Hui C. Liu

Co-formulated elvitegravir, cobicistat, emtricitabine, and tenofovir versus co-formulated efavirenz, emtricitabine, and tenofovir for initial treatment of HIV-1 infection: a randomised, double-blind, phase 3 trial, analysis of results after 48 weeks

BACKGROUND The integrase inhibitor elvitegravir (EVG) has been co-formulated with the CYP3A4 inhibitor cobicistat (COBI), emtricitabine (FTC), and tenofovir disoproxil fumarate (TDF) in a single tablet given once daily. We compared the efficacy and safety of EVG/COBI/FTC/TDF with standard of care-co-formulated efavirenz (EFV)/FTC/TDF-as initial treatment for HIV infection. METHODS In this phase 3 trial, treatment-naive patients from outpatient clinics in North America were randomly assigned by computer-generated allocation sequence with a block size of four in a 1:1 ratio to receive EVG/COBI/FTC/TDF or EFV/FTC/TDF, once daily, plus matching placebo. Patients and study staff involved in giving study treatment, assessing outcomes, and collecting and analysing data were masked to treatment allocation. Eligibility criteria included screening HIV RNA concentration of 5000 copies per mL or more, and susceptibility to efavirenz, emtricitabine, and tenofovir. The primary endpoint was HIV RNA concentration of fewer than 50 copies per mL at week 48. The study is registered with ClinicalTrials.gov, number NCT01095796. FINDINGS 700 patients were randomly assigned and treated (348 with EVG/COBI/FTC/TDF, 352 with EFV/FTC/TDF). EVG/COBI/FTC/TDF was non-inferior to EFV/FTC/TDF; 305/348 (87·6%) versus 296/352 (84·1%) of patients had HIV RNA concentrations of fewer than 50 copies per mL at week 48 (difference 3·6%, 95% CI -1·6% to 8·8%). Proportions of patients discontinuing drugs for adverse events did not differ substantially (13/348 in the EVG/COBI/FTC/TDF group vs 18/352 in the EFV/FTC/TDF group). Nausea was more common with EVG/COBI/FTC/TDF than with EFV/FTC/TDF (72/348 vs 48/352) and dizziness (23/348 vs 86/352), abnormal dreams (53/348 vs 95/352), insomnia (30/348 vs 49/352), and rash (22/348 vs 43/352) were less common. Serum creatinine concentration increased more by week 48 in the EVG/COBI/FTC/TDF group than in the EFV/FTC/TDF group (median 13 μmol/L, IQR 5 to 20 vs 1 μmol/L, -6 to 8; p<0·001). INTERPRETATION If regulatory approval is given, EVG/COBI/FTC/TDF would be the only single-tablet, once-daily, integrase-inhibitor-based regimen for initial treatment of HIV infection. FUNDING Gilead Sciences.

Effect of cobicistat on glomerular filtration rate in subjects with normal and impaired renal function.

Objective:This study evaluated the effect of cobicistat (COBI) on glomerular filtration rate in subjects with normal renal function (RF) or with mild/moderate renal impairment, by comparing creatinine clearance [estimated glomerular filtration rate (eGFR)] with actual GFR (aGFR) using iohexol, a probe drug excreted by glomerular filtration. COBI is a potent CYP3A inhibitor (pharmacoenhancer) currently in phase 3 testing with elvitegravir, atazanavir, and darunavir. Methods:Normal RF subjects received COBI 150 mg QD, ritonavir (RTV) 100 mg QD, or placebo for 7 days; subjects with mild/moderate renal impairment received COBI 150 mg QD. The eGFR and aGFR were measured on days 0, 7, and 14 and within-subject changes calculated relative to day 0. COBI and RTV pharmacokinetics were analyzed on day 7. Results:All 36 subjects in cohort 1 and 17 of 18 subjects in cohort 2 completed all study treatments. Study treatments were well tolerated. Small increases in serum creatinine with corresponding mean decreases in eGFR (∼10 mL/min or mL/min per 1.73 m2) were observed on day 7 relative to day 0 in subjects receiving COBI (P < 0.05). The decreases were reversible on COBI discontinuation; mean eGFR values returned to baseline on day 14 (P > 0.05). No statistically significant changes in aGFR on days 7 or 14 relative to day 0 were seen with COBI (P > 0.05). No statistically significant decreases in aGFR or eGFR were observed with RTV or placebo. Conclusions:COBI affects eGFR but not the actual GFR. The time to onset, magnitude, and time to resolution of changes in eGFR are consistent with altered proximal tubular secretion of creatinine through inhibition of drug transporters.

