Emerging mutations at virological failure of HAART combinations containing tenofovir plus lamivudine or emtricitabine

OBJECTIVE: To compare the emergence of drug-resistant HIV variants at failure of lamivudine (3TC)/tenofovir (TDF)-containing or emtricitabine (FTC)/TDF-containing HAART as a consequence of the different 3TC and FTC intracellular half-lives. DESIGN: Retrospective evaluation of 859 patients selected from an Italian HIV resistance database (Antiretroviral Resistance Cohort Analysis). METHODS: Patients were selected for analysis if treated with a HAART whose nucleoside/nucleotide reverse transcriptase inhibitor backbone was either 3TC/TDF or FTC/TDF; if they experienced a virological failure after at least 6 months of plasma HIV-RNA undetectability; and if HIV genotypes before treatment and at failure were available. Univariate and multivariate logistic regression analyses were done to detect predictors of resistance mutations emerging at failure. RESULTS: Of 714 patients failing with 3TC/TDF and 145 with FTC/TDF, 35.8 and 21.1% were in Centers for Disease Control and Prevention stage C, and 8.8 and 15.2% were on first-line HAART, respectively. At multivariate analysis, the emergence of K70R (P = 0.002), M184V (P = 0.031), T215F (P = 0.020) and Y181C (P = 0.005) was significantly more common in 3TC-treated than in FTC-treated patients, with an odds ratio of 4, 1.56, 1.89 and 3.84, respectively. CONCLUSION: Despite their close structural similarity, 3TC and FTC are associated with a significantly different rate of drug resistance at treatment failure when combined with TDF in HAART regimens independently of the third drug used

Emerging mutations at virological failure of HAART combinations containing tenofovir and lamivudine or emtricitabine

Abstract: Objective: To compare the emergence of drug-resistant HIV variants at failure of lamivudine (3TC)/tenofovir (TDF)-containing or emtricitabine (FTC)/TDF-containing HAART as a consequence of the different 3TC and FTC intracellular half-lives. Design: Retrospective evaluation of 859 patients selected from an Italian HIV resistance database (Antiretroviral Resistance Cohort Analysis). Methods: Patients were selected for analysis if treated with a HAART whose nucleoside/nucleotide reverse transcriptase inhibitor backbone was either 3TC/TDF or FTC/TDF; if they experienced a virological failure after at least 6 months of plasma HIV-RNA undetectability; and if HIV genotypes before treatment and at failure were available. Univariate and multivariate logistic regression analyses were done to detect predictors of resistance mutations emerging at failure. Results: Of 714 patients failing with 3TC/TDF and 145 with FTC/TDF, 35.8 and 21.1% were in Centers for Disease Control and Prevention stage C, and 8.8 and 15.2% were on first-line HAART, respectively. At multivariate analysis, the emergence of K70R (P = 0.002), M184V (P = 0.031), T215F (P = 0.020) and Y181C (P = 0.005) was significantly more common in 3TC-treated than in FTC-treated patients, with an odds ratio of 4, 1.56, 1.89 and 3.84, respectively. Conclusion: Despite their close structural similarity, 3TC and FTC are associated with a significantly different rate of drug resistance at treatment failure when combined with TDF in HAART regimens independently of the third drug used. (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkin

Prevalence of mutations and determinants of genotypic resistance to etravirine (TMC125) in a large Italian resistance database (ARCA)

Abstract: Objectives To evaluate whether etravirine (TMC125) might be effective in patients failing therapy with current nonnucleoside reverse transcriptase inhibitors (NNRTIs), we analysed the prevalence of TMC125 mutations and the possible determinants of genotypic resistance to this drug among sequences reported to a large database in Italy [Antiretroviral Resistance Cohort Analysis (ARCA)]. Methods We analysed the prevalence of TMC125 resistance-associated mutations (RAMs) and the TMC125 weighted genotypic score (WGS) together with the determinants of genotypic resistance. A total of 5011 sequences from 2955 patients failing NNRTI therapy were evaluated. Results Among the sequences in ARCA, 68% had at least one and 9.8% at least three TMC125 RAMs, whereas 31% had a WGS > 2. Frequent RAMs were Y181C, G190A, K101E and A98G, whereas V179F, Y181V and G190S appeared in = 200 cells/mu L retained their protective effect. An increased risk of WGS > 2 was linked to higher HIV RNA values (maximum risk at > 5 log(10) copies/mL) and nevirapine exposure; CD4 counts >= 200 cells/mu L were protective. Conclusions The prevalence of TMC125 resistance mutations in the ARCA cohort was 68%. The DUET studies showed that at least three TMC125-associated mutations were required to impair the efficacy of the drug and Y181C/V, V179F and G190S had the greatest effect on response. The prevalence of these mutations among the patients examined in our study was low. However, WGS > 2 was found for one-third of our sequences. Previous nevirapine exposure was associated with an increased risk of having WGS > 2 (adjusted odds ratio 1.76)