Real-world efficacy and safety of direct-acting antiviral drugs in patients with chronic hepatitis C and inherited blood disorders.

Background: Patients with inherited blood disorders (IBLD) have a high risk of hepatitis C virus (HCV) infection. The aim of this work was to assess the efficacy and safety of HCV direct-acting antiviral (DAA)-based treatment in patients with IBLD and chronic HCV infection.

Methods: Twenty-seven patients (25 with sickle cell disease, 1 with β-thalassemia and 1 with hemoglobin D-Punjab), including 3 with compensated cirrhosis, were included. They were treated with sofosbuvir in combination with ribavirin, daclatasvir, ledipasvir, or velpatasvir or with grazoprevir/elbasvir for 8 or 12 weeks. In the case of treatment failure, in-vitro assessment of resistance-associated substitutions (RASs) and full-length genome sequence analysis by means of deep sequencing were performed.

Results: Treatment was safe and well-tolerated and there were no drug discontinuations due to DAA-related adverse events. Twenty-five out of the 27 patients (93%) achieved sustained virological response 12 weeks post-treatment. One patient discontinued after 18 days due to adverse events unrelated to the antiviral treatment. One patient infected with 'unusual' genotype 2 subtype 2m relapsed. Subtype 2m naturally carries the NS5A L31M RAS. In a genotype 2a subgenomic replicon model, L31M increased daclatasvir effective concentration 50% (EC50) by 97-fold, but velpatasvir EC50 by only 3-fold, without altering the replication capacity. This patient was successfully retreated with sofosbuvir/velpatasvir for 12 weeks.

Conclusion: DAA-based regimens are well tolerated and highly efficacious in patients with chronic hepatitis C and IBLD in the real-world setting. Thus, DAA-based antiviral treatment should be prioritized in this thus far neglected population of HCV-infected patients.