Monitoring the virus load can predict the emergence of drug-resistant hepatitis B virus strains in renal transplantation patients during lamivudine therapy

The development of resistant hepatitis B virus (HBV) strains during lamivud ine treatment has been described repeatedly. To investigate whether the dev elopment of such resistant HBV strains can be predicted in an early phase o f therapy, the HBV loads of 11 renal transplantation patients were screened at 3-month intervals by a quantitative HBV polymerase chain reaction (PCR) assay. Lamivudine resistance was detected by sequence analysis. Five patie nts developed resistance to lamivudine in the 12-15-month follow-up period. In all of them, a virus load of 1 x 10(3) HBV DNA copies still was detecta ble after 3 months of therapy. This was statistically significantly differe nt from those patients who did not develop lamivudine resistance within the observation period, all of whom had no HBV DNA detectable after 3 months o f treatment (P = .0022). Thus, virus load testing by use of a sensitive PCR assay allows the early prediction of the emergence of lamivudine-resistant HBV strains.