Kirsten White

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.

Co-formulated elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate versus ritonavir-boosted atazanavir plus co-formulated emtricitabine and tenofovir disoproxil fumarate for initial treatment of HIV-1 infection: a randomised, double-blind, phase 3, non-inferiority trial.

BACKGROUND The HIV integrase strand transfer inhibitor elvitegravir (EVG) has been co-formulated with the CYP3A4 inhibitor cobicistat (COBI), emtricitabine (FTC), and tenofovir disoproxil fumarate (TDF) into a once-daily, single tablet. We compared EVG/COBI/FTC/TDF with a ritonavir-boosted (RTV) protease inhibitor regimen of atazanavir (ATV)/RTV+FTC/TDF as initial therapy for HIV-1 infection. METHODS This phase 3, non-inferiority study enrolled treatment-naive patients with an HIV-1 RNA concentration of 5000 copies per mL or more and susceptibility to atazanavir, emtricitabine, and tenofovir. Patients were randomly assigned (1:1) to receive EVG/COBI/FTC/TDF or ATV/RTV+FTC/TDF plus matching placebos, administered once daily. Randomisation was by a computer-generated random sequence, accessed via an interactive telephone and web response system. Patients, and investigators and study staff who gave treatments, assessed outcomes, or analysed data were masked to the assignment. The primary endpoint was HIV RNA concentration of 50 copies per mL or less after 48 weeks (according to the US FDA snapshot algorithm), with a 12% non-inferiority margin. This trial is registered with ClinicalTrials.gov, number NCT01106586. FINDINGS 1017 patients were screened, 715 were enrolled, and 708 were treated (353 with EVG/COBI/FTC/TDF and 355 with ATV/RTV+FTC/TDF). EVG/COBI/FTC/TDF was non-inferior to ATV/RTV+FTC/TDF for the primary outcome (316 patients [89·5%] vs 308 patients [86·8%], adjusted difference 3·0%, 95% CI -1·9% to 7·8%). Both regimens had favourable safety and tolerability; 13 (3·7%) versus 18 (5·1%) patients discontinued treatment because of adverse events. Fewer patients receiving EVG/COBI/FTC/TDF had abnormal results in liver function tests than did those receiving ATV/RTV+FTC/TDF and had smaller median increases in fasting triglyceride concentration (90 μmol/L vs 260 μmol/L, p=0·006). Small median increases in serum creatinine concentration with accompanying decreases in estimated glomerular filtration rate occurred in both study groups by week 2; they generally stabilised by week 8 and did not change up to week 48 (median change 11 μmol/L vs 7 μmol/L). INTERPRETATION If regulatory approval is given, EVG/COBI/FTC/TDF would be the first integrase-inhibitor-based regimen given once daily and the only one formulated as a single tablet for initial HIV treatment. FUNDING Gilead Sciences.

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.

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.

Non-nucleoside reverse transcriptase inhibitor (NNRTI) cross-resistance: implications for preclinical evaluation of novel NNRTIs and clinical genotypic resistance testing

OBJECTIVES The introduction of two new non-nucleoside reverse transcriptase inhibitors (NNRTIs) in the past 5 years and the identification of novel NNRTI-associated mutations have made it necessary to reassess the extent of phenotypic NNRTI cross-resistance. METHODS We analysed a dataset containing 1975, 1967, 519 and 187 genotype-phenotype correlations for nevirapine, efavirenz, etravirine and rilpivirine, respectively. We used linear regression to estimate the effects of RT mutations on susceptibility to each of these NNRTIs. RESULTS Sixteen mutations at 10 positions were significantly associated with the greatest contribution to reduced phenotypic susceptibility (≥10-fold) to one or more NNRTIs, including: 14 mutations at six positions for nevirapine (K101P, K103N/S, V106A/M, Y181C/I/V, Y188C/L and G190A/E/Q/S); 10 mutations at six positions for efavirenz (L100I, K101P, K103N, V106M, Y188C/L and G190A/E/Q/S); 5 mutations at four positions for etravirine (K101P, Y181I/V, G190E and F227C); and 6 mutations at five positions for rilpivirine (L100I, K101P, Y181I/V, G190E and F227C). G190E, a mutation that causes high-level nevirapine and efavirenz resistance, also markedly reduced susceptibility to etravirine and rilpivirine. K101H, E138G, V179F and M230L mutations, associated with reduced susceptibility to etravirine and rilpivirine, were also associated with reduced susceptibility to nevirapine and/or efavirenz. CONCLUSIONS The identification of novel cross-resistance patterns among approved NNRTIs illustrates the need for a systematic approach for testing novel NNRTIs against clinical virus isolates with major NNRTI-resistance mutations and for testing older NNRTIs against virus isolates with mutations identified during the evaluation of a novel NNRTI.

