In a double-blind study in CHB patients with YMDD variant HBV and compensated liver disease (NUC20904), with a reduced virological and biochemical response to lamivudine (n=95), the addition of adefovir dipivoxil 10 mg once daily to ongoing lamivudine 100mg for 52 weeks resulted in a median decrease in HBV DNA of 4.6 log10 copies/ ml compared to a median increase of 0.3 log10 copies/ ml in those patients receiving lamivudine monotherapy.