Safety, antiviral activity and pharmacokinetics of JNJ-64530440, a novel capsid assembly modulator, as 4 week monotherapy in treatment-naive patients with chronic hepatitis B virus infection

Objectives We investigated JNJ-64530440 (a hepatitis B virus capsid assembly modulator) safety, antiviral activity and pharmacokinetics in patients with chronic hepatitis B (CHB) (Phase 1b, NCT03439488). Methods Twenty treatment-naive, HBeAg-positive or -negative CHB patients were randomized 4:1 to JNJ-64530440 750 mg once or twice daily, or placebo for 28 days. Results All patients (mean age 43.8 years; 85% male; 70% White; 20% HBeAg positive) completed dosing/28 day follow-up. Mild-to-moderate treatment-emergent adverse events occurred in 3/4 (placebo), 6/8 (once-daily) and 4/8 (twice-daily) patients; mostly fatigue, increased alanine aminotransferase, decreased neutrophil count, and headache. Hepatitis B virus (HBV) DNA was substantially reduced; mean (range) changes from baseline at day 29 were: −3.2 (−2.4 to −3.9) (once-daily) and −3.3 (−2.6 to −4.1) (twice-daily) log10 IU/mL; placebo 0.1 (0.7 to −0.6) log10 IU/mL. HBV DNA levels were below the lower limit of quantification (LLOQ) in 5/8 (once-daily) and 3/8 (twice-daily) patients. For patients with detectable baseline HBV RNA, mean (SE) changes versus baseline in HBV RNA at day 29 were: −2.65 (0.81) (once-daily) and −2.94 (0.33) (twice-daily) log10 copies/mL. HBV RNA levels were ‘target not detected’ in 4/6 (once-daily) and 3/7 (twice-daily) patients. JNJ-64530440 pharmacokinetics in CHB patients were comparable with those in healthy volunteers. Conclusions JNJ-64530440 750 mg once-daily or twice-daily for 28 days was well tolerated and achieved potent antiviral activity in CHB patients.