Ebola Virus Infection: a review on the pharmacokinetic and pharmacodynamic properties of drugs considered for testing in human efficacy trials

International audienceThe 2014-2015 outbreak of Ebola virus disease (EVD) is the largest epidemic to date in terms of number of cases, of death and affected areas. In October 2015, no antiviral agents had proven an antiviral efficacy in patients. However in September 2014 WHO inventoried and regularly updated since then a list of potential drug candidates with demonstrated antiviral efficacy in vitro or in animal models. This includes agents belonging to various therapeutic classes, namely direct antiviral agents (favipiravir and BCX4430), combination of antibodies (ZMapp), type I interferons, RNA interference-based drugs (TKM-Ebola and AVI-7537) and anticoagulant drug (rNAPc2).Here, we review the pharmacokinetic and pharmacodynamic information that are presently available on these drugs, using data obtained in healthy volunteers for pharmacokinetics and data obtained in human clinical trials or animal models for pharmacodynamics. Future studies evaluating these drugs in clinical trials will be critical to confirm their efficacy in humans, propose appropriate doses and evaluate the possibility of treatment combinations

Simplified Assessment of Antiretroviral Adherence and Prediction of Virological Efficacy in HIV-Infected Patients in Cambodia

Background. Adherence to antiviral therapy is important for HIV-infected people living in low- and middle-income countries, because of poor access to alternative regimens. Methods. We conducted a cross-sectional survey of adherence in Cambodian patients enrolled in the ESTHER program and treated with WHO first-line regimen for at least 6 months. The survey was based on a self-report questionnaire, drug assay, MCV measurement, visual analog scale, and viral load HIV RNA. Results. Two hundred fifty-nine patients treated for a median of 16 months participated in the survey. At inclusion in the program, 158 patients (61%) were ARV-naïve. The virological success rate was 71% overall and 81% in previously ARV-naive patients. Considered individually, the measures suggested perfect adherence in 71% to 93% of patients. In multivariate analysis adjusted for sex and therapeutic status before HAART initiation, only the biological markers were associated with virological efficacy. Self-funded treatment before entry to the program was highly predictive of virological failure. Conclusion. Adherence was excellent in these Cambodian patients. Biological markers were predictive of virological efficacy. MCV might thus serve as a simple alternative for assessing adherence and predicting virological efficacy among patients receiving AZT- or d4T-based regimens

Nevirapine versus Efavirenz for patients co-infected with HIV and Tuberculosis: A Randomised Non-Inferiority Trial

BACKGROUND: In countries with a high incidence of HIV and tuberculosis co-infection, nevirapine and efavirenz are widely used as antiretroviral therapy but both interact with antituberculosis drugs. We aimed to compare efficacy and safety of a nevirapine-based antiretroviral therapy (started at full dose) with an efavirenz-based regimen in co-infected patients. METHODS: We did a multicentre, open-label, randomised, non-inferiority trial at three health centres in Maputo, Mozambique. We enrolled adults (≥18 years) with tuberculosis and previously untreated HIV infection (CD4 cell counts <250 cells per μL) and alanine aminotransferase and total bilirubin concentrations of less than five times the upper limit of normal. 4-6 weeks after the start of tuberculosis treatment, we randomly allocated patients (1:1) with central randomisation, block sizes of two to six, and stratified by site and CD4 cell count to nevirapine (200 mg twice daily) or efavirenz (600 mg once daily), plus lamivudine and stavudine. The primary endpoint was virological suppression at 48 weeks (HIV-1 RNA <50 copies per mL) in all patients who received at least one dose of study drug (intention-to-treat population); death and loss to follow-up were recorded as treatment failure. The non-inferiority margin for the difference of efficacy was 10%. We assessed efficacy in intention-to-treat and per-protocol populations and safety in all patients who received study drug. This study is registered with ClinicalTrials.gov, number NCT00495326. FINDINGS: Between October, 2007, and March, 2010, we enrolled 285 patients into each group. 242 (85%) patients in the nevirapine group and 233 (82%) patients in the efavirenz group completed follow-up. In the intention-to-treat population, 184 patients (64·6%, 95% CI 58·7-70·1) allocated nevirapine achieved virological suppression at week 48, as did 199 patients (69·8%, 64·1-75·1) allocated efavirenz (one-sided 95% CI of the difference of efficacy 11·7%). In the per-protocol population, 170 (70·0%, 63·8-75·7) of 243 patients allocated nevirapine achieved virological suppression at week 48, as did 194 (78·9%, 73·2-83·8) of 246 patients allocated efavirenz (one-sided 95% CI 15·4%). The median CD4 cell count at randomisation was 89 cells per μL. 15 patients substituted nevirapine with efavirenz and six patients substituted efavirenz with nevirapine. 20 patients allocated nevirapine (7%) had grade 3-4 increase of alanine aminotransferase compared with 17 patients allocated efavirenz (6%). Three patients had severe rash after receipt of nevirapine (1%) but no patients did after receipt of efavirenz. 18 patients in the nevirapine group died, as did 17 patients in the efavirenz group. INTERPRETATION: Although non-inferiority of the nevirapine-regimen was not shown, nevirapine at full dose could be a safe, acceptable alternative for patients unable to tolerate efavirenz. FUNDING: French Research Agency for HIV/AIDS and hepatitis (ANRS)

