Rilpivirine vs. efavirenz-based single-tablet regimens in treatment-naive adults: Week 96 efficacy and safety from a randomized phase 3b study

Objectives: To compare efficacy, safety, tolerability, and patient-reported outcomes between two single-tablet regimens, rilpivirine/emtricitabine/tenofovir disoproxil fumarate (RPV/FTC/TDF) and efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF), in HIV-1-infected, treatment-naive adults. Design: This was a phase 3b, 96-week, randomized, open-label, international, noninferiority trial. Methods: A total of 799 participants were randomized (1: 1) to receive RPV/FTC/TDF or EFV/FTC/TDF. The primary efficacy endpoint evaluated proportions of participants with HIV-1 RNA less than 50 copies/ml using the Snapshot algorithm. Additional assessments included CD4 cell counts, genotypic/phenotypic resistance, adverse events, patient-reported outcomes, and quality of life questionnaires. Results: At week 96, trial completion rates were 80.2% (316/394; RPV/FTC/TDF) and 74.0% (290/392; EFV/FTC/TDF). Overall, RPV/FTC/TDF was noninferior to EFV/FTC/TDF [HIV-1 RNA <50 copies/ml: 77.9 vs. 72.4%, respectively; difference-5.5; 95%CI (-0.6, 11.5); P=0.076]. RPV/FTC/TDF was significantly more efficacious compared with EFV/FTC/TDF in participants with baseline HIV-1 RNA equal to or less than 100 000 copies/ml (78.8 vs. 71.2%; P=0.046) and in those with CD4 cell count greater than 200 cells/ml (80.6 vs. 73.0%; P=0.018). There was no significant betweengroup difference in the CD4 cell count increase (278189 vs. 259191 cells/ml; P=0.17). Few participants developed resistance after week 48 (1.0% RPV/FTC/TDF; 0.3% EFV/FTC/TDF). Compared with EFV/FTC/TDF, RPV/FTC/TDF was associated with fewer adverse event-related discontinuations (3.0 vs. 11.0%; P<0.001), significantly fewer adverse events due to central nervous system issues and rash, greater improvements in patient-reported symptoms, and significant improvements in the SF-12v2 quality of life questionnaire mental health composite score (P=0.014). Conclusion: In treatment-naive, HIV-1-infected participants, 96-week RPV/FTC/TDF treatment demonstrated noninferior efficacy and better tolerability than EFV/FTC/TDF

Repeat testing of low-level HIV-1 RNA: Assay performance and implementation in clinical trials

Objective: Assess the performance of HIV-1 RNA repeat testing of stored samples in cases of low-level viremia during clinical trials. Design: Prospective and retrospective analysis of randomized clinical trial samples and reference standards. Methods: To evaluate assay variability of the Cobas AmpliPrep/Cobas TaqMan HIV-1 Test, v2.0, three separate sources of samples were utilized: the World Health Organization (WHO) HIV reference standard (assayed using 50 independent measurements at six viral loads <200 copies/ml), retrospective analysis of four to six aliquots of plasma samples from four clinical trial participants, and prospective repeat testing of 120 samples from participants in randomized trials with low-level viremia. Results: The TaqMan assay on the WHO HIV-1 RNA standards at viral loads <200 copies/ml performed within the expected variability according to assay specifications. However, standards with low viral loads of 36 and 18 copies/ml reported values of ≥ 50 copies/ml in 66 and 18% of tests, respectively. In participants treated with antiretrovirals who had unexpected viremia of 50-200 copies/ml after achieving <50 copies/ml, retesting of multiple aliquots of stored plasma found <50 copies/ml in nearly all cases upon retesting (14/15; 93%). Repeat testing was prospectively implemented in four clinical trials for all samples with virologic rebound of 50-200 copies/ml (n = 120 samples from 92 participants) from which 42% (50/120) had a retest result of less than 50 copies/ml and 58% (70/120) retested ≥ 50 copies/ml. Conclusion: The TaqMan HIV-1 RNA assay shows variability around 50 copies/ml that affects clinical trial results and may impact clinical practice. In participants with a history of viral load suppression, unexpected low-level viremia may be because of assay variability rather than low drug adherence or true virologic failure. Retesting a stored aliquot of the same sample may differentiate between assay variability and virologic failure as the source of viremia. This retesting strategy could save time, money, and anxiety for patients and their providers, as well as decrease follow-up clinic visits without increasing the risk of virologic failure and resistance development

Virological outcomes of EVG/COBI/FTC/TDF and EVG/COBI/FTC/TAF in antiretroviral-naive HIV-1-infected participants with baseline HIV-1 RNA ≥1,000,000 copies/ml: A post hoc analysis of Phase III clinical trials

We address a data gap identified by Adams et al., of virological efficacy outcomes and emergent drug resistance in HIV-1-infected, antiretroviral treatment (ART)-naive participants with baseline (BL) viral loads (VL) >1,000,000 copies/ml. Initial ART regimens including an integrase strand transfer inhibitor (INSTI) cause a rapid decline in VL. In two cases described, the VL response on the single tablet regimen (STR) of co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF) was <2 log10 copies/ml and associated with emergent drug resistance [1]. Double-blind, Phase III studies of EVG/COBI/FTC/TDF (Studies 102/103 and 128), and co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir alafenamide (EVG/COBI/FTC/TAF; Studies 104/111), have investigated the efficacy and safety of both EVG-containing STRs in ART-naive participants [2–10]. We present a post hoc analysis of efficacy of these STRs in participants with VL ≥1,000,000 copies/ml