Bictegravir versus dolutegravir, each with emtricitabine and tenofovir alafenamide, for initial treatment of HIV-1 infection: a randomised, double-blind, phase 2 trial

BACKGROUND All recent treatment guidelines recommend integrase strand transfer inhibitors (INSTIs) as components of initial HIV therapy. Bictegravir, a novel, once-daily, unboosted INSTI, showed potent activity in a 10 day monotherapy study and has a high in-vitro resistance barrier. On the basis of these results, we did a phase 2 trial comparing bictegravir with dolutegravir. METHODS In this randomised, double-blind, phase 2 trial, we recruited previously untreated adults (aged ≥18 years) with HIV-1 infections from 22 outpatient centres in the USA. Eligible patients had HIV-1 RNA concentrations of at least 1000 copies per mL, CD4 counts of at least 200 cells per μL, estimated glomerular filtration rates of at least 70 mL per min, and HIV-1 genotypes showing sensitivity to emtricitabine and tenofovir. We excluded patients if they were hepatitis B-co-infected or hepatitis C-co-infected, had new AIDS-defining conditions within 30 days of screening, or were pregnant. We randomly allocated participants (2:1) to receive oral once-daily 75 mg bictegravir or 50 mg dolutegravir with matching placebo plus the fixed-dose combination of 200 mg emtricitabine and 25 mg tenofovir alafenamide for 48 weeks. We randomly allocated participants via an interactive web system, stratified by HIV-1 RNA concentration. Investigators, patients, study staff giving treatment, collecting data, and assessing outcomes, and the funder were masked to treatment group. The primary outcome was the proportion of participants with plasma HIV-1 RNA concentrations of less than 50 copies per mL at week 24 according to the US Food and Drug Administration-defined snapshot algorithm. We included all participants receiving one dose of study drug in analyses. This trial is registered with ClinicalTrials.gov, number NCT02397694. FINDINGS Between March 23, 2015, and May 21, 2015, we screened 125 patients, randomly allocating and giving study drug to 98 (65 received bictegravir plus emtricitabine and tenofovir alafenamide and 33 received dolutegravir plus emtricitabine and tenofovir alafenamide). At week 24, 63 (96·9%) of 65 in the bictegravir group had HIV-1 RNA loads of less than 50 copies per mL compared with 31 (93·9%) of 33 in the dolutegravir group (weighted difference 2·9%, 95% CI -8·5 to 14·2; p=0·50). Treatment-emergent adverse events were reported by 55 (85%) of 65 participants in the bictegravir plus emtricitabine and tenofovir alafenamide group versus 22 (67%) of 33 in the dolutegravir plus emtricitabine and tenofovir alafenamide group. The most common adverse events were diarrhoea (eight [12%] of 65 vs four [12%] of 33) and nausea (five [8%] of 65 vs four [12%] of 33). One participant taking bictegravir plus emtricitabine and tenofovir alafenamide discontinued because of a drug-related adverse event (urticaria) after week 24. No treatment-related serious adverse events or deaths occurred. INTERPRETATION Bictegravir plus emtricitabine and tenofovir alafenamide and dolutegravir plus emtricitabine and tenofovir alafenamide both showed high efficacy up to 24 weeks. Both treatments were well tolerated. Administration of bictegravir, a novel, potent, once-daily INSTI designed to improve on existing INSTI options with the backbone of emtricitabine and tenofovir alafenamide, might provide an advantage to patients. FUNDING Gilead Sciences.