A randomized double-blind comparison of coformulated elvitegravir/ cobicistat/emtricitabine/tenofovir disoproxil fumarate versus efavirenz/emtricitabine/tenofovir disoproxil fumarate for initial treatment of HIV-1 infection: Analysis of week 96 results

Abstract:We report week 96 results from a phase 3 trial of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF, n = 348) vs efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF, n = 352). At week 48, EVG/COBI/FTC/TDF was noninferior to EFV/FTC/TDF (88% vs 84%, difference +3.6%, 95% confidence interval: −1.6% to 8.8%). Virologic success (HIV-1 RNA <50 copies/mL) was maintained at week 96 (84% vs 82%, difference +2.7%, 95% CI: −2.9% to 8.3%). Discontinuation due to adverse events was low (5% vs 7%). Median changes in serum creatinine (mg/dL) at week 96 were similar to week 48. These results support the durable efficacy and long-term safety of EVG/COBI/FTC/TDF.

Randomized, phase 2 evaluation of two single-tablet regimens elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate versus efavirenz/emtricitabine/tenofovir disoproxil fumarate for the initial treatment of HIV infection.

Objective:To assess the safety and efficacy of two, single-tablet regimens for the initial treatment of HIV infection. Design:Phase 2, randomized, double-blind, double-dummy, multicenter, active-controlled study. Methods:Antiretroviral treatment-naive adults with a screening HIV-1 RNA at least 5000 copies/ml and a CD4 cell count more than 50 cells/μl were randomized 2: 1 to receive fixed-dose combination tablets of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF; N = 48) or efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF; n = 23) for 48 weeks. The primary endpoint was proportion of participants with HIV-1 RNA less than 50 copies/ml at week 24. Results:Participants receiving EVG/COBI/FTC/TDF exhibited a more rapid decline in HIV-1 RNA and a greater proportion suppressed viral load to less than 50 copies/ml than participants receiving EFV/FTC/TDF. Both EVG/COBI/FTC/TDF and EFV/FTC/TDF resulted in high rates of viral suppression and increases in CD4 cell count. Ninety and 83% of participants suppressed HIV-1 RNA to less than 50 copies/ml both at the 24-week and 48-week visits for EVG/COBI/FTC/TDF and EFV/FTC/TDF, respectively. Once-daily administration of EVG/COBI/FTC/TDF provided a mean EVG trough concentration 10-fold over its protein binding-adjusted IC95 across study visits. EVG/FTC/TDF/GS-9350 was generally well tolerated with a lower rate of drug-related central nervous system (17%) and psychiatric (10%) adverse events versus EFV/FTC/TDF (26 and 44%, respectively). Decreases in estimated glomerular filtration rate occurred within the first few weeks of dosing in participants receiving EVG/COBI/FTC/TDF, remained within the normal range and did not progress at week 24 or 48; no participant experienced a clinical adverse event or discontinued study drug due to changes in serum creatinine or renal function. Conclusion:Once-daily EVG/COBI/FTC/TDF achieved and maintained a high rate of virologic suppression with fewer central nervous system and psychiatric adverse events compared to a current standard-of-care regimen of EFV/FTC/TDF.

Phase 2 study of cobicistat versus ritonavir each with once-daily atazanavir and fixed-dose emtricitabine/ tenofovir df in the initial treatment of HIV infection

Objective:To assess efficacy and safety of cobicistat versus ritonavir as pharmacoenhancers for atazanavir when administered with emtricitabine/tenofovir df as initial treatment for HIV-1 infection. Design:Randomized, partially placebo-controlled, double-blind, multicenter study. Participants:Antiretroviral treatment-naive adults, screening HIV-1 RNA of at least 5000 copies/ml and CD4 cell count more than 50 cells/&mgr;l. Intervention:Randomized 2 : 1 (stratified by HIV RNA ⩽ or >100 000 copies/ml) to receive placebo-blinded once-daily cobicistat 150 mg or ritonavir 100 mg with open-label atazanavir and fixed-dose emtricitabine/tenofovir df. Main outcome measures:Efficacy and safety at weeks 24 and 48. Results:Eighty-four percent of ATV/co participants and 86% of ATV/r participants suppressed HIV-1 RNA (<50 copies/ ml) at week 24, and 82 and 86% at week 48, respectively, and mean CD4 cell count increased 203 and 199 cells/&mgr;l at week 24 and 208 and 177 cells/&mgr;l at week 48, respectively. Study treatment discontinuation due to adverse events occurred in 4% ATV/co and in 3% ATV/r participants through 48 weeks. Treatment-related adverse events occurred in 36% ATV/co and 48% ATV/r participants; hyperbilirubinemia occurred in 96 and 100%, and ocular icterus or jaundice occurred in 14 and 17%, respectively. Mean estimated glomerular filtration rate (Cockcroft–Gault, ml/min) decrease occurred in both treatment groups and was evident at week 2 (ATV/co −9, ATV/r −4), reached a nadir by week 24 (−15, −14, respectively), and did not progress further through week 48 (−13, −14). Conclusion:Using cobicistat and ritonavir as pharmacoenhancers for atazanavir and administered with emtricitabine/tenofovir df achieved comparable rates of virologic suppression and CD4 cell count increase with satisfactory safety profiles.

