Which nucleoside and nucleotide backbone combinations select for the K65R mutation in HIV-1 reverse transcriptase?
Alan Winston (Chelsea and Westminster Hospital, London, UK) reported an oral talk also in the Clinical Implications of Resistance session. BACKGROUND: The K65R mutation has been reported to be associated with the use of abacavir (ABC), didanosine (DDI) and tenofovir (TDF). With the advent of TDF this study assesses the change in prevalence of the K65R mutation and its association with TDF, DDI and ABC therapy. METHODS: In Chelsea and Westminster Hospital individuals failing therapy have a resistance test. Genotypes were analysed on individuals failing nucleoside and nucleotide containing regimens from October 2000 to October 2002 (time 2). This was compared to genotypes pre-October 2000 (time 1) in TDF-naive individuals. RESULTS: The K65R was identified in viruses from 28 of 705 individuals having resistance tests for virological failure during time 2 (prevalence 4.0%). The prevalence of this mutation during time 1 was significantly lower at 1.7% (P=0.004). Winston reported that for pa
