Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1) After failure of several successive antiretroviral regimens, HIV-infected patients are normally treated with an optimised regimen based on resistance profiling, combined with tipranavir or darunavir and also an antiretroviral belonging to another class (maraviroc, enfuvirtide or raltegravir); (2) Etravirine is a non-nucleoside reverse transcriptase inhibitor first authorized for sale in the European Union in 2008; (3) Its clinical evaluation is based on two double-blind trials of identical design in a total of 1200 patients with multiple prior treatment failures. The patients received an optimised antiretroviral regimen including darunavir and ritonavir, plus either etravirine or placebo. After 24 weeks of treatment the proportion of patients whose viral load was below 50 copies/ml was higher in the etravirine group than in the placebo group (56.3% versus 33.6%), provided enfuvirtide was not introduced at the same time as etravirine; (4) The main known adverse effect of etravirine is potentially severe skin rash; nausea, vomiting and hypercholesterolaemia can also occur; (5) Etravirine has a high potential for drug-drug interactions, due to its inducing and inhibitory effects on various cytochrome P450 isoenzymes; (6) Etravirine is an additional option for HIV-infected patients with multiple treatment failure.
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PMID:Etravirine: new drug. Multidrug-resistant HIV: another option. 1963 14

Etravirine (ETR) is a second-generation nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) active against common human immunodeficiency virus type 1 (HIV-1) drug-resistant strains. This study was designed to determine the extent to which each of the Y181C or G190A mutations in RT might confer resistance to ETR and other members of the NNRTI family of drugs. Recombinant HIV-1 RT enzymes containing either the Y181C or the G190A mutation, or both mutations in tandem, were purified. Both RNA- and DNA-dependent DNA polymerase assays were performed in order to determine the extent to which each of these mutations might confer resistance in cell-free biochemical assays against each of ETR, efavirenz, and nevirapine. Both the biochemical and the cell-based phenotypic assays confirmed the susceptibility of G190A-containing enzymes and viruses to ETR. The results of this study indicate that the G190A mutation is not associated with resistance to ETR.
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PMID:Human immunodeficiency virus type 1 recombinant reverse transcriptase enzymes containing the G190A and Y181C resistance mutations remain sensitive to etravirine. 1970 27

Etravirine is a next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) developed for the treatment of HIV-1 infection. It has a high genetic barrier to the emergence of viral resistance, and maintains its antiviral activity in the presence of common NNRTI mutations. The pharmacokinetics of etravirine in HIV-infected patients at the recommended dosage of 200 mg twice daily demonstrates moderate intersubject variability and no time dependency. Due to substantially lower exposures when taken on an empty stomach, etravirine should be administered following a meal. The drug is highly protein bound (99.9%) to albumin and alpha(1)-acid glycoprotein and shows a relatively long elimination half-life of 30-40 hours. Etravirine is metabolized by cytochrome P450 (CYP) 3A, 2C9 and 2C19; the metabolites are subsequently glucuronidated by uridine diphosphate glucuronosyltransferase. Renal elimination of etravirine is negligible. Etravirine has the potential for interactions by inducing CYP3A and inhibiting CYP2C9 and 2C19; it is a mild inhibitor of P-glycoprotein but not a substrate. The drug interaction profile of etravirine has been well characterized and is manageable. No dosage adjustments are needed in patients with renal impairment or mild to moderate hepatic impairment. Race, sex, bodyweight and age do not affect the pharmacokinetics of etravirine. In the two phase III trials DUET-1 and DUET-2, no relationship was demonstrated between the pharmacokinetics of etravirine and the primary efficacy endpoint of viral load below 50 copies/mL or the safety profile of etravirine.
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PMID:Clinical pharmacokinetics and pharmacodynamics of etravirine. 1972 91

