Pharmacokinetics of efavirenz in patients on antituberculosis treatment in high human immunodeficiency virus and tuberculosis burden countries: A systematic review

Comorbidity and concomitant medication use in an integrase strand transfer inhibitor naïve cohort on first-line dolutegravir-based antiretroviral therapy

Introduction

people living with HIV/AIDS using antiretroviral therapy sometimes present with comorbid conditions or co-infections. This could lead to an increased risk of drug interactions due to the concomitant use of drugs. The aim of the study was to explore the overall impact of dolutegravir on such comorbidities and the effect of concomitant medication on the safety and efficacy of dolutegravir.

Methods

data was collected using a survey questionnaire and a retrospective review of medical records of a prospective study sample. Medical records were retrospectively reviewed for up to 12 months after dolutegravir initiation. Concomitantly used drugs and supplements that were identified to have a potential interaction with dolutegravir were further characterized. Descriptive and summary statistics were used to describe the data, t-tests were performed on blood glucose levels and cross-tabulations were done on some variables.

Results

of the 461 participants enrolled into the study, 172 (37.3%) and 54 (11.7%) experienced comorbidity and coinfection respectively. More than 50% of the participants used concomitant medicines. Metformin use led to increased blood glucose levels (p=0.009); participants on rifampicin (n=8) received an additional daily dose of dolutegravir. Virological outcomes in participants on sodium valproate (n=2) and St John´s wort (n=1) did not show safety concerns, whilst 3 dolutegravir discontinuations were observed in participants using supplements and antacids containing divalent cations.

Conclusion

even though dolutegravir was safe and effective in the study population, with possible drug interactions leading to treatment discontinuations in only 3(0.7%) participants, further investigation into dolutegravir-induced hyperglycemia needs investigation.

Clinical Relevance of Drug Interactions in People Living with Human Immunodeficiency Virus on Antiretroviral Therapy-Update 2022: Systematic Review

BACKGROUND

The clinical outcomes of antiretroviral drugs may be modified through drug interactions; thus, it is important to update the drug interactions in people living with HIV (PLHIV).

AIM

To update clinically relevant drug interactions in PLHIV on antiretroviral therapy with novel drug interactions published from 2017 to 2022.

METHODS

A systematic review in Medline/PubMed database from July 2017 to December 2022 using the Mesh terms antiretroviral agents and drug interactions or herb-drug interactions or food-drug interactions. Publications with drug interactions in humans, in English or Spanish, and with full-text access were retrieved. The clinical relevance of drug interactions was grouped into five levels according to the gravity and probability of occurrence.

RESULTS

A total of 366 articles were identified, with 219 (including 87 citation lists) were included, which allowed for the identification of 471 drug interaction pairs; among them, 291 were systematically reported for the first time. In total 42 (14.4%) and 137 (47.1%) were level one and two, respectively, and 233 (80.1%) pairs were explained with the pharmacokinetic mechanism. Among these 291 pairs, protease inhibitors (PIs) and ritonavir/cobicistat-boosted PIs, as well as integrase strand transfer inhibitors (InSTIs), with 70 (24.1%) and 65 (22.3%) drug interaction pairs of levels one and two, respectively, were more frequent.

CONCLUSIONS

In PLHIV on antiretroviral therapy, we identify 291 drug interaction pairs systematically reported for the first time, with 179 (61.5%) being assessed as clinically relevant (levels one and two). The pharmacokinetic mechanism was the most frequently identified. PIs, ritonavir/cobicistat-boosted PIs, and InSTIs were the antiretroviral groups with the highest number of clinically relevant drug interaction pairs (levels one and two).

Prevalence of neurotoxicity symptoms among postpartum women on isoniazid preventive therapy and efavirenz-based treatment for HIV: an exploratory objective of the IMPAACT P1078 randomized trial

BACKGROUND

This exploratory analysis investigates the prevalence and risk factors of neurocognitive toxicity in postpartum women on HIV treatment in response to a concern of an Isoniazid Preventive Therapy (IPT)/Efavirenz interaction.

TRIAL DESIGN

Pregnant women on HIV treatment from countries with high TB prevalence were randomized in IMPAACT P1078 to 28 weeks of IPT started either during pregnancy or at 12 weeks postpartum. Partway through study implementation, the Patient Health Questionnaire 9, the cognitive complaint questionnaire, and the Pittsburg Sleep Quality Index were added to evaluate depression, cognitive function, and sleep quality at postpartum weeks. Screening for peripheral neuropathy was conducted throughout the study.

METHODS

We summarized percentages of women with depression symptoms, cognitive dysfunction, poor sleep quality and peripheral neuropathy and assessed the association of 11 baseline risk factors of neurotoxicity using logistic regression, adjusted for gestational age stratum.

RESULTS

Of 956 women enrolled, 749 (78%) had at least one neurocognitive evaluation. During the postpartum period, the percentage of women reporting at least mild depression symptoms, cognitive complaint and poor sleep quality peaked at 13%, 8% and 10%, respectively, at 12 weeks, and the percentage of women reporting peripheral neuropathy peaked at 13% at 24 weeks. There was no evidence of study arm differences in odds of all four neurotoxic symptoms.

