Time To Loss Of Virological Response Research Articles

P17.36 Effectiveness, safety and tolarebility profile of stribild®(elvitegravir/cobicistat/emitricitabine/tenofovir disoproxil fumarate) in hiv-1-infected patients in the clinical setting

Introduction The efficacy of Stribild ® , an integrase strand transfer inhibitor (INSTI) -based STR, has been evaluated in randomised clinical trials. However, restricted selection criteria, monitoring frequency and selection bias hamper data extrapolation in routine practice. Here we analysed the virologic outcomes, safety and tolerability profile of Stribild ® in clinical practice. Methods Retrospective monocentric analysis on HIV-1-infected patients, who started with or were switched to Stribild ® . The percentage of patients remaining free of therapeutic failure was estimated using the time-to-loss-of-virologic-response (TLOVR) algorithm, by intent-to-treat analysis. Results We analysed the data of 197 patients (56 ART-naive and 141 treatment-experienced patients). At the end of follow-up (median 33 months), 87.3% of treatment-naive and 80.3% of treatment-experienced patients remained free of therapeutic failure. A total of 17 patients stopped treatment with Stribild ® , 5.4% (3/56) of them were treatment-naive and 9.9% (14/141) were treatment-experienced patients. The Stribild ® therapy was discontinued in 2 because of VF, loss to follow-up in 4, and drug-drug interactions in 2 patients. Adverse events were in 7 (3.6%) patients the reason to switch from therapy with Stribild ® and further 2 (1.0%)patients decided personally to switch. In two patients novel resistances in integrase-gene (N155H and S119R) emerged. In one further patient with VF two novel mutations in the RT-gene were observed when compared to historical genotypic test result (V106I/M and M184V). Conclusion In treatment-naive patients effectiveness of Stribild ® was consistent with data obtained in clinical trials. The safety and tolerability profile as well as resistance development confirmed clinical efficacy of Stribild ® in a daily practice setting. Disclosure of interest statement Heiko Jessen received honoraria related to speakers’ activities and consulting from ViiV Healthcare, AbbVie Germany, Bristol-Myers Squibb and Gilead Sciences, grants from MSD Sharp and Dohme and ViiV Healthcare and an additional grant from Gilead Sciences for this study.

The ASSURE study: HIV-1 suppression is maintained with bone and renal biomarker improvement 48 weeks after ritonavir discontinuation and randomized switch to abacavir/lamivudine + atazanavir.

Objectives HIV treatment guidelines endorse switching or simplification of antiretroviral therapy in therapy‐experienced patients with suppressed viraemia; ritonavir discontinuation may also enhance tolerability and reduce long‐term adverse events (AEs). This open‐label, multicentre, noninferiority study enrolled HIV‐1‐infected, treatment‐experienced adults with confirmed HIV‐1 RNA ≤ 75 HIV‐1 RNA copies/mL currently receiving tenofovir/emtricitabine + atazanavir/ritonavir (TDF/FTC + ATV/r) for ≥ 6 months with no reported history of virological failure.MethodsParticipants were randomized 1:2 to continue current treatment or switch to abacavir/lamivudine + atazanavir (ABC/3TC + ATV). Endpoints included the proportion of participants with HIV‐1 RNA < 50 copies/mL by time to loss of virological response (TLOVR), AEs, fasting lipids, and inflammatory, coagulation, bone and renal biomarkers.ResultsAfter 48 weeks, 76% (152 of 199) of ABC/3TC + ATV‐treated and 79% (77 of 97) of TDF/FTC + ATV/r‐treated participants had HIV‐1 RNA < 50 copies/mL (TLOVR; P = 0.564). Other efficacy analyses yielded similar results. Rates of new grade 2–4 AEs were 45% in both groups, but an excess of hyperbilirubinaemia made the rate of treatment‐emergent grade 3–4 laboratory abnormalities higher with TDF/FTC + ATV/r (36%) compared with ABC/3TC + ATV (19%). Most fasting lipid levels remained stable over time; high‐density lipoprotein (HDL) cholesterol increased modestly in ABC/3TC + ATV‐treated participants. Bone and renal biomarkers improved significantly between baseline and week 48 in participants taking ABC/3TC + ATV and were stable in participants taking TDF/FTC + ATV/r. No significant changes occurred in any inflammatory or coagulation biomarker within or between treatment groups.ConclusionsThe ABC/3TC + ATV treatment‐switch group had similar viral suppression rates up to 48 weeks to the TDF/FTC + ATV/r comparator group, with lower rates of moderate‐ to high‐grade hyperbilirubinaemia and improvements in bone and renal biomarkers.

