Background/aims: Ganciclovir is a nucleoside analogue with an excellent safety record; it is effective against cytomegalovirus infection in both its intravenous and its oral form. Intravenous administration of ganciclovir is active against hepatitis B virus but the efficacy of oral ganciclovir is unknown. The aim of this study was to evaluate the tolerability and primary efficacy in reducing HBV DNA levels and liver enzymes of 2 dosing schedules of oral ganciclovir in HBeAg-positive and -negative patients with chronic hepatitis B.
Methods: Oral ganciclovir was administered to 15 consecutive patients with active chronic hepatitis B (age 43+/-12 years; 73% males; seven HBeAg-positive and eight negative; no cirrhosis) in a pilot, phase I, open-label study. Before treatment, all patients were screened for 8 weeks to ascertain the persistence of biochemical and virological activity, and then randomized to receive 3 g (eight patients), or 6 g (seven patients) of oral ganciclovir daily for 8 weeks; following therapy, they were closely observed for 8 more weeks.
Results: Baseline HBV DNA declined by 99% or 2 log10 at the end of treatment (405.0 vs 3.9 MEq/ml, respectively) and in four patients serum HBV DNA became undetectable by the Monitor assay. Oral ganciclovir suppressed HBV equally well in HBeAg-positive and -negative patients, and the 3- and 6-g daily dose regimens were equally effective. The pre-treatment viral load, however, was a determinant of response, with patients in the lowest quartile of baseline HBV DNA levels responding significantly better than those in the upper quartile (3.0 vs 0.6 log10 respectively, p=0.002). Serum alanine aminotransferase levels became normal or declined in most patients. Oral ganciclovir was very well tolerated. Within 8 weeks after stopping medication, a relapse in serum HBV DNA levels occurred in nine of the 15 patients (60%).
Conclusions: These findings suggest that ganciclovir administered orally at a dose of 3 g can achieve sufficient suppression of HBV replication. This dose, and even higher doses, are well tolerated and could be used as an alternative or in combination with other antivirals for the treatment of chronic hepatitis B.