CONCLUSIONS

Timing of IPT initiation and EFV use were not associated with symptoms of neurotoxicity. Further study is advised to formally assess risk factors of neurotoxicity.

Effects of rifampicin, CYP2B6 and ABCB1 polymorphisms on efavirenz plasma concentration in Chinese patients living with HIV and tuberculosis

BACKGROUND

Tuberculosis (TB) is the leading opportunistic infection of people living with human immunodeficiency virus (HIV; PLWH). Cytochrome P450 (CYP) 2B6 and ATP-binding cassette sub-family B member 1 (ABCB1) are involved in the metabolism and transportation of efavirenz. The study was aimed to investigate the effects of rifampicin, CYP2B6 and ABCB1 polymorphisms on efavirenz exposure in Chinese PLWH co-infected with TB.

METHOD

PLWH were screened according to inclusion and exclusion criteria and divided into HIV group and HIV/TB group. Efavirenz plasma concentration (C₀) was determined, dose-adjusted concentration (C₀/D) was calculated, and genotypes of CYP2B6 516G>T, 785A>G, and ABCB1 2677G>T, 3435C>T were analyzed.

RESULTS

252 PLWH were enrolled, including 75 co-infected with TB and concomitant with rifampicin. Efavirenz C₀ and C₀/D were both higher in HIV group (1.94 μg/mL, 0.2007 (μg/ml)/(mg/kg/d)) compared with HIV/TB group (1.52 μg/mL, 0.1557 (μg/ml)/(mg/kg/d)) (p = .001). Efavirenz C₀/D was significantly higher in patients with variant genotypes of CYP2B6 516G>T and 785A>G (p<.001), and was significantly lower in HIV/TB group compared with HIV group among patients with CYP2B6 516 GG, TT, and 785 AA, AG genotypes (p < .05).

CONCLUSION

Efavirenz exposure is reduced by co-administration with rifampicin, and related to genetic polymorphisms of CYP2B6.

Landscape of TB Infection and Prevention among People Living with HIV

Tuberculosis (TB) is one of the leading causes of mortality in people living with HIV (PLHIV) and contributes to up to a third of deaths in this population. The World Health Organization guidelines aim to target early detection and treatment of TB among PLHIV, particularly in high-prevalence and low-resource settings. Prevention plays a key role in the fight against TB among PLHIV. This review explores TB screening tools available for PLHIV, including symptom-based screening, chest radiography, tuberculin skin tests, interferon gamma release assays, and serum biomarkers. We then review TB Preventive Treatment (TPT), shown to reduce the progression to active TB and mortality among PLHIV, and available TPT regimens. Last, we highlight policy-practice gaps and barriers to implementation as well as ongoing research needs to lower the burden of TB and HIV coinfection through preventive activities, innovative diagnostic tests, and cost-effectiveness studies.

Brief Report: Efficacy and Safety of Efavirenz, Raltegravir, and Dolutegravir in HIV-1/TB Coinfection. A Multicenter Retrospective Cohort Study in France

BACKGROUND

There are limited data comparing the efficacy and safety of raltegravir and dolutegravir to that of efavirenz in HIV-1/tuberculosis (TB) coinfected patients.

METHODS

We conducted a 10-year retrospective study in 4 centers in France. We included all HIV-1/tuberculosis coinfected patients starting antiretroviral therapy with a rifampicin-based regimen, with a plasma HIV RNA level (VL) > 1000 copies/mL. The primary endpoint was the proportion of patients with virological success that is, with VL <50 copies/mL at W48 using an Intention-To-Treat analysis, using last-observation-carried-forward to impute missing data. We also assessed antiretroviral therapy safety, analyzing treatment discontinuation for adverse events.

RESULTS

Between 2010 and 2020, 117 patients were included. Thirty-nine (33.3%) were treated with raltegravir and 2 nucleoside reverse transcriptase inhibitors (NRTIs), 19 (16.2%) with dolutegravir (and 2 NRTIs) and 59 (50.4%) with efavirenz (and 2 NRTIs). At W48, the primary endpoint was achieved in 24 patients (61.5%) in the raltegravir group, in 12 (63.2%) in the dolutegravir group, and in 41 (69.5%) in the efavirenz group using an Intention-To-Treat analysis ( P = 0.68). Emergence of drug resistance in patients with virological failure, defined as a VL >50 copies/mL, was observed in 3 patients with efavirenz and one patient with raltegravir. Rate of treatment discontinuation for drug-related adverse events was 10.3%, 10.6%, 16.9% for raltegravir, dolutegravir and efavirenz respectively ( P = 0.67).

CONCLUSIONS

In this retrospective cohort study, raltegravir and dolutegravir yielded similar efficacy and safety results to efavirenz for the treatment of HIV-1/TB coinfected patients.