A Randomized, Double-Blind Comparison of Single-Tablet Regimen Elvitegravir/Cobicistat/Emtricitabine/Tenofovir DF Versus Single-Tablet Regimen Efavirenz/Emtricitabine/Tenofovir DF for Initial Treatment of HIV-1 Infection: Analysis of Week 144 Results

INTRODUCTION The first integrase inhibitor-based single-tablet regimen combines elvitegravir (an integrase inhibitor), cobicistat (a pharmacoenhancer), emtricitabine (FTC), and tenofovir DF (TDF) (EVG/ COBI/FTC/TDF). In 2 phase 3 randomized trials, EVG/COBI/FTC/TDF demonstrated noninferior efficacy at week 48 to efavirenz (EFV)/FTC/TDF (study 102) and to ritonavir-boosted atazanavir ATV + RTV + FTC/TDF (study 103) with durable efficacy through week 96. We present week 144 data from study 102. METHODS A full description of the methods has been published. A brief description is provided below.

Tenofovir Alafenamide Versus Tenofovir Disoproxil Fumarate in the First Protease Inhibitor-Based Single-Tablet Regimen for Initial HIV-1 Therapy: A Randomized Phase 2 Study.

Objectives:To evaluate the safety and efficacy of the novel tenofovir prodrug, tenofovir alafenamide (TAF), as part of the first protease inhibitor–based single-tablet regimen (STR) for initial treatment of HIV-1 infection. Methods:Antiretroviral therapy (ART)-naive adults with estimated glomerular filtration rate ≥70 mL/min were randomized 2:1 to receive the darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) STR (TAF: N = 103) or darunavir + cobicistat + emtricitabine/tenofovir disoproxil fumarate (TDF: N = 50) once daily with matched placebos for 48 weeks. Results:At week 24, viral suppression (HIV-1 RNA <50 copies/mL) rates were similar (TAF 74.8% vs. TDF 74.0%). At week 48, rates were TAF 76.7% vs. TDF 84.0%; the difference was driven by higher rate of discontinuations in TAF (6.8%) vs. TDF (2%). Among those with virologic failure, none developed resistance. Most adverse events were of mild/moderate severity. The mean change in serum creatinine from baseline at week 48 was 0.06 mg/dL (95% confidence interval: 0.04 to 0.08) for TAF vs. 0.09 mg/dL (95% confidence interval: 0.05 to 0.14) for TDF (P = 0.053). The % change in retinol binding protein/Cr ratio was +9 (TAF) vs. +54 (TDF), P = 0.003; the % change in urine &bgr;-2 microglobulin/Cr ratio was −42.0 (TAF) vs. +2.3 (TDF), P = 0.002. The % change in hip bone mineral density (BMD) was −0.84 (TAF) vs. −3.82 (TDF), P < 0.001 and in spine BMD was −1.57 (TAF) vs. −3.62 (TDF), P = 0.003. There were no fractures in either group. Conclusions:The TAF arm had significantly improved renal and bone safety parameters: less proteinuria and less change in hip and spine BMD, consistent with results from a similarly designed study of the elvitegravir/C/F/TAF STR. This D/C/F/TAF STR offers a promising option for initial HIV treatment, with the high barrier to resistance of darunavir, and the potential for improved long-term renal and bone safety with TAF.

Brief Report: Cobicistat Compared With Ritonavir as a Pharmacoenhancer for Atazanavir in Combination With Emtricitabine/Tenofovir Disoproxil Fumarate: Week 144 Results.

Background:Cobicistat (COBI) is a pharmacoenhancer with no antiretroviral activity. Methods:International, randomized double-blind active-controlled trial to evaluate the efficacy and safety of COBI vs ritonavir (RTV) as a pharmacoenhancer of atazanavir in combination with emtricitabine/tenofovir disoproxil fumarate in HIV treatment-naive patients followed through week 144. Results:At Week 144, virologic suppression was achieved in 72% (COBI) and 74% (RTV) of patients. Adverse events leading to study drug discontinuation occurred in 11% of patients in each group. Median changes in serum creatinine (mg/dL) were +0.13 (COBI) and +0.07 (RTV) and were unchanged from week 48. Conclusions:Once-daily COBI is a safe and effective pharmacoenhancer of the protease inhibitor atazanavir.

