10119473 -VIROMARKERS HDV Biomarkers Study

This is an observational study, in which clinical data, samples, and any other procedures possibly already performed on participants, were performed within the scope of clinical practice or within the scope of otherwise authorized projects, and that therefore there are no procedures performed specifically for this study, which instead uses data collected previously or prospectively during an extended follow-up, but in any case within the scope of current clinical practice. Most participants have been enrolled and followed up at the project partners' clinical sites over 2023-2025. Their follow-up and sample collection will continue over the duration of the project. At the time of enrollment, demographics, medical history, medications and treatments prescribed were recorded and will be used in this study if the participant consent to be included also in VIROMARKERS. HDV genotypes/subgenotypes will be determined ex-novo on existing baseline stored samples.

The harmonization of HDV-RNA assays by utilizing standardized and validated flowcharts still represents a relevant diagnostic unmet clinical need for the appropriate monitoring of patients with CHD receiving BLV treatment. Furthermore, information on long-term virological response and factors predictive of virological outcome is scarce.

Specific primary objectives to characterise the response to bulevirtide in CHD include:

* To estimate the percentage of participants who will achieve virological response (defined as a decline in serum HDV RNA of \>2 log or to undetectable HDV-RNA) and the proportion achieving undetectable HDV-RNA at week 48, 96 and 144 weeks of BLV treatment. * To estimate the percentage of participants who will achieve biochemical response and combined response (defined as achievement of virological response and ALT normalization) at week 48, 96 and 144 weeks of BLV treatment. * To evaluate whether HDV-RNA levels at baseline or their kinetics during the first 12 weeks of BLV treatment can predict the achievement of undetectable serum HDV-RNA during BLV treatment.