[Evaluation of a quantitative HBV-DNA PCR assay in lamivudine treated hepatitis B-infected patients]

Lamivudine (3TC) is a nucleoside analogue which inhibits replication of HIV and HBV and which is used in the treatment of chronic hepatitis B-infected patients with safety and efficacy. The activity of lamivudine was evaluated by the measurement of DNA-HBV concentration in plasma using a very sensitive assay (1,000 copies/mL) (Amplicor VHB Monitor. Roche). Ten patients chronically infected with hepatitis B (group A) and 24 patients with HIV-1 co-infection (group B) were enrolled. In 9 patients of group A, HBVDNA load was undetectable a median of 3.5 months after the beginning of treatment and remained negative for 2 years with hepatitis Be antigen disappearing and normal alanine aminotransferase concentration. In the last immunodeficient patient, the virus which had been resistant to three interferon treatments, was also resistant to lamivudine. In five patients of group B, HBV DNA load remained undetectable after 18 months with HBe antigen disappearing and baseline concentration of alanine aminotransferase. In the remaining 19 patients after a transient decrease of HBV DNA concentration for one year, HBV DNA load increased again without disappearing of HBe antigen and without decrease of alanine aminotransferase concentration showing lamivudine resistant hepatitis B virus. Mutations in the YMDD motif of the DNA polymerase gene were identified in 11 patients (3 with M550V/I mutation; 7 with M550V/I and L256M mutations; 1 with M550V/I, L526M and V519L mutations). In 6 of these patients, was found a M184V mutation in the VIH polymerase. No correlation could be observed between the mutations detected in the two viruses. Using a sensitive HBV-DNA assay, efficacy of lamivudine for a long time in HBV infected patients was proved. However, the prevalence of lamivudine resistance is related to duration of treatment and it may be necessary to use a multitherapy.