Bictegravir, emtricitabine, and tenofovir alafenamide versus dolutegravir, abacavir, and lamivudine for initial treatment of HIV-1 infection (GS-US-380-1489): a double-blind, multicentre, phase 3, randomised controlled non-inferiority trial

BACKGROUND Integrase strand transfer inhibitors (INSTIs) are recommended components of initial antiretroviral therapy with two nucleoside reverse transcriptase inhibitors. Bictegravir is a novel, potent INSTI with a high in-vitro barrier to resistance and low potential as a perpetrator or victim of clinically relevant drug-drug interactions. We aimed to assess the efficacy and safety of bictegravir coformulated with emtricitabine and tenofovir alafenamide as a fixed-dose combination versus coformulated dolutegravir, abacavir, and lamivudine. METHODS We did this double-blind, multicentre, active-controlled, randomised controlled non-inferiority trial at 122 outpatient centres in nine countries in Europe, Latin America, and North America. We enrolled HIV-1 infected adults (aged ≥18 years) who were previously untreated (HIV-1 RNA ≥500 copies per mL); HLA-B*5701-negative; had no hepatitis B virus infection; screening genotypes showing sensitivity to emtricitabine, tenofovir, lamivudine, and abacavir; and an estimated glomerular filtration rate of 50 mL/min or more. Participants were randomly assigned (1:1), via a computer-generated allocation sequence (block size of four), to receive coformulated bictegravir 50 mg, emtricitabine 200 mg, and tenofovir alafenamide 25 mg or coformulated dolutegravir 50 mg, abacavir 600 mg, and lamivudine 300 mg, with matching placebo, once daily for 144 weeks. Randomisation was stratified by HIV-1 RNA (≤100 000 copies per mL, >100 000 to ≤400 000 copies per mL, or >400 000 copies per mL), CD4 count (<50 cells per μL, 50-199 cells per μL, or ≥200 cells per μL), and region (USA or ex-USA). Investigators, participants, and study staff giving treatment, assessing outcomes, and collecting data were masked to group assignment. The primary endpoint was the proportion of participants with plasma HIV-1 RNA less than 50 copies per mL at week 48, as defined by the US Food and Drug Administration snapshot algorithm, with a prespecified non-inferiority margin of -12%. All participants who received one dose of study drug were included in primary efficacy and safety analyses. This trial is registered with ClinicalTrials.gov, number NCT02607930. FINDINGS Between Nov 13, 2015, and July 14, 2016, we randomly assigned 631 participants to receive coformulated bictegravir, emtricitabine, and tenofovir alafenamide (n=316) or coformulated dolutegravir, abacavir, and lamivudine (n=315), of whom 314 and 315 patients, respectively, received at least one dose of study drug. At week 48, HIV-1 RNA less than 50 copies per mL was achieved in 92·4% of patients (n=290 of 314) in the bictegravir, emtricitabine, and tenofovir alafenamide group and 93·0% of patients (n=293 of 315) in the dolutegravir, abacavir, and lamivudine group (difference -0·6%, 95·002% CI -4·8 to 3·6; p=0·78), demonstrating non-inferiority of bictegravir, emtricitabine, and tenofovir alafenamide to dolutegravir, abacavir, and lamivudine. No individual developed treatment-emergent resistance to any study drug. Incidence and severity of adverse events was mostly similar between groups except for nausea, which occurred less frequently in patients given bictegravir, emtricitabine, and tenofovir alafenamide than in those given dolutegravir, abacavir, and lamivudine (10% [n=32] vs 23% [n=72]; p<0·0001). Adverse events related to study drug were less common with bictegravir, emtricitabine, and tenofovir alafenamide than with dolutegravir, abacavir, and lamivudine (26% [n=82] vs 40% [n=127]), the difference being driven by a higher incidence of drug-related nausea in the dolutegravir, abacavir, and lamivudine group (5% [n=17] vs 17% [n=55]; p<0·0001). INTERPRETATION At 48 weeks, coformulated bictegravir, emtricitabine, and tenofovir alafenamide achieved virological suppression in 92% of previously untreated adults and was non-inferior to coformulated dolutegravir, abacavir, and lamivudine, with no treatment-emergent resistance. Bictegravir, emtricitabine, and tenofovir alafenamide was safe and well tolerated with better gastrointestinal tolerability than dolutegravir, abacavir, and lamivudine. Because coformulated bictegravir, emtricitabine, and tenofovir alafenamide does not require HLA B*5701 testing and provides guideline-recommended treatment for individuals co-infected with HIV and hepatitis B, this regimen might lend itself to rapid or same-day initiation of therapy in the clinical setting. FUNDING Gilead Sciences.

