Retrospective and prospective, pharmacological, multicentre, non-profit observational study.

Consecutive patients with HDV-related compensated cirrhosis starting Bulevirtide 2 mg/day from September 2019 to December 2025 will be enrolled in the study.

Aim of this study is to investigate virological and clinical effectiveness of Bulevirtide 2 mg/day in patients with HDV-related compensated cirrhosis in the real-life setting.

Primary endpoint of the study is the rate of virological response, defined as at least 2 Log decline or undetectable HDV RNA compared to baseline, at week 96 of treatment.

Inclusion Criteria:

• Age≥18 years
• HDV-related compensated cirrhosis defined by positivity of HDV RNA for at least 6 months and clinical or laboratory or histological diagnosis of cirrhosis
• Started treatment with BLV monotherapy between September 1st 2019 and 2025

Exclusion Criteria:

• Chronic hepatitis without any evidence of cirrhosis
• Decompensated cirrhosis
• PegIFN alpha therapy

The study will enrol patients with chronic HDV infection (defined by HDV RNA positivity for at least 6 months) who started or will start BLV 2 mg/day during the study period at the S.C. Gastroenterology and Hepatology (Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico) and at participating centers, and who meet the inclusion criteria and do not present any of the exclusion criteria. The decision to treat patients with BLV is determined based on the clinical judgment of the treating physicians prior to study enrolment.