Articles Nevirapine versus efavirenz for patients co-infected with HIV and tuberculosis: a randomised non-inferiority trial

Summary Background In countries with a high incidence of HIV and tuberculosis co-infection, nevirapine and efavirenz are widely used as antiretroviral therapy but both interact with antituberculosis drugs. We aimed to compare effi cacy and safety of a nevirapine-based antiretroviral therapy (started at full dose) with an efavirenz-based regimen in coinfected patients

Randomised pharmacokinetic trial of rifabutin with lopinavir/ritonavir-antiretroviral therapy in patients with HIV-associated tuberculosis in Vietnam.

BACKGROUND: Rifampicin and protease inhibitors are difficult to use concomitantly in patients with HIV-associated tuberculosis because of drug-drug interactions. Rifabutin has been proposed as an alternative rifamycin, but there is concern that the current recommended dose is suboptimal. The principal aim of this study was to compare bioavailability of two doses of rifabutin (150 mg three times per week and 150 mg daily) in patients with HIV-associated tuberculosis who initiated lopinavir/ritonavir-based antiretroviral therapy in Vietnam. Concentrations of lopinavir/ritonavir were also measured. METHODS: This was a randomized, open-label, multi-dose, two-arm, cross-over trial, conducted in Vietnamese adults with HIV-associated tuberculosis in Ho Chi Minh City (Clinical trial registry number NCT00651066). Rifabutin pharmacokinetics were evaluated before and after the introduction of lopinavir/ritonavir -based antiretroviral therapy using patient randomization lists. Serial rifabutin and 25-O-desacetyl rifabutin concentrations were measured during a dose interval after 2 weeks of rifabutin 300 mg daily, after 3 weeks of rifabutin 150 mg daily with lopinavir/ritonavir and after 3 weeks of rifabutin 150 mg three times per week with lopinavir/ritonavir. RESULTS: Sixteen and seventeen patients were respectively randomized to the two arms, and pharmacokinetic analysis carried out in 12 and 13 respectively. Rifabutin 150 mg daily with lopinavir/ritonavir was associated with a 32% mean increase in rifabutin average steady state concentration compared with rifabutin 300 mg alone. In contrast, the rifabutin average steady state concentration decreased by 44% when rifabutin was given at 150 mg three times per week with lopinavir/ritonavir. With both dosing regimens, 2 - 5 fold increases of the 25-O-desacetyl- rifabutin metabolite were observed when rifabutin was given with lopinavir/ritonavir compared with rifabutin alone. The different doses of rifabutin had no significant effect on lopinavir/ritonavir plasma concentrations. CONCLUSIONS: Based on these findings, rifabutin 150 mg daily may be preferred when co-administered with lopinavir/ritonavir in patients with HIV-associated tuberculosis. TRIAL REGISTRATION: ClinicalTrials.gov NCT00651066

Immunovirological response to combined antiretroviral therapy and drug resistance patterns in children: 1- and 2-year outcomes in rural Uganda

Children living with HIV continue to be in urgent need of combined antiretroviral therapy (ART). Strategies to scale up and improve pediatric HIV care in resource-poor regions, especially in sub-Saharan Africa, require further research from these settings. We describe treatment outcomes in children treated in rural Uganda after 1 and 2 years of ART start

Variabilité pharmacocinétique de la névirapine et de l'éfavirenz et rôle du polymorphisme des enzymes et transporteurs dans une population de patients cambodgiens infectés par le VIH et traités par une association d'antirétroviraux comprenant névirapine ou éfavirenz

