Clinical and Pathophysiological Considerations Related to the Impact of Bulevirtide, a New Entry Inhibitor, in HBV-HDV Infection.

This review critically examines the inhibition of viral entry as an emerging disease-modifying strategy in chronic hepatitis B (HBV) and delta (HDV) virus infection, with particular emphasis on bulevirtide, the first-in-class of the sodium taurocholate cotransporting polypeptide entry inhibitor. This paper summarizes the analysis of 7 clinical trials that either underpinned the registration of bulevirtide or are important European real-life trials. We synthesize virological, pathophysiological and clinical evidence, highlighting the impact of this novel bulevirtide-based therapy on virological control, liver inflammation, fibrosis dynamics and long-term prognosis, as well as the limitations of this therapy. The observation of these trials is a greater than 2 log decrease from baseline in hepatitis D virus ribonucleic acid (HDV RNA) in 54-92% of patients and normalization of alanine transaminase (ALT) in 48.8-74% of patients after 23-144 weeks of treatment, and a significant decrease in liver fibrosis, as quantified by Fibroscan, at 12 months of treatment. The conclusion of the study is that this therapy represents an important leap in the etiological approach to chronic HDV infection and in improving the prognosis of these patients, but future clinical studies are needed to define the criteria for discontinuation of therapy, the long-term impact, as well as studies targeting new therapies that can intervene in other stages of the HDV and HBV life cycle not only to achieve HDV RNA negativity but also HBsAg clearance.