Real-world use and outcomes of dolutegravir-containing antiretroviral therapy in HIV and tuberculosis co-infection: a site survey and cohort study in sub-Saharan Africa

INTRODUCTION

Dolutegravir is being scaled up globally as part of antiretroviral therapy (ART), but for people with HIV and tuberculosis co-infection, its use is complicated by a drug-drug interaction with rifampicin requiring an additional daily dose of dolutegravir. This represents a disadvantage over efavirenz, which does not have a major drug-drug interaction with rifampicin. We sought to describe HIV clinic practices for prescribing concomitant dolutegravir and rifampicin, and characterize virologic outcomes among patients with tuberculosis co-infection receiving dolutegravir or efavirenz.

METHODS

Within the four sub-Saharan Africa regions of the International epidemiology Databases to Evaluate AIDS consortium, we conducted a site survey (2021) and a cohort study (2015-2021). The cohort study used routine clinical data and included patients newly initiating or already receiving dolutegravir or efavirenz at the time of tuberculosis diagnosis. Patients were followed from tuberculosis diagnosis until viral suppression (<1000 copies/ml), a competing event (switching ART regimen; loss to program/death) or administrative censoring at 12 months.

RESULTS

In the survey, 86 of 90 (96%) HIV clinics in 18 countries reported prescribing dolutegravir to patients who were receiving rifampicin as part of tuberculosis treatment, with 77 (90%) reporting that they use twice-daily dosing of dolutegravir, of which 74 (96%) reported having 50 mg tablets available to accommodate twice-daily dosing. The cohort study included 3563 patients in 11 countries, with 67% newly or recently initiating ART. Among patients receiving dolutegravir (n = 465), the cumulative incidence of viral suppression was 58.9% (95% confidence interval [CI]: 54.3-63.3%), switching ART regimen was 4.1% (95% CI: 2.6-6.2%) and loss to program/death was 23.4% (95% CI: 19.7-27.4%). Patients receiving dolutegravir had improved viral suppression compared with patients receiving efavirenz who had a tuberculosis diagnosis before site dolutegravir availability (adjusted subdistribution hazard ratio [aSHR]: 1.47, 95% CI: 1.28-1.68) and after site dolutegravir availability (aSHR 1.28, 95% CI: 1.08-1.51).

CONCLUSIONS

At a programmatic level, dolutegravir was being widely prescribed in sub-Saharan Africa for people with HIV and tuberculosis co-infection with a dose adjustment for the drug-drug interaction with rifampicin. Despite this more complex regimen, our cohort study revealed that dolutegravir did not negatively impact viral suppression.

Pharmacogenetic predictors of variability in efavirenz pharmacokinetics in an admixed Brazilian HIV cohort

AIMS

To investigate the influence of pharmacogenetic polymorphisms on efavirenz (EFV) exposure and metabolism in HIV-infected Brazilians under treatment with EFV-containing antiretroviral (ART) regimens.

METHODS

HIV-positive adults (n=82) on stable ART regimens containing 600 mg EFV once daily for at least 6 months were recruited at two university hospitals. Blood samples collected at mid-dose interval were used to quantify the plasma concentrations of EFV (denoted [EFV]), its major metabolite 8-OH-EFV ([8-OH-EFV]) and [8-OH-EFV]/[EFV] metabolic ratio, and to genotype single nucleotide polymorphisms (SNPs) in CYP2B6 (rs3745274, c.516G>T; rs28399499, c.983T>C) and ABCB1 (rs3842, c.4036G>A). CYP2B6 metabolic phenotypes were inferred from the CYP2B6 diplotypes. Linear regression modeling was applied to identify sociodemographic, clinical and pharmacogenetic predictors of [EFV] and [8-OH-EFV]/[EFV] metabolic ratio.

RESULTS

Wide (50-fold) interindividual variation in [EFV], [8-OH-EFV] and [8-OH-EFV]/[EFV] was observed; 69.5% of participants had [EFV] within the nominal therapeutic range (1000-4000 ng/ml), while 19.5%, and 11.0% had [EFV] below and above this range, respectively. Multiple regression modeling retained only CYP2B6 metabolic phenotypes or the combined rs3745274 and rs28399499 genotypes, as significant predictors of [EFV] and [8-OH-EFV]/[EFV].

CONCLUSION

EFV exposure and disposition varied widely among HIV-infected Brazilians under stable treatment with EFV-containing ART regimens. About one-tenth of the participants had [EFV] exceeding nominal supratherapeutic concentration (4000 ng/mL), but reported tolerance to the ARV regimens, while one fifth of participants had nominal subtherapeutic [EFV] (<1000 ng/ml) but adequate virological response. Genotype for the two CYP2B6 SNPs studied explained 48% of variation in [EFV] and 35% of variation in [8-OH-EFV]/[EFV].

