In vitro activity of structurally diverse nucleoside analogs against human immunodeficiency virus type 1 with the K65R mutation in reverse transcriptase

Abstract

Human immunodeficiency virus type 1 (HIV-1) with a lysine-to-arginine substitution at codon 65 (HIV-1(65R)) of reverse transcriptase (RT) can rapidly emerge in patients being treated with specific combinations of nucleoside analog RT inhibitors (NRTIs). A better understanding of the activity of approved and investigational NRTIs against HIV-1(65R) is needed to select optimal therapy for patients infected with this mutant and to devise strategies to prevent its emergence. Therefore, we tested a broad panel of NRTIs that differed by enantiomer, pseudosugar, and base component against HIV-1(65R) to determine how NRTI structure affects activity. Drug susceptibilities of recombinant wild-type (HIV-1(65K)) or mutant HIV-1(65R) were determined using a single-replication-cycle susceptibility assay with P4/R5 cells and/or a multiple-replication-cycle susceptibility assay with MT-2 cells. All D, L, and acyclic NRTIs were significantly less active against HIV-1(65R) than against HIV-1(65K) except for analogs containing a 3'-azido moiety. Pseudosugar structure and base component but not enantiomer influenced NRTI activity against HIV-1(65R). These findings support the inclusion of 3'-azido-3'-deoxythymidine in drug combinations to treat patients having HIV-1(65R) and to prevent its emergence.

FIG. 1.

Pseudosugar structures of NRTIs tested. (1) 2′,3′-Dideoxynucleosides (ddC, ddT, ddI, ddG); (2) 2′,3′-didehydro-2′3′-dideoxynucleosides (d4C, d4T); (3) 2′-fluoro-2′,3′-didehydro-2′3′-dideoxynucleosides (2′-F-d4FC, 2′-F-d4A); (4) 2′-deoxy-3′-oxa-4′-thiocytidines (dOTC); (5) dioxolane-nucleosides (DOC, DXG); (6) 2′,3′-dideoxy-3′-thiacytidines (3TC, FTC); (7) 3′-azido-3′-deoxynucleosides (AZT, AZC, AZG, AZA); (8) 3′-fluoro-3′deoxynucleosides (FLT, FLG); (9) 9-[2-(phosphonomethoxy)ethyl nucleotide (PMEA); (10) 9-[(R)-2-(phosphonomethoxy)propyl] nucleotide (PMPA).