scholarly journals Single-dose pharmacokinetics of delavirdine mesylate and didanosine in patients with human immunodeficiency virus infection.

1997 ◽  
Vol 41 (1) ◽  
pp. 169-174 ◽  
Author(s):  
G D Morse ◽  
M A Fischl ◽  
M J Shelton ◽  
S R Cox ◽  
M Driver ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Single Dose ◽  
Nucleoside Analogs ◽  
Concurrent Administration ◽  
Time Curve ◽  
Single Dose Study ◽  
Cd4 Cell Count ◽  
Immunodeficiency Virus ◽  
Delavirdine Mesylate

Delavirdine is a nonnucleoside reverse transcriptase inhibitor with in vitro activity against human immunodeficiency virus type 1 (HIV-1) that is currently being evaluated in combination regimens with various nucleoside analogs, including didanosine. Due to the pH-dependent solubility of delavirdine, the buffering agents in didanosine formulations may reduce delavirdine absorption. To evaluate the potential interaction between these agents, 12 HIV-infected patients (mean [+/- standard deviation] CD4+ cell count, 304 +/- 213/mm3) were enrolled in a three-way crossover single-dose study. Didanosine (125 to 200 mg given as buffered tablets) and delavirdine mesylate (400 mg) pharmacokinetics were evaluated when each drug was given alone (treatments A and B, respectively), when the two drugs were given concurrently (treatment C), and when didanosine was given 1 h after delavirdine (treatment D). Delavirdine exposure was reduced by concurrent administration of didanosine. The maximum drug concentration in serum (Cmax) was reduced from 7.22 +/- 4.0 to 3.51 +/- 1.9 microM, and the area under the concentration-time curve from 0 h to infinity (AUC0-->infinity) was reduced from 22.5 +/- 14 to 14 +/- 5.7 microM.h. The extent of N-dealkylation, as indicated by the ratio of the N-dealkylated delavirdine AUC0-->infinity to the delavirdine AUC0-->infinity, was unchanged across study treatments (P = 0.708). Reductions in didanosine exposure were observed during concurrent administration with delavirdine with a Cmax reduction from 4.65 +/- 2.0 to 3.22 +/- 0.59 microM and an AUC0-->infinity reduction from 7.93 +/- 3.9 to 6.54 +/- 2.3 microM.h. Thus, concurrent administration of delavirdine and didanosine may reduce the AUC0-->infinity of both drugs, although the clinical significance of this reduction is unknown. Administration of delavirdine 1 h before didanosine avoided the interaction. Due to the single-dose nature of this study, these findings require further evaluation at steady state.

scholarly journals Didanosine reduces atevirdine absorption in subjects with human immunodeficiency virus infections.

1996 ◽  
Vol 40 (3) ◽  
pp. 767-771 ◽  
Author(s):  
G D Morse ◽  
M A Fischl ◽  
M J Shelton ◽  
M T Borin ◽  
M R Driver ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Maximum Concentration ◽  
Concurrent Administration ◽  
Time Curve ◽  
Concentration Time ◽  
Immunodeficiency Virus ◽  
Combination Regimens

Atevirdine is a nonnucleoside reverse transcriptase inhibitor with in vitro activity against human immunodeficiency virus type 1 and is currently in phase II clinical trials. Atevirdine is most soluble at a pH of < 2, and therefore, normal gastric acidity is most likely necessary for optimal bioavailability. Because of the rapid development of resistance in vitro, atevirdine is being evaluated in combination with didanosine and/or zidovudine in both two- and three-drug combination regimens. To examine the influence of concurrent didanosine (buffered tablet formulation) on the disposition of atevirdine, 12 human immunodeficiency virus type 1-infected subjects (mean CD4+ cell count, 199 cells per mm3; range, 13 to 447 cells/mm3) participated in a three-way, partially randomized, crossover, single-dose study to evaluate the pharmacokinetics of didanosine and atevirdine when each drug was given alone (treatments A and B, respectively) versus concurrently (treatment C). Concurrent administration of didanosine and atevirdine significantly reduced the maximum concentration of atevirdine in serum from 3.45 +/- 2.8 to 0.854 +/- 0.33 microM (P = 0.004). Likewise, the mean atevirdine area under the concentration-time curve from 0 to 24 h after administration of the combination was reduced to 6.47 +/- 2.2 microM.h (P = 0.004) relative to a value of 11.3 +/- 4.8 microM.h for atevirdine alone. Atevirdine had no statistically significant effect on the pharmacokinetic parameters of didanosine. Concurrent administration of single doses of atevirdine and didanosine resulted in a markedly lower maximum concentration of atevirdine in serum and area under the concentration-time curve, with a minimal effect on the disposition of didanosine. It is unknown whether an interaction of similar magnitude would occur under steady-state conditions; thus, combination regimens which include both atevirdine and didanosine should be designed so that their administration times are separated. Since the duration of the buffering effect of didanosine formulations is unknown, atevirdine should be given prior to didanosine.

