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The aims of the study were to investigate the efficacy of rescue therapy with lamivudine (LAM) and adefovir (ADV) combination for 6 months followed by ADV monotherapy in lamivudine-resistant chronic hepatitis B (LAM-R CHB) patients, and to analyze the frequency of ADV resistance mutant development in such patients. A total of 170 consecutive LAM-R CHB patients (male/female: 130/40, mean age: 42.9+/-13.4 years) with viral breakthrough under LAM therapy were analyzed. A total of 68 had HBeAg-positive. Patients received rescue therapy with LAM [100 mg (qd)]+ADV [10 mg (qd)] for 6 months after which LAM was discontinued. HBV-DNA was assessed with the HBV-DNA 3.0 bDNA assay. ADV-resistant mutations were identified by sequencing the reverse transcriptase region. The median duration of rescue therapy was 24 months. Cumulative probability of becoming HBV-DNA undetectable was 33.8%, 59.6% and 68.2% after 24, 48 and 96 weeks of treatment, respectively. These figures were 43.2%, 58.0% and 73.1% for ALT normalization. Among 68 HBeAg-positive CHB patients, 10 patients had an e-antigen seroconversion. Low baseline HBV-DNA level (<10(7) copies/mL) was a significant predictor of response to ADV treatment (P<0.01). Cumulative probability of ADV resistance was 1.2%, 15.1% and 37.3% at 12, 24 and 36 months of therapy, respectively. By multivariate analysis, baseline high viral load and primary nonresponse to treatment at week 24 predicted ADV resistance. The data indicate that a time limited add-on strategy does not provide benefit over the switch strategy with respect emergence of ADV resistant mutants in LAM-R CHB patients.

Background: Pegylated interferon alpha2b (PEG-IFN-alpha(2b) is effective for the treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, although its mechanism of action remains unclear. HBeAg loss is achieved in 36% of patients after one year of PEG-IFN-alpha2b treatment and combination therapy with lamivudine is not superior to PEG-IFN-alpha2b monotherapy., Methods: Early pharmacokinetics and viral kinetics were analysed in patients treated for 52 weeks with PEG-IFN-alpha2b with or without lamivudine., Results: After 4 weeks of treatment, there was a median viral decline of 2.94 log10 copies/ml in those treated with PEG-IFN-alpha2b and lamivudine and only 0.45 log10 copies/ml in the PEG-IFN-alpha2b monotherapy group. Peak PEG-IFN-alpha2b levels were reached approximately one day after administration and subsequently declined exponentially, consistent with a viral load rebound near to baseline levels at the end of the dosing period in most patients receiving PEG-IFN-alpha2b monotherapy. Modelling of pharmacokinetics and viral kinetics data in this group revealed that viral load was minimal 3.6 days after PEG-IFN-alpha2b administration, the mean maximal and mean antiviral effectiveness was 70% and 48% with a mean infected cell loss rate of 0.07 per day, while no significant biphasic decline was observed., Conclusions: PEG-IFN-alpha2b induces a sustained response in a considerable number of patients despite limited direct antiviral activity during the first weeks of antiviral therapy.

Objectives: Antiviral therapy leads to HBeAg seroconversion in 10-40% of the patients with HBeAg-positive chronic hepatitis B. Nonresponse may result in progression of liver disease and increased risk of hepatocellular carcinoma. As part of a global randomized controlled trial we investigated the efficacy (i.e., loss of HBeAg at the end of follow-up) of peginterferon alfa-2b (Peg-IFN alpha2b) in patients who failed to respond to previous courses of standard interferon (IFN) or lamivudine., Methods: We analyzed a total of 76 previous nonresponders: 37 were nonresponders to standard IFN, 17 were nonresponders to lamivudine, and 22 were nonresponders to both therapies. All patients received a 52-wks course of 100 microg Peg-IFN alpha2b weekly combined with either 100 mg lamivudine daily or a placebo. After therapy patients were followed for 26 wks., Results: Thirteen (35%) nonresponders to previous IFN, five (29%) nonresponders to previous lamivudine, and four (22%) nonresponders to both IFN and lamivudine responded to treatment with Peg-IFN alpha2b. No difference in response was found for those treated with Peg-IFN alpha2b alone or in combination with lamivudine. Nonresponders to prior IFN therapy with baseline ALT (alanine aminotransferase) > 4 x ULN (upper limit of normal) responded better to Peg-IFN alpha2b than those with ALT levels

Background/aims: Lamivudine is effective in treatment-naive patients with chronic hepatitis B, but its role in interferon nonresponders has not been described. We assessed lamivudine treatment, with or without added interferon, in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B who had failed interferon therapy previously., Methods: Patients were randomized to lamivudine (100 mg) or placebo for 52 weeks or to a 24-week regimen of lamivudine plus interferon. Primary treatment comparisons were at week 52, with a 16-week posttreatment follow-up period. Measurements included histology (primary endpoint), HBeAg response, normalization of alanine aminotransferase, reduction of hepatitis B virus (HBV) DNA, and safety., Results: Among 238 patients, histologic response was significantly more common in patients treated with lamivudine (52 versus placebo 25%, P=0.002) or the combination regimen (32%, P=0.01). HBeAg loss was also more common with lamivudine (33 versus 13 versus 21%), as were virologic and alanine aminotransferase responses. Among 28 subjects with HBeAg loss/seroconversion, 71% had durable responses 16 weeks posttreatment., Conclusions: Lamivudine for 52 weeks is as effective in interferon nonresponders as in previously reported treatment-naive patients; however, a combination of lamivudine for 24 weeks and interferon for 16 weeks was not effective in this population.

Forty subjects with chronic hepatitis B and hepatitis B e antigen (HBeAg) seroconversion following lamivudine therapy in previous trials were monitored after treatment to assess the durability of serologic responses. Patient follow-up began a median of 4.3 months after completion of therapy in previous trials. At months 2, 4, 6, 9, and 12 of year 1, and every 6 months thereafter, we tested for HBeAg and hepatitis B surface antigen (HBsAg), hepatitis B virus (HBV) DNA, and alanine aminotransferase (ALT). After a median (range) of 36.6 (4.8-45.6) months of follow-up monitoring, HBeAg seroconversion was demonstrated at the last visit by 77% (30 of 39) of patients. In a post hoc analysis of a slightly different population of all 65 patients with HBeAg seroconversion in previous trials, the 3-year durability of HBeAg seroconversion measured from the time immediately after discontinuing lamivudine therapy was 64%. Nine (9 of 40, 23%) patients were HBsAg negative at the last assessment. Seventy-four percent (17 of 23) of patients with baseline undetectable HBV DNA and normal ALT maintained these responses at the last visit. Eight patients (8 of 40, 20%) initiated retreatment for reappearance of HBV markers, and 7 showed biochemical and/or virologic improvement (including regained HBeAg seroconversion in 2). No safety issues of concern emerged. In conclusion, most HBeAg responses achieved during lamivudine therapy were durable, and most responders experienced prolonged clinical benefit after HBeAg seroconversion and subsequent discontinuation of lamivudine. Lamivudine retreatment for reappearance of hepatitis B markers can achieve resumption of viral suppression.