Pharmacokinetic interactions of modern antiretroviral therapy

Drug--drug interactions (DDIs) have been a clinical challenge in HIV medicine for over two decades. The newer antiretroviral drugs (ARTs) have significantly fewer DDIs than protease inhibitors and boosted integrase inhibitors (INSTIs). The lower propensity of such newer antiretrovirals (e.g. unboosted integrase inhibitors; doravirine) to cause DDIs, has been largely offset by the ageing cohort of patients with multiple comorbidities, who are taking multiple chronic medicines. Furthermore, the introduction of newly marketed drugs into clinical practice needs to be closely monitored, as the new drugs may be perpetrators of DDIs, leading to a potential change in the efficacy or toxicity of the coadministered antiretrovirals.

Effect of high-dose rifampicin on efavirenz pharmacokinetics: drug-drug interaction randomized trial

BACKGROUND

High-dose rifampicin is considered to shorten anti-TB treatment duration but its effect on antiretroviral metabolism is unknown.

OBJECTIVES

To assess the effect of doubling the rifampicin dose (to 20 mg/kg/day, R20) on efavirenz pharmacokinetics (PK) in HIV/TB coinfected patients.

METHODS

Open-label Phase 2 drug-drug interaction randomized trial. Pulmonary TB, ART-naive adults were randomized to R20 and either efavirenz 600 mg (EFV600) or 800 mg (EFV800), or rifampicin 10 mg/kg/day (R10) and EFV600 with a 1:1:1 ratio. Patients were first started on TB treatment and 2-4 weeks later started on ART. They were switched to R10 and EFV600 after 8 weeks. Full PK sampling was done 4 weeks (on rifampicin) and 24 weeks (off rifampicin) after ART initiation. Transaminases, plasma HIV-1 RNA and sputum cultures were monitored. The efavirenz geometric mean ratio (GMR) of AUC at 4 and 24 weeks after ART initiation within the same patient was calculated in each arm and its 90% CI was compared with a preset range (0.70-1.43).

RESULTS

Of 98 enrolled patients (32 in the R20EFV600 arm, 33 in the R20EFV800 arm and 33 in the R10EFV600 arm), 87 had full PK sampling. For the R20EFV600, R20EFV800 and R10EFV600 arms, GMRs of efavirenz AUC were 0.87 (90% CI: 0.75-1.00), 1.12 (90% CI: 0.96-1.30) and 0.96 (90% CI: 0.84-1.10). Twelve weeks after ART initiation, 78.6%, 77.4% and 72.4% of patients had HIV-1 RNA below 100 copies/mL and 85.7%, 86.7% and 80.0% had Week 8 culture conversion, respectively. Two patients per arm experienced a severe increase in transaminases.

CONCLUSIONS

Doubling the rifampicin dose had a small effect on efavirenz concentrations and was well tolerated.

Integrase inhibitors versus efavirenz combination antiretroviral therapies for TB/HIV coinfection: a meta-analysis of randomized controlled trials

BACKGROUND

Integrase inhibitors (INIs)-based antiretroviral therapies (ART) are more recommended than efavirenz (EFV)-based ART for people living with HIV/AIDS (PLWHA). Yet, the advantage of integrase inhibitors in treating TB/HIV coinfection is uncertain. Therefore, the objective of this systematic review is to evaluate the effects and safety of INIs- versus EFV-based ART in TB/HIV coinfection, and demonstrate the feasibility of the regimens.

METHODS

Four electronic databases were systematically searched through September 2020. Fixed-effects models were used to calculate pooled effect size for all outcomes. The primary outcomes were virologic suppression and bacteriology suppression for INIs- versus EFV-based ART. Secondary outcomes included CD4+ cell counts change from baseline, adherence and safety.

RESULTS

Three trials (including 672 TB/HIV patients) were eligible. ART combining INIs and EFV had similar effects for all outcomes, with none of the point estimates argued against the INIs-based ART on TB/HIV patients. Compared to EFV-based ART as the reference group, the RR was 0.94 (95% CI 0.85 to 1.05) for virologic suppression, 1.00 (95% CI 0.95 to 1.05) for bacteriology suppression, 0.98 (95% CI 0.95 to 1.01) for adherence. The mean difference in CD4+ cell counts increase between the two groups was 14.23 cells/μl (95% CI 0- 6.40 to 34.86). With regard to safety (adverse events, drug-related adverse events, discontinuation for drugs, grade 3-4 adverse events, IRIS (grade 3-4), and death), INIs-based regimen was broadly similar to EFV-based regimens. The analytical results in all sub-analyses of raltegravir- (RAL) and dolutegravir (DTG) -based ART were valid.

CONCLUSION

This meta-analysis demonstrates similar efficacy and safety of INIs-based ART compared with EFV-based ART. This finding supports INIs-based ART as a first-line treatment in TB/HIV patients. The conclusions presented here still await further validation owing to insufficient data.

Standard dose raltegravir or efavirenz-based antiretroviral treatment for patients co-infected with HIV and tuberculosis (ANRS 12 300 Reflate TB 2): an open-label, non-inferiority, randomised, phase 3 trial

BACKGROUND

In patients co-infected with HIV and tuberculosis, antiretroviral therapy options are limited due to drug-drug interactions with rifampicin. A previous phase 2 trial indicated that raltegravir 400 mg twice a day or efavirenz 600 mg once a day might have similar virological efficacy in patients given rifampicin. In this phase 3 trial, we assessed the non-inferiority of raltegravir to efavirenz.

