Dolutegravir Inhibition of Matrix Metalloproteinases Affects Mouse Neurodevelopment.

Dolutegravir (DTG) is a first-line antiretroviral drug (ARV) used in combination therapy for the treatment of human immunodeficiency virus type-1 (HIV-1) infection. The drug is effective, safe, and well tolerated. Nonetheless, concerns have recently emerged for its usage in pregnant women or those of child-bearing age. Notably, DTG-based ARV regimens have been linked to birth defects seen as a consequence of periconceptional usages. To this end, uncovering an underlying mechanism for DTG-associated adverse fetal development outcomes has gained clinical and basic research interest. We now report that DTG inhibits matrix metalloproteinases (MMPs) activities that could affect fetal neurodevelopment. DTG is a broad-spectrum MMPs inhibitor and binds to Zn++ at the enzyme's catalytic domain. Studies performed in pregnant mice show that DTG readily reaches the fetal central nervous system during gestation and inhibits MMP activity. Postnatal screenings of brain health in mice pups identified neuroinflammation and neuronal impairment. These abnormalities persist as a consequence of in utero DTG exposure. We conclude that DTG inhibition of MMPs activities during gestation has the potential to affect prenatal and postnatal neurodevelopment.

Case Report of Increased Exposure to Antiretrovirals following Sleeve Gastrectomy.

Bariatric surgery is increasingly performed in morbidly obese HIV patients. Limited data exist regarding antiretroviral drug exposure after bariatric surgery. We report a case of a morbidly obese HIV patient who underwent sleeve gastrectomy. Abacavir, lamivudine, and dolutegravir therapeutic drug monitoring was performed at several time points pre- and postsurgery. Significantly increased levels were measured, particularly for abacavir, whose levels increased ∼12-fold. Several mechanistic explanations for these findings are discussed.

Genetic Diversity in Drug Transporters: Impact in African Populations.

Polymorphisms in drug transporters, like the adenosine triposphate-binding cassette (ABC) and solute carrier (SLC) superfamilies, may contribute to the observed diversity in drug response in African patients. This review aims to provide a comprehensive summary and analysis of the frequencies and distributions in African populations of ABC and SLC variants that affect drug pharmacokinetics (PK) and pharmacodynamics (PD). Of polymorphisms evaluated in African populations, SLCO1B1 rs4149056 and SLC22A6 rs1158626 were found at markedly higher frequencies than in non-African populations. SLCO1B1 rs4149056 was associated with reduction in rifampin exposure, which has implications for dosing this important anti-tuberculosis therapy. SLC22A6 rs1158626 was associated with increased affinity for antiretroviral drugs. Genetic diversity in SLC and ABC transporters in African populations has implications for conventional therapies, notably in tuberculosis and HIV. More PK and PD data in African populations are needed to assess potential for a different response to drugs compared with other global populations.

Impact of Therapeutic Drug Monitoring of Antiretroviral Drugs in Routine Clinical Management of People Living With HIV: A Narrative Review.

BACKGROUND: The treatment of HIV infection has evolved significantly since the advent of highly active antiretroviral therapy. As a result, a response rate of 90%-95% now represents a realistically achievable target. Given this background, it is difficult to imagine the additional benefits that therapeutic drug monitoring (TDM) could provide in the management of HIV infection. METHODS: This article is not intended to provide a systematic literature review on TDM of antiretroviral agents; rather, the authors aim to discuss the potential added value of TDM in the optimal management of people living with HIV (PLWH) in selected real-life clinical scenarios based on data collected over 10 years by their TDM service. RESULTS: Some clinical situations, in which the selection of the optimal antiretroviral therapy is challenging, have been identified. These include poorly compliant patients, suboptimal antiretroviral therapies (in terms of both efficacy and toxicity), polypharmacy with a high risk of drug-drug interactions, and different patient populations, such as pregnant women. CONCLUSIONS: The transformation of HIV infection from a near-universally fatal illness to a lifelong chronic disease has resulted in an HIV population that is growing and aging, placing new and increasing demands on public programs and health services. Increasingly, the management of comorbidities, polypharmacy, and drug-drug interaction, and their impact on antiretroviral therapy will have to be undertaken. These clinical settings represent some of the new frontiers for the use of TDM with the goal of achieving optimal prescription and outcome for PLWH.