Simplification to abacavir/lamivudine + atazanavir maintains viral suppression and improves bone and renal biomarkers in ASSURE, a randomized, open label, non-inferiority trial.

ObjectiveSimplification of antiretroviral therapy in patients with suppressed viremia may minimize long-term adverse effects. The study’s primary objective was to determine whether abacavir/lamivudine + atazanavir (ABC/3TC+ATV) was virologically non-inferior to tenofovir/emtricitabine + atazanavir/ritonavir (TDF/FTC+ATV/r) over 24 weeks in a population of virologically suppressed, HIV-1 infected patients.DesignThis open-label, multicenter, non-inferiority study enrolled antiretroviral experienced, HIV-infected adults currently receiving a regimen of TDF/FTC+ATV/r for ≥6 months with no history of virologic failure and whose HIV-1 RNA had been ≤75 copies/mL on 2 consecutive measurements including screening. Patients were randomized 1∶2 to continue current treatment or simplify to ABC/3TC+ATV.MethodsThe primary endpoint was the proportion of patients with HIV-RNA<50 copies/mL at Week 24 by the Time to Loss of Virologic Response (TLOVR) algorithm. Secondary endpoints included alternative measures of efficacy, adverse events (AEs), and fasting lipids. Exploratory endpoints included inflammatory, coagulation, bone, and renal biomarkers.ResultsAfter 24 weeks, ABC/3TC+ATV (n = 199) was non-inferior to TDF/FTC+ATV/r (n = 97) by both the primary analysis (87% in both groups) and all secondary efficacy analyses. Rates of grade 2–4 AEs were similar between the two groups (40% vs 37%, respectively), but an excess of hyperbilirubinemia made the rate of grade 3–4 laboratory abnormalities higher in the TDF/FTC+ATV/r group (30%) compared with the ABC/3TC+ATV group (13%). Lipid levels were stable except for HDL cholesterol, which increased significantly in the ABC/3TC+ATV group. Bone and renal biomarkers improved significantly between baseline and Week 24 in patients taking ABC/3TC+ATV, and the difference between groups was significant at Week 24. No significant changes occurred in any inflammatory or coagulation biomarker within or between treatment groups.ConclusionsAfter 24 weeks, simplification to ABC/3TC+ATV from TDF/FTC+ATV/r maintained viral suppression was well-tolerated, and led to improvements in bone and renal biomarkers and HDL cholesterol.Trial RegistrationClinicalTrials.gov NCT01102972 GlaxoSmithKline Clinical Study Register #113734

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.

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. 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. 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 estimated glomerular filtration rate [corrected] (eGFR) was observed in both arms with a larger decrease in the FTC/TDF arm. 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.

Effect modification by sex and baseline CD4+ cell count among adults receiving combination antiretroviral therapy in Botswana: results from a clinical trial.

The Tshepo study was the first clinical trial to evaluate outcomes of adults receiving nevirapine (NVP)-based versus efavirenz (EFV)-based combination antiretroviral therapy (cART) in Botswana. This was a 3 year study (n=650) comparing the efficacy and tolerability of various first-line cART regimens, stratified by baseline CD4(+): <200 (low) vs. 201-350 (high). Using targeted maximum likelihood estimation (TMLE), we retrospectively evaluated the causal effect of assigned NNRTI on time to virologic failure or death [intent-to-treat (ITT)] and time to minimum of virologic failure, death, or treatment modifying toxicity [time to loss of virological response (TLOVR)] by sex and baseline CD4(+). Sex did significantly modify the effect of EFV versus NVP for both the ITT and TLOVR outcomes with risk differences in the probability of survival of males versus the females of approximately 6% (p=0.015) and 12% (p=0.001), respectively. Baseline CD4(+) also modified the effect of EFV versus NVP for the TLOVR outcome, with a mean difference in survival probability of approximately 12% (p=0.023) in the high versus low CD4(+) cell count group. TMLE appears to be an efficient technique that allows for the clinically meaningful delineation and interpretation of the causal effect of NNRTI treatment and effect modification by sex and baseline CD4(+) cell count strata in this study. EFV-treated women and NVP-treated men had more favorable cART outcomes. In addition, adults initiating EFV-based cART at higher baseline CD4(+) cell count values had more favorable outcomes compared to those initiating NVP-based cART.