METHODS

We did a multicentre, open-label, non-inferiority, randomised, phase 3 trial at six sites in Côte d'Ivoire, Brazil, France, Mozambique, and Vietnam. We included antiretroviral therapy (ART)-naive adults (aged ≥18 years) with confirmed HIV-1 infection and bacteriologically confirmed or clinically diagnosed tuberculosis who had initiated rifampicin-containing tuberculosis treatment within the past 8 weeks. Using computerised random numbers, we randomly assigned participants (1:1; stratified by country) to receive raltegravir 400 mg twice daily or efavirenz 600 mg once daily, both in combination with tenofovir and lamivudine. The primary outcome was the proportion of patients with virological suppression at week 48 (defined as plasma HIV RNA concentration <50 copies per mL). The prespecified non-inferiority margin was 12%. The primary outcome was assessed in the intention-to-treat population, which included all randomly assigned patients (excluding two patients with HIV-2 infection and one patient with HIV-1 RNA concentration of <50 copies per mL at inclusion), and the on-treatment population, which included all patients in the intention-to-treat population who initiated treatment and were continuing allocated treatment at week 48, and patients who had discontinued allocated treatment due to death or virological failure. Safety was assessed in all patients who received at least one dose of the assigned treatment regimen. This study is registered with ClinicalTrials.gov, NCT02273765.

FINDINGS

Between Sept 28, 2015, and Jan 5, 2018, 460 participants were randomly assigned to raltegravir (n=230) or efavirenz (n=230), of whom 457 patients (230 patients in the raltegravir group; 227 patients in the efavirenz group) were included in the intention-to-treat analysis and 410 (206 patients in the raltegravir group; 204 patients in the efavirenz group) in the on-treatment analysis. At baseline, the median CD4 count was 103 cells per μL and median plasma HIV RNA concentration was 5·5 log₁₀ copies per mL (IQR 5·0-5·8). 310 (68%) of 457 participants had bacteriologically-confirmed tuberculosis. In the intention-to-treat population, at week 48, 140 (61%) of 230 participants in the raltegravir group and 150 (66%) of 227 patients in the efavirenz had achieved virological suppression (between-group difference -5·2% [95% CI -14·0 to 3·6]), thus raltegravir did not meet the predefined criterion for non-inferiority. The most frequent adverse events were HIV-associated non-AIDS illnesses (eight [3%] of 229 patients in the raltegravir group; 21 [9%] of 230 patients in the efavirenz group) and AIDS-defining illnesses (ten [4%] patients in the raltegravir group; 13 [6%] patients in the efavirenz group). 58 (25%) of 229 patients in raltegravir group and 66 (29%) of 230 patients in the efavirenz group had grade 3 or 4 adverse events. 26 (6%) of 457 patients died during follow-up: 14 in the efavirenz group and 12 in the raltegravir group.

INTERPRETATION

In patients with HIV given tuberculosis treatment, non-inferiority of raltegravir compared with efavirenz was not shown. Raltegravir was well tolerated and could be considered as an option, but only in selected patients.

FUNDING

National French Agency for AIDS Research, Ministry of Health in Brazil, Merck.

TRANSLATIONS

For the Portuguese and French translations of the abstract see Supplementary Materials section.

Dolutegravir-based Antiretroviral Therapy for Patients Coinfected With Tuberculosis and Human Immunodeficiency Virus: A Multicenter, Noncomparative, Open-label, Randomized Trial

BACKGROUND

The concurrent treatment of tuberculosis and human immunodeficiency virus (HIV) is challenging, owing to drug interactions, overlapping toxicities, and immune reconstitution inflammatory syndrome (IRIS). The efficacy and safety of dolutegravir (DTG) were assessed in adults with HIV and drug-susceptible tuberculosis.

METHODS

International Study of Patients with HIV on Rifampicin ING is a noncomparative, active-control, randomized, open-label study in HIV-1-infected antiretroviral therapy-naive adults (CD4+ ≥50 cells/mm3). Participants on rifampicin-based tuberculosis treatment ≤8 weeks were randomized (3:2) to receive DTG (50 mg twice daily both during and 2 weeks after tuberculosis therapy, then 50 mg once daily) or efavirenz (EFV; 600 mg daily) with 2 nucleoside reverse transcriptase inhibitors for 52 weeks. The primary endpoint was the proportion of DTG-arm participants with plasma HIV-1-RNA <50 copies/mL (responders) by the Food and Drug Administration Snapshot algorithm (intent-to-treat exposed population) at Week 48. The study was not powered to compare arms.