The Incidence and Severity of Drug Interactions Before and After Antiretroviral Therapy Simplification in Treatment-Experienced Patients With HIV Infection.

Background: Current guidelines advocate for antiretroviral therapy (ART) simplification in patients on complicated regimens. Simplifying ART improves patient adherence and quality of life, but changes in drug interactions (DIs) are uncertain. Objective: This study assessed changes in DIs following ART simplification in patients with HIV. Methods: This was an observational, retrospective cohort study of patients attending an urban HIV clinic. Patients were included if they had ART simplification (a decreased number of daily tablets) and ≥1 concomitant medication (CM). Total DI scores were generated for each patient pre-ART simplification and post-ART simplification using an online DI database. Each ART-CM pair labeled as "do not co-administer" was given a score of 2, "potential interaction" a score of 1, or "no interaction" a score of 0. Differences in total DI scores following simplification were analyzed with a Wilcoxon Signed-Rank test. Predictors of DI score reductions were examined with linear regression. Results: A total of 99 patients were included. Their median age was 54 years, and 79% were male. The median durations of HIV infection and ART were 16 and 10 years, respectively. Patients were receiving an average of 4.5 CMs. Median interaction scores presimplification and postsimplification were 3 (interquartile range [IQR], 1-6) and 1 (IQR, 0-2) respectively (P < 0.001). Predictors of score reductions were the patient's number of CMs, discontinuing a protease inhibitor, and switching to a dolutegravir-based regimen. Conclusion and Relevance: ART simplification decreased the incidence of DIs in this analysis of patients with advanced age who had ART experience and polypharmacy.

CROI 2019: advances in antiretroviral therapy.

The 2019 Conference on Retroviruses and Opportunistic Infections included many exciting advances in antiretroviral therapy (ART). Investigators presented a case report of a second patient possibly cured of HIV through an allogeneic hematopoietic stem cell transplant from a CC chemokine receptor 5-delta 32 donor. Two clinical trials of long-acting injectable cabotegravir and rilpivirine showed promising safety, efficacy, and tolerability as maintenance ART. Test-and-treat and rapid-ART-start strategies show promise in advancing progress toward the HIV care cascade 90-90-90 Joint United Nations Programme on HIV/AIDS/World Health Organization targets. However, late diagnosis and mortality after ART initiation remain high, even in the context of HIV service scale-up, and mortality from unintentional opioid overdose in people living with HIV in the United States is on the rise. In vitro studies were presented that identified and evaluated the effect of resistance-associated mutations on ART susceptibility and elucidated mechanisms of resistance. Epidemiologic data were reported on the prevalence, impact, regional variation, and changes over time of resistance-associated mutations. Decreasing regional and national rates of resistance may be a benefit of increasing use of integrase strand transfer inhibitors (InSTIs). New findings were presented on maternal and fetal health outcomes in women of reproductive potential, drug-drug interactions between hormonal contraception and ART, and further exploration of the association between InSTIs and birth defects.

Managing Pharmacotherapy in People Living With HIV and Concomitant Malignancy.

