Impact of switching from lopinavir/ritonavir to atazanavir/ritonavir on body fat redistribution in virologically suppressed HIV-infected adults

Changes in body fat distribution in virologically suppressed HIV-infected patients switching from lopinavir/ritonavir (LPV/r) to atazanavir/ritonavir (ATV/r) were assessed. A prospective comparative study was conducted of 37 patients receiving LPV/r regimens switching to ATV/r with 46 patients continuing with LPV/r. Body composition was assessed with whole-body dual-energy x-ray absorptiometry (DXA). Abdominal CT scans were also performed in a subset of patients. Groups were comparable in baseline demographic, clinical, and anthropometric characteristics. After 12 months, peripheral fat did not change significantly, but an increase in trunk fat was observed only in the ATV/r group (0.87 kg, p = 0.021). The percentage of patients with an increase ≥20% in total fat was 37.8% and 15.2% in the ATV/r and LPV/r groups, respectively (p = 0.018). In the ATV/r group, the increase in trunk fat (9.4%) was significantly higher than in peripheral fat (3.7%) (p = 0.007), leading to a significant increase in fat mass ratio (3.76%, p = 0.028), whereas no significant differences were found among LPV/r patients. CT scans showed that abdominal fat increase corresponded to both visceral (28%, p = 0.008) and subcutaneous fat (42%, p = 0.008). These data suggest that switching from LPV/r to ATV/r is associated with increased trunk fat, both subcutaneous and visceral.     

The effects of HIV protease inhibitors atazanavir and lopinavir/ritonavir on insulin sensitivity in HIV-seronegative healthy adults

BACKGROUND: Therapy with some HIV protease inhibitors (PI) contributes to insulin resistance and type 2 diabetes mellitus, by inhibition of insulin-sensitive glucose transporters. Atazanavir (ATV) is a new PI with substantially less in vitro effect on glucose transport than observed with other PI, including lopinavir (LPV) or ritonavir (RTV). METHODS: Randomized, double-blind, crossover study of the effect of 5 days of administering ATV, lopinavir/ritonavir (LPV/r) or placebo on insulin-stimulated glucose disposal in 30 healthy HIV-negative subjects. Each subject was studied on two of three possible treatments with a wash-out period between treatments. RESULTS: The mean insulin-stimulated glucose disposal (mg/min per kg body weight) per unit insulin (microU/ml) (M/I) was 9.88, 9.80 and 7.52 for placebo, ATV and LPV/r, respectively (SEM, 0.84 for all). There was no significant difference between ATV and placebo. The M/I for LPV/r was 23% lower than that for ATV (P = 0.010) and 24% lower than that for placebo (P = 0.008). The mean glycogen storage rates were 3.85, 4.00 and 2.54 mg/min per kg for placebo, ATV and LPV/r, respectively (SEM, 0.39 for all). There was no significant difference between ATV and placebo. The glycogen storage rate for LPV/r was 36% lower than ATV (P = 0.003) and 34% lower than placebo (P = 0.006). CONCLUSIONS: ATV given to healthy subjects for 5 days did not affect insulin sensitivity, while LPV/r induced insulin resistance. This observation is consistent with differential in vitro effects of these PI on glucose transport. Further data are needed to assess clinical implications for body composition.     

Pharmacokinetics of rifabutin during atazanavir/ritonavir co-administration in HIV-infected TB patients

Background & objective

Rifabutin (RBT) is the rifamycin that is recommended to treat tuberculosis (TB) in HIV-infected individuals during combination antiretroviral therapy (ART) containing HIV protease inhibitors (PIs). We studied the pharmacokinetics of rifabutin at doses of 300 mg thrice weekly and 150 mg daily during concomitant atazanavir/ritonavir (ATZ/r) administration in adult HIV-infected TB patients treated in the Revised National TB Control Programme (RNTCP) in India.

Resistance to amprenavir before and after treatment with lopinavir/ritonavir in highly protease inhibitor-experienced HIV patients

Genotypes in nine highly protease inhibitor (PI)-experienced patients were studied before and after lopinavir/ritonavir (LPV/r) treatment. Resistance to amprenavir was the rule both before and after LPV/r treatment. Treatment with LPV/r can select for the 50 V mutation. In this setting, significant differences in the inference of the amprenavir phenotype from genotype were observed when using different algorithms.     