It is almost 20 years since NNRTIs were identified as a new class of antiretroviral drugs for the treatment of HIV-1 infection. Although they belong to different and diverse chemical families, they share a common and unique mechanism of action: their interaction with HIV-1 reverse transcriptase induces conformational changes that inhibit the catalytic activities of the enzyme. They are characterized by their specificity for HIV-1, which makes them very selective inhibitors of the virus. First generation NNRTIs nevirapine and efavirenz, in combination with other antiretroviral drugs, have become a cornerstone for the treatment of HIV-1 infection, in patients initiating antiretroviral therapy. Further research has led to the discovery and development of next generation NNRTIs with an increased genetic barrier to the development of resistance. Etravirine is the first NNRTI to show sustained virologic efficacy in patients with NNRTI resistant HIV-1. This review covers the NNRTI class of anti-HIV-1 drugs, from the initial discovery of the class in 1990 to the current compounds in clinical development, i.e. around 20 years of research and development efforts. It describes the characteristics of the NNRTIs, their mechanisms of action, HIV-1 resistance to the inhibitors, and the drugs that have been approved for the treatment of HIV-1 infection, or are currently in clinical development. The role of NNRTIs in prevention of HIV transmission is also addressed. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, vol. 85, issue 1, 2010.
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PMID:Non-nucleoside reverse transcriptase inhibitors (NNRTIs), their discovery, development, and use in the treatment of HIV-1 infection: a review of the last 20 years (1989-2009). 1978 78

Etravirine (ETR) is a second-generation nonnucleoside reverse transcriptase inhibitor (NNRTI) specifically designed for treatment-experienced patients infected with HIV-1. Its unique strength over other, older agents in the NNRTI class is its higher genetic barrier to resistance, allowing it to be used effectively in patients with limited treatment options. The arrival of ETR in the market has made sequential NNRTI therapy possible for the first time in the history of HIV treatment, as it can maintain virologic activity in the presence of certain (and sometimes multiple) NNRTI mutations. Although ETR has demonstrated efficacy in treatment-experienced and NNRTI-resistant patients in large trials, further analyses on its resistance profile are ongoing. As new data emerge on the weighting of ETR's resistance-associated mutations (RAMs), investigators and clinicians will no doubt be able to further characterize its specific place in the HIV treatment armamentarium.
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PMID:Etravirine for HIV-I: addressing the limitations of the nonnucleoside reverse transcriptase inhibitor class. 1985

Etravirine, a second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI), was approved in the USA in January, 2008, with approval in Europe expected later this year. It is dosed at 200 mg (two 100 mg tablets) twice daily foll owing a meal. It is approved for treatment of HIV-1 infection in adults failing a stable antiretroviral regimen with resistance to other NNRTIs and other antiretroviral agents. Etravirine is active against HIV with single mutations in the reverse transcriptase (e.g., K103N) that confer class resistance to first-generation NNRTIs. Clinical efficacy in Phase III trials has been demonstrated for up to 48 weeks of follow-up. In these Phase III trials, rash was the only adverse event that was significantly more prevalent with etravirine than with placebo. Etravirine has a tolerability and safety profile comparable to placebo with the exception of rash. Rash was generally grade 1 or 2, was not associated with prior NNRTI-related rash, was more common in women than in men, appeared a median of 12 days after treatment initiation and resolved spontaneously with continued therapy. Etravirine is the first agent in the NNRTI class that can be used for HIV-1 virus with resistance to other NNRTIs owing to a higher genetic barrier to resistance.
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PMID:Etravirine: a second-generation NNRTI for treatment-experienced adults with resistant HIV-1 infection. 1988 88

