Significance of viral load, core promoter/precore mutations and specific sequences of polymerase gene in HBV-infected patients on 3-year lamivudine treatment.

BACKGROUND: Comprehensive study on viral factors predicting treatment responsiveness to lamivudine is lacking. AIMS: To define the significance of various viral factors and changes of viral population with lamivudine treatment. PATIENTS AND METHODS: Hepatitis B virus (HBV) DNA levels at baseline, week 24, 52 and year 3 were measured in 80 patients on continuous lamivudine therapy for 3 years. Genotypes, core promoter/precore mutations, YMDD mutations, polymorphic sequence of polymerase gene (rt91 I/L, rt256S/C) were determined at baseline, week 12, 24 and 52. YMDD mutations were also determined at year 3. RESULTS: High alanine aminotransferase levels and presence of core promoter/ precore mutations at baseline were associated with higher chance of achieving HBV DNA <1,000 copies/ml (good response) and higher rate of hepatitis Be antigen (HBeAg) seroconversion at week 52. Achieving HBV DNA levels <1,000 copies/mi at week 24 as well as baseline core promoter/precore mutations were associated with higher chance of achieving good response, higher rate of HBeAg seroconversion and lower rate of YMDD mutations at year 3. Lamivudine reversed core promoter mutations to wild type in 25% of patients. All 5 patients with rt256C had poor HBV DNA response, persistent HBeAg and YMDD mutations by year 3. There was no difference in treatment response between patients with genotype B and C. CONCLUSIONS: Achieving HBV DNA levels <1,000 copies/ml at 24 week is the best target for short- and long-term treatment efficacy. Core promoter and precore mutations were associated with better treatment outcome, and rt256C polymorphism in the polymerase gene with poor response.

Evolution of primary and compensatory lamivudine resistance mutations in chronic hepatitis B virus-infected patients during long-term lamivudine treatment, assessed by a line probe assay.

With the availability of more potent nucleotide/nucleoside analogues, the early detection of drug-resistant mutants of hepatitis B virus (HBV) is important for the strategic treatment of chronic hepatitis B. We studied 336 serum samples from 80 patients chronically infected with HBV who were receiving lamivudine treatment for the presence of lamivudine resistance mutations at codons 80, 173, 180, and 204 of the HBV polymerase. The sequencing data were compared with the results generated with the INNO-LiPA HBV DR (drug resistance) v2 strip, a line probe assay (LiPA) covering wild-type and mutant motifs, for resistance mutations to lamivudine and adefovir dipivoxil. This method provided at least the same information as sequencing for 99.1% of all codons analyzed. On the basis of the LiPA results, 20 of 80 patients developed a lamivudine resistance mutation after 1 year. In all 20 patients, the mutation occurred in the YMDD motif at reverse transcriptase position 204 (rt204; M204V/I) either with or without the compensatory mutation at position rt180 (L180M). A compensatory mutation at position rt80 (L80V/I) was detected in half of these patients. After 36 months, a compensatory mutation was seen at position rt173 (V173L) in 3/15 patients. Time-to-event survival analysis indicated a 2.8 times greater chance for LiPA to detect a given mutation than sequencing at any moment in time (hazard ratio, 2.8, 95% confidence interval, 1.79, 4.41; P < 0.0001). These results demonstrate that a highly sensitive and specific assay such as the INNO-LiPA HBV DR v2 can precociously detect and monitor the emergence of primary and compensatory lamivudine resistance mutations in patients chronically infected with HBV and is more sensitive than sequencing.

Sensitive line probe assay that simultaneously detects mutations conveying resistance to lamivudine and adefovir.

The INNO-LiPA HBV DR v2 assay is designed to detect hepatitis B virus mutations conveying resistance to lamivudine and adefovir. Our study confirms that this assay can simultaneously detect the presence of lamivudine and adefovir resistance mutations in clinical samples, has a high degree of concordance with sequencing, and can detect mutants earlier.