scholarly journals Single-Dose Safety and Pharmacokinetics of Brecanavir, a Novel Human Immunodeficiency Virus Protease Inhibitor

2006 ◽  
Vol 50 (6) ◽  
pp. 2201-2206 ◽  
Author(s):  
Susan L. Ford ◽  
Y. Sunila Reddy ◽  
Maggie T. Anderson ◽  
Sharon C. Murray ◽  
Pedro Fernandez ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Single Dose ◽  
Polyethylene Glycol ◽  
Protease Inhibitor ◽  
Maximum Concentration ◽  
Glycol Succinate ◽  
Single Dose Study ◽  
Immunodeficiency Virus ◽  
Oral Doses

ABSTRACT Brecanavir (BCV, 640385) is a novel, potent protease inhibitor (PI) with low nanomolar 50% inhibitory concentrations against PI-resistant human immunodeficiency virus (HIV) in vitro. This phase I, double-blind, randomized, placebo-controlled, two-part single-dose study (first time with humans) was conducted to determine the safety, tolerability, and pharmacokinetics of BCV administered at 10 mg/ml in a tocopherol-polyethylene glycol succinate-polyethylene glycol 400-ethanol 50:40:10 solution. In part 1 of the study, single oral doses of BCV ranged from 25 mg to 800 mg. In part 2, single oral doses of BCV ranged from 10 mg to 300 mg and were coadministered with 100-mg oral ritonavir (RTV) soft gel capsules. Single doses of BCV and BCV/RTV were generally well tolerated. There were no severe adverse events (SAEs), and no subject was withdrawn due to BCV. The most commonly reported drug-related AEs during both parts of the study combined were gastrointestinal disturbances (similar to placebo) and headache. BCV was readily absorbed following oral administration with mean times to maximum concentration from >1 h to 2.5 h in part 1 and from 1.5 h to 3 h in part 2. Administration of BCV without RTV resulted in BCV exposures predicted to be insufficient to inhibit PI-resistant virus based on in vitro data. Coadministration of 300 mg BCV with 100 mg RTV, however, significantly increased the plasma BCV area under the concentration-time curve and maximum concentration 26-fold and 11-fold, respectively, achieving BCV concentrations predicted to inhibit PI-resistant HIV.

scholarly journals Human Immunodeficiency Virus Types 1 and 2 Exhibit Comparable Sensitivities to Zidovudine and Other Nucleoside Analog Inhibitors In Vitro

2007 ◽  
Vol 52 (1) ◽  
pp. 329-332 ◽  
Author(s):  
Robert A. Smith ◽  
Geoffrey S. Gottlieb ◽  
Donovan J. Anderson ◽  
Crystal L. Pyrak ◽  
Bradley D. Preston
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Replication ◽  
Reverse Transcriptase ◽  
Antiviral Therapy ◽  
Nucleoside Analogs ◽  
Nucleoside Analog ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Indicator Cell

ABSTRACT Using an indicator cell assay that directly quantifies viral replication, we show that human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2, respectively) exhibit similar sensitivities to 3′-azido-3′-deoxythymidine (zidovudine) as well as other nucleoside analog inhibitors of reverse transcriptase. These data support the use of nucleoside analogs for antiviral therapy of HIV-2 infection.

scholarly journals Single-Dose Pharmacokinetics and Safety of Abacavir (1592U89), Zidovudine, and Lamivudine Administered Alone and in Combination in Adults with Human Immunodeficiency Virus Infection

1999 ◽  
Vol 43 (7) ◽  
pp. 1708-1715 ◽  
Author(s):  
Laurene H. Wang ◽  
Gregory E. Chittick ◽  
James A. McDowell
Keyword(s):  
Human Immunodeficiency Virus ◽  
Adverse Events ◽  
Nucleoside Analogs ◽  
Neck Stiffness ◽  
Time Curve ◽  
Pharmacokinetic Interactions ◽  
Immunodeficiency Virus ◽  
The Mean ◽  
Clinically Significant ◽  
Hiv 1

