scholarly journals 1448. Forgiveness of BIC/FTC/TAF: In Vitro Simulations of Intermittent Poor Adherence Find Limited HIV-1 Breakthrough and High Barrier to Resistance

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S726-S727
Author(s):  
Andrew Mulato ◽  
Rima K Acosta ◽  
Stephen R Yant ◽  
Tomas Cihlar ◽  
Kirsten L White
Keyword(s):  
Virologic Failure ◽  
Resistance Development ◽  
Drug Concentrations ◽  
Suboptimal Adherence ◽  
Trough Concentrations ◽  
Tenofovir Alafenamide ◽  
Emergence Of Resistance ◽  
Perfect Adherence ◽  
Hiv 1

Abstract Background Short lapses in adherence to ARVs can lead to virologic failure and emergence of resistance. Previous in vitro studies of regimen “forgiveness” simulated drug exposures of perfect adherence or short-term suboptimal adherence with bictegravir+emtricitabine+tenofovir alafenamide (BIC+FTC+TAF) and with dolutegravir and lamivudine (DTG+3TC). Here, viral breakthrough (VB) and resistance development were evaluated under alternating high and low drug exposures simulating variable adherence levels. Methods Wild-type HIV-1 (IIIb)-infected MT-2 cells were exposed to drug combinations and monitored for VB. Experiments alternated between high and low drug concentrations of either BIC+FTC+TAF or DTG+3TC (Table 1). Drug concentrations for each regimen were determined using human plasma-free adjusted clinical trough concentrations (Cmin), at simulated Cmin after missing 2 or 4 consecutive doses (Cmin-2 and Cmin-4) based on drug half-lives. Emergent HIV-1 were genotyped by deep sequencing and a 2% threshold. Results In these experiments, constant drug concentrations corresponding to full adherence (Cmin) did not lead to VB. Using Cmin concentrations for one week followed by constant Cmin-2 exposures for 4 weeks, DTG+3TC had VB and emergence of M184V/I in reverse transcriptase (RT) but there was no VB for BIC+FTC+TAF. Using alternating drug exposures of Cmin (weeks 1 and 3) and Cmin-2 or Cmin -4 (weeks 2, 4, and 5), VB was not observed with BIC+FTC+TAF, and VB was decreased or delayed with DTG+3TC compared to DTG+3TC held at Cmin-2 or Cmin-4. Resistance development was observed in some cultures with VB: 1 culture with BIC+FTC+TAF had G163R in IN and 19 cultures with DTG+3TC had INSTI and RT resistance including 10 with M184V/I. Table 1. Summary of Breakthrough Frequency and Resistance Development Conclusion BIC+FTC+TAF has high in vitro forgiveness and consistent protection against emergence of drug resistance during simulations of short lapses in adherence. Higher DTG+3TC exposure, whether constant or intermittent, was better at preventing or delaying VB than lower DTG+3TC exposures, but DTG+3TC was less forgiving than BIC+FTC+TAF. Prevention of viral replication and resistance development is necessary to maintain lifelong viral suppression, particularly in the real world where drug adherence is often imperfect. Disclosures Andrew Mulato, BS, MBA, Gilead Sciences, Inc. (Employee, Shareholder) Rima K. Acosta, BS, Gilead Sciences, Inc. (Employee, Shareholder) Stephen R. Yant, PhD, Gilead Sciences, Inc. (Employee, Shareholder) Tomas Cihlar, PhD, Gilead Sciences, Inc. (Employee, Shareholder) Kirsten L. White, PhD, Gilead Sciences, Inc. (Employee, Shareholder)

scholarly journals 2509. Pooled Resistance Analyses of Darunavir (DRV) Once Daily (QD) Regimens and Formulations Across 10 Clinical Studies of Treatment-Naïve (TN) and Treatment-Experienced (TE) Patients with Human Immunodeficiency Virus (HIV)-1 Infection

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S870-S871 ◽  
Author(s):  
Erkki Lathouwers ◽  
Sareh Seyedkazemi ◽  
Donghan Luo ◽  
Kimberley Brown ◽  
Sandra De Meyer ◽  
...  
Keyword(s):  
Clinical Studies ◽  
Virologic Failure ◽  
Transcriptase Inhibitor ◽  
Resistance Testing ◽  
Resistance Development ◽  
Single Tablet Regimen ◽  
Treatment Naïve ◽  
Tenofovir Alafenamide ◽  
Hiv 1 ◽  
Phenotypic Susceptibility

