Resistance profiles of emtricitabine and lamivudine in tenofovir-containing regimens.

OBJECTIVES: To compare the frequency of the selection of the M184V/I resistance mutation in HIV-infected patients who experienced virological failure while receiving emtricitabine (FTC) or lamivudine (3TC), administered with tenofovir disoproxil fumarate (TDF) and either efavirenz (EFV) or a ritonavir-boosted protease inhibitor (PI; lopinavir or atazanavir). METHODS: Patient data held at two clinical centres in France were analysed retrospectively. Eligible patients had experienced virological suppression (plasma HIV RNA <200 copies/mL) for ≥ 6 months before experiencing their first virological failure (at least two measurements of plasma HIV RNA ≥ 200 copies/mL). RESULTS: Of the 880 patients eligible for the study, 278 patients had experienced virological failure while receiving FTC + TDF + ritonavir-boosted PI, 257 while receiving FTC + TDF + EFV, 178 while receiving 3TC + TDF + EFV and 167 while receiving 3TC + TDF + ritonavir-boosted PI. Proportions of patients harbouring the M184V/I mutation were 24% (n = 62) for those who received FTC + TDF + EFV versus 51% (n = 91) for 3TC + TDF + EFV (P < 0.0001; Fisher's exact test); proportions were 11% (n = 30) for FTC + TDF + ritonavir-boosted PI versus 22% (n = 37) for 3TC + TDF + ritonavir-boosted PI (P = 0.002; Fisher's exact test). The use of lamivudine versus emtricitabine (P = 0.001), non-nucleoside reverse transcriptase inhibitors versus ritonavir-boosted PIs (P = 0.01) and the level of viral load at the time of virological failure (P = 0.01) were associated with selection of the M184V/I mutation (logistic regression analysis). CONCLUSIONS: Emtricitabine and lamivudine showed differing resistance profiles when administered in combination with tenofovir disproxil fumarate and either efavirenz or a ritonavir-boosted PI. The prevalence of the M184V/I resistance mutation was significantly lower in patients who received emtricitabine and tenofovir disoproxil fumarate than in those who received lamivudine and tenofovir disoproxil fumarate.

Switching the nucleoside reverse transcriptase inhibitor backbone to tenofovir disoproxil fumarate + emtricitabine promptly improves triglycerides and low-density lipoprotein cholesterol in dyslipidaemic patients.

OBJECTIVES: To assess the impact of switching to tenofovir disoproxil fumarate + emtricitabine on lipid parameters. METHODS: HIV-infected patients with plasma viral load <400 copies/mL, fasted triglycerides from 2.3 to 11.4 mmol/L and/or fasted low-density lipoprotein (LDL)-cholesterol >4.1 mmol/L were randomized to switch the nucleoside reverse transcriptase inhibitor (NRTI) backbone to fixed-dose combination tenofovir disoproxil fumarate + emtricitabine or to maintain the baseline antiretroviral regimen (the control group). The study has been registered with ClinicalTrials.gov under the identifier NCT00323492. RESULTS: Ninety-one patients were included in the intent-to-treat (ITT) analysis with triglycerides 2.4 mmol/L and LDL-cholesterol 4.0 mmol/L (median values). At week 12, the median changes from baseline of triglycerides were -0.5 mmol/L (-25%; n = 46) and -0.1 mmol/L (-6%; n = 45) in the tenofovir disoproxil fumarate + emtricitabine and control groups, respectively, indicating a difference of -0.4 mmol/L (P = 0.034) [95% confidence interval (CI): -0.9 to -0.0]. Similarly for LDL-cholesterol, changes of -0.4 mmol/L (-9%) and -0.1 mmol/L (-1%) were observed in the tenofovir disoproxil fumarate + emtricitabine and control groups, respectively, indicating a difference of -0.4 mmol/L (P = 0.031) [95% CI: -0.7 to -0.0]. The proportion of patients with LDL-cholesterol >4.1 mmol/L decreased from 48% at baseline to 26% at week 12 in the tenofovir disoproxil fumarate + emtricitabine group versus no change in the control group. No virological failure was observed during the study. CONCLUSIONS: Switching to tenofovir disoproxil fumarate + emtricitabine in dyslipidaemic HIV-infected patients improves triglycerides and LDL-cholesterol.

Discontinuation of maintenance therapy for cytomegalovirus retinitis in HIV-infected patients receiving highly active antiretroviral therapy.

OBJECTIVE: To study the safety of discontinuing cytomegalovirus (CMV) maintenance therapy among patients with cured CMV retinitis receiving highly active antiretroviral therapy (HAART). METHODS: Patients with a history of CMV retinitis who were receiving anti-CMV maintenance therapy and who had a CD4 cell count > 75 x 10(6) cells/l and a plasma HIV RNA level < 30000 copies/ml while on HAART were included in a multicentre prospective study. Maintenance therapy for CMV retinitis was discontinued at enrolment and all the patients were monitored for 48 weeks by ophthalmological examinations and by determination of CMV markers, CD4 cell counts and plasma HIV RNA levels. T helper-1 anti-CMV responses were assessed in a subgroup of patients. The primary study endpoint was recurrence of CMV disease. RESULTS: At entry, the 48 assessable patients had been taking HAART for a median of 18 months. The median CD4 cell count was 239 x 10(6) cells/l and the median HIV RNA load was 213 copies/ml. Over the 48 weeks, 2 of the 48 patients had a recurrence of CMV disease. The cumulative probability of CMV retinitis relapse was 2.2% at week 48 (95% confidence interval, 0.4-11.3) and that of all forms of CMV disease 4.2%. CMV blood markers remained negative throughout follow-up. The proportion of patients with CMV-specific CD4 T cell reactivity was 46% at baseline and 64% at week 48. CONCLUSIONS: CMV retinitis maintenance therapy may be safely discontinued in patients with CD4 cell counts above 75 x 10(6) cells/l who have been taking HAART for at least 18 months.