Clinical trial: A phase II, randomized study evaluating the safety, pharmacokinetics and anti-viral activity of clevudine for 12 weeks in patients with chronic hepatitis B

Abstract

Background: Clevudine is a polymerase inhibitor that has the unusual feature of delayed viral rebound after therapy in some patients which may be related to its pharmacokinetics. Aim: To characterize pharmacokinetic and pharmacodynamic profile of clevudine, a potent hepatitis B polymerase inhibitor. Methods: A multicenter, randomized study comparing 10, 30 and 50 mg clevudine once daily for 12 weeks with 24 weeks off-treatment follow-up. Patients had chronic HBV infection, were nucleoside-naïve without co-infection. HBV viral load (VL) was assayed using Digene Hybrid Capture II with a lower limit of detection of 4700 copies/mL (940 IU/mL). Clevudine levels were measured using a liquid chromatography/mass spectrometery method. Results: A total of 31 patients were enrolled into the 10 mg (n = 10), 30 mg (n = 11) and 50 mg (n = 10) groups, respectively. At week 12, the median VL change was -3.2, -3.7 and -4.2 log10 copies/mL (-0.64, -0.74 and -0.84 log10 IU/mL) in the 10, 30 and 50 mg groups, respectively (P = 0.012). At week 12, one of 10, five of 11 and two of 10 patients had VL below the assay lower limit of detection. Clevudine was well tolerated with no severe/serious adverse events. The mean plasma half-life of clevudine was 70 h and consequently is not the cause of the delayed viral rebound seen in some patients. Through modelling, 97% of the maximal treatment effect was reached with a 30 mg daily dose. Six patients had genomic changes without viral rebound. Conclusion: Clevudine appears to be a potent and tolerable (over 12 weeks) anti-viral and the optimal dosage appears to be 30 mg once daily. © 2008 The Authors.