Abstract Background DRV has demonstrated high efficacy and barrier to resistance development across diverse populations, from TN to heavily TE patients. We evaluated resistance data from 10 clinical studies of different DRV 800 mg QD–based antiretroviral regimens and formulations. Methods The analysis included patients from 10 phase 2/3 studies (48–192 weeks in duration) of ritonavir- and cobicistat-boosted DRV 800 mg QD–based regimens in TN and virologically failing or suppressed TE patients with HIV-1 (table). Three were phase 3 studies of the DRV/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg single-tablet regimen (STR). Post-baseline resistance was evaluated in patients experiencing protocol-defined virologic failure (PDVF); definitions and criteria for resistance testing varied slightly among studies. Resistance-associated mutations (RAMs) were based on respective International Antiviral Society–USA mutation lists over time. Results Of the 3,635 patients evaluated, 250 met PDVF criteria and 205 had post-baseline genotypes/phenotypes. Overall, 4 (0.1%) patients developed (or had identified [switch studies]) ≥1 DRV and/or primary protease inhibitor (PI) RAM (table), and only 1 (< 0.1%, ODIN) patient lost DRV phenotypic susceptibility; this TE patient had prior VF with lopinavir. Among those who used a nucleos(t)ide reverse transcriptase inhibitor (NRTI) backbone (mostly emtricitabine [FTC] + tenofovir [TFV]), 12 (0.4%) patients had ≥1 NRTI RAM, including 10 with M184I/V associated with FTC resistance. No TFV RAMs were observed. Among patients receiving D/C/F/TAF (n = 1,949), none had post-baseline DRV, primary PI, or TFV RAMs; only 2 (0.1%) patients developed an FTC RAM. Conclusion Across a large, diverse population using DRV 800 mg QD–based regimens and formulations, resistance development remains rare; 0.1% of patients had ≥1 DRV and/or primary PI RAM post-baseline. Among 3 trials of the D/C/F/TAF STR, no patients developed a DRV or primary PI RAM. After > 10 years of investigating DRV 800 mg QD–based regimens in clinical trials, loss of phenotypic susceptibility to DRV has never been observed in TN or TE virologically suppressed patients and was only once observed in a TE patient with prior VF on multiple antiretrovirals, including a PI. Disclosures All authors: No reported disclosures.

scholarly journals 888. In Vitro Forgiveness of INSTI-Containing Regimens at Drug Concentrations Simulating Variable Adherence

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S535-S535
Author(s):  
Rima K Acosta ◽  
Andrew Mulato ◽  
Michelle L D’Antoni ◽  
Stephen R Yant ◽  
Tomas Cihlar ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Term Treatment ◽  
Strand Transfer ◽  
Drug Concentrations ◽  
Long Term Treatment ◽  
Fixed Drug ◽  
Transfer Inhibitor ◽  
Trough Concentrations ◽  
Tenofovir Alafenamide

