Pharmacokinetics of single oral doses of apricitabine, a novel deoxycytidine analogue reverse transcriptase inhibitor, in healthy volunteers

Interactions of Antiretroviral Drugs with Food, Beverages, Dietary Supplements, and Alcohol: A Systematic Review and Meta-analyses

Multiple factors may affect combined antiretroviral therapy (cART). We investigated the impact of food, beverages, dietary supplements, and alcohol on the pharmacokinetic and pharmacodynamic parameters of 33 antiretroviral drugs. Systematic review in adherence to PRISMA guidelines was performed, with 109 reports of 120 studies included. For each drug, meta-analyses or qualitative analyses were conducted. We have found clinically significant interactions with food for more than half of antiretroviral agents. The following drugs should be taken with or immediately after the meal: tenofovir disoproxil, etravirine, rilpivirine, dolutegravir, elvitegravir, atazanavir, darunavir, lopinavir, nelfinavir, ritonavir, saquinavir. Didanosine, zalcitabine, zidovudine, efavirenz, amprenavir, fosamprenavir, and indinavir should be taken on an empty stomach for maximum patient benefit. Antiretroviral agents not mentioned above can be administered regardless of food. There is insufficient evidence available to make recommendations about consuming juice or alcohol with antiretroviral drugs. Resolving drug-food interactions may contribute to maximized cART effectiveness and safety.

Apricitabine: A Novel Deoxycytidine Analogue Nucleoside Reverse Transcriptase Inhibitor for the Treatment of Nucleoside-Resistant HIV Infection

Existing nucleoside reverse transcriptase inhibitors for HIV disease are limited by problems of resistance and, in some cases, long-term toxicity. Apricitabine (ATC; formerly BCH10618, SPD754 and AVX754) is a deoxycytidine analogue nucleoside reverse transcriptase inhibitor in clinical development. ATC retains substantial in vitro activity against HIV-1 containing many mutations associated with nucleoside reverse transcriptase inhibitor resistance, showing a less than twofold reduction in susceptibility in the presence of either up to five thymidine analogue mutations or the M184V mutation. ATC showed a low potential for cellular or mitochondrial toxicity in vitro. ATC is well absorbed orally, with a bioavailability of 65–80%. Its plasma elimination half-life (approximately 3 h), and the intracellular half-life of its triphosphate (TP) metabolite (6–7 h) support twice-daily dosing. Intracellular ATC-TP levels are markedly reduced in the presence of lamivudine or emtricitabine, indicating that clinical co-administration of ATC together with these agents will not be possible. The drug is renally eliminated, giving a low potential for hepatic drug interactions. In a double-blind, randomized, placebo-controlled Phase II monotherapy trial in antiretroviral-naive patients, ATC doses of 1,200 and 1,600 mg/day reduced plasma viral load levels by 1.65 and 1.58 log10 HIV RNA copies/ml, respectively, after 10 days of treatment ( P<0.0001 versus placebo). ATC showed a low propensity to select for resistance mutants in vitro and during clinical monotherapy. ATC was well tolerated in volunteers and in HIV-infected patients. This promising profile suggests that ATC may be useful in treating patients who have failed previous lamivudine- or emtricitabine-containing regimens. Further studies to evaluate the long-term efficacy and tolerability of ATC are underway.

Renal excretion of apricitabine in rats: ex vivo and in vivo studies

Apricitabine (ATC) is a novel nucleoside reverse transcriptase inhibitor undergoing phase 2/3 clinical development for the treatment of HIV infection. In this investigation, the renal handling of ATC was evaluated in the isolated perfused rat kidney (IPK) model with follow-up in vivo studies. IPK experiments were performed to characterize the renal excretion of ATC, to probe mechanisms of ATC excretion using known inhibitors of organic cation (cimetidine) and organic anion (probenecid) transport systems, and to screen for potential drug-drug interactions between ATC and clinically relevant medications (dapsone, metformin, pentamidine, stavudine, tenofovir and ritonavir). ATC demonstrated net tubular secretion in the IPK with a baseline excretion ratio (XR) of 2.1 ± 0.56. ATC XR decreased 3.6-fold in the presence of cimetidine and 2-fold in the presence of probenecid. Among the clinically relevant medications, metformin produced the greatest inhibitory effect on ATC excretion. In vivo studies were conducted in rats to evaluate ATC disposition upon co-administration with compounds that showed a significant effect on ATC clearance in the IPK model. Co-administration of cimetidine and trimethoprim significantly reduced ATC renal clearance, but resulted in only a moderate increase in plasma exposure. Metformin had no apparent effect on ATC clearance in rats. These findings indicate that the IPK model is more sensitive to secretory inhibition as compared to in vivo. The medications screened showed minimal effects on ATC renal excretion in the IPK, and should thus be excluded as potential in vivo interactants. Overall, this study generated important information on renal handling of ATC to support its development and commercialization.

Comparison of the pharmacokinetics of apricitabine in the presence and absence of ritonavir-boosted tipranavir: a phase I, open-label, controlled, single-centre study

BACKGROUND AND OBJECTIVE

Apricitabine is a deoxycytidine analogue nucleoside reverse transcriptase inhibitor for the treatment of HIV infection. The aim of this phase I study was to investigate whether administration of apricitabine with the HIV protease inhibitor tipranavir (ritonavir-boosted) affects the pharmacokinetic profile of apricitabine.

