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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

All 178 HIV-infected individuals who had initiated tenofovir-emtricitabine-nevirapine (TDF/FTC/NVP) at our institution and were adherent to their medication were retrospectively examined. Only 22% were antiretroviral naive. After a median follow-up of 16 months, only five (2.8%) individuals (all with prior exposure to other antiretroviral regimens) experienced virological failure. In all instances, viral rebound occurred after 12 weeks of therapy. These results do not support an increased risk of early virological failure using TDF/FTC/NVP.
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PMID:Safety and efficacy of tenofovir/emtricitabine plus nevirapine in HIV-infected patients. 2016 1

The increasing number of antiretroviral drugs leads to mounting possibilities of combinations for the antiretroviral therapy (ART) of HIV-1 infected patients. Thus, it is of interest to determine the most potent combination of antiretroviral drugs for the first ART to delay the development of drug resistance. We have investigated the differences in the inhibitory potencies of the nucleoside reverse transcriptase inhibitors (NRTI) lamivudine (3TC) and emtricitabine (FTC) using an in vitro model based on simultaneous infection of T cells with drug-sensitive and drug-resistant viruses. Changes of frequencies in these virus populations have been measured by allele-specific real-time PCR allowing simultaneous quantification of different HIV-1 variants in the same sample. We show that the suppression of drug-sensitive viruses is significantly enhanced by FTC compared to 3TC. Mathematical modeling of the distinct rates of suppression of drug-sensitive viruses revealed an approximately 3-fold higher antiretroviral potency for FTC compared to 3TC.
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PMID:The antiretroviral potency of emtricitabine is approximately 3-fold higher compared to lamivudine in dual human immunodeficiency virus type 1 infection/competition experiments in vitro. 2030 87

We analyzed drug resistance in HIV-infected Ugandan children who received antiretroviral therapy in a prospective, observational study (2004-2006); some children had prior single-dose nevirapine (sdNVP) exposure. Children received stavudine (d4T), lamivudine (3TC), and nevirapine (NVP); treatment was continued if they were clinically and immunologically stable. Samples with >1,000 copies/ml HIV RNA were analyzed by using the ViroSeq HIV Genotyping System (ViroSeq). Subtype A and D pretreatment samples also were analyzed with the LigAmp assay (for K103N, Y181C, and G190A). ViroSeq results were obtained for 74 pretreatment samples (35 from sdNVP-exposed children (median age, 19 months) and 39 from sdNVP-unexposed children (median age, 84 months). This included 39 subtype A, 22 subtype D, 1 subtype C, and 12 inter-subtype recombinant samples. One sample had nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance, one had nucleoside reverse transcriptase inhibitor (NRTI) resistance, and three had protease inhibitor (PI) resistance. Y181C was detected by using LigAmp in five pretreatment samples [four (14.8%) of 37 samples from sdNVP-exposed children, one (4.2%) of 24 samples from children without prior sdNVP exposure; p = 0.35]. Among children who were not virally suppressed at 48 weeks of treatment, all 12 tested had NNRTI resistance, as well as resistance to 3TC and emtricitibine (FTC); three had resistance to other NRTIs. Seven of those children had a ViroSeq result at 96 weeks of treatment; four of the seven acquired resistance to additional NRTIs by 96 weeks. In Uganda, clinically and immunologically stable children receiving nonsuppressive antiretroviral treatment regimens are at risk for development of drug resistance.
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PMID:Analysis of drug resistance in children receiving antiretroviral therapy for treatment of HIV-1 infection in Uganda. 2045 58

Emtricitabine (FTC) is an antiretroviral compound that inhibits the HIV-1 reverse transcriptase. For the quantification of FTC related substances, a liquid chromatography (LC) method coupled with ultraviolet (UV) detection was developed earlier in our laboratory. Several unknown compounds were detected during the analysis of a commercial sample. However, most of these impurities were not characterized. In this study, impurity profiling in a selected FTC sample was done using LC-mass spectrometry (MS). Due to the presence of a non-volatile buffer, a desalting procedure was carried out before sending the impurity into the MS. Totally, nine peaks were studied and most of them could be characterized.
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PMID:Characterization of emtricitabine related substances by liquid chromatography coupled to an ion trap mass spectrometer. 2068 46

The objective of this study was to assess the patterns of genotypic and phenotypic resistance in a population of blood donor patients infected with HIV-1 subtype B' (Thai B', a clade of HIV-1 B) from central China, previously treated and harboring NRTI and NNRTI resistance mutations, with the purpose of designing effective therapeutic regimens. The HIV-1 pol genes from 65 patients were sequenced and estimated for drug resistance while the viruses isolated from the patients were used to analyze the phenotype based on the TZM-bl cell line. All the HIV-1 strains harboring one or more drug resistance mutations to HIV-1 RTIs possessed high cross-resistance to EFV (100%) and DLV (92%), as well as to ABC (84%) and TDF (77%), which are much higher than both FTC and 3TC (42%). There were more thymidine analog mutation (TAM)-associated mutations in the AZT/ddI/NVP group (62.5%) than in the d4T/ddI/NVP group (32.65%). A phenotypic assay showed high concordance between genotypic and phenotypic cross-resistance. This study showed there was a high level of cross-drug resistance to HIV-1 RTIs among Chinese AIDS patients harboring resistant strains, and there is also a high prevalence of primary resistance to 3TC, suggesting that one important recommendation should be the realization of genotypes in all naive patients due to the high prevalence of NRTI and NNRTI mutations.
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PMID:Genotypic and phenotypic cross-drug resistance of harboring drug-resistant HIV type 1 subtype B' strains from former blood donors in central Chinese provinces. 2071 29