Abstract Background The integrase strand transfer inhibitor (INSTI)-based regimens bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF), dolutegravir (DTG)+FTC/TAF, DTG/lamivudine (3TC), and DTG/rilpivirine (RPV) are all used for treatment of HIV-infected patients. Here, relative time to in vitro viral breakthrough (VB) and resistance barrier using simulated human drug exposures at either full or suboptimal treatment adherence to each regimen were compared. Methods Wild-type HIV-1 (IIIb)-infected MT-2 cells were exposed to the combinations of BIC+FTC+TAF, DTG+FTC+TAF, DTG+3TC, or DTG+RPV for up to 35 days or until VB. Fixed drug concentrations were the human plasma-free adjusted clinical trough concentrations (Cmin) or fixed at simulated Cmin after missing 1 to 4 consecutive doses (Cmin-1 to -4), with many replicates. Drug resistance was studied by next-generation sequencing at ≥2% frequency. Results At drug concentrations corresponding to full adherence and 1 missed dose (Cmin and Cmin-1), no VB occurred with any regimen (Table). At Cmin-2, only DTG+3TC had VB, with some emergent resistance to both drugs. At Cmin-3, all regimens had VB: by day 12, 100% of DTG+3TC wells had VB; for BIC+FTC+TAF, DTG+FTC+TAF, and DTG+RPV, &lt; 15% of wells had VB which began after day 14. Emergent RT or IN resistance was seen for DTG+RPV and DTG+3TC but not for BIC+FTC+TAF or DTG+FTC+TAF. At Cmin-4, all DTG+3TC and DTG+FTC+TAF wells had VB by day 12, while DTG+RPV had 94% VB by day 25 and BIC+FTC+TAF had 50% VB by day 35. Emergent Cmin-4 drug resistance was seen for all regimens but at differing frequencies; DTG+RPV had the most wells with resistance. Cumulatively, emergent RT and/or IN resistance was found in 1.3% BIC+FTC+TAF, 2.5% DTG+FTC+TAF, 7.9% DTG+3TC, and 8.8% DTG+RPV cultures. Summary of Forgiveness and Barrier to Resistance of INSTI-Containing Regimens Conclusion Regimen forgiveness and resistance barrier are important factors in long term treatment. These INSTI-based regimens had high in vitro forgiveness and resistance barriers with concentrations simulating high adherence. When multiple missed doses were simulated in vitro, BIC+FTC+TAF had the highest forgiveness and barrier to resistance. When compared to DTG+3TC and DTG+FTC+TAF, DTG+RPV had higher forgiveness but lower resistance barrier after several simulated missed doses. Disclosures Rima K. Acosta, BS, Gilead Sciences, Inc. (Employee, Shareholder) Andrew Mulato, BS, MBA, Gilead Sciences, Inc. (Employee, Shareholder) Michelle L. D’Antoni, PhD, Gilead Sciences (Employee, Shareholder)Gilead Sciences, Inc (Employee, Shareholder) Stephen R. Yant, PhD, Gilead Sciences, Inc. (Employee, Shareholder) Tomas Cihlar, PhD, Gilead Sciences, Inc. (Employee, Shareholder) Kirsten L. White, PhD, Gilead Sciences, Inc (Employee, Shareholder)

scholarly journals A new combination bictegravir+tenofovir alafenamide nanoformulation with prolonged sustained-drug-release potency for HIV-1 PrEP: A concept evaluation study.

2021 ◽  
Author(s):  
Subhra Mandal ◽  
Pavan Kumar Prathipati ◽  
Shawnalyn W Sunagawa ◽  
Christopher J. Destache
Keyword(s):  
Sustained Release ◽  
Evaluation Study ◽  
New Combination ◽  
Sustained Drug Release ◽  
Drug Concentrations ◽  
Concept Evaluation ◽  
Tenofovir Alafenamide ◽  
Hiv 1

The antiretroviral treatment (ART) approach is the best-prescribed approach to date for pre-exposure prophylaxis (PrEP) for high-risk individuals. However, the daily combination ARVs (cARVs) regimen has become cumbersome for healthy individuals leading to non-adherence. Recent surveys showed high acceptance of parenteral sustained-release ART enhancing PrEP adherence. Our approach is to design a parenteral nanoparticle (NP)-based cARV sustained-release (cARV-SR) system as long-acting HIV PrEP. In this work, we reported a new combination of two potent ARV, (tenofovir alafenamide fumarate (TAF) and bictegravir (BIC)) loaded nanoformulation intended as cARV-SR for PrEP. The BIC+TAF NPs were fabricated by standardized in-house methodology. In-vitro intracellular kinetics, cytotoxicity, and HIV-1 protection studies demonstrated BIC+TAF encapsulation prolonged drug retention, reduced drug-associated cytotoxicity, and enhanced HIV protection. In human PBMCs, nanoformulated BIC+TAF demonstrated significant (p < 0.05) improvement in the drug’s selectivity index by 472 times compared to the BIC+TAF in solution. In-vivo pharmacokinetic (PK) study of BIC, TAF and respective drug metabolite in female BALB/c mice after single subcutaneous BIC+TAF NPs demonstrated plasma drug concentrations of BIC and tenofovir (TFV) above intracellular IC50 level during the entire 30-day study period, and prolonged persistence of both active drugs in the HIV target organs including vagina, colon, spleen, and lymph nodes. This report demonstrated encapsulation of BIC+TAF in a nanoformulation improved its therapeutic selectivity and in-vivo pharmacokinetics of free drugs. Based on these preliminary studies, we hypothesize cARV-SR has potential as an innovative once monthly delivery for PrEP.