ABSTRACT Abacavir (1592U89), a nucleoside reverse transcriptase inhibitor with in vitro activity against human immunodeficiency virus type-1 (HIV-1), has been evaluated for efficacy and safety in combination regimens with other nucleoside analogs, including zidovudine (ZDV) and lamivudine (3TC). To evaluate the potential pharmacokinetic interactions between these agents, 15 HIV-1-infected adults with a median CD4+ cell count of 347 cells/mm3 (range, 238 to 570 cells/mm3) were enrolled in a randomized, seven-period crossover study. The pharmacokinetics and safety of single doses of abacavir (600 mg), ZDV (300 mg), and 3TC (150 mg) were evaluated when each drug was given alone or when any two or three drugs were given concurrently. The concentrations of all drugs in plasma and the concentrations of ZDV and its 5′-glucuronide metabolite, GZDV, in urine were measured for up to 24 h postdosing, and pharmacokinetic parameter values were calculated by noncompartmental methods. The maximum drug concentration (C max), the area under the concentration-time curve from time zero to infinity (AUC0–∞), time to C max(T max), and apparent elimination half-life (t 1/2) of abacavir in plasma were unaffected by coadministration with ZDV and/or 3TC. Coadministration of abacavir with ZDV (with or without 3TC) decreased the meanC max of ZDV by approximately 20% (from 1.5 to 1.2 μg/ml), delayed the median T max for ZDV by 0.5 h, increased the mean AUC0–∞ for GZDV by up to 40% (from 11.8 to 16.5 μg · h/ml), and delayed the medianT max for GZDV by approximately 0.5 h. Coadministration of abacavir with 3TC (with or without ZDV) decreased the mean AUC0–∞ for 3TC by approximately 15% (from 5.1 to 4.3 μg · h/ml), decreased the meanC max by approximately 35% (from 1.4 to 0.9 μg/ml), and delayed the median T max by approximately 1 h. While these changes were statistically significant, they are similar to the effect of food intake (for ZDV) or affect an inactive metabolite (for GZDV) or are relatively minor (for 3TC) and are therefore not considered to be clinically significant. No significant differences were found in the urinary recoveries of ZDV or GZDV when ZDV was coadministered with abacavir. There was no pharmacokinetic interaction between ZDV and 3TC. Mild to moderate headache, nausea, lymphadenopathy, hematuria, musculoskeletal chest pain, neck stiffness, and fever were the most common adverse events reported by those who received abacavir. Coadministration of ZDV or 3TC with abacavir did not alter this adverse event profile. The three-drug regimen was primarily associated with gastrointestinal events. In conclusion, no clinically significant pharmacokinetic interactions occurred between abacavir, ZDV, and 3TC in HIV-1-infected adults. Coadministration of abacavir with ZDV or 3TC produced mild changes in the absorption and possibly the urinary excretion characteristics of ZDV-GZDV and 3TC that were not considered to be clinically significant. Coadministration of abacavir with ZDV and/or 3TC was generally well tolerated and did not produce unexpected adverse events.

scholarly journals Highly potent oxathiin carboxanilide derivatives with efficacy against nonnucleoside reverse transcriptase inhibitor-resistant human immunodeficiency virus isolates.

1997 ◽  
Vol 41 (4) ◽  
pp. 831-837 ◽  
Author(s):  
R W Buckheit ◽  
M J Snow ◽  
V Fliakas-Boltz ◽  
T L Kinjerski ◽  
J D Russell ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
In Vitro Selection ◽  
Nucleoside Analogs ◽  
Side Chain ◽  
Resistant Virus ◽  
Immunodeficiency Virus ◽  
Virus Isolates ◽  
Hiv 1

