Efavirenz

Effect of a moderate CYP3A inducer efavirenz on the pharmacokinetics of fuzuloparib: An open-label, fixed sequence study in Chinese healthy male subjects

To evaluate the potential drug-drug interaction (DDI), safety and tolerability of fuzuloparib co-administered with a moderate CYP3A inducer efavirenz in healthy male subjects. Eighteen healthy male subjects were enrolled in a single-center, single-arm, open-label, fixed-sequence study. Fuzuloparib was administered as a single oral 50 mg under a fasting state on day 1, efavirenz (600 mg once daily) was given on days 4-17 before bed time, concomitantly with fuzuloparib on day 18, and for the follow-up 3 additional days (days 19-20). Pharmacokinetic sampling was performed following each fuzuloparib dose. Safety and tolerability were assessed during the whole process via clinical laboratory tests. Ratios of least-squares means (GMRs) and 90% geometric confidence interval (90% CI) of maximum plasma concentration (C_max), the area under the curve of plasma concentration-time from zero to the last measurable concentration (AUC_0 - t) and the area under the curve of blood concentration from zero to infinity (AUC_0-∞) for fuzuloparib combined with efavirenz to fuzuloparib alone were 0.473 (0.394, 0.568), 0.220 (0.185, 0.263) and 0.221 (0.185, 0.263), respectively. Co-administration with efavirenz led to 53% and 78% decreases in fuzuloparib C_max and AUC_0-∞. All 18 subjects enrolled in this study were included in the safety analysis set. A total of 16 subjects had 62 AEs during the study period. No serious adverse events (SAE) were reported. Most treatment-emergent adverse events were grade 1 or 2 based on CTCAE. Only one grade 3 adverse event was observed. Concomitant intake of fuzuloparib with the moderate CYP3A inhibitor efavirenz resulted in a decrease in fuzuloparib AUC_0-∞ and C_max of 78% and 53% respectively. The results suggested that concomitant moderate CYP3A inducers should be avoided during the administration of fuzuloparib, or else the dosage adjustments should be required. (This trial was registered at http://www.chinadrugtrials.org.cn . The registration No. is CTR20211022, and the date of registration is 2021-05-13).

Nose to brain delivery of Efavirenz nanosuspension for effective neuro AIDS therapy: in-vitro, in-vivo and pharmacokinetic assessment

Efavirenz is inhibitor of non-nucleoside reverse transcriptase enzyme; BCS class II drug. The objective of the present research was to prepare and evaluate nanosuspension of Efavirenz for the treatment of neuro-AIDS. Efavirenz is the substrate for drug resistant proteins at BBB prone to efflux and could not reach brain with effective levels. Current need of the therapy is to develop drug delivery systems targeting viral reservoirs at effective concentration in the brain. With this need we developed Efavirenz nanosuspension for nose to brain drug transport to bypass blood brain barrier. Nanosuspension prepared with high-pressure homogenization had a mean particle size of 223 nm, PDI of 0.2 and -21.2 mV zeta potential. Histopathology study on goat nasal mucosa showed no adverse effects of formulation on nasal tissues. Gamma scintigraphy study and in-vivo study on Wistar rat model reveals drug transport to the CNS after nasal administration. Pharmacokinetic parameters and drug targeting potential of 99.46 % suggest direct nose to brain transport of Efavirenz nanoparticle. Results reveal that nose to brain delivery of Efavirenz is the best possible alternative for neuro -AIDS treatment.

Single Tablet Regimen Usage and Efficacy in the Treatment of HIV Infection in Australia

Single tablet regimens (STRs) for HIV infection improve patient satisfaction, quality of life, medication adherence, and virological suppression compared to multitablet regimens (MTRs). This is the first study assessing STR uptake and durability in Australia. This retrospective audit of all patients receiving an STR (n = 299) at a large Sydney HIV clinic (January 2012–December 2013) assessed patient demographics, treatment prior to STR, HIV RNA load and CD4 during MTR and STR dosing, and reasons for STR switch. 206 patients switched from previous antiretroviral treatment to an STR, of which 88% switched from an MTR. Reasons for switching included desire to simplify treatment (57%), reduced side effects or toxicity (18%), and cost-saving for the patient. There was no switching for virological failure. Compared to when on an MTR, patients switching to an STR had significantly lower HIV RNA counts (p < 0.001) and significantly higher CD4 counts (p < 0.001). The discontinuation rate from STR was very low and all patients who switched to an STR maintained virological suppression throughout the study duration, although the study is limited by the absence of a control group.

