scholarly journals Novel Nucleotide Human Immunodeficiency Virus Reverse Transcriptase Inhibitor GS-9148 with a Low Nephrotoxic Potential: Characterization of Renal Transport and Accumulation

2008 ◽  
Vol 53 (1) ◽  
pp. 150-156 ◽  
Author(s):  
Tomas Cihlar ◽  
Genevieve LaFlamme ◽  
Robyn Fisher ◽  
Anne C. Carey ◽  
Jennifer E. Vela ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Organic Anion ◽  
Transcriptase Inhibitor ◽  
Renal Transport ◽  
Immunodeficiency Virus ◽  
Reverse Transcriptase Inhibitor ◽  
In Cells

ABSTRACT Accumulation of antiviral nucleotides in renal proximal tubules is controlled by their basolateral uptake via the human renal organic anion transporters type 1 (hOAT1) and 3 (hOAT3) and apical efflux via the multidrug resistance protein 4 (MRP4). GS-9148 is a novel ribose-modified nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitor, and its oral prodrug GS-9131 is currently being evaluated in the clinic as an anti-HIV agent. To assess the potential of GS-9148 for nephrotoxicity, its mechanism of renal transport, cytotoxicity, and renal accumulation were explored in vitro and in vivo. In comparison with the acyclic nucleotides cidofovir, adefovir, and tenofovir, GS-9148 showed 60- to 100-fold lower efficiency of transport (V max/K m ) by hOAT1 and was 20- to 300-fold less cytotoxic in cells overexpressing hOAT1, indicating its lower hOAT1-mediated intracellular accumulation and reduced intrinsic cytotoxicity. GS-9148 was also relatively inefficiently transported by hOAT3. Similar to acyclic nucleotides, GS-9148 was a substrate for MRP4 as evidenced by its reduced intracellular retention in cells overexpressing the efflux pump. Consistent with these molecular observations, GS-9148 was inefficiently taken up by fresh human renal cortex tissue in vitro and showed a limited accumulation in kidneys in vivo following oral administration of [14C]GS-9131 to dogs. Compared to acyclic nucleotide analogs, GS-9148 was also found to have lower net active tubular secretion in dogs. Collectively, these results suggest that GS-9148 exhibits a low potential for renal accumulation and nephrotoxicity.

scholarly journals Anti-Human Immunodeficiency Virus Type 1 Activity of the Nonnucleoside Reverse Transcriptase Inhibitor GW678248 in Combination with Other Antiretrovirals against Clinical Isolate Viruses and In Vitro Selection for Resistance

2005 ◽  
Vol 49 (11) ◽  
pp. 4465-4473 ◽  
Author(s):  
Richard J. Hazen ◽  
Robert J. Harvey ◽  
Marty H. St. Clair ◽  
Robert G. Ferris ◽  
George A. Freeman ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Transcriptase Inhibitor ◽  
Amino Acid Substitutions ◽  
Nonnucleoside Reverse Transcriptase Inhibitor ◽  
Immunodeficiency Virus ◽  
Antiviral Activities ◽  
Approved Drugs ◽  
Reverse Transcriptase Inhibitor

ABSTRACT GW678248, a novel nonnucleoside reverse transcriptase inhibitor, has been evaluated for anti-human immunodeficiency virus activity in a variety of in vitro assays against laboratory strains and clinical isolates. When GW678248 was tested in combination with approved drugs in the nucleoside and nucleotide reverse transcriptase inhibitor classes or the protease inhibitor class, the antiviral activities were either synergistic or additive. When GW678248 was tested in combination with approved drugs in the nonnucleoside reverse transcriptase inhibitor class, the antiviral activities were either additive or slightly antagonistic. Clinical isolates from antiretroviral drug-experienced patients were selected for evaluation of sensitivity to GW678248 in a recombinant virus assay. Efavirenz (EFV) and nevirapine (NVP) had ≥10-fold increases in their 50% inhibitory concentrations (IC50s) for 85% and 98% of the 55 selected isolates, respectively, whereas GW678248 had a ≥10-fold increase in the IC50 for only 17% of these isolates. Thus, 81 to 83% of the EFV- and/or NVP-resistant viruses from this data set were susceptible to GW678248. Virus populations resistant to GW678248 were selected by in vitro dose-escalating serial passage. Resistant progeny viruses recovered after eight passages had amino acid substitutions V106I, E138K, and P236L in the reverse transcriptase-coding region in one passage series and amino acid substitutions K102E, V106A, and P236L in a second passage series.

scholarly journals In Vitro Antiretroviral Activity and In Vitro Toxicity Profile of SPD754, a New Deoxycytidine Nucleoside Reverse Transcriptase Inhibitor for Treatment of Human Immunodeficiency Virus Infection