Objective: To describe data with selected malignancies in people living with HIV (PLWH) and HIV in individuals affected by both conditions and to summarize drug-drug interactions (DDIs) with clinical recommendations for point-of-care review of combination therapies. Data Sources: Literature searches were performed (2005 to December 2018) in MEDLINE and EMBASE to identify studies of malignancies in PLWH in the modern era. Study Selection and Data Extraction: Article bibliographies and drug interaction databases were reviewed. Search terms included HIV, antiretroviral therapy, antineoplastic agents, malignancies, and drug interactions. Data Synthesis: In the pre-antiretroviral therapy (ART) era, malignancies in PLWH were AIDS-defining illnesses, and life expectancy was shorter. Nowadays, PLWH are living longer and developing malignancies, including lung, anal, and prostate cancers. Concurrently, the oncology landscape has evolved, with novel oral targeted agents and immunotherapies becoming routine elements of care. The increased need for and complexity with antineoplastics in PLWH has led to recommendations for multidisciplinary care of this unique population. Evaluation of DDIs requires review of metabolic pathways, absorption mechanisms, and various drug transporters associated with antineoplastics and ART. Relevance to Patient Care and Clinical Practice: This review summarizes available data of non-AIDS-defining malignancies, principles of HIV care in the patient with malignancy, and guidance for assessing DDIs between antineoplastics and ART. Summary DDI tables provide point-of-care recommendations. Conclusions: The availability of ART has transformed AIDS into a chronic medical condition, and PLWH are experiencing age-related malignancies. Pharmacists play an important role in the management of this patient population.

Chylomicron-pretended nano-bio self-assembling vehicle to promote lymphatic transport and GALTs target of oral drugs.

Lymphatic transport of oral drugs allows extraordinary gains in bioavailability and efficacy through avoidance of first-pass hepatic metabolism and preservation of drugs at lymphatic tissues against lymph-mediated diseases. Chylomicrons can transport dietary lipids absorbed from the intestine to the tissues through lymphatic circulation. Herein, we engineered for the first time a chylomicron-pretended mesoporous silica nanocarrier that utilizes the digestion, re-esterification, and lymphatic transport process of dietary triglyceride to promote lymphatic transport of oral drugs. Taking lopinavir (LNV) as a model antiretroviral drug with disadvantages such as poor solubility, high first-pass effect and off-target deposition, this vehicle exhibited several properties belonging to ideal nanocarriers, including high drug load, amorphous dispersion and controlled release in the gastrointestinal tract. Additionally, a nano-bio interaction was demonstrated between nanoparticles and a key protein involved in chylomicron assembly; this biochemical reaction in cellular was utilized for the first time to promote lymphatic transport of nanocarriers for oral delivery. As a result, the chylomicron-pretended nanocarrier afforded 10.6-fold higher oral bioavailability compared with free LNV and effectively delivered LNV to gut-associated lymphoid tissues, where HIV persists and actively evolves. This approach not only promises a potential application to HIV-infected individuals but also opens a new avenue to other lymph-mediated pathologies such as autoimmune diseases and lymphatic tumor metastasis.

Improving the clinical relevance of a mouse pregnancy model of antiretroviral toxicity; a pharmacokinetic dosing-optimization study of current HIV antiretroviral regimens.

Animal models can be useful tools for the study of HIV antiretroviral (ARV) safety/toxicity in pregnancy and the mechanisms that underlie ARV-associated adverse events. The utility and translatability of animal model-based ARV safety/toxicity data is improved if ARVs are tested in clinically relevant concentrations. The objective of this work was to improve the clinical relevance of our mouse pregnancy model of ARV toxicity, by determining the doses of currently prescribed ARV regimens that would yield human therapeutic plasma concentrations. Pregnant mice were administered increasing doses of ARV combinations by oral gavage, followed by measurement of drug concentrations in the maternal plasma and amniotic fluid. Concentrations of ten different ARVs in maternal plasma and amniotic fluid samples of pregnant mice are presented, with dosing optimization to yield human pregnancy-relevant plasma drug concentrations. We have proposed optimal dosing for different regimen component drugs to achieve human therapeutic plasma levels, so that a clinically relevant standard dosing is established. A review of related ARV pharmacokinetic studies in (pregnant/non-pregnant) rodents and human pregnancy is also shown. We hope these data will inform and encourage the use of mouse pregnancy models in the study of ARV safety/toxicity.

Optimizing Clinical Trial Design to Maximize Evidence Generation in Pediatric HIV.

