A randomized, double-blind, phase 3, non-inferiority trial of pradefovir mesylate versus tenofovir disoproxil fumarate in Chinese patients with chronic hepatitis B

BACKGROUND AND AIMS: Pradefovir mesylate is a novel liver-targeting prodrug of adefovir developed using HepDirect technology. We report that the phase 3 trial is to compare the efficacy and safety of pradefovir versus tenofovir disoproxil fumarate (TDF) in patients with chronic hepatitis B (CHB). APPROACH AND RESULTS: This ongoing randomized, double-blind, non-inferiority, phase 3 study was conducted at 58 sites in China. Patients with CHB were randomly assigned (2:1) to receive either 45 mg daily pradefovir or 300 mg daily TDF with a matching placebo. The primary efficacy endpoint was defined as the proportion of patients whose HBV DNA level was <29 IU/mL at week 48. All participants who received at least 1 dose of the study drug were included in efficacy and safety analyses with pre-specified renal and bone endpoints at week 96. A total of 1170 patients were screened during the study, and 908 patients received the study drug. At week 48, viral suppression (HBV DNA <29 IU/mL) rates of pradefovir were non-inferior to TDF in HBeAg-positive [-1.8% (95% CI: -9.7 to 6.1)] and HBeAg-negative [2.6% (95% CI: -5.1 to 10.3)] patients, using a non-inferiority margin of -12%. By week 96, HBeAg-positive patients showed significantly greater HBsAg decline (≥1 log 10 IU/mL) with pradefovir (39.3% vs. 29.9%). Pradefovir demonstrated a more favorable safety profile at week 96, including significantly fewer drug-related adverse events (58.6% vs. 71.9%), improved bone/renal safety, and a lower incidence of elevated creatine phosphokinase-MB. CONCLUSIONS: Pradefovir should be a highly recommended treatment option for adult patients with CHB.