequently (51 %) FVIII concentrates. This study provides the incidence of bleeding episodes and treatment choices in non-severe haemophilia A patients with inhibitors. The 10-fold increase to a median ABR of 1.1 episodes per year emphasizes the impact of inhibitor development for non-severe haemophilia A patients.

Inhibitors in nonsevere haemophilia A: outcome and eradication strategies.

In nonsevere haemophilia A (HA) patients the presence of an inhibitor may exacerbate the bleeding phenotype dramatically. There are very limited data on the optimal therapeutic approach to eradicate inhibitors in these patients. We aimed to describe inhibitor eradication treatment in a large cohort of unselected nonsevere HA patients with inhibitors. We included 101 inhibitor patients from a source population of 2,709 nonsevere HA patients (factor VIII 2-40 IU/dl), treated in Europe and Australia (median age 37 years, interquartile range (IQR) 15-60; median peak titre 7 BU/ml, IQR 2-30). In the majority of the patients (71 %; 72/101) the inhibitor disappeared; either spontaneously (70 %, 51/73) or after eradication treatment (75 %, 21/28). Eradication treatment strategies varied widely, including both immune tolerance induction and immunosuppression. Sustained success (no inhibitor after rechallenge with factor VIII concentrate after inhibitor disappearance) was achieved in 64 % (30/47) of those patients rechallenged with FVIII concentrate. In high-titre inhibitor patients sustained success was associated with eradication treatment (unadjusted relative risk 2.3, 95 % confidence interval 1.3-4.3), compared to no eradication treatment. In conclusion, in nonsevere HA patients most inhibitors disappear spontaneously. However, in 35 % (25/72) of these patients an anamnestic response still can occur when rechallenged, thus disappearance in these patients does not always equal sustained response. Treatment for those requiring eradication has to be decided case by case, as one single approach is unlikely to be appropriate for all.

Early and prolonged antiretroviral therapy is associated with an HIV-1-specific T-cell profile comparable to that of long-term non-progressors.

BACKGROUND: Intervention with antiretroviral treatment (ART) and control of viral replication at the time of HIV-1 seroconversion may curtail cumulative immunological damage. We have therefore hypothesized that ART maintenance over a very prolonged period in HIV-1 seroconverters could induce an immuno-virological status similar to that of HIV-1 long-term non-progressors (LTNPs). METHODOLOGY/PRINCIPAL FINDINGS: We have investigated a cohort of 20 HIV-1 seroconverters on long-term ART (LTTS) and compared it to one of 15 LTNPs. Residual viral replication and reservoirs in peripheral blood, as measured by cell-associated HIV-1 RNA and DNA, respectively, were demonstrated to be similarly low in both cohorts. These two virologically matched cohorts were then comprehensively analysed by polychromatic flow cytometry for HIV-1-specific CD4(+) and CD8(+) T-cell functional profile in terms of cytokine production and cytotoxic capacity using IFN-γ, IL-2, TNF-α production and perforin expression, respectively. Comparable levels of highly polyfunctional HIV-1-specific CD4(+) and CD8(+) T-cells were found in LTTS and LTNPs, with low perforin expression on HIV-1-specific CD8(+) T-cells, consistent with a polyfunctional/non-cytotoxic profile in a context of low viral burden. CONCLUSIONS: Our results indicate that prolonged ART initiated at the time of HIV-1 seroconversion is associated with immuno-virological features which resemble those of LTNPs, strengthening the recent emphasis on the positive impact of early treatment initiation and paving the way for further interventions to promote virological control after treatment interruption.

Progression to end-stage liver disease in patients with inherited bleeding disorders and hepatitis C: an international, multicenter cohort study.

Prior to 1990, many patients with inherited bleeding disorders were infected with hepatitis C virus (HCV). This study assessed the risk of end-stage liver disease (ESLD) in patients with hemophilia with chronic hepatitis C. Patients were infected between 1961 and 1990 and were followed up to August 2005. Of 847 anti-HCV(+) patients, 160 (19%) spontaneously cleared HCV and 687 (81%) developed chronic hepatitis C. Coinfection with HIV was present in 210 patients. After 35 years of infection the cumulative incidence of ESLD was 11.5% (95% CI, 8.2%-14.8%) in HIV(-) patients and 35.1% (95% CI, 29.2%-41.0%; P < .001) in patients coinfected with HIV. Independent risk factors of ESLD were HIV coinfection (hazard ratio 13.8; 95% CI, 7.5-25.3), older age at infection (hazard ratio 2.3 per 10 years; 95% CI, 2.0-2.8), alcohol abuse (hazard ratio 4.9; 95% CI, 2.5-9.6), and presence of HCV genotype 1 (hazard ratio 2.2; 95% CI, 1.1-4.2). With longer duration of HCV infection, the risk of developing ESLD is emerging in patients with inherited bleeding disorders. Risk factors for rapid progression to ESLD are alcohol abuse, coinfection with HIV, older age at infection, and presence of HCV genotype 1.

Transfusion-transmitted infection in hemophilia in developing countries.