Abstract Six randomized clinical trials have been implemented to examine the efficacy of tenofovir disoproxil fumarate (TDF) and/or TDF/emtricitabine (TDF/FTC) as preexposure prophylaxis for HIV-1 infection (PrEP). Although largely complementary, the six trials have many similar features. As the earliest results become available, an urgent question may arise regarding whether changes should be made in the conduct of the other trials. To consider this in advance, a Consultation on the Implications of HIV Pre-Exposure Prophylaxis (PrEP) Trials Results sponsored by the Division of AIDS (DAIDS) of the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), and the Bill and Melinda Gates Foundation (BMGF) was held on January 29, 2010, at the Natcher Conference Center, NIH, Bethesda, MD. Participants included basic scientists, clinical researchers (including investigators performing the current PrEP trials), and representatives from the U.S. Food and Drug Administration (FDA) and the agencies sponsoring the trials: the U.S. Centers for Disease Control and Prevention (CDC), the U.S. Agency for International Development (USAID), the BMGF, and the U.S. NIH. We report here a summary of the presentations and highlights of salient discussion topics from this workshop.
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PMID:Implications of HIV PrEP trials results. 2096 83

The aim was to evaluate emtricitabine (FTC) and tenofovir (TFV) neonatal ingestion through breast milk. Median TFV and FTC breast milk doses represented 0.03% and 2%, respectively, of the proposed oral infant doses. Neonatal simulated plasma concentrations were extremely low for TFV but between the half-maximal inhibitory concentration and the adult minimal expected concentration for FTC. The rare children who will acquire HIV despite TDF-FTC therapy will need to be monitored for viral resistance acquisition.
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PMID:Concentrations of tenofovir and emtricitabine in breast milk of HIV-1-infected women in Abidjan, Cote d'Ivoire, in the ANRS 12109 TEmAA Study, Step 2. 2117 82

An estimated 56,000 human immunodeficiency virus (HIV) infections occur each year in the United States. Men who have sex with men (MSM) account for 53% of the estimated incident infections, and surveillance data suggest that the annual number of new HIV infections among MSM has been rising since the mid-1990s. Strategies for reducing acquisition of HIV infection by MSM have included 1) expanded HIV testing so that infected persons can be treated and their risk for transmitting infection minimized; 2) individual, small-group, and community-level behavioral interventions to reduce risk behaviors; 3) promotion of condom use; 4) detection and treatment of sexually transmitted infections; and 5) mental health and substance abuse counseling when needed. On November 23, 2010, investigators for the Pre-Exposure Prophylaxis Initiative (iPrEX) study announced results from a multinational, randomized, double-blind, placebo-controlled, phase III clinical trial of daily oral antiretrovirals (tenofovir disoproxil fumarate [TDF] and emtricitabine [FTC]) to prevent acquisition of HIV infection among uninfected but exposed MSM. This report provides interim guidance to health-care providers based on the reported results of that trial, which indicated that TDF plus FTC taken orally once a day as preexposure prophylaxis (PrEP) is safe and partially effective in reducing HIV acquisition among MSM when provided with regular monitoring of HIV status and ongoing risk-reduction and PrEP medication adherence counseling.
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PMID:Interim guidance: preexposure prophylaxis for the prevention of HIV infection in men who have sex with men. 2127 Jul 43

This article reviews the status of current research evaluating oral preexposure prophylaxis (PrEP) for prevention of HIV infection in high-risk populations. In animal model studies, the use of antiretrovirals has been shown to be effective in preventing HIV acquisition. Early-phase PrEP studies have established safety in humans. Currently, more than 20,000 men and women will soon be enrolled in studies of oral or topical chemoprophylaxis, testing a variety of drug delivery methods including tenofovir disoproxil fumarate (TDF) gel applied vaginally or rectally, as well as oral PrEP using TDF by itself or coformulated with emtricitabine (FTC). The largest global PrEP trial in men who have sex with men (MSM), known as iPrEx has demonstrated that oral chemoprophylaxis can decrease HIV incidence in this population. Although TDF/FTC PrEP was generally well tolerated, side effects such as nausea, as well as mild and reversible renal abnormalities were increased among the men who received active medication, suggesting that PrEP users will need ongoing PrEP clinical monitoring. The prophylactic benefits of TDF/FTC were substantially attenuated by nonadherence, indicating that effective PrEP implementation programs will need to focus on this behavioral variable, in addition to safer sex counseling. This article considers biological, policy, and practical implications of large-scale oral PrEP implementation.
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PMID:Oral preexposure anti-HIV prophylaxis for high-risk U.S. populations: current considerations in light of new findings. 2128 97

Transmission of drug-resistant HIV has been widely documented. We generated tenofovir (TFV)- and emtricitabine (FTC)-resistant SHIV162P3 mutants that can be used to investigate the transmission efficiency of drug-resistant viruses and their impact on the efficacy of pre-exposure prophylaxis. Both SHIV162p3(M184V) and SHIV162p3(K65R) replicated in vitro at high titers. Drug resistance profiles were similar to those seen in HIV. Virus infectivity to virion particle ratios were 4- and 10-fold lower in SHIV162p3(M184V) and SHIV162p3(K65R), compared to a concurrently generated WT SHIV162p3, respectively. Mucosal transmissibility studies using a repeat low-dose macaque model of rectal and vaginal transmission showed that both mutants were able to efficiently infect macaques only after the dose was increased to adjust for fitness reductions due to K65R and M184V. Our results in limited number of macaques suggest that the reduction in fitness due to M184V and K65R decreases virus transmissibility, and identify in vitro infectivity parameters that associate with mucosal transmissibility.
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PMID:Generation and mucosal transmissibility of emtricitabine- and tenofovir-resistant SHIV162P3 mutants in macaques. 2133 8


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