HBV precore mutants and response to interferon

Relationship of genotypes of hepatitis B virus to mutations, disease progression and response to antiviral therapy

Phylogenetic analysis has led to the classification of hepatitis B virus into eight genotypes, designated A to H. The genotypes have differences in biological properties and show heterogeneity in their global distribution. These attributes of the genotypes may account not only for differences in the prevalence of hepatitis B virus mutants in various geographic regions, but also be responsible for differences in the clinical outcome and response to antiviral treatment in different population groups.

Lamivudine does not increase the efficacy of interferon in the treatment of mutant type chronic viral heaptitis B

AIM: To study the role of lamivudine in improving the efficiency of interferon for the treatment of mutant type chronic hepatitis B.

METHODS: Fifteen patients with mutant type chronic hepatitis B were prospectively studied. All patients had liver histology and serology to prove the diagnosis of chronic hepatitis B. Each patient received 4.5 millionunits of interferon alpha-2a thrice weekly and 100 mg of oral lamivudine daily for 24 wk. Patients were observed and tested for blood chemistry every week for the initial 4 wk and every 2 wk thereafter during the treatment until 24 wk. After the end of treatment, patients were followed up at 4-week intervals for an additional 6 mo. Serum HBV DNA levels were tested using the liquid phase molecular hybridization assay. Those with non-detectable HBV DNA were also tested using the real-time polymerase chain reaction. One patient, who did not finish treatment due to depression, was excluded.

RESULTS: At the end of treatment, 7 (50%) patients had serum ALT levels within normal limits; 12 (86%) patients had serum HBV DNA levels < 5 pg/mL using the liquid phase molecular hybridization assay, but only 8 (67%) were < 20 copies/dL using the real-time polymerase chain reaction. Six months after treatment, only two (14%) patients had a sustained complete response to the combination therapy with serum ALT level < 35 iu/L and undetectable serum HBV DNA levels.

CONCLUSION: These pilot data showed that lamivudine did not increase the efficacy of interferon in the treatment of mutant type chronic hepatitis B. The liquid phase molecular hybridization assay was not sensitive enough to detect the low HBV DNA levels during combined interferon and lamivudine therapy.