scholarly journals No Emergent Resistance in HIV-1 Infected Virologically-Suppressed Subjects Who Switched to R/F/TAF

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S427-S427
Author(s):  
Danielle Porter ◽  
Rima Kulkarni ◽  
Huyen Cao ◽  
Devi Sengupta ◽  
Kirsten White
Keyword(s):  
Dna Analysis ◽  
Virologic Failure ◽  
Success Rates ◽  
Resistance Mutations ◽  
Double Blind ◽  
Resistance Development ◽  
Safety And Efficacy ◽  
Proviral Dna ◽  
Tenofovir Alafenamide ◽  
Hiv 1

Abstract Background GS-US-366-1216 and GS-US-366-1160 are randomized, double-blind, phase 3b studies evaluating the safety and efficacy of switching to rilpivirine/emtricitabine/tenofovir alafenamide (R/F/TAF) from R/F/tenofovir disoproxil fumarate (TDF) or efavirenz (EFV)/F/TDF, respectively, in HIV-1-infected virologically-suppressed subjects. At Week 48, switching to R/F/TAF was non-inferior to staying on R/F/TDF (94% vs. 94%, respectively) or EFV/F/TDF (90% vs. 92%) for HIV-1 RNA &lt;50 c/mL (virologic success) by FDA snapshot analysis. Here, we present integrated resistance analyses of these two studies through Week 48. Methods Historical genotypes were collected when available. Subjects in the resistance analysis population (subjects with HIV-1 RNA ≥400 c/mL at virologic failure, discontinuation, or Week 48) had genotypic/phenotypic analyses at failure for protease and reverse transcriptase (RT; PhenoSense GT, Monogram). Subjects with post-baseline resistance mutations detected had their baseline proviral DNA analyzed retrospectively (GenoSure Archive, Monogram). Results Of the 1504 randomized and treated subjects, resistance development was analyzed for 7 subjects (0.9%; 7/754) on R/F/TAF, 1 subject (0.3%; 1/313) on R/F/TDF, and 2 subjects (0.5%; 2/437) on EFV/F/TDF. No R/F/TAF (0%) or R/F/TDF (0%) subjects developed primary NNRTI or NRTI resistance mutations. One EFV/F/TDF subject (0.2%; 1/437) developed primary NNRTI and NRTI resistance mutations (NNRTI: Y188L; NRTI: M184V). Three subjects on R/F/TAF had virologic rebound with mutations also detected at baseline by proviral DNA analysis. Historical genotypes were available for 527 subjects; virologic success rates were high among subjects with pre-existing mutations (Table 1). Conclusion No emergent resistance to any of the components of R/F/TAF was detected through 48 weeks after switching. Virologic success rates were high among subjects with pre-existing mutations. Disclosures D. Porter, Gilead Sciences, Inc.: Employee and Shareholder, Salary; R. Kulkarni, Gilead Sciences, Inc.: Employee and Shareholder, Salary; H. Cao, Gilead Sciences, Inc.: Employee and Shareholder, Salary; D. Sengupta, Gilead Sciences Inc.: Employee and Shareholder, Salary; K. White, Gilead Sciences, Inc.: Employee and Shareholder, Salary

scholarly journals 629. High Efficacy of Bictegravir/Emtricitabine/Tenofovir Alafenamide (B/F/TAF) in African American Adults with HIV Including Those with Preexisting Resistance, Viral Blips, and Suboptimal Adherence

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S418-S418
Author(s):  
Kristen Andreatta ◽  
Michelle L D'Antoni ◽  
Silvia Chang ◽  
Aiyappa Parvangada ◽  
Ross Martin ◽  
...  
Keyword(s):  
African American ◽  
Reverse Transcriptase ◽  
Virologic Failure ◽  
Pill Count ◽  
Controlled Study ◽  
Virologic Suppression ◽  
African American Adults ◽  
Suboptimal Adherence ◽  
Tenofovir Alafenamide ◽  
Hiv 1