The MONET trial: week 144 analysis of the efficacy of darunavir/ritonavir (DRV/r) monotherapy versus DRV/r plus two nucleoside reverse transcriptase inhibitors, for patients with viral load &lt; 50 HIV‐1 RNA copies/mL at baseline

In the MONotherapy in Europe with Tmc114 (MONET) trial, darunavir/ritonavir (DRV/r) monotherapy showed noninferior efficacy vs. two nucleoside reverse transcriptase inhibitors (NRTIs) plus DRV/r at the primary 48-week analysis. The trial was continued to week 144 to assess the durability of the results. A total of 256 patients with viral load < 50 HIV-1 RNA copies/mL on current highly active antiretroviral therapy (HAART) for at least 6 months switched to DRV/r 800/100 mg once daily, either as monotherapy (n=127) or with two NRTIs (n=129). Treatment failure was defined as two consecutive HIV RNA levels above 50 copies/mL [time to loss of virological response (TLOVR)] by week 144, or discontinuation of study drugs. Eighty-one per cent of patients were male and 91% were Caucasian, and they had a median baseline CD4 count of 575 cells/uL. More patients in the DRV/r monotherapy arm had hepatitis C virus coinfection at baseline than in the control arm (18% vs. 12%, respectively). By week 144, the percentage of patients with HIV RNA < 50 copies/mL [intent to treat (ITT), TLOVR, switch=failure method] was 69% vs. 75% in the DRV/r monotherapy and triple therapy arms [difference= -5.9%; 95% confidence interval (CI) -16.9%, +5.1%]; by a strict ITT analysis (switches not considered failures), the percentage of patients with HIV RNA < 50 copies/mL was 84% vs. 83.5%, respectively (difference= +0.5%; 95% CI -8.7%, +9.7%). Twenty-one and 13 patients had two consecutive HIV RNA results above 50 copies/mL in the DRV/r monotherapy arm and triple therapy arm, respectively, of whom 18 of 21 (86%) and 10 of 13 (77%) had HIV RNA < 50 copies/mL at week 144. In this study, for patients with HIV RNA < 50 copies/mL at baseline, switching to DRV/r monotherapy showed noninferior efficacy to DRV/r plus two NRTIs in a strict ITT (switches not considered failures) analysis, but not in a TLOVR switch equals failure analysis.

Phase 2 double-blind, randomized trial of etravirine versus efavirenz in treatment-naive patients

The Study of Etravirine Neuropsychiatric Symptoms versus Efavirenz (SENSE) trial compared etravirine with efavirenz in treatment-naive patients. The primary endpoint was neuropsychiatric adverse events up to week 12; HIV RNA suppression at week 48 was a secondary endpoint. Patients with HIV RNA more than 5000 copies/ml were randomized to etravirine 400 mg once daily (n = 79) or efavirenz (n = 78), plus two nucleoside analogues. HIV RNA less than 50 copies/ml at week 48 was analysed using the time to loss of virological response (TLOVR) algorithm. Drug resistance at treatment failure and safety endpoints were also evaluated. At baseline, the median CD4 cell count was 302 cells/μl and HIV RNA was 4.8 log10 copies/ml. In the intent to treat TLOVR analysis at week 48, 60 of 79 (76%) patients on etravirine versus 58 of 78 (74%) on efavirenz had HIV RNA less than 50 copies/ml. In the on-treatment analysis, 60 of 65 (92%) taking etravirine had HIV RNA les than 50 copies/ml versus 58 of 65 (89%) for efavirenz: etravirine showed noninferior efficacy versus efavirenz in both analyses (P < 0.05). Four patients had virological failure in the etravirine arm: none developed resistance to nucleoside analogues or nonnucleosides. Seven patients had virological failure in the efavirenz arm: three developed treatment-emergent resistance to nucleoside analogues and/or nonnucleosides. At the week 48 visit, the percentage with ongoing neuropsychiatric adverse events was 6.3% for etravirine and 21.5% for efavirenz (P = 0.011). First-line treatment with etravirine 400 mg once daily and two nucleoside reverse transcriptase inhibitors (NRTIs) led to similar rates of HIV RNA suppression, compared with efavirenz and two NRTIs. None of the patients with virological failure in the etravirine arm developed resistance to nonnucleosides.

