Hepatitis C in haemophilia: time for treatment for all

Translational Potential of Immune Tolerance Induction by AAV Liver-Directed Factor VIII Gene Therapy for Hemophilia A

Hemophilia A (HA) is an X-linked bleeding disorder due to deficiencies in coagulation factor VIII (FVIII). The major complication of current protein-based therapies is the development of neutralizing anti-FVIII antibodies, termed inhibitors, that block the hemostatic effect of therapeutic FVIII. Inhibitors develop in about 20-30% of people with severe HA, but the risk is dependent on the interaction between environmental and genetic factors, including the underlying F8 gene mutation. Recently, multiple clinical trials evaluating adeno-associated viral (AAV) vector liver-directed gene therapy for HA have reported promising results of therapeutically relevant to curative FVIII levels. The inclusion criteria for most trials prevented enrollment of subjects with a history of inhibitors. However, preclinical data from small and large animal models of HA with inhibitors suggests that liver-directed gene therapy can in fact eradicate pre-existing anti-FVIII antibodies, induce immune tolerance, and provide long-term therapeutic FVIII expression to prevent bleeding. Herein, we review the accumulating evidence that continuous uninterrupted expression of FVIII and other transgenes after liver-directed AAV gene therapy can bias the immune system toward immune tolerance induction, discuss the current understanding of the immunological mechanisms of this process, and outline questions that will need to be addressed to translate this strategy to clinical trials.

Elimination of hepatitis C virus infection in patients with haemophilia in Belgium: A single-centre experience

INTRODUCTION

Patients with haemophilia are one of the subgroups with a high prevalence of hepatitis C virus (HCV) infection. They are a potential target group to eliminate HCV infection thanks to the availability of direct-acting antiviral (DAA) therapy.

AIM

To investigate the results of DAA therapy in a cohort of patients with bleeding disorders.

METHODS

This retrospective study was conducted between July 2018 and April 2019. All patients born before 1990 with haemophilia, von Willebrand factor Disease, factor V deficiency, factor VII deficiency or afibrinogenemia were included in this study.

RESULTS

Of 299 patients, 297 (99.3%) were tested for HCV antibody presence and 211 (71.0%) were positive. Of these, 205 (97.1%) were tested for HCV RNA and 153 (72.1%) were chronically infected. In total, 127 (83.0%) received antiviral therapy, and 110 (71.8%) patients were cured by antiviral treatment. The presence of cirrhosis was significantly higher in patients without a cure for HCV infection when compared to patients who achieved sustained virologic response by treatment or never infected (32.6% vs. 12.8% vs. 0%; P < .001). At the end of follow-up in 2019, only 14 (9.1%) patients had a remaining HCV infection. Ten (71.4%) were lost to follow-up, one (7.1%) patient refused, two (14.2%) had comorbidities and one (7.1%) will start treatment soon.

CONCLUSION

In this cohort, the elimination targets for HCV infection in 2030 as proposed by the World Health Organization were already reached. Nevertheless, in order to cure every patient, monitoring tools are necessary.

Haemophilia and ageing

Advances in the development of effective and safe treatments for haemophilia over the last 50 years have resulted in a significant increase in the life expectancy of persons with haemophilia (PWH). The management of this new cohort of middle-aged and elderly PWH is challenging because of the opposing risks of haemophilia and age-related cardiovascular disease and malignancy. Furthermore, this cohort of ageing PWH has the additional comorbidities of human immunodeficiency virus/hepatitis C and chronic haemophilic arthropathy. This article reviews the prevalence, underlying mechanisms and treatment strategies for managing these comorbidities. International collaboration is essential for registry data and further prospective trials to inform optimal evidence-based management for this rare disorder in the future.