Abstract Background BRAAVE 2020 demonstrated the efficacy of switching to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) among African American adults with suppressed HIV through Week (W) 48 (Figure 1). We present resistance, viral blips, adherence, and virologic outcomes through W72. Figure 1. BRAAVE 2020 study design (phase 3, randomized, open-label, multicenter [USA], active-controlled study) and virologic suppression at weeks 24 and 48 *Allowed 3rd agents: any FDA-approved protease inhibitor, nonnucleoside reverse transcriptase inhibitor (except etravirine), integrase strand transfer inhibitor (except bictegravir), or maraviroc. Methods Enrollment criteria permitted NNRTI resistance (-R), PI-R, and certain NRTI-R (M184V/I allowed; K65R/E/N, ≥3 thymidine analog mutations [TAMs], or T69-insertions excluded) and excluded known primary INSTI-R. Preexisting drug resistance was assessed with historical genotypes and retrospective baseline proviral DNA genotyping. Adherence was calculated by pill count. Viral blips (transient HIV-1 RNA ≥50 copies/mL) and outcomes based on last available on-treatment HIV-1 RNA were assessed. Results 489 participants received B/F/TAF and had ≥1 post-switch HIV-1 RNA measurement. Baseline genotypic data from cumulative historical and/or proviral genotypes were available for 96% (468/489) in protease/reverse transcriptase and 93% (453/489) in integrase. Preexisting NRTI-R, M184V/I, ≥1 TAMs, NNRTI-R, and PI-R were observed in 15% (68/468), 11% (50/468), 8% (36/468), 22% (101/468), and 13% (61/468), respectively. Primary INSTI-R was detected post-randomization in 2% (11/453); all remained in the study and were included in efficacy analyses. Through W72, 99% (486/489) of participants had HIV-1 RNA &lt; 50 copies/mL at their last study visit, including all with baseline NRTI-R or INSTI-R (Figure 2). Mean frequency of viral blips was 1% per timepoint, and blips were not associated with virologic failure. 112 participants (23%) had &lt; 95% adherence by pill count, 98% (110/112) of whom had HIV-1 RNA &lt; 50 copies/mL at last visit, including 14 of 14 (100%) with &lt; 80% adherence. No participant discontinued due to lack of efficacy or had treatment emergent resistance to study drugs. Figure 2. Virologic suppression by preexisting resistance, viral blips, and adherence Conclusion Virologic suppression was maintained through W72 of B/F/TAF treatment, including those with preexisting resistance, viral blips, and suboptimal adherence. Continued HIV suppression and absence of treatment-emergent resistance demonstrate the efficacy of B/F/TAF in African Americans regardless of adherence or preexisting resistance to NNRTIs, PIs, or non-tenofovir NRTIs. Disclosures Kristen Andreatta, MSc, Gilead Sciences, Inc (Employee, Shareholder) Michelle L. D'Antoni, PhD, Gilead Sciences (Employee, Shareholder)Gilead Sciences, Inc (Employee, Shareholder) Silvia Chang, Masters, Gilead Sciences, Inc (Employee, Shareholder) Aiyappa Parvangada, MS Computational Biology, Gilead Sciences, Inc (Employee, Shareholder) Ross Martin, PhD, Gilead Sciences, Inc (Employee, Shareholder) Christiana Blair, MS, Gilead Sciences, Inc (Employee, Shareholder) Sean E. Collins, MD, MS, Gilead Sciences, Inc (Employee, Shareholder) Kirsten L. White, PhD, Gilead Sciences, Inc (Employee, Shareholder)

scholarly journals Antiviral Activity of Tenofovir Alafenamide against HIV-1 with Thymidine Analog-Associated Mutations and M184V

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Nicolas Margot ◽  
Renee Ram ◽  
Michael Abram ◽  
Richard Haubrich ◽  
Christian Callebaut
Keyword(s):  
Physiological Concentration ◽  
Viral Breakthrough ◽  
Phenotypic Resistance ◽  
Thymidine Analog ◽  
Drug Concentrations ◽  
Tenofovir Alafenamide ◽  
Hiv 1 ◽  
M184v Mutation