RESULTS

For DTG (n = 69), the baseline HIV-1 RNA was >100 000 copies/mL in 64% of participants, with a median CD4+ count of 208 cells/mm3; for EFV (n = 44), 55% of participants had HIV-1 RNA >100 000 copies/mL, with a median CD4+ count of 202 cells/mm3. The Week 48 response rates were 75% (52/69, 95% confidence interval [CI] 65-86%) for DTG and 82% (36/44, 95% CI 70-93%) for EFV. The DTG nonresponses were driven by non-treatment related discontinuations (n = 10 lost to follow-up). There were no deaths or study drug switches. There were 2 discontinuations for toxicity (EFV). There were 3 protocol-defined virological failures (2 DTG, no acquired resistance; 1 EFV, emergent resistance to nucleoside reverse transcriptase inhibitors and nonnucleoside reverse transcriptase inhibitors). The tuberculosis treatment success rate was high. Tuberculosis-associated IRIS was uncommon (4/arm), with no discontinuations for IRIS.

CONCLUSIONS

Among adults with HIV receiving rifampicin-based tuberculosis treatment, twice-daily DTG was effective and well tolerated.

CLINICAL TRIALS REGISTRATION

NCT02178592.

Pharmacokinetics of antiretroviral and tuberculosis drugs in children with HIV/TB co-infection: a systematic review

INTRODUCTION

Management of concomitant use of ART and TB drugs is difficult because of the many drug-drug interactions (DDIs) between the medications. This systematic review provides an overview of the current state of knowledge about the pharmacokinetics (PK) of ART and TB treatment in children with HIV/TB co-infection, and identifies knowledge gaps.

METHODS

We searched Embase and PubMed, and systematically searched abstract books of relevant conferences, following PRISMA guidelines. Studies not reporting PK parameters, investigating medicines that are not available any longer or not including children with HIV/TB co-infection were excluded. All studies were assessed for quality.

RESULTS

In total, 47 studies met the inclusion criteria. No dose adjustments are necessary for efavirenz during concomitant first-line TB treatment use, but intersubject PK variability was high, especially in children <3 years of age. Super-boosted lopinavir/ritonavir (ratio 1:1) resulted in adequate lopinavir trough concentrations during rifampicin co-administration. Double-dosed raltegravir can be given with rifampicin in children >4 weeks old as well as twice-daily dolutegravir (instead of once daily) in children older than 6 years. Exposure to some TB drugs (ethambutol and rifampicin) was reduced in the setting of HIV infection, regardless of ART use. Only limited PK data of second-line TB drugs with ART in children who are HIV infected have been published.

CONCLUSIONS

Whereas integrase inhibitors seem favourable in older children, there are limited options for ART in young children (<3 years) receiving rifampicin-based TB therapy. The PK of TB drugs in HIV-infected children warrants further research.

In Vitro Assessment of the Interaction Potential of Ocimum basilicum (L.) Extracts on CYP2B6, 3A4, and Rifampicin Metabolism

Ocimum basilicum L. or basilicum is a common culinary herb, used as a traditional medicine for various medical conditions including HIV/AIDS and tuberculosis, in Africa. The objective of this study was to evaluate the effect of methanol, ethanol, aqueous and ethyl acetate extracts of the dried leaves and inflorescence of O. basilicum, on the activity of cytochrome P450 enzymes (CYPs) CYP2B6 and 3A4, as well as esterase-mediated metabolism of rifampicin to 25-O-desacetyl rifampicin (25ODESRIF). Human liver microsomes (HLM) were used to evaluate inhibition and CYP2B6/3A4 mRNA expression HepG2 assays were used to measure induction. Furthermore, the phytoconstituents likely involved in causing the observed effect were analyzed using biochemical tests and LC-MS. The aqueous and methanolic extracts showed reversible and time-dependent inhibition (TDI) of CYP2B6 with TDI-IC₅₀s 33.35 μg/ml (IC₅₀ shift-fold >1.5) and 4.93 μg/ml (IC₅₀ shift-fold >7) respectively, while the methanolic and ethanolic extracts inhibited 25ODESRIF formation (IC₅₀s 31 μg/ml, 8.94 μg/ml). In HepG2 assays, the methanolic and ethanolic extracts moderately induced CYP2B6, 3A4 mRNA with 38%-, 28%-fold shift, and 22%-, 44%-fold shift respectively. LC-MS full scans identified phenols rosmarinic acid [m/z 359 (M-H)^-, approximately 2298 mg/L in aqueous extract] and caftaric acid along with flavones salvigenin [m/z 329 (M+H)⁺, approximately 1855 mg/L in ethanolic extract], eupatorin [m/z 345 (M+H)⁺, 668.772 mg/L in ethanolic extract], rutin [m/z 609 (M-H)^-] and isoquercetin [m/z 463 (M-H)^-] and other compounds—linalool [m/z 153 (M-H)^-], hydroxyjasmonic acid [m/z 225 (M-H)^-], eucommiol [m/z 187 (M-H)^-] and trihydroxy octadecenoic acid [m/z 329 (M-H)^-, 530 mg/L in ethanolic extract]. The putative gastrointestinal tract (GIT) concentration for all extracts was calculated as 2,400 μg/ml and hepatic circulation concentrations were estimated at 805.68 μg/ml for the aqueous extract, and 226.56 μg/ml for methanolic extract. Based on the putative GIT concentration, estimated hepatic circulation concentration [I] and inhibition constant K_i, the predicted percentile of inhibition in vivo was highest for the aqueous extract on CYP2B6 (96.7%). The observations indicated that O. basilicum extracts may have the potential to cause clinically relevant herb-drug interactions (HDI) with CYP2B6 and rifampicin metabolism in vivo, if sufficient hepatic concentrations are reached in humans.