Identification of potential drug-drug interactions between antiretroviral drugs from prescriptions in the private health-care sector in South Africa

The aim of this study was to identify potential drug-drug interactions (DDIs) between antiretroviral drugs (ARVs) and to determine whether prescribed daily doses (PDDs) from prescriptions can be used in the evaluation of these interactions. A quantitative, retrospective drug utilization study was performed on 49,995 and 81,096 ARV prescriptions from a South African pharmacy benefit management company, which were prescribed to 7664 and 10,162 HIV patients for 2005 and 2006, respectively. Potential DDIs identified across different age groups were 778 for 2005 and 1155 for 2006; the majority occurred in patients aged 19 to ≤45 years. The potential DDIs identified between ARVs were all interacting at clinical significance level 2 according to guidelines indicated by Tatro. These results demonstrate that potential DDIs were identified between ARVs mostly in three ARV combinations: Kaletra(®) (lopinavir/ritonavir) and efavirenz, lopinavir/ritonavir and nevirapine and combinations of indinavir and ritonavir. There is a need for more education on the prescribing protocols for ARVs in the treatment of HIV-infected patients in the private health-care sector in South Africa.

Projecting the clinical benefits and risks of using efavirenz-containing antiretroviral therapy regimens in women of childbearing age

OBJECTIVES

To project the outcomes of using either efavirenz or nevirapine as part of initial antiretroviral therapy (ART) in women of childbearing age in Côte d'Ivoire.

METHODS

We used an HIV computer simulation model to project both the mother's survival and the birth defects at 10 years for a cohort of women who started ART with either efavirenz or nevirapine. The primary outcome was the ratio at 10 years of the difference in the number of women alive to the difference in the cumulative number of birth defects in women who started ART with efavirenz compared with nevirapine. In the base case analysis, the birth defect rate was 2.9% on efavirenz and 2.7% on nevirapine. In sensitivity analyses, we varied all inputs across confidence intervals reported in the literature.

RESULTS

In the base case analysis, for a cohort of 100 000 women, the additional number of women alive initiating ART with efavirenz at 10 years was 15 times the additional number of birth defects (women alive: nevirapine 67 969, efavirenz 68 880, difference =  911; birth defects: nevirapine 1128, efavirenz 1187, difference = 59). In sensitivity analysis, the teratogenicity rate with efavirenz had to be 6.3%, or 2.3 times higher than the rate with nevirapine, for the excess number of birth defects to outweigh the additional number of women alive at 10 years.

CONCLUSION

In Côte d'Ivoire, initiating ART with efavirenz instead of nevirapine is likely to substantially increase the number of women alive at 10 years with a smaller potential number of birth defects.

In vitro evaluation of the activities of the novel anticytomegalovirus compound AIC246 (letermovir) against herpesviruses and other human pathogenic viruses

AIC246 (letermovir) is a potent anticytomegalovirus drug in clinical development. Here, we report a consistent antiviral efficacy of AIC246 against human cytomegalovirus laboratory strains, clinical isolates, and virus variants resistant to approved drugs. Furthermore, we describe a remarkable selectivity of AIC246 for human cytomegaloviruses compared to that of other alpha-, beta-, or gammaherpesviruses or nonrelated pathogenic viruses, including adeno-, hepadna-, retro-, orthomyxo-, and flaviviruses. Our data confirm and support an excellent and selective anticytomegaloviral activity of AIC246.

Lersivirine, a nonnucleoside reverse transcriptase inhibitor with activity against drug-resistant human immunodeficiency virus type 1

The nonnucleoside reverse transcriptase inhibitors (NNRTIs) are key components of highly active antiretroviral therapy (HAART) for the treatment of human immunodeficiency virus type 1 (HIV-1). A major problem with the first approved NNRTIs was the emergence of mutations in the HIV-1 reverse transcriptase (RT), in particular K103N and Y181C, which led to resistance to the entire class. We adopted an iterative strategy to synthesize and test small molecule inhibitors from a chemical series of pyrazoles against wild-type (wt) RT and the most prevalent NNRTI-resistant mutants. The emerging candidate, lersivirine (UK-453,061), binds the RT enzyme in a novel way (resulting in a unique resistance profile), inhibits over 60% of viruses bearing key RT mutations, with 50% effective concentrations (EC(50)s) within 10-fold of those for wt viruses, and has excellent selectivity against a range of human targets. Altogether lersivirine is a highly potent and selective NNRTI, with excellent efficacy against NNRTI-resistant viruses.