La variabilité de la pharmacocinétique de la névirapine et de l éfavirenz, deux médicamentsantirétroviraux inhibiteurs non nucléosidiques de la transcriptase inverse du VIH, a été étudiéechez des patients cambodgiens infectés par le VIH par une méthode de pharmacocinétique depopulation. Cent soixante dix patients traités par névirapine faisaient partie de la cohorteESTHER de l hôpital Calmette de Phnom-Penh et 312 patients co-infectés par le VIH et latuberculose et traités par éfavirenz étaient inclus dans l essai clinique CAMELIA (ANRS1295 CIPRA KH001) conduit au Cambodge. Les dosages plasmatiques de névirapine et d éfavirenz ontété réalisés par des méthodes CLHP avec détection UV. Après 18 et 36 mois de traitement, lesconcentrations plasmatiques médianes de la névirapine sont de 5,7 g/mL. Après 22 et 50semaines de traitement, les concentrations médianes d éfavirenz sont de 2,7 g/mL, quel éfavirenz soit associé (22 semaines) ou non (50 semaines) à la rifampicine. Les clairancesapparentes estimées de la névirapine et de l éfavirenz sont respectivement de 2,6 L/h et de 7,7L/h. Les variabilités intra et inter individuelles des clairances apparentes sont respectivement de17% et 28% pour la névirapine et 15% et 37% pour l éfavirenz. Parmi les covariablesdémographiques, biologiques ou génétiques étudiées, seul le polymorphisme génétique duCYP2B6 G516T est significativement associé à la clairance apparente de ces deux médicaments.Ainsi la clairance apparente estimée de la névirapine est de 2,95 L/h, 2,62 L/h et 1,86 L/hrespectivement pour les génotypes CYP2B6 516GG, 516GT, et 516TT. La fréquence de l allèlemutée T qui code pour une enzyme non fonctionnelle est de 34% dans cette population de 442patients d Asie du Sud-Est.HIV-infected patients by population method. 170 patients on nevirapine-based antiretroviraltherapy were from the ESTHER cohort of the Calmette hospital in Phnom-Penh. 312 patients onefavirenz-based therapy were included in the CAMELIA (ANRS1295 CIPRAKH001) clinical trialconducted in Cambodia. Plasma concentrations of nevirapine and efavirenz were measured byHPLC and UV detection. Median plasma concentrations of nevirapine and efavirenz were 5.7 g/mL and 2.7 g/mL respectively. Apparent plasma clearances of nevirapine and efavirenz were2.6 L/h and 7.7 L/h respectively. Among demographic, clinical, biological or genetic covariates,genetic polymorphism of CYP2B6 G516T was the only one which was shown to affect theclearance of the 2 drugs. Frequency of the T allele was 34% in this population of South-East Asia.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Interaction entre médicaments antirétroviraux chez des patients en traitement de sauvetage (sous-étude de l'essai ANRS 138 EASIER)

PARIS-BIUP (751062107) / SudocSudocFranceF

Niveau de preuve du suivi thérapeutique pharmacologique du lopinavir

Le lopinavir, inhibiteur de la protéase du virus de l’immunodéficience humaine (VIH), présente une variabilité pharmacocinétique importante, du fait d’un métabolisme hépatique et intestinal par le CYP3A. Les données de la littérature ont été analysées pour évaluer le niveau de preuve du suivi thérapeutique du lopinavir. Chez les patients naïfs ou prétraités, la relation entre concentrations et efficacité virologique n’a pas été mise en évidence, les concentrations obtenues chez un patient adhérent sont probablement supérieures aux concentrations virales inhibitrices. La survenue d’hyperlipidémie semble associée à des concentrations résiduelles de lopinavir > 8 000 ng/mL. Ces données permettent de proposer un niveau de preuve pour le suivi thérapeutique du lopinavir, recommandé chez les enfants, la femme enceinte, les patients en échec virologique, sous réserve que le nombre de mutations sur la protéase du virus soit < 5, en cas d’association avec des inducteurs enzymatiques, et en cas de toxicité

Impact of modelling intra-subject variability on tests based on non-linear mixed-effects models in cross-over pharmacokinetic trials with application to the interaction of tenofovir on atazanavir in HIV patients.

We evaluated the impact of modelling intra-subject variability on the likelihood ratio test (LRT) and the Wald test based on non-linear mixed effects models in pharmacokinetic interaction and bioequivalence cross-over trials. These tests were previously found to achieve a good power but an inflated type I error when intra-subject variability was not taken into account. Trials were simulated under H0 and several H1 and analysed with the NLME function. Different configurations of the number of subjects n and of the number of samples per subject J were evaluated for pharmacokinetic interaction and bioequivalence trials. Assuming intra-subject variability in the model dramatically improved the type I error of both interaction tests. For the Wald test, the type I error decreased from 22, 14 and 7.7 per cent for the original (n = 12, J = 10), intermediate (n = 24, J = 5) and sparse (n = 40, J = 3) designs, respectively, down to 7.5, 6.4 and 3.5 per cent when intra-subject variability was modelled. The LRT achieved very similar results. This improvement seemed mostly due to a better estimation of the standard error of the treatment effect. For J = 10, the type I error was found to be closer to 5 per cent when n increased when modelling intra-subject variability. Power was satisfactory for both tests. For bioequivalence trials, the type I error of the Wald test was 6.4, 5.7 and 4.2 per cent for the original, intermediate and sparse designs, respectively, when modelling intra-subject variability. We applied the Wald test to the pharmacokinetic interaction of tenofovir on atazanavir, a novel protease inhibitor. A significant decrease of the area under the curve of atazanavir was found when patients received tenofovir