The challenge of HIV treatment in an era of polypharmacy

INTRODUCTION

The availability of potent antiretroviral therapy has transformed HIV infection into a chronic disease such that people living with HIV (PLWH) have a near normal life expectancy. However, there are continuing challenges in managing HIV infection, particularly in older patients, who often experience age-related comorbidities resulting in complex polypharmacy and an increased risk for drug-drug interactions. Furthermore, age-related physiological changes may affect the pharmacokinetics and pharmacodynamics of both antiretrovirals and comedications thereby predisposing elderly to adverse drug reactions. This review provides an overview of the therapeutic challenges when treating elderly PLWH (i.e. >65 years). Particular emphasis is placed on drug-drug interactions and other common prescribing issues (i.e. inappropriate drug use, prescribing cascade, drug-disease interaction) encountered in elderly PLWH.

DISCUSSION

Prescribing issues are common in elderly PLWH due to the presence of age-related comorbidities, organ dysfunction and physiological changes leading to a higher risk for drug-drug interactions, drugs dosage errors and inappropriate drug use.

CONCLUSIONS

The high prevalence of prescribing issues in elderly PLWH highlights the need for ongoing education on prescribing principles and the optimal management of individual patients. The knowledge of adverse health outcomes associated with polypharmacy and inappropriate prescribing should ensure that there are interventions to prevent harm including medication reconciliation, medication review and medication prioritization according to the risks/benefits for each patient.

Prevalence and management of drug-drug interactions with antiretroviral treatment in 2069 people living with HIV in rural Tanzania: a prospective cohort study

OBJECTIVES

Widespread access to antiretroviral therapy (ART) has substantially increased life expectancy in sub-Saharan African countries. As a result, the rates of comorbidities and use of co-medications among people living with HIV are increasing, necessitating a sound understanding of drug-drug interactions (DDIs). We aimed to assess the prevalence and management of DDIs with ART in a rural Tanzanian setting.

METHODS

We included consenting HIV-positive adults initiating ART in the Kilombero and Ulanga Antiretroviral Cohort (KIULARCO) between January 2013 and December 2016. DDIs were classified using www.hiv-druginteractions.org as red (contra-indicated), amber (potential clinical relevance requiring dosage adjustment/monitoring), yellow (weak clinical significance unlikely to require further management) or green (no interaction). We assessed management of amber DDIs by evaluating monitoring of laboratory or clinical parameters, or changes in drug dosages.

RESULTS

Of 2069 participants, 1945 (94%) were prescribed at least one co-medication during a median follow-up of 1.8 years. Of these, 645 (33%) had at least one potentially clinically relevant DDI, with the highest grade being red in nine (< 1%) and amber in 636 (33%) participants. Of the 23 283 prescriptions, 19 (< 1%) and 1745 (7%) were classified as red and amber DDIs, respectively. Overall, 351 (2%) prescriptions were red DDIs or not appropriately managed amber DDIs.

CONCLUSIONS

Co-medication use was common in this rural sub-Saharan cohort. A third of participants had DDIs requiring further management. Of the 9% of participants with not appropriately managed DDIs, most were with cardiovascular and analgesic drugs. This highlights the importance of physicians' awareness of DDIs for their recognition and management.

Prescribing issues in elderly individuals living with HIV

Introduction: Combined antiretroviral therapy has transformed HIV infection into a chronic disease thus people living with HIV (PLWH) live longer. As a result, the management of HIV infection is becoming more challenging as elderly experience age-related comorbidities leading to complex polypharmacy and a higher risk for drug-drug or drug-disease interactions. Furthermore, age-related physiological changes affect pharmacokinetics and pharmacodynamics thereby predisposing elderly PLWH to incorrect dosing or inappropriate prescribing and consequently to adverse drug reactions and the subsequent risk of starting a prescribing cascade. Areas covered: This review discusses the demographics of the aging HIV population, physiological changes and their impact on drug response as well as comorbidities. Particular emphasis is placed on common prescribing issues in elderly PLWH including drug-drug interactions with antiretroviral drugs. A PubMed search was used to compile relevant publications until February 2019. Expert opinion: Prescribing issues are highly prevalent in elderly PLWH thus highlighting the need for education on geriatric prescribing principles. Adverse health outcomes potentially associated with polypharmacy and inappropriate prescribing should promote interventions to prevent harm including medication reconciliation, medication review, and medication prioritization according to the risks/benefits for a given patient. A multidisciplinary team approach is recommended for the care of elderly PLWH.

