Clinical Data Safety and Efficacy of GS-4774 in combination with TDF in Patients with Chronic Hepatitis B not on Antiviral Medication

Results: Baseline demographics were similar across all groups. The mean age of patients was 43 to 46 years and 59-67% were men. The majority (74-89%) of patients was Asian, 37-41% were HBeAg positive, the mean baseline HBV DNA was 5.8-6.0 log10 IU/mL and the mean baseline HBsAg was 3.7-3.8 log10 IU/mL. Grade 3 or 4 adverse events (AEs) occurred in 7.7% of GS-4774 treated patients. There were no treatment discontinuations due to AEs and no serious AEs related to the study drug. Injection site reactions were the most frequent AE, occurring in up to 86% of subjects in the 40 YU arm. Grade 3-4 ALT elevations were seen in 3% of GS-4774 treated subjects. No significant differences in mean HBsAg changes were seen at Week 24 between GS-4774 groups and the TDF group (Panel A), though more patients in the GS-4774 groups had >0.5 log10 reductions in HBsAg at Week 24 (Panel B). Predictors for having a >0.5 log10 IU/mL reduction in HBsAg by Week 24 include younger age, higher baseline HBV DNA level and lower baseline HBsAg level. No patients achieved HBsAg loss by Week 24. Full 48 week results will be presented. Conclusions: GS-4774 in combination with TDF was safe and well-tolerated in CHB patients,Reductions in HBsAg were modest and only observed in patients treated with GS-4774.