Clinical validation of atazanavir/ritonavir genotypic resistance score in protease inhibitor-experienced patients

OBJECTIVE: To develop a clinically relevant genotypic resistance score for boosted atazanavir (ATV) in protease inhibitor-experienced patients. METHODS: At baseline, 62 patients with HIV-1 RNA > 1000 copies/ml switched to a boosted ATV regimen (300 mg ATV, 100 mg ritonavir once daily); two were excluded from analysis at 3 months as they had undetectable plasma ATV. The impact of baseline protease mutations on virological response (> 1 log10 copies/ml plasma HIV RNA decrease) at 3 months was analysed using Fisher's exact test. Mutations with prevalence > 8% and P < 0.2 were retained. Cochran-Armitage's test was used to select the combination of mutations most strongly associated with reduced virological response. Robustness of the score was investigated using bootstrap resampling. RESULTS: At 3 months, 82% of patients had a virological response and 56% had RNA < 50 copies/ml. Eight mutations (10F/I/V, 16E, 33I/F/V, 46I/L, 60E, 84V, 85V and 90M) were retained in the genotypic resistance score (P = 8.67 x 10) and virological response was observed in 100%, 100%, 80%, 42%, and 0% of patients with none, one, two, three, and four/five mutations, respectively. There was 100% response in patients with a score < 2 independently of the number of active drugs, whereas in patients with a score > or = 3 there was a gradient of response according to the number of active drugs (0%, 29% and 60% with none, one and two/three active drugs, respectively). CONCLUSIONS: The occurrence of three of the eight mutations in the ATV/RTV genotypic resistance score predicted a clinically identifiable reduced response in patients.     

Predictive factors of hyperlipidemia in HIV-infected subjects receiving lopinavir/ritonavir

We studied 382 multiexperienced HIV-infected patients followed up for > or =3 months after starting lopinavir/ritonavir (LPV/r) to identify the factors predicting hypertriglyceridemia and high non-HDL cholesterol levels (triglycerides > or =200 mg/dl and/or non-HDL cholesterol > or =190 mg/dl) after 6 and 12 months of LPV/r exposure. The predictors of hypertriglyceridemia were higher baseline triglyceride levels [OR: 2.28 (95% CI: 1.67-3.12) for each additional 100 mg/dl; p = 0.001], the total duration of antiretroviral treatment [OR: 1.26 (95% CI: 1.12-1.41) for each additional year; p = 0.01], CDC stage C (OR: 2.06; 95% CI: 1.24-3.88; p = 0.02), and male gender (OR: 2.52; 95% CI: 1.42-4.74; p = 0.02); intravenous drug abusers seem less likely to develop the event (OR: 0.52; 95% CI: 0.37-0.92; p = 0.03). The predictors of high non-HDL cholesterol levels were higher baseline levels [OR: 3.92 (95% CI: 1.92-6.24) for each additional 100 mg/dl; p = 0.001) and the combination of NRTIs and NNRTIs with LPV/r (OR: 1.83; 95% CI: 1.10-3.69; p = 0.03). The 75 patients stopping LPV/r showed a significant reduction in median triglyceride and non-HDL cholesterol levels after 3 months of 39 mg/dl and 20 mg/dl (p = 0.01 for both), respectively. Patients with high triglyceride and non- HDL cholesterol levels at the start of LPV/r treatment are at higher risk of developing hyperlipidemia.     

Effects of atazanavir/ritonavir and lopinavir/ritonavir on glucose uptake and insulin sensitivity: demonstrable differences in vitro and clinically

BACKGROUND: The HIV protease inhibitor (PI) atazanavir does not impair insulin sensitivity acutely but ritonavir and lopinavir induce insulin resistance at therapeutic concentrations. OBJECTIVE: To test the hypothesis that atazanavir combined with a lower dose of ritonavir would have significantly less effect on glucose metabolism than lopinavir/ritonavir in vitro and clinically. METHODS: Glucose uptake was measured following insulin stimulation in differentiated human adipocytes in the presence of ritonavir (2 micromol/l) combined with either atazanavir or lopinavir (3-30 micromol/l). These data were examined clinically using the hyperinsulinemic euglycemic clamp and oral glucose tolerance testing (OGTT) in 26 healthy HIV-negative men treated with atazanavir/ritonavir (300/100 mg once daily) and lopinavir/ritonavir (400/100 mg twice daily) for 10 days in a randomized cross-over study. RESULTS: Atazanavir inhibited glucose uptake in vitro significantly less than lopinavir and ritonavir at all concentrations. Ritonavir (2 micromol/l) combined with either atazanavir or lopinavir (3-30 micromol/l) did not further inhibit glucose uptake. During euglycemic clamp, there was no significant change from baseline insulin sensitivity with atazanavir/ritonavir (P = 0.132), while insulin sensitivity significantly decreased with lopinavir/ritonavir from the baseline (-25%; P < 0.001) and from that seen with atazanavir/ritonavir (-18%; P = 0.023). During OGTT, the HOMA insulin resistance index significantly increased from baseline at 120 min with atazanavir/ritonavir and at 150 min with lopinavir/ritonavir. The area under the curve of glucose increased significantly with lopinavir/ritonavir but not with atazanavir/ritonavir. CONCLUSIONS: Both glucose uptake in vitro and clinical insulin sensitivity in healthy volunteers demonstrate differential effects on glucose metabolism by the combination PI atazanavir/ritonavir and lopinavir/ritonavir.     

