The participants were already receiving a nucleoside reverse transcriptase inhibitor (NUC).

EDP-514 is a new class II oral HBV core inhibitor. Core inhibitors are known to act at various lifecycle stages of HBV, which leads to acute and chronic liver disease.

The double-blind, placebo-controlled Phase Ib study is the second part of a Phase Ia/Ib trial evaluating the safety, tolerability, pharmacokinetics (PK) and antiviral activity of EDP-514’s three different doses in 24 chronic HBV patients who are NUC-suppressed with either hepatitis B e-antigen (HBeAg)-positive or negative.

Trial subjects were randomly given 200mg, 400mg, and 800mg daily doses of EDP-514 or placebo for 28 days.

According to the trial data, EDP-514 was found to be safe and well-tolerated and demonstrated a PK profile that supports once-daily dosing.

Furthermore, after 28 days, EDP-514 provided a mean reduction in HBV ribonucleic acid (RNA) of 1log versus 0.3log with a placebo.

Enanta Pharmaceuticals senior vice-president and chief medical officer Nathalie Adda said: “These positive clinical trial results from the 200mg and 400mg cohorts are very encouraging and support the continued advancement of EDP-514 as a potential treatment for HBV.

“We are particularly encouraged by the emerging safety and tolerability profile of EDP-514 in combination with NUC treatment, which could provide a foundation for a combination therapy approach to achieve functional cures in patients with chronic HBV infection.”

The company noted that the 800mg cohort is progressing and the final trial results are expected to be reported soon.

According to results from Part 1 of the Phase Ia/Ib study, EDP-514 was well tolerated and had a favourable safety profile in healthy participants who were given single or multiple doses of the therapeutic for up to 14 days.