For HIV-infected children, formulation development, pharmacokinetic (PK) data, and evaluation of early toxicity are critical for licensing new antiretroviral drugs; direct evidence of efficacy in children may not be needed if acceptable safety and PK parameters are demonstrated in children. However, it is important to address questions where adult trial data cannot be extrapolated to children. In this fast-moving area, interventions need to be tailored to resource-limited settings where most HIV-infected children live and take account of decreasing numbers of younger HIV-infected children after successful prevention of mother-to-child HIV transmission. Innovative randomized controlled trial (RCT) designs enable several questions relevant to children's treatment and care to be answered within the same study. We reflect on key considerations, and, with examples, discuss the relative merits of different RCT designs for addressing multiple scientific questions including parallel multi-arm RCTs, factorial RCTs, and cross-over RCTs. We discuss inclusion of several populations (eg, untreated and pretreated children; children and adults) in "basket" trials; incorporation of secondary randomizations after enrollment and use of nested substudies (particularly PK and formulation acceptability) within large RCTs. We review the literature on trial designs across other disease areas in pediatrics and rare diseases and discuss their relevance for addressing questions relevant to HIV-infected children; we provide an example of a Bayesian trial design in prevention of mother-to-child HIV transmission and consider this approach for future pediatric trials. Finally, we discuss the relevance of these approaches to other areas, in particular, childhood tuberculosis and hepatitis.

Sleeve Gastrectomy in Morbidly Obese HIV Patients: Focus on Anti-retroviral Treatment Absorption After Surgery.

CONTEXT: Anti-retroviral therapy (ART) dramatically reduced AIDS development, thus enabling patients to live as long as the general population. New challenges have emerged particularly cardiometabolic diseases and weight gain, with some HIV patients seeking bariatric surgery (BS). However, BS outcomes during HIV remain poorly described, with scarce data on ART pharmacokinetic post-BS. OBJECTIVE: Describing sleeve gastrectomy (SG) results in HIV patients in terms of ART pharmacokinetic, HIV control, weight loss, and metabolic outcomes. DESIGN, SETTING, AND PATIENTS: Prospective study of HIV patients undergoing SG in a referral academic center, with at least 6 months follow-up. MAIN OUTCOME MEASURE: Clinical and biological parameters, HIV medical history, and ART pharmacokinetics were gathered before and post-SG. RESULTS: Seventeen patients (mean BMI = 44.2 ± 5.7 kg m-2) and major obesity-related diseases (47% type-2 diabetes, 64% obstructive sleep apnea, 70% hypertension) underwent SG during a mean 2 years of follow-up. They displayed an average of 20% reduction of initial BMI and improved body composition, similarly to obese non-HIV patients. SG improved metabolic status. All patients had undetectable viral load before BS. Upon HIV follow-up, 12 patients had undetectable viral load with correct ART kinetic parameters (3 and 6 months); 4 displayed detectable viral load along with significant decrease in raltegravir and atazanavir treatment exposure, leading to ART change with subsequent undetectable viral load; and 1 had persistent detectable viral load despite ART change. CONCLUSIONS: SG seems effective and safe in obese HIV patients. However, ART treatment should be monitored post-SG to control HIV infection. We suggest that some ART should be adapted before SG conjoints with infectious disease specialists.

Pharmacokinetics of Tenofovir Alafenamide When Coadministered With Other HIV Antiretrovirals.

BACKGROUND: Tenofovir alafenamide (TAF), a prodrug of the nucleotide analogue tenofovir (TFV), is an antiretroviral (ARV) agent approved either as a complete regimen [elvitegravir/cobicistat/emtricitabine (F)/TAF, rilpivirine/F/TAF, bictegravir/F/TAF], or for use with other ARVs (F/TAF), for treatment of HIV. TAF is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) transporters. Disposition of TAF may be altered by comedications that can inhibit or induce P-gp or BCRP transporters. The effects of ARVs on the pharmacokinetics of TAF were evaluated in 3 studies. METHODS: Healthy participants received TAF administered alone or with rilpivirine in study 1, with dolutegravir, ritonavir-boosted atazanavir (ATV + RTV), lopinavir (LPV/RTV), or darunavir (DRV + RTV) in study 2, and with the pharmacokinetic enhancer cobicistat or efavirenz in study 3. RESULTS: Across the 3 studies, 98 participants received treatment with TAF and a coadministered agent (n = 10-34/cohort). All study treatments were well tolerated. TAF and TFV exposures were unaffected after co-administration with rilpivirine and dolutegravir. Coadministration with P-gp/BCRP inhibitors such as cobicistat or PI-based regimens (ATV + RTV, LPV/r, or DRV + RTV) resulted in a range of 6%-183% increases in TAF and 105%-316% increases in TFV exposure, whereas coadministration with a P-gp inducer, efavirenz, resulted in a 15%-24% decrease in TAF and TFV exposure. CONCLUSIONS: Evaluation of the drug interaction between TAF and other commonly prescribed boosted and unboosted ARVs provides characterization of the susceptibility of TAF and/or TFV pharmacokinetics to inhibitors or inducers of P-gp/BCRP transporters.