Combined therapy with saquinavir, ritonavir and stavudine in moderately to severely immunosuppressed HIV-infected protease inhibitor-naive patients

¹ Basel Centre for HIV Research, Outpatient Department of Internal Medicine, University Hospital Basel, ² Department of Internal Medicine, Cantonal Hospital St Gallen, ³ Department of Internal Medicine, Regional Hospital Lugano, ⁴ Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, ⁵ Basel Centre for HIV Research, Institute for Medical Microbiology, University Basel, ⁶ Division of Infectious Diseases, University Hospital Bern, ⁷ Division of Infectious Diseases, University Hospital Lausanne, ⁸ Roche Pharma AG, Reinach, and ⁹ Division of Infectious Diseases, University Hospital Geneva, Switzerland Objective To assess the short‐term and long‐term effect of a combination of saquinavir, ritonavir and stavudine in moderately to severely immunosuppressed protease inhibitor‐naive patients. Design Prospective open‐label multicentre study. Patients and Methods A total of 64 protease inhibitor‐naive and stavudine‐naive HIV‐infected patients with a CD4 count of < 250 cells/μL and > 10 000 HIV‐1 RNA copies/mL received saquinavir hard‐gelatin capsules, ritonavir and stavudine. Full (drop in viraemia of > 2 log₁₀ and/or < 500 copies/mL) and partial responders (drop to between 500 and 5000 viraemia copies/mL) at week 9 (end of phase I) entered the second phase (additional 12‐month period). Results Fifty‐six patients completed phase I, 45 (70%) full responders and nine (14%) partial responders by intent‐to‐treat analysis. Thirty‐nine patients completed phase II, 33 (52%) full responders and two (3%) partial responders. Six patients had < 50 HIV‐1 RNA copies/mL at week 9, and 20 (31%) patients at month 12 of phase II. Mean CD4 cell counts increased significantly in the 56 patients from 89 to 184 cells/μL after 9 weeks and from 100 to 292 cells/μL in the 39 patients treated for another 12 months. Higher baseline viraemia and lower baseline CD4 cell counts were not associated with an unfavourable virological response at week 9 and month 12 of phase II. HIV DNA in peripheral blood monocytes decreased substantially (? 1.5 log₁₀) but was detectable in all except one patient at the end of phase II. Conclusion In protease‐ and stavudine‐naive HIV‐infected patients with moderate to severe immunosuppression, saquinavir in combination with ritonavir and stavudine caused a substantial long‐term decrease in plasma viral load in approximately half the participants and a substantial increase in CD4 cell counts.     

Fat tissue distribution changes in HIV-infected patients treated with lopinavir/ritonavir. Results of the MONARK trial

Given the decline in mortality among HIV-infected patients, it has become increasingly important to consider delayed disease-related and/or anti-HIV therapy-related adverse effects, such as lipodystrophy, when choosing initial therapy. Data from the MONARK trial allowed for comparison of the potential lipodystrophic effects of lopinavir/ritonavir (LPV/r) monotherapy with those of triple therapy with LPV/r plus zidovudine (ZDV) and lamivudine (3TC). This was a randomized, open-label, multinational study that included 136 antiretroviral-naive HIV-infected patients. A portion of study patients underwent evaluations of limb and trunk fat tissue by dual-energy x-ray absorptiometry at baseline and after 48 weeks of treatment (and 96 weeks in some patients). Sixty-three patients had paired absorptiometry data at baseline and week 48 (13 patients at week 96). At week 48, median change in limb fat was -63 g on LPV/r monotherapy versus -703 g on LPV/r + ZDV/3TC triple therapy (p=0.014). The proportion of patients with fat loss (>20% loss in limb fat) was significantly lower with LPV/r monotherapy (4.9% versus 27.3%; p=0.018). Changes in trunk fat did not differ significantly between treatments. Nonetheless, limb fat and trunk fat varied in the same direction with both treatments. The decrease in arm lean mass was also significantly less in patients receiving LPV/r monotherapy. Only treatment type emerged as a significant predictor of fat loss (odds ratio, 7.06; 95% CI, 1.11-78.69). These results suggest that LPV/r, and possibly other protease inhibitors, may not be the main contributor to lipoatrophy in HIV-infected patients receiving triple therapy.