Effect of Rifampin-Isoniazid-Containing Antituberculosis Therapy on Efavirenz Pharmacokinetics in HIV-Infected Children 3 to 14 Years Old

We compared efavirenz pharmacokinetic (PK) parameters in children with tuberculosis (TB)/human immunodeficiency virus (HIV) coinfection on and off first-line antituberculosis therapy to that in HIV-infected children. Children 3 to 14 years old with HIV infection, with and without TB, were treated with standard efavirenz-based antiretroviral therapy without any efavirenz dose adjustments. The new World Health Organization-recommended antituberculosis drug dosages were used in the coinfected participants. Steady-state efavirenz concentrations after 4 weeks of antiretroviral therapy were measured using validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) assays. Pharmacokinetic parameters were calculated using noncompartmental analysis. Between groups, PK parameters were compared by Wilcoxon rank-sum test and within group by signed-rank test. Of the 105 participants, 43 (41.0%) had TB coinfection. Children with TB/HIV coinfection compared to those with HIV infection were younger, had lower median weight-for-age Z score, and received a higher median efavirenz weight-adjusted dose. Geometric mean (GM) efavirenz peak concentration (Cmax), concentration at 12 h (C12h), Cmin, and total area under the curve from time 0 to 24 h (AUC0-24h) values were similar in children with HIV infection and those with TB/HIV coinfection during anti-TB therapy. Geometric mean efavirenz C12h, Cmin, and AUC0-24h values were lower in TB/HIV-coinfected patients off anti-TB therapy than in the children with HIV infection or TB/HIV coinfection on anti-TB therapy. Efavirenz clearance was lower and AUC0-24h was higher on than in patients off anti-TB therapy. Reduced efavirenz clearance by first-line anti-TB therapy at the population level led to similar PK parameters in HIV-infected children with and without TB coinfection. Our findings do not support modification of efavirenz weight-band dosing guidelines based on TB coinfection status in children. (The study was registered with ClinicalTrials.gov under registration number NCT01704144.).

The dawn of precision medicine in HIV: state of the art of pharmacotherapy

INTRODUCTION

Combination antiretroviral therapy (ART) reduces viral load to under the limit of detection, successfully decreasing HIV-related morbidity and mortality. Due to viral mutations, complex drug combinations and different patient response, there is an increasing demand for individualized treatment options for patients.

AREAS COVERED

This review first summarizes the pharmacokinetic and pharmacodynamic profile of clinical first-line drugs, which serves as guidance for antiretroviral precision medicine. Factors which have influential effects on drug efficacy and thus precision medicine are discussed: patients' pharmacogenetic information, virus mutations, comorbidities, and immune recovery. Furthermore, strategies to improve the application of precision medicine are discussed.

EXPERT OPINION

Precision medicine for ART requires comprehensive information on the drug, virus, and clinical data from the patients. The clinically available genetic tests are a good starting point. To better apply precision medicine, deeper knowledge of drug concentrations, HIV reservoirs, and efficacy associated genes, such as polymorphisms of drug transporters and metabolizing enzymes, are required. With advanced computer-based prediction systems which integrate more comprehensive information on pharmacokinetics, pharmacodynamics, pharmacogenomics, and the clinically relevant information of the patients, precision medicine will lead to better treatment choices and improved disease outcomes.

Pharmacokinetics of efavirenz in patients on antituberculosis treatment in high human immunodeficiency virus and tuberculosis burden countries: A systematic review

AIMS

Efavirenz (EFV) and rifampicin-isoniazid (RH) are cornerstone drugs in human immunodeficiency virus (HIV)-tuberculosis (TB) coinfection treatment but with complex drug interactions, efficacy and safety challenges. We reviewed recent data on EFV and RH interaction in TB/HIV high-burden countries.

METHODS

We conducted a systematic review of studies conducted in the high TB/HIV-burden countries between 1990 and 2016 on EFV pharmacokinetics during RH coadministration in coinfected patients. Two reviewers conducted article screening and data collection.

RESULTS

Of 119 records retrieved, 22 were included (two conducted in children), reporting either EFV mid-dose or pre-dose concentrations. In 19 studies, median or mean concentrations of RH range between 1000 and 4000 ng ml^-1 , the so-called therapeutic range. The proportion of patients with subtherapeutic concentration of RH ranged between 3.1 and 72.2%, in 12 studies including one conducted in children. The proportion of patients with supratherapeutic concentration ranged from 19.6 to 48.0% in six adult studies and one child study. Five of eight studies reported virological suppression >80%. The association between any grade hepatic and central nervous system adverse effects with EFV/RH interaction was demonstrated in two and three studies, respectively. The frequency of the CYP2B6 516G > T polymorphism ranged from 10 to 28% and was associated with higher plasma EFV concentrations, irrespective of ethnicity.

CONCLUSIONS

Anti-TB drug coadministration minimally affect the EFV exposure, efficacy and safety among TB-HIV coinfected African and Asian patients. This supports the current 600 mg EFV dosing when coadministered with anti-TB drugs.