Safety, tolerability, pharmacokinetics, and antiviral activity of the novel core protein allosteric modulator ZM-H1505R (Canocapavir) in chronic hepatitis B patients: a randomized multiple-dose escalation trial.

BACKGROUND: Hepatitis B virus (HBV) core protein-targeting antivirals (CpTAs) are promising therapeutic agents for treating chronic hepatitis B (CHB). In this study, the antiviral activity, pharmacokinetics (PK), and tolerability of ZM-H1505R (Canocapavir), a chemically unique HBV CpTA, were evaluated in patients with CHB. METHODS: This study was a double-blind, randomized, placebo-controlled phase 1b trial in Chinese CHB patients. Noncirrhotic and treatment-naive CHB patients were divided into three cohorts (10 patients per cohort) and randomized within each cohort in a ratio of 4:1 to receive a single dose of 50, 100, or 200 mg of Canocapavir or placebo once a day for 28 consecutive days. RESULTS: Canocapavir was well tolerated, with the majority of adverse reactions being grade I or II in severity. There were no serious adverse events, and no patients withdrew from the study. Corresponding to 50, 100, and 200 mg doses of Canocapavir, the mean plasma trough concentrations of the drug were 2.7-, 7.0-, and 14.6-fold of its protein-binding adjusted HBV DNA EC50 (135 ng/mL), respectively, with linear PK and a low-to-mild accumulation rate (1.26-1.99). After 28 days of treatment, the mean maximum HBV DNA declines from baseline were -1.54, -2.50, -2.75, and -0.47 log10 IU/mL for the 50, 100, and 200 mg of Canocapavir or placebo groups, respectively; and the mean maximum pregenomic RNA declines from baseline were -1.53, -2.35, -2.34, and -0.17 log10 copies/mL, respectively. CONCLUSIONS: Canocapavir treatment is tolerated with efficacious antiviral activity in CHB patients, supporting its further development in treating HBV infection. TRIAL REGISTRATION: ClinicalTrials.gov, number NCT05470829).

Safety, Tolerability, and Pharmacokinetics of a Novel Human Hepatitis B Virus Capsid Assembly Modulator Canocapavir: A Randomized First-in-Human Study.

Background and Aims: Canocapavir (ZM-H1505R) is a small-molecule hepatitis B virus capsid assembly modulator with a novel pyrazole structure. This is the first-in-human study to investigate its safety, tolerability, and pharmacokinetics (PK) following oral administration in healthy subjects. Methods: This was a randomized, double-blind, placebo-controlled study including single ascending dose (SAD) study with an additional crossover food-effect arm, and multiple ascending dose study. In SAD, 40 subjects, 8 in each cohort, were randomized in a 3:1 ratio to receive a single dose of 25, 75, 150, 300, and 450 mg of Canocapavir or placebo in fasted state. For food-effect study, subjects in the 150 mg cohort of SAD received a second dose (150 mg) of Canocapavir in the fed state after a 7-day washout period. In multiple ascending dose, 24 subjects, 8 in each cohort, were randomized in a 3:1 ratio to receive 75, 150, and 300 mg of Canocapavir or placebo once daily for 14 days. The safety and tolerability were assessed using vital signs, physical evaluation, electrocardiogram, laboratory investigations, and adverse events (AEs). Plasma PK parameters measured included area under the curves, Cmax, Cmin, Tmax, and T1/2. Results: Oral administration of single doses (25-450 mg) and multiple doses (75-300 mg) of Canocapavir was well tolerated. The most common AE seen was increased alanine aminotransferase. No dose dependency was observed in incidence and intensity of AEs. Mean plasma area under the curve and Cmax of Canocapavir increased dose-proportionally. A significant margin was observed between plasma exposure of Canocapavir and its in vitro anti-hepatitis B virus activity. Food had an effect on its absorption. Conclusion: The safety and PK profile of Canocapavir support its further evaluation in chronic hepatitis B patients. The study was registered on ClinicalTrial.gov with the number NCT04220801.