Body composition changes in protease inhibitor-naive HIV-infected patients treated with two nucleoside reverse transcriptase inhibitors

Objectives

In the era of highly active antiretroviral treatment (HAART), there are insufficient data regarding lipodystrophy syndromes in HIV‐1‐infected patients treated with regimens that do not include protease inhibitors (PIs). We studied changes in body composition in HIV‐1‐infected patients before and 2 years after starting a non‐PI‐containing antiretroviral treatment regimen.

Methods

We studied retrospectively the whole body dual energy X‐ray absorptiometry (DEXA) scans of 23 PI‐naive HIV‐1‐infected patients (17 males, six females), aged 37.4 ± 9.3 years with mean CD4 count 401 ± 130 cells/µL. Thirteen patients were on zidovudine (ZDV) + lamivudine (3TC) and 10 on ZDV + didanosine (ddI). Subjects were evaluated before the beginning of antiretroviral treatment and approximately 24 months later. For each patient body weight, CD4 T‐cell counts, bone mineral content (BMC), bone mineral density (BMD) and whole body as well as regional fat and lean body mass were evaluated.

Results

A significant decrease in BMC was observed, although the T scores remained within the normal limits. Our patients also exhibited a significant decrease in body weight due almost exclusively to fat loss, while lean mass was minimally affected. Fat loss was statistically significant in the arms and legs, but not in the trunk. The above changes were most prominent in the ZDV + 3TC treatment group; in this group of patients, fat loss was also evident in the trunk. Patients on ZDV + ddI, on the other hand, only showed a significant increase in their legs' lean mass; they preserved their total fat mass and exhibited no other significant changes between the two assessments.

Conclusions

Dual NRTI therapy contributes to fat loss and reduction of bone mineral content in otherwise healthy, clinically stable, PI‐naive HIV‐infected adults. Compared with patients on ZDV + ddI, patients on ZDV + 3TC had a more prominent fat loss in all body regions.

     

High rate of virological failure in maintenance antiretroviral therapy with didanosine and tenofovir

We evaluated the virological outcome of tenofovir plus didanosine-based regimens in 67 HIV-suppressed patients. After a median follow-up of 26 months (IQR 10.5-40.5), 12 (18%) discontinued the therapy because of virological failure. At virological failure 'de novo' selected mutations were identified in 11 of the 12 failing patients, including the K65R mutation in seven patients. These results argue against the use of tenofovir-didanosine not only in naive patients, but also in previously suppressed patients.     

Intensification of a triple-nucleoside regimen with tenofovir or efavirenz in HIV-1-infected patients with virological suppression

OBJECTIVE: To compare a quadruple-nucleoside with an efavirenz-containing regimen for treatment of HIV-1 infection. DESIGN: A randomized, open-label study of the AIDS Clinical Trials Group (ACTG). METHODS: Subjects receiving zidovudine/lamivudine/abacavir on ACTG 5095 with HIV-1 RNA less than 200 copies/ml were randomly assigned to intensify either with tenofovir or efavirenz. Subjects were followed for time to treatment failure, defined as either virological failure or treatment discontinuation. Analyses were intent-to-treat. RESULTS: One hundred and seventy subjects (21% women; 56% non-white) entered the study. At baseline, 95 and 73% had HIV-1-RNA levels less than 200 and 50 copies/ml, respectively; the median CD4 cell count was 453 cells/microl. Over a median 79 weeks follow-up, 165 (97%) completed the study, three (2%) discontinued, and two (1%) died. Treatment failure occurred in 31 subjects: 18 (21%) (quadruple nucleosides) and 13 (15%) (efavirenz-containing regimen); however the failure-time curves crossed and demonstrated a non-constant treatment effect over time, characterized by more early treatment failures on the efavirenz-containing regimen and more late treatment failures on the four-nucleoside regimen. HIV-1 RNA remained suppressed in more than 88% of subjects to less than 200 copies/ml and in more than 78% to less than 50 copies/ml at weeks 24, 48, and 72, without differences by treatment arm. There were no significant differences between the regimens in CD4 cell increases, time to new grade 3/4 adverse events, or adherence. CONCLUSION: The safety, tolerability, and efficacy of the four-nucleoside regimen were not significantly different from the efavirenz-containing regimen. These pilot data support further investigation of the quadruple-nucleoside regimen.     

Interruption of reverse transcriptase inhibitors or a switch from reverse transcriptase to protease inhibitors resulted in a fast reappearance of virus strains with a reverse transcriptase inhibitor-sensitive genotype

OBJECTIVES: To study the effect of the interruption of reverse transriptase inhibitor (RTI) therapy or a switch from RTI to protease inhibitors, on the genotypic drug-resistance pattern of plasma HIV-1. METHODS: Nine patients who completely stopped all medication, and five patients who switched from a treatment with RTI to a regimen containing protease inhibitors only, were studied. Direct sequencing of the plasma HIV-1 RT and protease gene was performed on follow-up samples taken before and after the interruption of treatment. RESULTS: Comparison of the amino acid sequence of the RT and protease genes in successive samples showed the rapid reappearance of wild-type viral variants in 12 of the 14 patients studied. Wild-type virus replaced the mutant strains 14 days to 2 months after the interruption of therapy, even in patients with a long treatment history. CONCLUSION: The results of this study indicate the sustained lower fitness of mutant strains in vivo. As a result, wild-type virus remains capable of outcompeting the RT or protease mutant strains very fast after removal of the drug. These findings highlight the importance of 'treatment history' in addition to genotypic and phenotypic markers determined at one time-point, when making therapeutic decisions for patients.