Coformulated bictegravir, emtricitabine, and tenofovir alafenamide versus dolutegravir with emtricitabine and tenofovir alafenamide, for initial treatment of HIV-1 infection (GS-US-380–1490): a randomised, double-blind, multicentre, phase 3, non-inferiority trial

BACKGROUND Integrase strand transfer inhibitors (INSTIs) coadministered with two nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs) are recommended as first-line treatment for HIV, and coformulated fixed-dose combinations are preferred to facilitate adherence. We report 48-week results from a study comparing initial HIV-1 treatment with bictegravir-a novel INSTI with a high in-vitro barrier to resistance and low potential as a perpetrator or victim of clinically relevant drug interactions-coformulated with the NRTI combination emtricitabine and tenofovir alafenamide as a fixed-dose combination to dolutegravir administered with coformulated emtricitabine and tenofovir alafenamide. METHODS In this randomised, double-blind, multicentre, placebo-controlled, non-inferiority trial, HIV-infected adults were screened and enrolled at 126 outpatient centres in 10 countries in Australia, Europe, Latin America, and North America. Participants were previously untreated adults (HIV-1 RNA ≥500 copies per mL) with estimated glomerular filtration rate of at least 30 mL/min. Chronic hepatitis B virus or hepatitis C co-infection was allowed. We randomly assigned participants (1:1) to receive oral fixed-dose combination bictegravir 50 mg, emtricitabine 200 mg, and tenofovir alafenamide 25 mg or dolutegravir 50 mg with coformulated emtricitabine 200 mg and tenofovir alafenamide 25 mg, with matching placebo, once a day for 144 weeks. Investigators, participants, study staff, and those assessing outcomes were masked to treatment group. All participants who received at least one dose of study drug were included in primary efficacy and safety analyses. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of less than 50 copies per mL at week 48 (US Food and Drug Administration snapshot algorithm), with a prespecified non-inferiority margin of -12%. This study is registered with ClinicalTrials.gov, number NCT02607956. FINDINGS Between Nov 11, 2015, and July 15, 2016, 742 participants were screened for eligibility, of whom 657 were randomly assigned to treatment (327 with bictegravir, emtricitabine, and tenofovir alafenamide fixed-dose combination [bictegravir group] and 330 with dolutegravir plus emtricitabine and tenofovir alafenamide [dolutegravir group]). 320 participants who received the bictegravir regimen and 325 participants who received the dolutegravir regimen were included in the primary efficacy analyses. At week 48, HIV-1 RNA <50 copies per mL was achieved in 286 (89%) of 320 participants in the bictegravir group and 302 (93%) of 325 in the dolutegravir group (difference -3·5%, 95·002% CI -7·9 to 1·0, p=0·12), showing non-inferiority of the bictegravir regimen to the dolutegravir regimen. No treatment-emergent resistance to any study drug was observed. Incidence and severity of adverse events were similar between groups, and few participants discontinued treatment due to adverse events (5 [2%] of 320 in the bictegravir group and 1 [<1%] 325 in the dolutegravir group). Study drug-related adverse events were less common in the bictegravir group than in the dolutegravir group (57 [18%] of 320 vs 83 [26%] of 325, p=0·022). INTERPRETATION At 48 weeks, virological suppression with the bictegravir regimen was achieved and was non-inferior to the dolutegravir regimen in previously untreated adults. There was no emergent resistance to either regimen. The fixed-dose combination of bictegravir, emtricitabine, and tenofovir alafenamide was safe and well tolerated compared with the dolutegravir regimen. FUNDING Gilead Sciences Inc.