Definitions of antiretroviral treatment failure for measuring quality outcomes

Our aim was to compare three different definitions of treatment failure and discuss their use as quality outcome measures for a clinical service. Data for treatment-naïve patients who attended the Melbourne Sexual Health Centre (MSHC) between 1 January 2000 and 31 December 2008 were analysed. Definition 1 was the strict Food and Drug Administration (FDA) definition of treatment failure as determined using the time to loss of virological response (TLOVR) algorithm. Definition 2 defined treatment failure as occurring in those whose viral load never fell to <400 HIV-1 RNA copies/mL or who developed two consecutive viral loads > or =400 copies/mL on any treatment (switching or stopping treatment with a viral load <400 copies/mL was permitted). Definition 3 was the same as definition 2 except that individuals were also deemed to have failed if they stopped treatment for 6 months or longer. There were 310 antiretroviral-naïve patients who started treatment in the study period. Of these, 156 [50.3%; 95% confidence interval (CI) 42.1-53.3%] experienced treatment failure under definition 1, 10 (3.2%; 95% CI 1.5-5.8%) experienced treatment failure under definition 2, and 16 (4.5%; 95% CI 2.5-7.4%) experienced treatment failure under definition 3 over the 108 months of follow-up. The probability of failing definition 1 was statistically different from the probability of failing definition 2 or 3 (P=0.01). There were significant differences in treatment failure for the three definitions. If definition 1 were used, the outcomes would be sufficiently common to enable clinics to be compared but would be less meaningful. If definition 2 or 3 were used, the events would be too rare to enable clinics to be compared, but it would be possible to set a benchmark level of success that clinics could aim to reach.

Efficacy and Safety of Maraviroc Versus Efavirenz, Both With Zidovudine/Lamivudine: 96-Week Results From the MERIT Study

Background: The MERIT study evaluated maraviroc versus efavirenz, both with zidovudine/lamivudine, in treatment-naïve patients with CCR5-tropic (R5) HIV-1. Post hoc analyses previously assessed week 48 outcomes in patients rescreened with R5 virus by a more sensitive tropism assay. Methods: Week 96 efficacy (post hoc, n = 614) and safety (n = 721) were assessed. Results: Proportions of subjects <50 copies/mL (58.8% maraviroc, 62.7% efavirenz) and time to loss of virologic response (TLOVR) responders (<50 copies/mL: 60.5% vs 60.7%) were similar. Maraviroc recipients had greater CD4 increases (+ 212 vs + 171 cells/mm3) and fewer adverse event discontinuations (6.1% vs 15.5%), malignancies, and category C events. Conclusion: Week 96 data confirm week 48 observations in MERIT.

Causes and Consequences of Incomplete HIV RNA Suppression in Clinical Trials

The current goal of antiretroviral treatment is suppression of HIV RNA below 50 copies/mL. However, there is evidence for residual low-level plasma viraemia below 50 copies/mL for people with HIV RNA suppression on antiretroviral treatment. It is not clear whether more profound suppression of HIV RNA would lead to a lower risk of virological failure on antiretroviral treatment or emergent drug resistance. There is high variability in the currently used HIV RNA PCR assays for samples with HIV RNA levels close to the detection lower limit of 40–50 copies/mL. For patients who have HIV RNA levels just above 50 copies/mL (often called “single blips”), a repeat sample should be taken to investigate the possibility of technical error. In a systematic review of 48-week effi cacy from randomized clinical trials (N = 8,083), patients were signifi cantly more likely to show HIV RNA levels between 50–400 copies/mL while taking fi rst-line boosted PI-based HAART (7.3%) compared with fi rst-line NNRTI-based HAART (4.5%) (p < 0.01). However in a systematic review of emergent drug resistance at failure in the same trials, there was also a signifi cantly lower risk of emerging drug resistance after virological failure of boosted PI-based HAART (p < 0.01). Therefore, HIV RNA blips between 50–400 copies/mL may have different consequences for different classes of antiretrovirals. The most widely used method to analyse HIV RNA in clinical trials — time to loss of virological response (TLOVR) — uses two consecutive HIV RNA measurements to define both virological success and failure. However, other methods may improve precision and increase statistical power.