Switching from tenofovir disoproxil fumarate to tenofovir alafenamide coformulated with rilpivirine and emtricitabine in virally suppressed adults with HIV-1 infection: a randomised, double-blind, multicentre, phase 3b, non-inferiority study

BACKGROUND Tenofovir alafenamide, a tenofovir prodrug, results in 90% lower tenofovir plasma concentrations than does tenofovir disproxil fumarate, thereby minimising bone and renal risks. We investigated the efficacy, safety, and tolerability of switching to a single-tablet regimen containing rilpivirine, emtricitabine, and tenofovir alafenamide compared with remaining on rilpivirine, emtricitabine, and tenofovir disoproxil fumarate. METHODS In this randomised, double-blind, multicentre, placebo-controlled, non-inferiority trial, HIV-1-infected adults were screened and enrolled at 119 hospitals in 11 countries in North America and Europe. Participants were virally suppressed (HIV-1 RNA <50 copies per mL) on rilpivirine, emtricitabine, and tenofovir disoproxil fumarate for at least 6 months before enrolment and had creatinine clearance of at least 50 mL/min. Participants were randomly assigned (1:1) to receive a single-tablet regimen of either rilpivirine (25 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg) or to remain on a single-tablet regimen of rilpivirine (25 mg), emtricitabine (200 mg), and tenofovir disoproxil fumarate (300 mg), with matching placebo, once daily for 96 weeks. Investigators, participants, study staff, and those assessing outcomes were masked to treatment group. All participants who received one dose of study drug and were on the tenofovir disoproxil fumarate regimen before screening were included in primary efficacy analyses. The primary endpoint was the proportion of participants with less than 50 copies per mL of plasma HIV-1 RNA at week 48 (by the US Food and Drug Administration snapshot algorithm), with a prespecified non-inferiority margin of 8%. This study was registered with ClinicalTrials.gov, number NCT01815736. FINDINGS Between Jan 26, 2015, and Aug 25, 2015, 630 participants were randomised (316 to the tenofovir alafenamide group and 314 to the tenofovir disoproxil fumarate group). At week 48, 296 (94%) of 316 participants on tenofovir alafenamide and 294 (94%) of 313 on tenofovir disoproxil fumarate had maintained less than 50 copies per mL HIV-1 RNA (difference -0·3%, 95·001% CI -4·2 to 3·7), showing non-inferiority of tenofovir alafenamide to tenofovir disoproxil fumarate. Numbers of adverse events were similar between groups. 20 (6%) of 316 participants had study-drug related adverse events in the tenofovir alafenamide group compared with 37 (12%) of 314 in the tenofovir disoproxil fumarate group; none of these were serious. INTERPRETATION Switching to rilpivirine, emtricitabine, and tenofovir alafenamide was non-inferior to continuing rilpivirine, emtricitabine, tenofovir disoproxil fumarate in maintaining viral suppression and was well tolerated at 48 weeks. These findings support guidelines recommending tenofovir alafenamide-based regimens, including coformulation with rilpivirine and emtricitabine, as initial and ongoing treatment for HIV-1 infection. FUNDING Gilead Sciences.

Equivalent Decline in Inflammation Markers with Tenofovir Disoproxil Fumarate vs. Tenofovir Alafenamide

Background Initiation of antiretroviral therapy (ART) and subsequent virologic suppression reduces immune activation and systemic inflammation. Methods We examined longitudinal changes in biomarkers of monocyte activation (sCD14, sCD163), and systemic (IL-6, hsCRP, sTNFR-I and D-dimer) and vascular (Lp-PLA2) inflammation in a subgroup (N = 100 per arm) of participants enrolled in a randomized, placebo-controlled trial comparing elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF; TAF) to E/C/F/tenofovir disoproxil fumarate (E/C/F/TDF; TDF) in treatment-naïve adults. Results For 194 participants (TAF, 98; TDF, 96), baseline levels of biomarkers did not differ by treatment arm; there were no differences in biomarker values between groups at weeks 12, 24, or 48 (p > 0.05), except IL-6 at week 12 (p = 0.012). Among all participants (combining groups), there were statistically significant declines from baseline observed for D-dimer, sCD163, and sTNFR-1 by week 12 and IL-6 by week 24. The proportion of participants with Lp-LA2 levels < 200 ng per mL (p = 0.250) or hsCRP levels < 3000 mg per L (p = 0.586) was unchanged through week 48. Conclusions We observed equivalent declines in biomarkers of monocyte activation and systemic inflammation in treatment-naïve adults treated with TAF or TDF for 48 weeks, suggesting that TAF and TDF have equivalent impact on immune activation and inflammation.