Integrase inhibitor versus protease inhibitor based regimen for HIV-1 infected women (WAVES): a randomised, controlled, double-blind, phase 3 study

BACKGROUND Women are under-represented in HIV antiretroviral therapy (ART) studies. Guidelines for selection of ART as initial therapy in patients with HIV-1 infection do not contain sex-specific treatment. We aimed to assess the safety and efficacy of the single tablet integrase inhibitor regimen containing elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate compared with a boosted protease inhibitor regimen of ritonavir-boosted atazanavir with emtricitabine and tenofovir disoproxil fumarate. METHODS In this international, randomised, controlled, double-blind, phase 3 study (Women AntiretroViral Efficacy and Safety study [WAVES]), we recruited treatment-naive HIV-infected women with an estimated creatinine clearance of 70 mL/min or higher from 80 centres in 11 countries. Women were randomly assigned (1:1) to receive elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (integrase inhibitor regimen) or ritonavir-boosted atazanavir with emtricitabine and tenofovir disoproxil fumarate (protease inhibitor based regimen); regimens were masked with matching placebos. Randomisation was done by a computer-generated allocation sequence (block size four) and was stratified by HIV-1 RNA viral load and race. Investigators, patients, study staff, and those assessing outcomes were masked to treatment group. All participants who received one dose of study drug were included in the primary efficacy and safety analyses. The main outcome was the proportion of patients with plasma HIV-1 RNA less than 50 copies per mL at week 48 as defined by US Food and Drug Administration snapshot algorithm (prespecified non-inferiority margin of 12%). This study is registered with ClinicalTrials.gov, number NCT01705574. FINDINGS Between Nov 28, 2012, and March 12, 2014, 575 women were enrolled. 289 were randomly assigned to receive the integrase inhibitor regimen and 286 to receive the protease inhibitor based regimen. 252 (87%) women in the integrase inhibitor group had plasma HIV-1 RNA less than 50 copies per mL at week 48 compared with 231 (81%) women in the protease inhibitor group (adjusted difference 6·5%; 95% CI 0·4-12·6). No participant had virological failure with resistance in the integrase inhibitor group compared with three participants ([1%]; all Met184Val/Ile) in the protease inhibitor group. 19 women in the protease inhibitor group discontinued because of adverse events compared with five in the integrase inhibitor group. INTERPRETATION WAVES shows that clinical trials of ART regimens in global and diverse populations of treatment-naive women are possible. The findings support guidelines recommending integrase inhibitor based regimens in first-line antiretroviral therapy. FUNDING Gilead Sciences.

A randomized study of tenofovir disoproxil fumarate in treatment-experienced HIV-1 infected adolescents.

Background: There are few data on the safety and antiviral activity of tenofovir disoproxil fumarate (TDF) in HIV-1 infected adolescents. Methods: A randomized, double-blinded, placebo-controlled study was conducted. Ninety adolescents (12 to <18 years) who were viremic while receiving antiretroviral treatment were randomized to receive TDF 300 mg (mean, 216.8 mg/m2) or placebo in combination with an optimized background regimen (OBR) for 48 weeks. The primary efficacy endpoint was time-weighted average change in plasma HIV-1 RNA from baseline at week 24 Results: Eighty-seven subjects (45 TDF, 42 placebo) received the study drug. Through week 24, the median time-weighted average change in plasma HIV-1 RNA was not different between the TDF and placebo groups (−1.6 versus −1.6 log10copies/mL, P = 0.55). The percentages of subjects who achieved HIV-1 RNA <400 copies/mL were similar at week 24 (40.9 versus 41.5%). One fourth of subjects in the TDF and placebo groups (24.4 versus 28.6%) had at least 3 active agents in the OBR. Many subjects in both groups had baseline genotypic resistance to TDF (48.9 versus 33.3%). TDF was generally safe and well tolerated. There were no statistically significant differences in changes of renal function and bone mineral density between the 2 groups. Conclusion: This study of TDF in combination with an OBR in antiretroviral-experienced adolescents did not meet its primary or secondary efficacy endpoints. The effectiveness of the OBR and baseline genotypic resistance to TDF in both groups may have confounded the efficacy findings. No clinically relevant TDF-related renal or bone toxicities were observed in this adolescent population.