Treatment of patients with bleeding disorders (especially those with hemophilia) with blood products has been associated with infections with blood-borne viruses. Of these, hepatitis B and C viruses (HBV and HCV, respectively) and the human immunodeficiency virus (HIV) have created major health problems. Although virus-inactivation procedures have virtually eliminated these viruses from newer factor concentrates since 1985, the risk remains in developing countries where there is no ready access to these concentrates. Although a few of these countries have established their own fractionation facilities and in others the respective governments make concentrates available, the large majority of countries still face the problems of blood-borne infections. HCV will invariably lead to liver damage and many hemophiliacs who were exposed to the HCV virus will succumb to cirrhosis. Only approximately 10% of hemophilic patients infected with HCV will clear the infection naturally. Coinfection with HIV shortens the life expectancy. The HIV epidemic in hemophiliacs began in the mid-1980s. Patients in developed countries were especially affected because they were predominantly treated with factor concentrates that were manufactured from thousands of blood donors. Hemophiliacs in developing countries have considerably less HIV infection, although it does exist and depends largely on the source of the plasma fractions. Progress has been made not only in the purification of factor concentrates, but also in the understanding of the HIV virus and in the development of antiretroviral treatment modalities. However, there are still several challenges in delivering antiretroviral treatment that must be addressed before the full impact of these transmitted infections is known.

Long-term patterns of hepatitis C virus RNA concentrations in a cohort of HIV seronegative men with bleeding disorders.

Little is known about the natural history of hepatitis C virus (HCV) RNA concentrations over the course of infection. The aim of this study was to describe the natural history of HCV RNA concentrations in 85 HIV negative men with bleeding disorders infected with HCV for up to 30 years. HCV RNA concentrations were measured in yearly serum samples using a branched DNA assay. HCV RNA concentrations increased over time in this cohort. Two years after exposure to HCV, 53% of patients had undetectable concentrations and no patients had levels >7 log(10)(genome Eq/ml); by 20 years, these proportions had changed to 23% and 32% respectively. The RNA concentration correlated strongly with alanine aminotransferase (ALT; correlations of 0.41-0.71 depending on stage of infection) and aspartate aminotransferase (AST; 0.20-0.51) levels. Patients with haemophilia A had significantly higher HCV concentrations than those with other disorders. An effect of HCV genotype on HCV RNA concentrations became nonsignificant after excluding patients who were persistently HCV PCR negative and who could not be genotyped. The correlation of HCV RNA concentrations with other markers of liver function, such as ALT, means that studies with clinical outcomes are required to assess whether HCV RNA concentrations provide additional prognostic information to that provided by these other markers.

Markers of HIV-1 disease progression in individuals with haemophilia coinfected with hepatitis C virus: a longitudinal study.

BACKGROUND: Low serum albumin concentration is associated with short-term survival in individuals with HIV-1. However, few investigators have assessed whether individuals with a low serum albumin concentration have delayed progression to AIDS, or survive in the long term. We aimed to assess the relation between markers of liver function and progression to AIDS and death in individuals with haemophilia infected with HIV-1 and hepatitis C virus. METHODS: We measured markers of liver function and took CD4 counts every 3 months in 111 patients registered at the Royal Free Hospital Haemophilia Centre, London, UK. HIV RNA concentrations were measured yearly and then every 3-6 months from 1996. We used Cox's regression models to assess the independent prognostic value of these markers for AIDS and death. FINDINGS: As a fixed covariate, albumin concentrations measured shortly after HIV-1 seroconversion were associated with risk of AIDS (relative hazard 0.91 [95% CI 0.84-1.00], p=0.04) and death (0.89 [0.82-0.96], p=0.004) over a 15-year period. These findings were independent of the CD4 count and HIV-1 RNA concentration. As a time-updated covariate, after adjustment for CD4 count and HIV-1 RNA concentrations, albumin was not associated with progression to AIDS (0.96 [0.90-1.01], p=0.13), but was strongly associated with death (0.88 [0.84-0.93], p<0.0001) in the short term. INTERPRETATION: Low concentrations of albumin in individuals infected with HIV-1 could indicate a poor outlook and should therefore prompt concern at any stage of infection.

Two classes of germline genes both derived from the V(H)1 family direct the formation of human antibodies that recognize distinct antigenic sites in the C2 domain of factor VIII.

Most plasmas from patients with inhibitors contain antibodies that are reactive with the C2 domain of factor VIII. Previously, we have shown that the variable heavy chain (V(H)) regions of antibodies to the C2 domain are encoded by the closely related germline gene segments DP-10, DP-14, and DP-88, which all belong to the V(H)1 gene family. Here, we report on the isolation and characterization of additional anti-C2 antibodies that are derived from V(H) gene segments DP-88 and DP-5. Competition experiments using murine monoclonal antibodies CLB-CAg 117 and ESH4 demonstrated that antibodies derived from DP-5 and DP-88 bound to different sites within the C2 domain. Epitope mapping studies using a series of factor VIII/factor V hybrids revealed that residues 2223 to 2332 of factor VIII are required for binding of the DP-10-, DP-14-, and DP-88-encoded antibodies. In contrast, binding of the DP-5-encoded antibodies required residues in both the amino- and carboxy-terminus of the C2 domain. Inspection of the reactivity of the antibodies with a series of human/porcine hybrids yielded similar data. Binding of antibodies derived from germline gene segments DP-10, DP-14, and DP-88 was unaffected by replacement of residues 2181 to 2243 of human factor VIII for the porcine sequence, whereas binding of the DP-5-encoded antibodies was abrogated by this replacement. Together these data indicate that antibodies assembled from V(H) gene segments DP-5 and the closely related germline gene segments DP-10, DP-14, and DP-88 target 2 distinct antigenic sites in the C2 domain of factor VIII.