2006 ◽  
Vol 50 (2) ◽  
pp. 625-631 ◽  
Author(s):  
Z. Gu ◽  
B. Allard ◽  
J. M. de Muys ◽  
J. Lippens ◽  
R. F. Rando ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Amino Acid Position ◽  
Transcriptase Inhibitor ◽  
In Vitro Toxicity ◽  
Mitochondrial Toxicity ◽  
Immunodeficiency Virus ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1

ABSTRACT SPD754 (AVX754) is a deoxycytidine analogue nucleotide reverse transcriptase inhibitor (NRTI) in clinical development. These studies characterized the in vitro activity of SPD754 against NRTI-resistant human immunodeficiency virus type 1 (HIV-1) and non-clade B HIV-1 isolates, its activity in combination with other antiretrovirals, and its potential myelotoxicity and mitochondrial toxicity. SPD754 was tested against 50 clinical HIV-1 isolates (5 wild-type isolates and 45 NRTI-resistant isolates) in MT-4 cells using the Antivirogram assay. SPD754 susceptibility was reduced 1.2- to 2.2-fold against isolates resistant to zidovudine (M41L, T215Y/F, plus a median of three additional nucleoside analogue mutations [NAMs]) and/or lamivudine (M184V) and was reduced 1.3- to 2.8-fold against isolates resistant to abacavir (L74V, Y115F, and M184V plus one other NAM) or stavudine (V75T/M, M41L, T215F/Y, and four other NAMs). Insertions at amino acid position 69 and Q151M mutations (with or without M184V) reduced SPD754 susceptibility 5.2-fold and 14- to 16-fold, respectively (these changes gave values comparable to or less than the corresponding values for zidovudine, lamivudine, abacavir, and didanosine). SPD754 showed similar activity against isolates of group M HIV-1 clades, including A/G, B, C, D, A(E), D/F, F, and H. SPD754 showed additive effects in combination with other NRTIs, tenofovir, nevirapine, or saquinavir. SPD754 had no significant effects on cell viability or mitochondrial DNA in HepG2 or MT-4 cells during 28-day exposure at concentrations up to 200 μM. SPD754 showed a low potential for myelotoxicity against human bone marrow. In vitro, SPD754 retained activity against most NRTI-resistant HIV-1 clinical isolates and showed a low propensity to cause myelotoxicity and mitochondrial toxicity.

scholarly journals Safety Assessment, In Vitro and In Vivo, and Pharmacokinetics of Emivirine, a Potent and Selective Nonnucleoside Reverse Transcriptase Inhibitor of Human Immunodeficiency Virus Type 1

2000 ◽  
Vol 44 (1) ◽  
pp. 123-130 ◽  
Author(s):  
G. M. Szczech ◽  
P. Furman ◽  
G. R. Painter ◽  
D. W. Barry ◽  
K. Borroto-Esoda ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Oral Dose ◽  
Transcriptase Inhibitor ◽  
Nonnucleoside Reverse Transcriptase Inhibitor ◽  
Immunodeficiency Virus ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1

ABSTRACT Emivirine (EMV), formerly known as MKC-442, is 6-benzyl-1-(ethoxymethyl)-5-isopropyl-uracil, a novel nonnucleoside reverse transcriptase inhibitor that displays potent and selective anti-human immunodeficiency virus type 1 (HIV-1) activity in vivo. EMV showed little or no toxicity towards human mitochondria or human bone marrow progenitor cells. Pharmacokinetics were linear for both rats and monkeys, and oral absorption was 68% in rats. Whole-body autoradiography showed widespread distribution in tissue 30 min after rats were given an oral dose of [14C]EMV at 10 mg/kg of body weight. In rats given an oral dose of 250 mg/kg, there were equal levels of EMV in the plasma and the brain. In vitro experiments using liver microsomes demonstrated that the metabolism of EMV by human microsomes is approximately a third of that encountered with rat and monkey microsomes. In 1-month, 3-month, and chronic toxicology experiments (6 months with rats and 1 year with cynomolgus monkeys), toxicity was limited to readily reversible effects on the kidney consisting of vacuolation of kidney tubular epithelial cells and mild increases in blood urea nitrogen. Liver weights increased at the higher doses in rats and monkeys and were attributed to the induction of drug-metabolizing enzymes. EMV tested negative for genotoxic activity, and except for decreased feed consumption at the high dose (160 mg/kg/day), with resultant decreases in maternal and fetal body weights, EMV produced no adverse effects in a complete range of reproductive toxicology experiments performed on rats and rabbits. These results support the clinical development of EMV as a treatment for HIV-1 infection in adult and pediatric patient populations.

scholarly journals 1592U89, a novel carbocyclic nucleoside analog with potent, selective anti-human immunodeficiency virus activity.

