Safety and efficacy of a 36-week induction regimen of abacavir/lamivudine and ritonavir-boosted atazanavir in HIV-infected patients.

PURPOSE: The ARIES study assessed safety and efficacy of an induction regimen with atazanavir/ritonavir (ATV/RTV) + abacavir/lamivudine (ABC/3TC) followed by simplification to ATV + ABC/3TC in antiretroviral-naïve patients. METHODS: This report includes a noncomparative analysis of all patients in the induction phase of the ARIES study through 36 weeks (clinicaltrials.gov: NCT00440947). This open-label study included 515 antiretroviral-naïve,HLA-B*5701-negative patients receiving a regimen of ATV 300 mg, RTV 100 mg, and ABC/3TC 600 mg/300 mg once daily for 36 weeks; eligible patients were then randomized to continue the induction regimen or simplify to ATV 400 mg plus ABC/3TC 600 mg/300 mg once daily. RESULTS: Eighty-six percent (442/515) of patients completed 36 weeks on study; 80% (410/515) achieved HIV RNA <50 copies/mL (84% and 76% of patients with baseline HIV RNA of < and >or=100,000 copies/mL achieved this endpoint). Virologic failure (VF) was uncommon (3%); treatment-emergent major protease inhibitor and nucleoside reverse transcriptase inhibitor mutations were detected in 0/15 and 4/15 patients, respectively. Median CD4+ cell increase was 171 (range, -176 to 718) cells/mm(3). Hyperbilirubinemia (13%), diarrhea (4%), nausea (2%), and rash (2%) were the most frequent drug-related Grade 2-4 adverse events. Few adverse events (3%) led to study discontinuation. CONCLUSIONS: Induction with ATV/RTV + ABC/3TC once daily provides an efficacious and well-tolerated regimen for the initial treatment of HIV.

Efficacy and safety of darunavir-ritonavir at week 48 in treatment-experienced patients with HIV-1 infection in POWER 1 and 2: a pooled subgroup analysis of data from two randomised trials.

BACKGROUND: The continuing, randomised, multinational, phase IIB POWER 1 and 2 studies aim to evaluate efficacy and safety of darunavir in combination with low-dose ritonavir in treatment-experienced HIV-1-infected patients. We did a pooled subgroup analysis to update results at week 48 for patients receiving the recommended dose of darunavir-ritonavir compared with those receiving other protease inhibitors (PIs). METHODS: After 24-week dose-finding phases and primary efficacy analyses, patients randomised to receive darunavir-ritonavir were given 600/100 mg twice daily, and patients receiving control PIs continued on assigned treatment into the longer-term, open-label phase; all patients continued on optimised background regimen. We assessed patients who had reached week 48 or discontinued earlier at the time of analysis; for the darunavir-ritonavir group, only patients who received 600/100 mg twice daily from baseline were included. Analyses were intention-to-treat. The POWER 2 study (TMC114-C202) is registered with ClinicalTrials.gov (NCT00071097). FINDINGS: At week 48, 67 of 110 (61%) darunavir-ritonavir patients compared with 18 of 120 (15%) of control PI patients had viral load reductions of 1 log10 copies per mL or greater from baseline (primary endpoint; difference in response rates 46%, 95% CI 35%-57%, p<0.0001). Based on a logistic regression model including stratification factors (baseline number of primary PI mutations, use of enfuvirtide, baseline viral load) and study as covariates, the difference in response was 50% (odds ratio 11.72, 95% CI 5.75-23.89). In the darunavir-ritonavir group, rates of adverse events were mostly lower than or similar to those in the control group when corrected for treatment exposure. No unexpected safety concerns were identified. INTERPRETATION: Efficacy responses with darunavir-ritonavir 600/100 mg twice daily plus optimised background regimen were greater than those with control PI and were sustained to at least week 48, with favourable safety and tolerability in treatment-experienced patients. This regimen could expand the treatment options available for such patients.

Costs to achieve undetectable HIV RNA with darunavir-containing highly active antiretroviral therapy in highly pretreated patients: the POWER experience.