The structure-activity relationships of a series of compounds related to the nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) oxathiin carboxanilide have been described (R. W. Buckheit, Jr., T. L. Kinjerski, V. Fliakas-Boltz, J. D. Russell, T. L. Stup, L. A. Pallansch, W. G. Brouwer, D. C. Dao, W. A. Harrison, R. J. Schultz, J. P. Bader, and S. S. Yang, Antimicrob. Agents Chemother. 39:2718-2727, 1996). From these studies, the furanyl-containing analog UC10 was identified as the most potent inhibitor of human immunodeficiency virus type 1 (HIV-1) replication and a promising candidate for further development. Three new UC analogs (UC040, UC82, and UC781) have been determined to inhibit laboratory-derived and low-passage-number, primary virus isolates at low nanomolar concentrations in both established and fresh human cells. Each of the compounds synergistically interacted with the nucleoside analogs zidovudine, dideoxyinosine, dideoxycytosine, and lamivudine to inhibit HIV-1 replication. As a group, the UC compounds were found to be less active against viruses with the L100I, K103N, and Y181C amino acid changes in the RT and, upon in vitro selection, yielded resistant virus with the Y181C mutation in the RT. The most potent of the three new compounds, UC781, contains a furanyl side chain, similar to UC10, but differs in having an extended ether side chain instead of an oxime chain. The broad therapeutic index of UC781 (>62,000) resulted in effective inhibition of NNRTI-resistant virus isolates at high nanomolar concentrations. Furthermore, UC781 and the NNRTI costatolide were able to synergistically inhibit HIV-1 replication when used in combination, suggesting that UC781 may interact with the RT differently than the other UC analogs. The favorable anti-HIV properties of the UC compounds suggest they should be considered for further clinical development.

scholarly journals Pharmacokinetics of Ritonavir and Delavirdine in Human Immunodeficiency Virus-Infected Patients

2003 ◽  
Vol 47 (5) ◽  
pp. 1694-1699 ◽  
Author(s):  
Mark J. Shelton ◽  
Ross G. Hewitt ◽  
John Adams ◽  
Andrew Della-Coletta ◽  
Steven Cox ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Systemic Exposure ◽  
Pharmacokinetic Parameters ◽  
Time Curve ◽  
Minimum Concentration ◽  
Mean Values ◽  
Immunodeficiency Virus ◽  
The Mean ◽  
Full Dosage ◽  
Delavirdine Mesylate

ABSTRACT To evaluate the pharmacokinetic effect of adding delavirdine mesylate to the antiretroviral regimens of human immunodeficiency virus (HIV)-infected patients stabilized on a full dosage of ritonavir (600 mg every 12 h), 12 HIV-1-infected subjects had delavirdine mesylate (400 mg every 8 h) added to their current antiretroviral regimens for 21 days. Ritonavir pharmacokinetics were evaluated before (day 7) and after (day 28) the addition of delavirdine, and delavirdine pharmacokinetics were evaluated on day 28. The mean values (± standard deviations) for the maximum concentration in serum (C max) of ritonavir, the area under the concentration-time curve from 0 to 12 h (AUC0-12), and the minimum concentration in serum (C min) of ritonavir before the addition of delavirdine were 14.8 ± 6.7 μM, 94 ± 36 μM · h, and 3.6 ± 2.1 μM, respectively. These same parameters were increased to 24.6 ± 13.9 μM, 154 ± 83 μM · h, and 6.52 ± 4.85 μM, respectively, after the addition of delavirdine (P is <0.05 for all comparisons). Delavirdine pharmacokinetic parameters in the presence of ritonavir included a C max of 23 ± 16 μM, an AUC0-8 of 114 ± 75 μM · h, and a C min of 9.1 ± 7.5 μM. Therefore, delavirdine increases systemic exposure to ritonavir by 50 to 80% when the drugs are coadministered.

scholarly journals In vitro potency of inhibition by antiviral drugs of hematopoietic progenitor colony formation correlates with exposure at hemotoxic levels in human immunodeficiency virus-positive humans.

1996 ◽  
Vol 40 (2) ◽  
pp. 514-519 ◽  
Author(s):  
R E Dornsife ◽  
D R Averett
Keyword(s):  
Human Immunodeficiency Virus ◽  
Colony Formation ◽  
Rank Order ◽  
Bone Marrow Toxicity ◽  
Time Curve ◽  
Concentration Time ◽  
Immunodeficiency Virus ◽  
Nucleoside Drugs ◽  
Antiviral Nucleoside

Inhibition of in vitro colony formation of human hematopoietic progenitors (CFU-granulocyte-macrophage, burst-forming unit-erythroid) by the antiviral nucleoside drugs alovudine, zalcitabine, zidovudine, ganciclovir, stavudine, didanosine, lamivudine, and acyclovir was measured. Significant correlations between in vitro 50% inhibitory concentrations and the daily human exposures (area under the concentration-time curve from 0 to 24 h; in micromolar.hour) of these chronically administered drugs in human immunodeficiency virus-positive patients that induced neutropenia or anemia were demonstrated by both linear regression and Spearman rank-order analyses. These quantitative correlations allow estimation of the exposure at which bone marrow toxicity may occur with candidate compounds.

scholarly journals In vitro bone marrow toxicity of nucleoside analogs against human immunodeficiency virus.