Induction of multiple drug transporters by efavirenz

Efavirenz, an important component of human immunodeficiency virus 1 (HIV-1) therapy, causes substantial drug interactions as an inducer of cytochromes and the transporter ABCB1. So far its effect on the expression of other transporters is unknown. We therefore investigated the effect of long-term exposure of cells to efavirenz on expression of a large number of important drug transporters and on cell proliferation as a surrogate of intracellular availability. LS180 cells were used as a surrogate for the major site of drug interactions and Jurkat cells were used as a surrogate for the main target cells of HIV therapy. Cells were treated with efavirenz over 4 weeks and mRNA expression of drug transporters was repeatedly quantified. After 4 weeks, efavirenz significantly up-regulated the mRNA of ABCB1, ABCG2, ABCC2, ABCC3, ABCC5, and SLCO3A1 in LS180 cells and ABCG2, ABCC1, ABCC4, ABCC5, and SLCO2B1 in Jurkat cells. However these changes in transporter expression did not influence cell proliferation indicating that intracellular efavirenz concentrations were likely not altered. Efavirenz induces mRNA expression of several drug transporters critically modulating the kinetics of other drugs. While these expressional changes will most likely not influence the efficiency of efavirenz itself, they might change the effect of other co-administered drugs.

Efavirenz--still first-line king?

BACKGROUND

Efavirenz is a potent, safe and tolerable non-nucleoside reverse transcriptase inhibitor (NNRTI) recommended as initial therapy. Recently, several new antiretroviral drugs, including second generation NNRTIs, protease-inhibitors, an integrase-inhibitor and a CCR5 inhibitor, have become or will be shortly available.

OBJECTIVE

This article will review relevant efficacy and safety data of efavirenz compared to these novel agents or certain common alternate drugs currently used as initial therapy in treatment-naive patients.

METHODS

Published articles and conference presentations pertaining to efavirenz and/or the newer antiretroviral agents were evaluated.

RESULTS/CONCLUSIONS

Efavirenz will continue to be preferred initial therapy for now. If longer-term studies of integrase inhibitors and second-generation NNRTIs confirm initial findings, they will eventually supplant efavirenz as preferred first-line agents.

Effects of the HIV treatment drugs nevirapine and efavirenz on brain creatine kinase activity

Nevirapine (NVP) and efavirenz (EFV) are antiretroviral drugs belonging to potent class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) widely used for the treatment human immunodeficiency virus (HIV) infection. It has been demonstrated that NVP and EFV are able to cross the blood-brain barrier and arrive at the central nervous system (CNS), causing important adverse effects related to their presence within this tissue. Considering that the exact mechanisms responsible for CNS toxicity associated with NVP and EFV remain unknown and that creatine kinase (CK) plays an important role in cell energy homeostasis, in the present work we evaluated CK activity in brain of mice after chronic administration of these drugs. Our results demonstrated that NVP and EFV significantly inhibited CK activity in cerebellum, hippocampus, striatum and cortex of mice. Although it is difficult to extrapolate our findings to the human condition, the inhibition of brain CK activity by NVP and EFV may be associated with neurological adverse symptoms of these drugs.

Novel HIV-1 reverse transcriptase inhibitors

HIV-1 reverse transcriptase (RT) was the first viral enzyme to be targeted by anti-HIV drugs. Despite 20 years of experience with RT inhibitors, new ways to inhibit this target and address viral resistance continue to emerge. In both licensed RT inhibitor classes, nucleosides (NRTIs) and non-nucleosides (NNRTIs), compounds with better resistance, pharmacokinetic and toxicity profiles are being developed. Second-generation NNRTIs active against HIV-1 strains resistant to current NNRTIs are being clinically evaluated. Beyond the classical NRTIs, nucleoside analogs that are no longer obligate chain terminators but nevertheless impede reverse transcription or even lead to viral ablation after several replication cycles, are being studied. RT inhibitor research has also yielded additional mechanisms to block RT. Driven by new insights the RNase H field remains in evolution. In addition, the binding of both substrates (deoxynucleotide and primer/template) to RT is now subject to competition by novel inhibitors. Further development of aptamers bears promise for gene therapy but perhaps more importantly, reveals additional new platforms for the development of small-molecule RT inhibitors. This promising research provides much optimism that RT inhibitors will continue to evolve with subsequent clinical benefit.