METHODS

This phase I study was conducted in 18 healthy adult male subjects. Subjects received a single dose of apricitabine 800 mg on the morning of day 1 followed by tipranavir 500 mg plus ritonavir 200 mg every 12 hours from day 2 to day 9 to achieve steady-state concentrations of tipranavir/ritonavir. On day 10, subjects received a single morning dose of apricitabine 800 mg and a single dose of tipranavir 500 mg plus ritonavir 200 mg. Following dosing on days 1, 9 and 10, pharmacokinetic sampling was undertaken over 12 hours post-dosing to determine the plasma concentrations of apricitabine and tipranavir.

RESULTS

The administration of a single dose of apricitabine 800 mg in the presence of steady-state tipranavir/ritonavir concentrations resulted in an increase in the apricitabine area under the plasma concentration-time curve of approximately 40% and in the apricitabine maximum plasma concentration of approximately 25% relative to apricitabine 800 mg administered alone. Apricitabine was well tolerated when administered with tipranavir/ritonavir.

CONCLUSION

A moderate increase in apricitabine exposure was seen after co-administration with ritonavir-boosted tipranavir but this increase was not of clinical significance. No adjustment of apricitabine dosing is required when administered with ritonavir-boosted tipranavir.

Apricitabine: a nucleoside reverse transcriptase inhibitor for HIV infection

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, and safety of apricitabine, a nucleoside reverse transcriptase inhibitor that is currently under investigation and has fast-track approval status with the Food and Drug Administration.

DATA SOURCES

A literature search was conducted using PubMed (1966-June 2009) to retrieve relevant material using the search terms apricitabine, SPD754, and AVX754. References from selected articles were evaluated to identify other pertinent trials. Information was also obtained from the manufacturer.

STUDY SELECTION AND DATA EXTRACTION

All English-language in vitro and in vivo studies and abstracts evaluating apricitabine were reviewed and considered for inclusion. Preference was given to human data.

DATA SYNTHESIS

Apricitabine is a prodrug that is phosphorylated to its active triphosphate form intracellularly, which ultimately results in chain termination and inhibition of reverse transcription. Apricitabine is administered orally, displays linear pharmacokinetics, and is renally excreted with minimal to no hepatic metabolism. It has demonstrated antiretroviral activity against drug-resistant strains both in vitro and in vivo. In clinical studies, in both antiretroviral-naïve and treatment-experienced patients, apricitabine achieved the primary endpoint of significant reductions in plasma viral load versus comparator. Further Phase 2 and 3 studies are currently enrolling. Safety analysis indicates that apricitabine is well tolerated and has a low potential for causing mitochondrial damage. The most common adverse events reported include headache and rhinitis. Development of resistance or further gene mutations has not been shown in clinical studies to date.

CONCLUSIONS

Although the role of apricitabine in the treatment of HIV-1 infection has yet to be established, its activity against resistant HIV-1 strains and its tolerability profile will likely make it a viable second-line treatment option in patients who have failed regimens containing lamivudine or emtricitabine.

Pharmacokinetics and drug-drug interactions of antiretrovirals: an update

Current antiretroviral treatment has allowed HIV infection to become a chronic manageable condition with many HIV patients living longer. However, available antiretrovirals are not without limitations, for example the development of resistance and adverse effects. Consequently, new drugs in existing and novel classes are urgently required to provide viable treatment options to patients with few remaining choices. Darunavir, etravirine, maraviroc and raltegravir have been recently approved for treatment-experienced patients and other agents such as rilpivirine, vicriviroc and elvitegravir are currently under phase III study. Clinical studies are necessary to optimise potential treatment combinations and to manage drug-drug interactions to help avoid toxicity or therapy failure. This review aims to summarise the pharmacokinetics and key drug-drug interaction studies for newly available antiretrovirals and those in development. Further information regarding drug-drug interactions of well established antiretrovirals and those recently approved are readily available online at sites such as http://www.hiv-druginteractions.org, http://www.clinicaloptions.com/hiv, http://hivinsite.ucsf.edu. 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.

Effects of Trimethoprim on the Clearance of Apricitabine, a Deoxycytidine Analog Reverse Transcriptase Inhibitor, and Lamivudine in the Isolated Perfused Rat Kidney

Apricitabine (ATC) is a novel deoxycytidine analog reverse transcriptase inhibitor in development for the treatment of human immunodeficiency virus infection. Studies were performed to characterize the excretion of ATC and its metabolite, BCH-335 (-1-(2-hydroxymethyl-[1,3]oxathiolan-4-yl)-1H-pyrimidine-2,4-dione), in the isolated perfused rat kidney (IPK). A second objective was to investigate the effect of trimethoprim on ATC excretion because trimethoprim inhibits the excretion of lamivudine, structurally similar to ATC, in the IPK. ATC excretion was nonlinear at doses of 80 to 1600 microg. The excretion ratio (ratio of clearance to glomerular filtration rate, assuming negligible protein binding) was greater than 1.0, indicating net tubular secretion. In contrast, the excretion of BCH-335 was independent of the dose of BCH-335. Concomitant administration of ATC and BCH-335 did not affect the excretion of either compound. Trimethoprim significantly inhibited the excretion of both ATC and BCH-335, with IC(50) values of 0.45 and 0.54 microg/ml, respectively. In the presence of trimethoprim, the excretion ratios for both compounds were less than 1.0, indicating tubular reabsorption. Trimethoprim inhibited the excretion of ATC and lamivudine to similar extents. Following concomitant administration of ATC, lamivudine, and trimethoprim, there was no evidence of an interaction between ATC and lamivudine. These results suggest that ATC undergoes active tubular secretion in the kidney. Because the renal excretion of both ATC and lamivudine is inhibited by trimethoprim to similar extents, in clinical practice exposure to ATC, it would be expected to be increased in the presence of therapeutic concentrations of trimethoprim to a similar extent as has been shown previously for lamivudine.