BACKGROUND: Very few studies have evaluated the cost of highly active antiretroviral therapy (HAART) per successful treatment in HIV-infected patients. OBJECTIVES: To evaluate the cost of achieving undetectable plasma HIV-RNA levels in highly treatment-experienced, HIV-1-infected adults receiving darunavir/ritonavir (DRV/r 600 mg/100 mg twice a day) or control protease inhibitor (PI)-based HAART. METHODS: The mean annual per-patient cost of DRV/r and control PI-based HAART was determined from the proportional use of antiretroviral agents in the DRV/r and control PI arms of the pooled POWER 1 and 2 trials, applying drug acquisition costs for 13 healthcare settings. The mean annual cost per patient of achieving undetectable plasma HIV-RNA levels (<50 copies/mL) was calculated by dividing the cost of each treatment by the proportion of patients with undetectable plasma HIV-RNA levels after 48 weeks in the DRV/r (45%) and control PI (10%) arms of the POWER trials. RESULTS: Whereas absolute costs of treatment were 1-19% higher with DRV/r versus control PI-based HAART depending on the healthcare setting, the mean annual per-patient cost of achieving undetectable plasma HIV-RNA levels was 73-78% lower. These cost savings were maintained in the sensitivity analyses, adjusting for control PI and enfuvirtide use, and the number of active drugs in the background regimen. The incremental annual cost per additional patient achieving undetectable plasma HIV-RNA levels with DRV/r versus control PI-based HAART in POWER 1 and 2 (£4148) compared favourably with that determined for enfuvirtide (£137, 740; TORO trials) and tipranavir/ritonavir (£32,176; RESIST) versus control therapy. CONCLUSIONS: DRV/r-based HAART provided consistent reductions in the cost of achieving undetectable plasma HIV-RNA levels compared with control PI-based therapy in highly treatment-experienced patients across various healthcare settings. The incremental cost per additional patient achieving undetectable plasma HIV-RNA levels with DRV/r versus control PI-based HAART was also lower than that calculated for other treatment options in this population. These results suggest that DRV/r is an economically viable option for highly treatment-experienced patients.

Enfuvirtide does not require dose adjustment in patients with chronic kidney failure: results of a pharmacokinetic study of enfuvirtide in HIV-1-infected patients with impaired kidney function.

OBJECTIVE: The aim of this study was to examine the influence of kidney disease and hemodialysis on the pharmacokinetics ofenfuvirtide. DESIGN: An open-label, multicenter, parallel group study of HIV-1-infected patients with varying degrees of kidney dysfunction. METHODS: A 90-mg dose of enfuvirtide was administered by subcutaneous injection to 3 groups of patients: group A, patients with normal kidney function; group B, patients with chronic kidney disease; and group C, patients with end-stage renal disease (ESRD) requiring dialysis. Patients with ESRD requiring dialysis received the 90-mg dose of enfuvirtide on 2 separate occasions; a dialysis day and a nondialysis day. After each dose, a full 48-hour pharmacokinetic profile was collected and pharmacokinetic parameters were estimated using model-independent techniques. RESULTS: Enfuvirtide area under the curve (AUCinfinity) and maximum observed enfuvirtide plasma concentration (Cmax) for patients with normal kidney function (group A) was 49.6 microg h/mL and 3.79 microg/mL, respectively. Patients with chronic kidney disease (group B) had higher AUCinfinity (80.3 microg h/mL) and Cmax (5.72 microg/mL), which was similar to patients with ESRD (group C) on both nondialysis days (AUCinfinity 71.1 microg h/mL; Cmax 5.34 microg/mL) and dialysis days (AUCinfinity 66.9 microg h/mL; Cmax 6.31 microg/mL). An average of< 13% of enfuvirtide was removed during the dialysis procedure. The incidence of adverse events was comparable for all study groups. CONCLUSION: Enfuvirtide exposure observed in patients with ESRD requiring dialysis or chronic kidney disease was slightly higher than in patients with normal kidney function and similar to historical Cmax and AUC values from studies in patients with normal kidney function. Thus, enfuvirtide does not require dosage adjustment in patients with impaired kidney function.

Persistent antiretroviral activity of nucleoside analogues after prolonged zidovudine and lamivudine therapy as demonstrated by rapid loss of activity after discontinuation.

Antiretroviral (ARV) treatment decisions are difficult for HIV-1-infected patients on complex treatment regimens who have partial suppression of HIV-1 replication and limited treatment options. Information on the ARV activity of the components of a complex regimen would be useful. Sixteen subjects who had received prolonged therapy with zidovudine (ZDV) and lamivudine (3TC), with a median duration of 32.5 months, were discontinuing this dual-nucleoside regimen and volunteered to have plasma HIV-1 RNA levels monitored over the 2 weeks after discontinuation. All subjects experienced an increase in HIV-1 RNA after discontinuation, with a median increase of 0.54 log10 copies/mL over 2 weeks (range: 0.31-1.71; P < 0.001). An inverse correlation existed between the decline in HIV-1 RNA levels over 2 to 3 years on nucleoside analogue therapy and the increase over the 10 to 14 days off therapy (Spearman r = -0.53; P = 0.036). Over the 2-week period, a subset of individuals who had genotype testing at multiple reverse transcriptase codons associated with ZDV and 3TC resistance had no changes in genotype off therapy. Nucleoside analogue reverse transcriptase inhibitors may have continued ARV activity despite long durations of partially suppressive therapy and the presence of resistant HIV-1.