A study to look at how safe different doses of an experimental medicine called ‘PD-L1 LNA’ was when given to people with long-term hepatitis B virus infection

The study will be conducted in one (or potentially two) parts, Part A and Part B. The study drug of interest, RO7191863, will be administered via subcutaneous injection at an appropriate body site, e.g. abdomen or upper thigh at a dose of up to 3 mg/kg body weight (BW). The administration site will be rotated so that the nature of any injection site reactions may be better understood.

Part A consists of 5 cohorts:
MAD1: 0.4 mg/kg RO7191863 x 3 doses over 7 weeks
MAD2: 1.2 mg/kg RO7191863 x 3 doses over 7 weeks
MAD3: 1.2 mg/kg RO7191863 x 3 doses over 5 weeks
MAD4: 1.2 mg/kg RO7191863 or placebo x 5 doses over 9 weeks
MAD5: Maximum of 3.0 mg/kg RO7191863 or placebo x 5 doses over 9 weeks
MAD5a (Potential cohort): RO7191863 x 5 doses over 9 weeks

The increase of doses (from 0.4 to 1.2 mg/kg, and from 1.2 to 3.0 mg/kg body weight, respectively) will be informed by the safety data of the completed cohorts.

This study consists of an optional sub-study, Fine Needle Aspirate (FNA) of the liver that may be offered to participants entering cohort MAD5 at one or more selected sites with established expertise. FNAs of the liver will be assessed to explore one or more intra-hepatic PD measures and potentially PK measures to explore the effects of RO7191863 in the target organ.

A further cohort (MAD5a, following the same dosing schedule as in MAD5) may be opened if required to allow for the inclusion of additional participants into the FNA sub-study.

Depending on the numbers enrolled in Part A of, e.g., female participants or HBeAg-positive participants, conduct of the corresponding optional Part B cohorts might be justified for the collection of additional safety data in these patient groups.

Part B (potential):
Two open-label MAD cohorts (MAD6, MAD7): anticipated dose level (3.0 mg/kg) once a week, ranging from 5 up to 12 doses.

Participants must discontinue study treatment if there is non-compliance with study requirements as judged by the Investigator and in consultation with the Sponsor.