Patent ID: 7186700

Claim:
A method for the treatment of a host infected with a drug-resistant form of HBV that exhibits a mutation at the 552 codon from methionine to valine in the DNA polymerase region, comprising administering an effective amount of a compound of the formula (I): or a pharmaceutically acceptable salt, ester or prodrug thereof, to the host wherein: R 1 and R 2 are independently hydrogen, straight chained, branched or cyclic alkyl, acyl, acetyl, butyryl, CO-alkyl, CO-aryl, CO-alkoxyalkyl, CO-aryloxyalkyl, CO-substituted aryl, alkylsulfonyl, arylsulfonyl, aralkylsulfonyl, amino acid residue, mono, di, or triphosphate, or a phosphate derivative; X is O; and BASE is a thymine or cytosine.