SWIFT: Prospective 48-Week Study to Evaluate Efficacy and Safety of Switching to Emtricitabine/Tenofovir From Lamivudine/Abacavir in Virologically Suppressed HIV-1 Infected Patients on a Boosted Protease Inhibitor Containing Antiretroviral Regimen

Virologic suppression was well maintained when HIV patients receiving 3TC/ABC with a boosted protease inhibitor were switched to emtricitabine/tenofovir disoproxil fumarate (FTC/TDF). Subjects randomized to FTC/TDF) had fewer virologic failures; in addition, improvements in lipids and Framingham risk scores were noted, while slight declines in estimated GFR were observed. Background.  In the United States, emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) is a preferred nucleoside reverse transcriptase inhibitor (NRTI) backbone with lamivudine/abacavir (3TC/ABC) as a commonly used alternative. For patients infected with human immunodeficiency virus (HIV-1) virologically suppressed on a boosted protease inhibitor (PI) + 3TC/ABC regimen, the merits of switching to FTC/TDF as the NRTI backbone are unknown. Methods.  SWIFT was a prospective, randomized, open-label 48-week study to evaluate efficacy and safety of switching to FTC/TDF. Subjects receiving 3TC/ABC + PI + ritonavir (RTV) with HIV-1 RNA < 200 c/mL ≥3 months were randomized to continue 3TC/ABC or switch to FTC/TDF. The primary endpoint was time to loss of virologic response (TLOVR) with noninferiority measured by delta of 12%. Virologic failure (VF) was defined as confirmed rebound or the last HIV-1 RNA measurement on study drug ≥200 c/mL. Results.  In total, 311 subjects were treated in this study (155 to PI + RTV + FTC/TDF, 156 to PI + RTV + 3TC/ABC). Baseline characteristics were similar between the arms: 85% male, 28% black, median age, 46 years; and median CD4 532 cells/mm 3 . By TLOVR through week 48, switching to FTC/TDF was noninferior compared to continued 3TC/ABC (86.4% vs 83.3%, treatment difference 3.0% (95% confidence interval, −5.1% to 11.2%). Fewer subjects on FTC/TDF experienced VF (3 vs 11; P = .034). FTC/TDF showed greater declines in fasting low-density lipoproteins (LDL), total cholesterol (TC), and triglycerides (TG) with significant declines in LDL and TC beginning at week 12 with no TC/HDL ratio change. Switching to FTC/TDF showed improved NCEP thresholds for TC and TG and improved 10-year Framingham TC calculated scores. Decreased epidermal growth factor receptor (eGFR) was observed in both arms with a larger decrease in the FTC/TDF arm. Conclusions.  Switching to FTC/TDF from 3TC/ABC maintained virologic suppression, had fewer VFs, improved lipid parameters and Framingham scores but decreased eGFR. ClinicalTrials.gov identifier.  NCT00724711

Randomized study evaluating the efficacy and safety of switching from an an abacavir/lamivudine-based regimen to an elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide single-tablet regimen

Objective:To evaluate the efficacy and safety of switching from an abacavir/lamivudine (ABC/3TC)-based regimen to an elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) single-tablet regimen in virologically suppressed, HIV-1-infected adults.Design:Randomized, open-label, noninferiority study.Methods:Participants with HIV-1 RNA levels less than 50 copies/ml receiving ABC/3TC plus a third agent for at least 6 months were randomized 2 : 1 to switch immediately to E/C/F/TAF (immediate-switch group) for 48 weeks or to continue receiving ABC/3TC plus a third agent for 24 weeks followed by E/C/F/TAF for 24 weeks (delayed-switch group). The primary endpoint was HIV-1 RNA less than 50 copies/ml at Week 24 by Food and Drug Administration Snapshot algorithm (-12% noninferiority margin).Results:Baseline characteristics of 274 participants (183 in immediate-switch group and 91 in delayed-switch group) were similar. Virologic response was maintained at Week 24 by 93.4 and 97.8% of participants in the immediate-switch and delayed-switch groups, respectively, with a treatment difference of-4.4% (95% confidence interval:-9.4 to 1.9%), confirming noninferiority. Adverse events of any grade were similar between groups through Week 24 (66% E/C/F/TAF, 64% ABC/3TC); adverse event-related drug discontinuations occurred in 4% of participants switching to E/C/F/TAF (no discontinuations because of renal events) and no participants continuing ABC/3TC. Renal biomarkers of urine albumin:creatinine and beta-2-microglobulin:creatinine ratios significantly improved on E/C/F/TAF. Self-reported treatment satisfaction was significantly higher with E/C/F/TAF.Conclusion:Switching to E/C/F/TAF was noninferior to continuing ABC/3TC plus a third agent for maintenance of HIV RNA suppression at Week 24. This study supports E/C/F/TAF as an efficacious and well tolerated option for participants switching from ABC/3TC-based regimens