1997 ◽  
Vol 41 (5) ◽  
pp. 1082-1093 ◽  
Author(s):  
S M Daluge ◽  
S S Good ◽  
M B Faletto ◽  
W H Miller ◽  
M H St Clair ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Oral Bioavailability ◽  
Human Peripheral Blood ◽  
Cross Resistance ◽  
Immunodeficiency Virus ◽  
Carbocyclic Nucleoside ◽  
Hiv 1 ◽  
In Cells

1592U89, (-)-(1S,4R)-4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclo pentene-1-methanol, is a carbocyclic nucleoside with a unique biological profile giving potent, selective anti-human immunodeficiency virus (HIV) activity. 1592U89 was selected after evaluation of a wide variety of analogs containing a cyclopentene substitution for the 2'-deoxyriboside of natural deoxynucleosides, optimizing in vitro anti-HIV potency, oral bioavailability, and central nervous system (CNS) penetration. 1592U89 was equivalent in potency to 3'-azido-3'-deoxythymidine (AZT) in human peripheral blood lymphocyte (PBL) cultures against clinical isolates of HIV type 1 (HIV-1) from antiretroviral drug-naive patients (average 50% inhibitory concentration [IC50], 0.26 microM for 1592U89 and 0.23 microM for AZT). 1592U89 showed minimal cross-resistance (approximately twofold) with AZT and other approved HIV reverse transcriptase (RT) inhibitors. 1592U89 was synergistic in combination with AZT, the nonnucleoside RT inhibitor nevirapine, and the protease inhibitor 141W94 in MT4 cells against HIV-1 (IIIB). 1592U89 was anabolized intracellularly to its 5'-monophosphate in CD4+ CEM cells and in PBLs, but the di- and triphosphates of 1592U89 were not detected. The only triphosphate found in cells incubated with 1592U89 was that of the guanine analog (-)-carbovir (CBV). However, the in vivo pharmacokinetic, distribution, and toxicological profiles of 1592U89 were distinct from and improved over those of CBV, probably because CBV itself was not appreciably formed from 1592U89 in cells or animals (<2%). The 5'-triphosphate of CBV was a potent, selective inhibitor of HIV-1 RT, with Ki values for DNA polymerases (alpha, beta, gamma, and epsilon which were 90-, 2,900-, 1,200-, and 1,900-fold greater, respectively, than for RT (Ki, 21 nM). 1592U89 was relatively nontoxic to human bone marrow progenitors erythroid burst-forming unit and granulocyte-macrophage CFU (IC50s, 110 microM) and human leukemic and liver tumor cell lines. 1592U89 had excellent oral bioavailability (105% in the rat) and penetrated the CNS (rat brain and monkey cerebrospinal fluid) as well as AZT. Having demonstrated an excellent preclinical profile, 1592U89 has progressed to clinical evaluation in HIV-infected patients.

scholarly journals Clinical Impact of Pretreatment Human Immunodeficiency Virus Drug Resistance in People Initiating Nonnucleoside Reverse Transcriptase Inhibitor–Containing Antiretroviral Therapy: A Systematic Review and Meta-analysis

2020 ◽  
Author(s):  
Silvia Bertagnolio ◽  
Lucas Hermans ◽  
Michael R Jordan ◽  
Santiago Avila-Rios ◽  
Collins Iwuji ◽  
...  
Keyword(s):  
Systematic Review ◽  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Treatment Outcomes ◽  
Meta Analysis ◽  
Transcriptase Inhibitor ◽  
Nonnucleoside Reverse Transcriptase Inhibitor ◽  
Immunodeficiency Virus ◽  
Reverse Transcriptase Inhibitor

Abstract Background Increased access to antiretroviral therapy (ART) has resulted in rising levels of pretreatment human immunodeficiency virus drug resistance (PDR). This is the first systematic review and meta-analysis to assess the impact of PDR on treatment outcomes among people initiating nonnucleoside reverse transcriptase inhibitor (NNRTI)–based ART, including the combination of efavirenz (EFV), tenofovir (TDF), and lamivudine or emtricitabine (XTC). Methods We systematically reviewed studies and conference proceedings comparing treatment outcomes in populations initiating NNRTI-based ART with and without PDR. We conducted subgroup analyses by regimen: (1) NNRTIs + 2 nucleoside reverse transcriptase inhibitors (NRTIs), (2) EFV + 2 NRTIs, or (3) EFV/TDF/XTC; by population (children vs adults); and by definition of resistance (PDR vs NNRTI PDR). Results Among 6197 studies screened, 32 were analyzed (31 441 patients). We found that individuals with PDR initiating NNRTIs across all the subgroups had increased risk of virological failure compared to those without PDR. Risk of acquisition of new resistance mutations and ART switch was also higher in people with PDR. Conclusions This review shows poorer treatment outcomes in the presence of PDR, supporting the World Health Organization’s recommendation to avoid using NNRTIs in countries where levels of PDR are high.

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