Does treatment of hepatitis B virus (HBV) infection reduce hepatitis delta virus (HDV) replication in HIV-HBV-HDV-coinfected patients?

Background: Hepatitis delta virus (HDV) has a unique replication process that requires coinfection with hepatitis B virus (HBV). Treatment is currently limited to interferon therapy. The role of potent nucleos(t)ide analogues active against HBV has not been well examined in chronic delta hepatitis (CDH). Methods: HIV-positive patients with CDH attending our hospital were identified and longitudinally studied. Serum HBV DNA, HDV RNA and HIV RNA, treatment regimens, and biochemical and serological markers were assessed at yearly intervals. Liver fibrosis was measured by transient elastography during the last 2 years. Results: Sixteen patients were identified and treated with anti-HBV therapy (median time 6.1 years). The majority were male and previous intravenous drug users. Median baselines were: HDV RNA 7 log10 copies/ml, HIV RNA 1.7 log10 copies/ml, HBV DNA 1.1 log10 IU/ml and alanine aminotransferase (ALT) 98 IU/ml. A significant correlation was found between HDV RNA and HBV DNA (r=0.226, P=0.015), aspartate aminotransferase (r=0.430, P<0.0001), ALT (r=0.441, P<0.0001) and hepatitis B surface antigen (HBsAg) (r=0.557, P<0.0001). Overall, 13 patients showed a reduction in HDV viraemia and ALT levels, and three of them achieved undetectable HDV RNA and normal ALT levels. Conclusion: Patients undergoing successful anti-HBV therapy with potent nucleos(t)ide analogues seem to indirectly benefit from suppression of HDV replication, albeit not very efficiently. Hypothetically, a significant and sustained reduction in serum HDV RNA might only be seen when a reduction in HBV covalently closed circular DNA or HBV surface antigen is achieved, which may require long periods of successful anti-HBV therapy. To our knowledge, this is the first evidence of the benefit of potent anti-HBV nucleos(t)ide analogue therapy in CDH.