ABSTRACT Tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) are prodrugs of the HIV-1 nucleotide reverse transcriptase inhibitor tenofovir (TFV). In vivo, TAF achieves >4-fold-higher intracellular levels of TFV diphosphate (TFV-DP) compared to TDF. Since thymidine analog-associated mutations (TAMs) in HIV-1 confer reduced TFV susceptibility, patients with TAM-containing HIV-1 may benefit from higher TFV-DP levels delivered by TAF. Moreover, the presence of the M184V mutation increases TFV susceptibility during TDF- or TAF-based therapy. The susceptibilities to antiviral drugs of site-directed mutants (SDMs) and patient-derived mutants containing combinations of TAMs (M41L, D67N, K70R, L210W, T215Y, and K219Q) with or without the M184V mutation (TAMs±M184V) were evaluated using either 5-day multicycle (MC; n = 110) or 2-day single-cycle (SC; n = 96) HIV assays. The presence of M184V in TAM-containing HIV-1 SDMs (n = 48) significantly increased TAF sensitivity compared to SDMs without M184V (n = 48). The comparison of TAF and TDF resistance profiles was further assessed in viral breakthrough (VB) experiments mimicking clinically relevant drug concentrations. A total of 68 mutants were assayed at physiological concentration in VB experiments, with 15/68 mutants breaking through with TDF (TFV, the in vitro equivalent of TDF, was used in these experiments), and only 3 of 68 mutants breaking through under TAF treatment. Overall, in the VB assay mimicking the 4-fold-higher intracellular levels of TFV-DP observed clinically with TAF versus TDF, TAF inhibited viral breakthrough of most TAM-containing HIV-1, whereas TDF did not. These results indicate that TAF has a higher resistance threshold than TDF and suggest that higher resistance cutoffs should be applied for TAF compared to TDF in genotypic and phenotypic resistance algorithms.

scholarly journals 2504. Laboratory Evaluation of HIV-1 Viral Load Pooling with Marker-Assisted Deconvolution

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S868-S868
Author(s):  
Sabina Holland ◽  
Allison DeLong ◽  
Tao Liu ◽  
Anna Makaretz ◽  
Mia Coetzer ◽  
...  
Keyword(s):  
Viral Load ◽  
Virologic Failure ◽  
Low Cost ◽  
Clinical Information ◽  
Laboratory Evaluation ◽  
Clinical Markers ◽  
First Line Therapy ◽  
Resource Limited ◽  
Hiv 1

Abstract Background Cost still limits HIV-1 viral load (VL) routine monitoring in resource limited settings (RLS), preventing early detection of virologic failure (VF). Pooled VL testing reduces cost over individual testing (IND). We previously showed in simulation, that additional cost benefits over previously-used pooling deconvolution algorithms can be achieved by using low-cost, routinely-collected clinical markers to determine the order for VL testing in deconvolution (termed marker-assisted minipool plus algorithm; mMPA). This algorithm has not been assessed in-vitro. Methods 150 samples from 99 Ghanaian adults with HIV on first-line therapy (VF 17%; CD4-VL correlation −0.35) were used to construct 30, 5-sample pools: n = 10 with 0, n = 5 with 1, and n = 15 with 2 individuals with VF. VL testing was with Abbott M2000. Accuracy, number of tests and rounds of testing to deconvolute pools were estimated using four strategies: (1) IND; (2) Minipooling (MP); (3) Minipooling with algorithm (MPA); and (4) mMPA. Results Compared with IND, MP and MPA, mMPA reduced total number of tests per pool needed to ascertain VF: MP average 4.3 (95% confidence interval (CI) 3.5–5.2, p> 0.05), MPA 3.0 (95% CI 2.4–3.5, P < 0.001), and mMPA 2.5 (CI 2.0–3.0, P < 0.001). Compared with MP and MPA, mMPA further reduced VL tests by 42% (1.9 tests/pool, CI 1.3–2.4, P < 0.001) and 17% (0.5, CI 0.2–0.8, p = 0.004); and required fewer testing rounds than MPA by 17% (P < 0.01), thus producing results quicker. IND and MP had 100% sensitivity and specificity. MPA and mMPA had similar sensitivity of 96.1% (MPA CI 90.7–100%; mMPA CI 88.0–100.0%) and specificity of 99.5% and 99.2% (98.5–100.0% for MPA and 97.5–100.0% for mMPA). Specifically, 3/150 samples were misclassified with MPA and mMPA: one suppression as VF, and two VF as suppressed. Conclusion Laboratory evaluation confirms that deconvolution using mMPA with CD4 or other routinely-collected clinical information as low-cost biomarkers reduces the number of VL assays required to identify VF in a setting with a low prevalence of VF. Implementation of pooled VL testing using mMPA for deconvolution may increase the availability of VL monitoring in RLS. Work is ongoing to reduce complexity and misclassification, required prior to widespread implementation. Disclosures All authors: No reported disclosures.

scholarly journals Impact of Y143 HIV-1 Integrase Mutations on Resistance to Raltegravir In Vitro and In Vivo