Concomitant medication polypharmacy, interactions and imperfect adherence are common in Australian adults on suppressive antiretroviral therapy.

OBJECTIVES: We quantified concomitant medication polypharmacy, pharmacokinetic and pharmacodynamic interactions, adverse effects and adherence in Australian adults on effective antiretroviral therapy. DESIGN: Cross-sectional. METHODS: Patients recruited into a nationwide cohort and assessed for prevalence and type of concomitant medication (including polypharmacy, defined as ≥5 concomitant medications), pharmacokinetic or pharmacodynamic interactions, potential concomitant medication adverse effects and concomitant medication adherence. Factors associated with concomitant medication polypharmacy and with imperfect adherence were identified using multivariable logistic regression. RESULTS: Of 522 participants, 392 (75%) took a concomitant medication (mostly cardiovascular, nonprescription or antidepressant). Overall, 280 participants (54%) had polypharmacy of concomitant medications and/or a drug interaction or contraindication. Polypharmacy was present in 122 (23%) and independently associated with clinical trial participation, renal impairment, major comorbidity, hospital/general practice-based HIV care (versus sexual health clinic) and benzodiazepine use. Seventeen participants (3%) took at least one concomitant medication contraindicated with their antiretroviral therapy, and 237 (45%) had at least one pharmacokinetic/pharmacodynamic interaction. Concomitant medication use was significantly associated with sleep disturbance and myalgia, and polypharmacy of concomitant medications with diarrhoea, fatigue, myalgia and peripheral neuropathy. Sixty participants (12%) reported imperfect concomitant medication adherence, independently associated with requiring financial support, foregoing necessities for financial reasons, good/very good self-reported general health and at least 1 bed day for illness in the previous 12 months. CONCLUSION: In a resource-rich setting with universal healthcare access, the majority of this sample took a concomitant medication. Over half had at least one of concomitant medication polypharmacy, pharmacokinetic or pharmacodynamic interaction. Concomitant medication use was associated with several adverse clinical outcomes.

The challenge of polypharmacy in an aging population and implications for future antiretroviral therapy development.

: It is estimated that by 2030 nearly three-quarters of persons living with HIV will be 50 years and older. The aging HIV population presents a new clinical concern for HIV providers: adverse effects from polypharmacy. An aging population means more comorbidities and potentially more drug-drug interactions for providers to manage. This review discusses major comorbidities including cardiovascular disease, anticoagulation, hypertension, diabetes mellitus and malignancy and considerations for drug-interactions with antiretrovirals.

Therapeutic Potential and Utility of Elacridar with Respect to P-glycoprotein Inhibition: An Insight from the Published In Vitro, Preclinical and Clinical Studies.

The occurrence of efflux mechanisms via Permeability-glycoprotein (P-gp) recognized as an important physiological process impedes drug entry or transport across membranes into tissues. In some instances, either low oral bioavailability or lack of brain penetration has been attributed to P-gp mediated efflux activity. Therefore, the objective of development of P-gp inhibitors was to facilitate the attainment of higher drug exposures in tissues. Many third-generation P-gp inhibitors such as elacridar, tariquidar, zosuquidar, etc. have entered clinical development to fulfil the promise. The body of evidence from in vitro and in vivo preclinical and clinical data reviewed in this paper provides the basis for an effective blockade of P-gp efflux mechanism by elacridar. However, clinical translation of the promise has been elusive not just for elacridar but also for other P-gp inhibitors in this class. The review provides introspection and perspectives on the lack of clinical translation of this class of drugs and a broad framework of strategies and considerations in the potential application of elacridar and other P-gp inhibitors in oncology therapeutics.

