Entecavir versus lamivudine for patients with HBeAg-negative chronic hepatitis B.

BACKGROUND: Entecavir is a potent and selective antiviral agent that has demonstrated efficacy in phase 2 studies in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. METHODS: In this phase 3, double-blind trial, we randomly assigned 648 patients with HBeAg-negative chronic hepatitis B who had not previously been treated with a nucleoside analogue to receive 0.5 mg of entecavir or 100 mg of lamivudine once daily for a minimum of 52 weeks. The primary efficacy end point was histologic improvement (a decrease by at least two points in the Knodell necroinflammatory score, without worsening of fibrosis). RESULTS: Histologic improvement after 48 weeks of treatment occurred in 208 of 296 patients in the entecavir group who had adequate baseline liver-biopsy specimens that could be evaluated (70 percent), as compared with 174 of 287 such patients in the lamivudine group (61 percent, P=0.01). More patients in the entecavir group than in the lamivudine group had undetectable serum hepatitis B virus (HBV) DNA levels according to a polymerase-chain-reaction assay (90 percent vs. 72 percent, P<0.001) and normalization of alanine aminotransferase levels (78 percent vs. 71 percent, P=0.045). The mean reduction in serum HBV DNA levels from baseline to week 48 was greater with entecavir than with lamivudine (5.0 vs. 4.5 log [on a base-10 scale] copies per milliliter, P<0.001). There was no evidence of resistance to entecavir. Safety and adverse-event profiles were similar in the two groups. CONCLUSIONS: Among patients with HBeAg-negative chronic hepatitis B who had not previously been treated with a nucleoside analogue, the rates of histologic improvement, virologic response, and normalization of alanine aminotransferase levels were significantly higher at 48 weeks with entecavir than with lamivudine. The safety profile of the two agents was similar, and there was no evidence of viral resistance to entecavir. (ClinicalTrials.gov number, NCT00035789.).

A comparison of entecavir and lamivudine for HBeAg-positive chronic hepatitis B.

BACKGROUND: Entecavir is a potent and selective guanosine analogue with significant activity against hepatitis B virus (HBV). METHODS: In this phase 3, double-blind trial, we randomly assigned 715 patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B who had not previously received a nucleoside analogue to receive either 0.5 mg of entecavir or 100 mg of lamivudine once daily for a minimum of 52 weeks. The primary efficacy end point was histologic improvement (a decrease by at least two points in the Knodell necroinflammatory score, without worsening of fibrosis) at week 48. Secondary end points included a reduction in the serum HBV DNA level, HBeAg loss and seroconversion, and normalization of the alanine aminotransferase level. RESULTS: Histologic improvement after 48 weeks occurred in 226 of 314 patients in the entecavir group (72 percent) and 195 of 314 patients in the lamivudine group (62 percent, P=0.009). More patients in the entecavir group than in the lamivudine group had undetectable serum HBV DNA levels according to a polymerase-chain-reaction assay (67 percent vs. 36 percent, P<0.001) and normalization of alanine aminotransferase levels (68 percent vs. 60 percent, P=0.02). The mean reduction in serum HBV DNA from baseline to week 48 was greater with entecavir than with lamivudine (6.9 vs. 5.4 log [on a base-10 scale] copies per milliliter, P<0.001). HBeAg seroconversion occurred in 21 percent of entecavir-treated patients and 18 percent of those treated with lamivudine (P=0.33). No viral resistance to entecavir was detected. Safety was similar in the two groups. CONCLUSIONS: Among patients with HBeAg-positive chronic hepatitis B, the rates of histologic, virologic, and biochemical improvement are significantly higher with entecavir than with lamivudine. The safety profile of the two agents is similar, and there is no evidence of viral resistance to entecavir. (ClinicalTrials.gov number, NCT00035633.).

Entecavir is superior to lamivudine in reducing hepatitis B virus DNA in patients with chronic hepatitis B infection.

BACKGROUND & AIMS: Entecavir is a novel and selective nucleoside analogue with potent activity against hepatitis B virus (HBV). METHODS: In a 24-week, double-blind, randomized, multicenter, phase II clinical trial, the safety and efficacy of entecavir (0.01 mg/day, 0.1 mg/day, or 0.5 mg/day orally) were compared with lamivudine (100 mg/day orally). Patients (n = 169) chronically infected with HBV (hepatitis B e antigen [HBeAg]-positive and -negative) were evaluated for efficacy. RESULTS: Compared with lamivudine, entecavir reduced HBV DNA by an additional 0.97 log(10) at the 0.1-mg/day dose and an additional 1.28 log(10) at the 0.5-mg/day dose (P < 0.0001). A clear dose-response relationship was observed for entecavir with the higher doses showing significantly greater viral suppression. In patients treated with entecavir 0.5 mg/day, 83.7% had an HBV-DNA level below the lower limit of detection of the Quantiplex branched DNA (bDNA) assay (Bayer-Versant Diagnostics, formerly Chiron Diagnostics, Emeryville, CA), compared with 57.5% treated with 100 mg/day lamivudine (P = 0.008). In both treatment arms, very few patients achieved HBeAg loss and/or seroconversion by week 22. More patients treated with the 0.1-mg/day and 0.5-mg/day doses of entecavir had normalization of alanine transaminase (ALT) levels at week 22 compared with lamivudine (P = not significant). Entecavir was well tolerated; most adverse events were mild to moderate, transient, and comparable in all study arms. CONCLUSIONS: This study showed that entecavir has potent antiviral activity against HBV at 0.1-mg/day and 0.5-mg/day doses, both of which were superior to lamivudine in chronically infected HBV patients.

Viral dynamics during and after entecavir therapy in patients with chronic hepatitis B.

BACKGROUND/AIMS: Nucleoside analogues inhibit hepatitis B virus (HBV) replication. Entecavir, a new guanine nucleoside, has also been shown to reduce covalently closed circular DNA (cccDNA) to undetectable levels in woodchucks chronically infected with hepatitis virus. Mathematical description of changes in viral load during and after therapy may help to understand the several events that take place during nucleoside analogue treatment. METHODS: Ten chronic hepatitis B patients were evaluated with a mathematical model during and after withdrawal of four doses of entecavir. Blood was drawn for HBV DNA measurement at frequent intervals. Non-linear modelling was used to fit individual patient data. RESULTS: The median effectiveness in blocking viral production is 96% (n=10, range 87-98%). The median half-life of viral turn-over was 16 h (range 12-29 h). The median half-life of infected hepatocytes was 257 h (=10.7 days) (n=9, range 112-762 h). Rebound of viral replication also followed a bi-phasic return to baseline levels. CONCLUSIONS: Decay and rebound of viral concentration during and after entecavir therapy, respectively, showed a bi-phasic pattern. Both can be described with a mathematical model. Data on levels of cccDNA in the liver in these patients could be helpful in supporting the parameters as calculated with the model.