2009 ◽  
Vol 54 (1) ◽  
pp. 491-501 ◽  
Author(s):  
Olivier Delelis ◽  
Sylvain Thierry ◽  
Frédéric Subra ◽  
Françoise Simon ◽  
Isabelle Malet ◽  
...  
Keyword(s):  
Viral Genome ◽  
Effective Concentration ◽  
Coding Region ◽  
Delayed Emergence ◽  
Infected Cells ◽  
High Level ◽  
Emergence Of Resistance ◽  
Hiv 1

ABSTRACT Integrase (IN), the HIV-1 enzyme responsible for the integration of the viral genome into the chromosomes of infected cells, is the target of the recently approved antiviral raltegravir (RAL). Despite this drug's activity against viruses resistant to other antiretrovirals, failures of raltegravir therapy were observed, in association with the emergence of resistance due to mutations in the integrase coding region. Two pathways involving primary mutations on residues N155 and Q148 have been characterized. It was suggested that mutations at residue Y143 might constitute a third primary pathway for resistance. The aims of this study were to investigate the susceptibility of HIV-1 Y143R/C mutants to raltegravir and to determine the effects of these mutations on the IN-mediated reactions. Our observations demonstrate that Y143R/C mutants are strongly impaired for both of these activities in vitro. However, Y143R/C activity can be kinetically restored, thereby reproducing the effect of the secondary G140S mutation that rescues the defect associated with the Q148R/H mutants. A molecular modeling study confirmed that Y143R/C mutations play a role similar to that determined for Q148R/H mutations. In the viral replicative context, this defect leads to a partial block of integration responsible for a weak replicative capacity. Nevertheless, the Y143 mutant presented a high level of resistance to raltegravir. Furthermore, the 50% effective concentration (EC50) determined for Y143R/C mutants was significantly higher than that obtained with G140S/Q148R mutants. Altogether our results not only show that the mutation at position Y143 is one of the mechanisms conferring resistance to RAL but also explain the delayed emergence of this mutation.

Synergistic cytotoxic effect of azidothymidine and recombinant interferon alpha on normal human bone marrow progenitor cells

Blood ◽  
1989 ◽  
Vol 74 (4) ◽  
pp. 1281-1286 ◽  
Author(s):  
E Berman ◽  
R Duigou-Osterndorf ◽  
SE Krown ◽  
MP Fanucchi ◽  
J Chou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Clinical Trials ◽  
Progenitor Cells ◽  
Interferon Alpha ◽  
Plasma Levels ◽  
Ifn Alpha ◽  
Drug Concentrations ◽  
Anti Hiv ◽  
Hiv 1

Abstract Azidothymidine (AZT) and interferon alpha (IFN-alpha) are among the drugs showing strong in vitro activity against the human immunodeficiency virus type-1 (HIV-1). Each drug, however, has significant toxicity against normal marrow progenitor cells that frequently proves dose-limiting in patients. In this study, AZT and recombinant IFN-alpha 2a (rIFN-alpha 2a) were tested as single agents and in combination against normal myeloid (CFU-GM) and erythroid (BFU- E) colony forming cells in a standard methylcellulose culture assay. The data were analyzed using a quantitative computerized analysis based on the median-effect principle and the isobologram equation as described by Chou and Talalay (Adv Enz Regul 22:27, 1984). The ED90 for BFU-E and CFU-GM inhibition was then compared with previously measured in vivo plasma levels of each drug and the ED90 for the anti-HIV-1 effect in vitro. We demonstrate that (a) the drugs are strongly synergistic in inhibiting marrow progenitor cell growth and that this synergism occurs at drug levels that are within the range of measured plasma levels in phase I clinical trials, (b) BFU-E are more sensitive than CFU-GM to the inhibiting effects of AZT, rIFN-alpha 2a or both drugs in combination, (c) the drug concentrations in combination that synergistically inhibit bone marrow progenitors are much higher than those required to inhibit HIV-1 replication in vitro, and (d) the anti- HIV-1 effect for the combination of AZT and rIFN-alpha 2a was clearly superior to the effect of AZT or rIFN-alpha 2a alone as indicated by the combination index and the dose-reduction index. These data suggest that substantially lower doses of AZT and rIFN-alpha than those currently being tested in clinical trials might not only maintain a strong synergistic anti-HIV-1 effect but might also avoid significant hematologic toxicity.

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