Lamivudine-resistant human immunodeficiency virus type 1 variants (184V) require multiple amino acid changes to become co-resistant to zidovudine in vivo.
Originally Published on January 1, 1997
Nijhuis M; Boucher CA; de Groot T; Keulen W, Danner S; Lange J; van Leeuwen R; de Jong D; Schuurman R.
Journal of Infectious Diseases. 1997; 176:398-405. (97379382)
ABSTRACT:
Exposure of human immunodeficiency virus to the nucleoside analogue lamivudine (3TC) rapidly selects for resistant variants with a valine at codon 184 (M184V) in the catalytic site of reverse transcriptase. In vitro, 184V demonstratedincreased enzyme fidelity and suppressed zidovudine resistance. Clinical trials demonstrated that 3TC-zidovudine combination therapy results in a strong and sustained antiviral response. To investigate the role of 184V on in vivo virusevolution, the effect of zidovudine addition in 3TC-pretreated patients harboring 184V was studied. In vivo, no significant change in fidelity was observed with 184V, shown by generation of the classical pattern of zidovudine mutations. Of interest, in contrast to zidovudine resistance, multiple substitutions are required for the same level of zidovudine resistance in strains harboring 184V. This need for multiple substitutions may be one of the mechanisms explaining the sustained antiretroviral response of the 3TC-zidovudine combination.