1989 ◽  
Vol 33 (4) ◽  
pp. 576-579 ◽  
Author(s):  
T Inoue ◽  
K Tsushita ◽  
T Itoh ◽  
M Ogura ◽  
T Hotta ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Human Immunodeficiency Virus ◽  
Nucleoside Analogs ◽  
Bone Marrow Toxicity ◽  
Immunodeficiency Virus

scholarly journals Relationship between Didanosine Exposure and Surrogate Marker Response in Human Immunodeficiency Virus-Infected Outpatients

1998 ◽  
Vol 42 (4) ◽  
pp. 821-826 ◽  
Author(s):  
John M. Adams ◽  
Mark J. Shelton ◽  
Ross G. Hewitt ◽  
Thaddeus H. Grasela ◽  
Mary DeRemer ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Exposure ◽  
Surrogate Marker ◽  
Pharmacokinetic Studies ◽  
Time Curve ◽  
Cd4 Cell Count ◽  
Concentration Time ◽  
Immunodeficiency Virus ◽  
The Mean ◽  
Cd4 Cell

ABSTRACT We used information available from routine clinic visits to characterize the pharmacokinetics of didanosine in 82 human immunodeficiency virus-infected patients. A total of 271 blood samples were collected for the measurement of didanosine concentrations in plasma (mean ± standard deviation [SD], 3.30 ± 2.21 samples/patient). Bayesian estimates of didanosine oral clearance (CLoral) were obtained for these patients by the POSTHOC option within the NONMEM software package. Population priors from a previous NONMEM analysis of didanosine pharmacokinetics were used. The mean ± SD CLoral was 132 ± 27.7 liters/h, which agrees reasonably well with estimates obtained from previous pharmacokinetic studies of didanosine. Estimates of individual didanosine exposure were then used to consider potential relationships between drug exposure and surrogate marker response over a 6-month period. No correlations were found between the didanosine area under the concentration-time curve from 0 to 6 months and the absolute CD4 cell count (r = 0.305; 0.1 <P < 0.2), weight response (r = 0.0857; P > 0.4), or percentage of CD4 lymphocytes (r = 0.0559; P > 0.4). Future efforts to characterize didanosine exposure in outpatients by random sampling methods should involve more directed efforts to limit residual variability in the data.

scholarly journals 3′-Azido-3′-Deoxythymidine (AZT) Mediates Cross-Resistance to Nucleoside Analogs in the Case of AZT-Resistant Human Immunodeficiency Virus Type 1 Variants

1998 ◽  
Vol 72 (6) ◽  
pp. 4858-4865 ◽  
Author(s):  
Eric J. Arts ◽  
Miguel E. Quiñones-Mateu ◽  
Jamie L. Albright ◽  
James-Paul Marois ◽  
Charles Hough ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Nucleoside Analogs ◽  
Cross Resistance ◽  
Treatment Regimens ◽  
Immunodeficiency Virus ◽  
Azt Resistance

ABSTRACT Difficulties in deciphering the mechanisms of 3′-azido-3′-deoxythymidine (AZT)-resistance by human immunodeficiency virus type 1 (HIV-1) variants are due in part to an inability to reconstitute resistance in vitro using AZT-resistant reverse transcriptases. We decided to characterize mechanisms of AZT resistance in tissue culture infections by studying the ability of drug-resistant viruses to synthesize viral DNA in the presence or absence of drug. Through use of PCR amplifications, we discovered an AZT-mediated stimulation of reverse transcription by AZT-resistant viruses carrying the M41L and T215Y mutations that can apparently override the inhibitory effects of AZT-5′-triphosphate. In addition, the presence of AZT also causes viruses containing the M41L and T215Y substitutions to have diminished sensitivity to other nucleoside analogs (i.e., ddC, ddI, and d4T). This AZT-mediated cross-resistance may help to explain the virological failure of treatment regimens that included ddI plus AZT or ddC plus AZT in situations in which the T215Y and/or M41L mutations were present (F. Brun-Vézinet, C. Boucher, C. Loveday, D. Descamps, V. Fauveau, J. Izopet, D. Jeffries, S. Kaye, C. Krzyanowski, A. Nunn, R. Schuurman, J. M. Seigneurin, C. Tamalet, R. Tedder, J. Weber, and G. J. Weverling, Lancet 350:983–990, 1997). Our results suggest that the use of AZT may be contraindicated in those patients for whom resistance to this compound (M41L and/or T215Y) has been demonstrated.

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