TABLE 8.

Mutations conferring resistance to hepatitis B nucleos(t)ide antivirals

	Domain
Agent	A	B	C	D
Lamivudine	L80V/I	V173L, L180M	M204V/I/S
Adefovir		A181V/T		N236T
Entecavir†		I169T, T184G	S202I	M250V
Telbivudine			M204I
Tenofovir‡

^*The number refers to the amino acid position. The letters before the numbers represents the wild type amino acid. The letters after the number represents the substituted amino acid;

^†The entecavir mutations only confer resistance in the presence of the M204V, M204I and the L180M mutations. In the absence of these additional mutations the entecavir mutations do not cause resistance;

^‡After five years of continuous tenofovir therapy, there are no confirmed reports of tenofovir-resistant hepatitis B virus polymerase mutation