RO7049389

The objectives of this phase I study are to assess the safety, tolerability, and pharmacokinetics (PKs) of RO7049389 in healthy Chinese volunteers (HVs) and evaluate potential ethnic differences in the safety and PKs using data from this study and the first‐in‐human study (in which most of the HVs were non‐Asian). HVs randomly received a single dose of 200–600 mg of RO7049389 or a placebo in a single ascending dose (n = 28) or multiple doses of 200–400 mg of RO7049389 or a placebo in multiple ascending doses (n = 24). Safety and tolerability were monitored throughout the study. Serial blood samples were collected for PK analysis. RO7049389 was safe and well‐tolerated in the HVs. The time to maximum concentration ranged from 1.5 to 3.0 h, and terminal half‐life ranged from 3.66 to 14.6 h. A single dose of 200–600 mg and multiple doses of 200–400 mg exhibited nonlinear PKs. In general, the safety profiles were comparable between non‐Asian and Asian HVs, but the plasma exposure of RO7049389 in Chinese HVs was higher than that in non‐Asian HVs. The data generated from this study will provide guidance for future clinical studies on RO7049389 in Chinese/Asian patients with hepatitis B virus.

RO7049389, a hepatitis B virus (HBV) core protein allosteric modulator being developed for the treatment of chronic HBV infection, was found to be safe and well tolerated in healthy participants (part 1 of this study). The objective of this proof-of-mechanism study (part 2) was to evaluate the safety, pharmacokinetics, and antiviral activity of RO7049389 in patients with chronic HBV infection.

This was a multicentre, randomised, placebo-controlled, phase 1 study. Patients with chronic HBV infection who were not currently on anti-HBV therapy were enrolled at 11 liver disease centres in Hong Kong, New Zealand, Singapore, Taiwan, and Thailand. Seven patients per dose cohort were randomly assigned (6:1) to receive oral administration of RO7049389 at 200 mg or 400 mg twice a day, or 200 mg, 600 mg, or 1000 mg once a day, for 4 weeks, or matching placebo. Randomisation was via interactive voice web response system-generated numbers, with study participants, investigators, and site personnel masked to treatment allocation. The primary endpoint of the study was safety of RO7049389 and its antiviral effect on HBV DNA concentration at the end of treatment, assessed in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT02952924.

Between May 21, 2017, and April 3, 2019, 62 patients were screened for eligibility, and 37 eligible patients were enrolled in five dose cohorts sequentially. All adverse events were of mild or moderate intensity. Among the 31 patients who received RO7049389, the most common adverse events were headache (in five [16%] of 31 patients), increased alanine aminotransferase (ALT; five [16%]), increased aspartate aminotransferase (AST; four [13%]), upper respiratory tract infection (four [13%]), and diarrhoea (three [10%]). The most common moderate adverse events were ALT increase (three [10%]) and AST increase (two [6%]), and there were no serious adverse events. At the end of 4 weeks treatment, mean HBV DNA declines from baseline in RO7049389-treated patients were 2·44 log₁₀ IU/mL (SD 0·98) in the 200 mg twice a day group, 3·33 log₁₀ IU/mL (1·14) in the 400 mg twice a day group, 3·00 log₁₀ IU/mL (0·54) in the 200 mg once a day group, 2·86 log₁₀ IU/mL (0·79) in the 600 mg once a day group, and 3·19 log₁₀ IU/mL (0·33) in the 1000 mg once a day group versus 0·34 log₁₀ IU/mL (0·54) in the pooled placebo patients.

RO7049389 was safe and well tolerated and demonstrated antiviral activity over 4 weeks of treatment in patients with chronic HBV infection. These findings support further clinical development of RO7049389 as a component of novel combination treatment regimens for patients with chronic HBV infection.

F Hoffmann-La Roche.