Novel Antiretroviral Drugs in Patients with Renal Impairment: Clinical and Pharmacokinetic Considerations.

Highly active antiretroviral therapy (HAART) has dramatically increased the survival of HIV-infected patients from Western countries reducing the incidence of opportunistic infections and AIDS-related malignancies, and improving the patients' quality of life compared with the pre-HAART era. HIV is thus now considered in the West as a chronic disease, with the majority of HIV-infected patients successfully reaching an optimal immune and virological outcome a few months after starting HAART. However, this switch from acute to chronic disease has been accompanied by an increased incidence of chronic kidney disease (CKD), reported in up to 60% of HIV-infected patients. Tenofovir disoproxil fumarate (TDF) is considered to play a significant role in the development of CKD in these patients. It has been proposed that tenofovir alafenamide (TAF), a prodrug formulation able to providing lower systemic and renal drug exposure, could potentially contribute to reduce the development of CKD in HAART-treated patients. On the other hand, the pharmacokinetics of some components of HAART can be significantly altered in HIV-infected patients developing CKD. TDF- or TAF-based antiretroviral regimens should be avoided in patients with a creatinine clearance of less than 50 or 30 mL/min, respectively. This review focuses on the pharmacokinetic changes of novel antiretroviral drugs in HIV-infected patients with renal impairment or requiring renal replacement therapy, and provides some suggestions on how to change drug doses in these clinical settings.

Triple Drug Combination of Zidovudine, Efavirenz and Lamivudine Loaded Lactoferrin Nanoparticles: an Effective Nano First-Line Regimen for HIV Therapy.

PURPOSE: To enhance efficacy, bioavailability and reduce toxicity of first-line highly active anti-retroviral regimen, zidovudine + efavirenz + lamivudine loaded lactoferrin nanoparticles were prepared (FLART-NP) and characterized for physicochemical properties, bioactivity and pharmacokinetic profile. METHODS: Nanoparticles were prepared using sol-oil protocol and characterized using different sources such as FE-SEM, AFM, NanoSight, and FT-IR. In-vitro and in-vivo studies have been done to access the encapsulation-efficiency, cellular localization, release kinetics, safety analysis, biodistribution and pharmacokinetics. RESULTS: FLART-NP with a mean diameter of 67 nm (FE-SEM) and an encapsulation efficiency of >58% for each drug were prepared. In-vitro studies suggest that FLART-NP deliver the maximum of its payload at pH5 with a minimum burst release throughout the study period with negligible toxicity to the erythrocytes plus improved in-vitro anti-HIV activity. FLART-NP has improved the in-vivo pharmacokinetics (PK) profiles over the free drugs; an average of >4fold increase in AUC and AUMC, 30% increase in the Cmax, >2fold in the half-life of each drug. Biodistribution data suggest that FLART-NP has improved the bioavailability of all drugs with less tissue-related inflammation as suggested with histopathological evaluation CONCLUSIONS: The triple-drug loaded nanoparticles have various advantages against soluble (free) drug combination in terms of enhanced bioavailability, improved PK profile and diminished drug-associated toxicity.

Relevancia clínica de las interacciones medicamentosas en pacientes infectados con el virus de la inmunodeficiencia humana: actualización 2009-2014 / The clinical relevance of drug interactions in patients with human immunodeficiency virus infection: update 2009-2014

Objective: To update information about drug interactions in patients with HIV/AIDS. Methods: Comprehensive literature review in MEDLINE/PubMed database from May of 2009 to December of 2014, using the Mesh terms: Anti-retroviral 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 were retrieved. Additionally, citation lists from identified articles were reviewed. The study inclusion was assessed by three independent researchers and by consensus among them when was necessary. