Observational study on HIV-infected subjects failing HAART receiving tenofovir plus didanosine as NRTI backbone

Conserved T cell and natural killer cell function in treatment-experienced adults receiving tenofovir plus didanosine as nucleoside reverse transcription inhibitor backbone

Anti-retroviral treatment (ART) usually results in efficient control of virus replication and in immune reconstitution. Among potential adverse effects, impairment of immune responses in terms of CD4(+) T cell counts has been attributed to some ART regimens, as with didanosine-tenofovir. We studied the functional integrity of adaptive and innate immunity during didanosine-tenofovir-containing ART. Two groups of extensively pretreated patients completing at least 48 weeks of ART containing either lamivudine-didanosine (n = 21) or tenofovir-didanosine (n = 25) were identified. In addition to standard clinical immune and virological parameters, we performed a flow cytometric analysis of natural killer (NK) cells, of memory and naive CD4(+) T cells and of T cell receptor alphabeta(+) T cells co-expressing inhibitory NK receptors. Functional analysis consisted in specific and total interferon-gamma production by NK cells and of recall antigen proliferation of peripheral blood mononuclear cells. Comparable clinical immunological reconstitution and virological control were confirmed in the two groups of patients in the absence of clinically relevant adverse effects. The proportion of CD4(+)CD45RA(+) T cells and of functionally inhibited killer immunoglobulin-like receptor T cell receptor alphabeta(+) cells, the proliferation to recall antigens as well as NK cell phenotype and function as determined by interferon-gamma production in patients treated with tenofovir-didanosine were comparable to those treated with a different regimen. Thus, no differences in functional innate or adaptive immune reconstitution are detected in drug-experienced human immunodeficiency virus-infected patients on tenofovir-didanosine nucleoside reverse transcription inhibitor regimens.

Efficacy and safety of ritonavir-boosted and unboosted atazanavir among antiretroviral-naïve patients

PURPOSE

Evaluate responses and safety of ritonavir-boosted atazanavir ("boosted atazanavir") compared to unboosted atazanavir among antiretroviral-naïve patients in the clinical managed care setting.

METHOD

Observational cohort analysis of atazanavir use (comparing ritonavir-boosted to non-boosted) at Kaiser Permanente and Group Health Cooperative from 2003 to 2006. Antiretroviral-naïve patients initiating atazanavir were followed through 52 weeks of treatment.

RESULTS

443 patients were prescribed atazanavir (69 non-boosted; 15.5%). Boosted and non-boosted atazanavir groups were similar with respect to gender and age. Boosted atazanavir use was associated with greater odds achieving HIV RNA <400 c/mL (odds ratio [OR] = 3.24, p = .008), greater decrease in HIV RNA (-0.37 log10/mL, p = .03), greater increase in CD4 T-cell count (+59 cells/microL, p = .01), and greater increase in total bilirubin (+1.21 mg/dL as opposed to +0.56 mg/dL, p .001). There were no statistically significant differences for glucose, liver transaminases, total cholesterol, or LDL cholesterol elevations. There were greater odds of maximal viral control when atazanavir was combined with tenofovir or zidovudine in combination with lamivudine (or emtricitabine).

CONCLUSIONS

Ritonavir-boosted atazanavir is associated with greater virologic control and immune response through 52 weeks compared to non-boosted atazanavir, without greater risk of adverse events except elevated bilirubin. Thus, ritonavir-boosted atazanavir is the preferred method of prescribing atazanavir.