Fosamprenavir/ritonavir in advanced HIV disease (TRIAD): a randomized study of high-dose, dual-boosted or standard dose fosamprenavir/ritonavir in HIV-1-infected patients with antiretroviral resistance

APV102002 was an open-label study comparing a dual-boosted HIV-1 protease inhibitor (PI) [fosamprenavir/lopinavir/ritonavir (FPV/LPV/RTV; 1400 mg/533 mg/133 mg twice daily)] and a high dose of FPV/RTV 1400 mg/100 mg twice daily (HD-FPV/RTV) versus the standard FPV/RTV 700 mg/100 mg twice-daily (STD-FPV/RTV) regimen for 24 weeks. Adult patients with prior failure to two or more PI-based regimens and on a failing PI regimen were randomized to STD-FPV/RTV (n = 24), HD-FPV/RTV (n = 25) or FPV/LPV/RTV (n = 25). The primary aim was to test week 24 superiority of HD-FPV/RTV and FPV/LPV/RTV over STD-FPV/RTV as measured by plasma HIV-1 RNA average area under the curve minus baseline (AAUCMB). There was no difference in the week 24 AAUCMB between the regimens. The proportion of patients with <50 copies/mL of plasma HIV RNA was 21%, 24% and 20%, respectively, by time to loss of virological response (TLOVR) analysis. High baseline drug resistance provided some explanation for the low efficacy. A lower baseline background drug resistance and higher fosamprenavir genotypic inhibitory quotient led to better antiviral responses. The plasma amprenavir trough concentartion (C(tau)) was 49% higher in the HD-FPV/RTV arm than in the STD-FPV/RTV arm and similar in the FPV/LPV/RTV and STD-FPV/RTV arms. The plasma lopinavir C(tau) was similar to historical data with standard LPV/RTV 400 mg/100 mg twice daily. All regimens were relatively well tolerated, although diarrhoea was more frequent in the HD-FPV/RTV and FPV/LPV/RTV arms, and hypertriglyceridaemia and increased total cholesterol were more common in the FPV/LPV/RTV arm. While the strategies of higher dose FPV/RTV and dual FPV/LPV/RTV were relevant at the time of study initiation, new therapies for antiretroviral-experienced patients make such strategies of limited interest. In addition, this study failed to demonstrate antiviral superiority of the HD-FPV/RTV or FPV/LPV/RTV regimen over the STD-FPV/RTV twice-daily regimen in highly treatment-experienced patients.

Comparative Efficacy of Nucleoside/Nucleotide Reverse Transcriptase Inhibitors in Combination with Efavirenz: Results of a Systematic Overview

Background: Many trials of antiretroviral therapy in treatment-naïve subjects have investigated the relative efficacy of the third drug in a treatment regimen. However, the nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) components may also affect efficacy. Method: A systematic overview of clinical trials studying initial treatment in naïve subjects receiving efavirenz-containing regimens and providing week 48 time to loss of virologic response (TLOVR) results was undertaken to compare results with different NRTI combinations. Results: Seven trials studying 3,807 subjects were identified that met the inclusion criteria. Baseline characteristics were similar across studies. Using the week 48 TLOVR results as the primary method of comparison, combinations of tenofovir and lamivudine or emtricitabine appeared to provide improved virologic responses. Similar results were obtained when the proportions of subjects with plasma HIV RNA levels <50 copies/mL were examined.

Emtricitabine

Emtricitabine (Emtriva) is an orally administered nucleoside reverse transcriptase inhibitor (NRTI) that is indicated in combination with other antiretroviral agents in the treatment of HIV infection in adults. As a component of antiretroviral therapy (ART), emtricitabine effectively reduces and/or maintains suppression of viral load in ART-naive adults or ART-experienced adults switching from stable combination regimens, and is generally well tolerated. Emtricitabine is a component of preferred initial HIV combination therapy regimens; it can be used in place of lamivudine as part of the dual NRTI backbone in non-nucleoside reverse transcriptase inhibitor (NNRTI)- and protease inhibitor (PI)-based regimens. Moreover, preliminary data from a randomised, open-label study suggest that emtricitabine plus tenofovir DF, a preferred dual-NRTI combination, is better tolerated than co-formulated lamivudine/zidovudine, another preferred dual-NRTI combination, resulting in a higher persistent virological response rate, as analysed using the US FDA time to loss of virological response (TLOVR) algorithm. With the convenience of once-daily (single pill) administration, no dietary restrictions and a favourable drug interaction and tolerability profile, emtricitabine should facilitate patient adherence to treatment, which, in turn, is central to the success of antiretroviral therapy. Similarly, emtricitabine is attractive as an option for ART-experienced stable adults requiring regimen simplification.