Etravirine (ETR) has demonstrated efficacy in patients with multiple prior treatments with prior virological failure and resistance mutations to various families of antiretroviral drugs. Most of the evidence concerning this drug has been drawn from the DUET studies, consisting of two multicenter, randomized, double-blind clinical trials with identical designs that included 1,200 patients. These trials showed that ETR obtained a superior virological and immunological response to placebo, reducing the incidence of hospital admissions and progression to AIDS/death. The most frequent adverse effect was rash, which was generally mild to moderate and required treatment discontinuation in only 2%. There were no differences in gastrointestinal, liver or lipid toxicities compared with the placebo arm. Because of the recent development of new drugs, effective regimens are now available for multi-treated patients. The TRIO study evaluated the efficacy and tolerability of one of the regimens most widely used today (ETR/raltegravir/darunavir/r) with excellent virological and immunological response (86% of viral load < 50 copies and CD4 +108 at 48 weeks) and excellent tolerance. ETR is effective and well tolerated and is the first non-nucleoside reverse transcriptase inhibitor (NNRTI) that allows the sequential use of drugs in this family, due to its high genetic barrier compared with firstgeneration NNRTI. Moreover, its long half-life allows once daily administration in patients requiring a QD regimen.
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PMID:[Etravirine in highly treatment-experienced patients]. 2011 22

Etravirine (ETR) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) with a potent and broad in vitro spectrum of activity against HIV-1 and viruses with NNRTI resistances, allowing sequential use of drugs of this family. The potency, efficacy and safety of etravirine have been demonstrated in multi-treated patients, but few data are available on first-line antiretroviral therapy (ART) and the role of this drug in initial treatment phases has not been defined. The presence of primary NNRTI resistances and those acquired during first-line therapy is increasingly frequent. Due to its genetic barrier and efficacy, ETR can form part of a second-line ART regimen in patients with failure to a first-line regimen. In the initial phases, adverse effects continue to be the main reason for modifying ART. ETR has demonstrated safety and tolerability, with no central nervous system adverse effects and a good liver, lipid and gastrointestinal safety profile. As with the other NNRTIs, the most common adverse effect is rash. Because of ETR good tolerability profile, this drug can be considered when a new treatment is required due to adverse effects. Because of the characteristics of ETR the possibility of once-daily administration and dissolution in water, as well as the absence of drug-drug interactions with methadone this drug is especially attractive as a firstline therapy and in patients with poor adherence, such as intravenous drug users receiving methadone treatment.
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PMID:[Etravirine in first-line therapy]. 2011 23

Etravirine (ETR) is the first representative of a new generation of non-nucleoside reverse transcriptase inhibitors (NNRTI) and is indicated in patients with HIV infection and virological failure. The recommended dose is 200 mg (two tablets) every 12 hours after a meal. ETR has good tolerability and the tablets can be dissolved in water, which can aid swallowing in some patients. This drug has a plasma half-life of 30-40 hours and consequently is a candidate for once-daily regimens. The most frequent adverse effect is rash (affecting 19% of patients), which is usually mild (grades 1 or 2) and does not lead to drug withdrawal. The DUET 1 and 2 studies, which compared ETR versus placebo, with both groups receiving boosted darunavir and an optimized background regimen, did not demonstrate a higher incidence of liver toxicity, neuropsychiatric symptoms, gastrointestinal disturbances or atherogenic dyslipidemia in patients receiving ETR. The safety profile of ETR suggests that it could be used as a substitute drug in patients with toxicity induced by first-generation NNRTIs or other antiretroviral drugs.
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PMID:[Safety and tolerability of etravirine]. 2011 24

Etravirine (ETR) belongs to the family of non-nucleoside analogue reverse transcriptase inhibitors (NNRTIs), with antiviral activity in patients with resistance to first-generation NNRTIs. The drug interactions caused by ETR are due to its dual effect on the CYP450 system. ETR acts as an inducer of CYP3A4 and inhibitor of CYP2C9 and CYP2C19. This drug shows few clinically significant drug interactions, the most important of which involve the unboosted protease inhibitors, the NNRTIs efavirenz and nevirapine, full-dose ritonavir and tipranavir/ritonavir. Interaction with fosamprenavir/ritonavir is not clinically significant, although their plasma levels vary slightly when used in combination with ETR. ETR shows no interactions with darunavir/ritonavir.
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PMID:[Etravirine drug interactions]. 2011 25


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