Assessing site performance in the Altair study, a multinational clinical trial

Background: Reviewing clinical trial site performance identifies strategies to control outcomes. Performance across 5 geographical regions (36 sites across Asia, Australia, Europe, North America and Latin America) was investigated in a study that randomised 322 HIV-infected individuals. Methods: Regional performance was compared using descriptive analysis for time to site opening, recruitment, quality of data and laboratory samples. Follow-up consisted of 10 visits (96 weeks), electronic data collection (EDC) within 7 days of a visit and serious adverse events (SAEs) reported within 24 hours of site awareness. Results: Median days to site opening was 250 (188 to 266), ranging from 177 (158 to 200) (Australia) to 265 (205 to 270) (Europe). Median days to ethics and regulatory approval was 182 (120 to 241) and 218 (182 to 341) days, respectively. Within regions, time to approval ranged from 187 (91 to 205) days (Australia) to 276 (175 to 384) days (Europe). Time to first randomisation ranged from 282 (250 to 313) days (Australia) to 426 (420 to 433) days (North America). Conclusions: Population availability and time to ethics and regulatory approvals influence recruitment; therefore accurate feasibility assessments are critical to site selection. Time to ethics and regulatory approval may not limit site inclusion if compensated by rapid recruitment. Identifying potential delays and methods for reduction can decrease time and costs for sponsors. Trial registration: Clinical Trials.Gov identifier: NCT00335322. Date of registration: 8 June 2006

Pharmacokinetics of lamivudine and lamivudine-triphosphate after administration of 300 milligrams and 150 milligrams once daily to healthy volunteers: Results of the ENCORE 2 Study

There is interest in evaluating the efficacy of lower doses of certain antiretrovirals for clinical care. We determined here the bio-equivalence of plasma lamivudine (3TC) and intracellular 3TC-triphosphate (3TC-TP) concentrations after the administration of two different doses. ENCORE 2 was a randomized crossover study. Subjects received 3TC at 300 and 150 mg once daily for 10 days (arm 1; n = 13) or vice versa (arm 2; n = 11), separated by a 10-day washout. Pharmacokinetic (PK) profiles (0 to 24 h) were assessed on days 10 and 30. Plasma 3TC and 3TC-TP levels in peripheral blood mononuclear cells were quantified by high-performance liquid chromatography-tandem mass spectrometry. Within-subject changes in PK parameters (the area under the concentration-time curve from 0 to 24 h [AUC0-24], the trough concentration of drug in plasma at 24 h [C24], and the maximum concentration of drug in plasma [Cmax]) were evaluated by determining the geometric mean ratios (GMRs) adjusted for study arm, period, and intra-individual variation. Regimens were considered bioequivalent if the 90% confidence interval (90% CI) fell within the range of 0.8 to 1.25. A total of 24 subjects completed the study. The GM (90% CI) 3TC AUC0-24), expressed as ng•h/ml, for the 300- and 150-mg doses were 8,354 (7,609 to 9,172) and 4,773 (4,408 to 5,169), respectively. Bioequivalence in 3TC PK following the administration of 300 and 150 mg was not demonstrated: the GMRs for AUC0-24, C24, and Cmax were 0.57 (0.55 to 0.60), 0.63 (0.59 to 0.67), and 0.56 (0.53 to 0.60), respectively. The GM (90% CI) 3TC-TP AUC0-24 values (pmol•h/106 cells) for the 300- and 150-mg doses were 59.5 (51.8 to 68.3) and 44.0 (38.0 to 51.0), respectively. Bioequivalence in 3TC-TP PK following the administration of 300 and 150 mg was not demonstrated: the GMRs for AUC0-24, C24, and Cmax were 0.73 (0.64 to 0.83), 0.82 (0.68 to 0.99), and 0.70 (0.61 to 0.82), respectively. We found that 3TC at 150 mg is not bioequivalent to the standard regimen of 300 mg, indicating that saturation of cytosine phosphorylation pathways is not achieved at a dose of 150 mg

Differences in the direction of change of cerebral function parameters are evident over three years in HIV-infected individuals electively commencing initial cART

Background: Changes in cerebral metabolite ratios (CMR) measured on H-MRS and changes in cognitive function (CF) are described in subjects commencing combination antiretroviral therapy (cART), although the dynamics of such changes are poorly understood. Methods: Neuroasymptomatic, HIV-infected subjects electively commencing cART were eligible. CMR were assessed in three anatomical voxels and CF assessed at baseline, week 48 and week 144. Overall differences in absolute change in CMRs and CF parameters between 0-48 and 48- 144 weeks were assessed. Results: Twenty-two subjects completed study procedures. Plasma HIV-RNA wa

536Systematic Review and Meta-Analysis of Randomized Controlled Trials (RCTs) Comparing Initial Non-Nucleoside Reverse-Transcriptase Inhibitor (NNRTI)- versus Ritonavir Boosted Protease Inhibitor (PI/r)-based Anti-Retroviral Therapy (ART)

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Comparison of central and local HIV-1 RNA quantification from two international clinical trials

Local and centrally measured plasma HIV RNA (pVL) were assessed for agreement in two trials, ENCORE1 and SECOND-LINE. The proportion less than 200 copies/ml at week 48 was qualitatively similar [ENCORE1 2.5% (95% confidence interval, 95% CI-1.6 to 6.6); 1.9% (95% CI-1.9 to 2.1); SECOND-LINE 0.3% (95% CI-6.4 to 10.0); 1.8% (95% CI-4.7 to 8.3)]. The mean difference in log10 pVL copies/ml at weeks 0 and 48 was less than 0.2 log10 copies/ml in both trials. Our data indicate that central testing of pVL in HIV therapeutic trials is not warranted

Comparison of Dried Blood Spots Versus Conventional Plasma Collection for the Characterization of Efavirenz Pharmacokinetics in a Large-Scale Global Clinical Trial-The ENCORE1 Study

The aim of this study was to determine the utility of dried blood spots (DBS) compared with conventional plasma collection methods for characterization of efavirenz pharmacokinetics, in the setting of a large-scale, global clinical trial (ENCORE1).Six hundred thirty patients were recruited from 38 sites and had single matched whole blood DBS and plasma samples (mid-dose interval) taken at weeks 4 and 12 of treatment. In addition, a subgroup of patients underwent intensive DBS and plasma sampling (0-24 hours) to provide full-profile data for pharmacokinetic parameters. Efavirenz concentrations were determined by validated high-performance liquid chromatography-mass spectrometry methods. A DBS-predicted plasma concentration was derived and linear regression and Bland-Altman plots were used to compare DBS-predicted plasma concentrations with that of measured plasma concentrations.Efavirenz DBS and plasma concentrations were significantly correlated (R = 0.904, P < 0.001; n = 1094), and DBS concentrations were, on average, 53% ± 9.5% lower than plasma. In the main study, the DBS-predicted plasma values significantly underestimated the true measured concentration of efavirenz in plasma; the mean difference (95% confidence interval) between efavirenz DBS-predicted concentrations and measured plasma concentrations was -0.451 mg/L (-0.504 to -0.398) at week 4 (n = 561). However, in the intensive study, the mean difference was only 0.086 mg/L (-0.006 to 0.178) at 12 hours after dose (n = 46) and was not statistically significant.Our data show a high correlation between measurements of efavirenz concentrations in plasma and in DBS. However, DBS concentrations significantly underestimated the true measured plasma concentrations in the sparse samples taken in this large multinational ENCORE1 trial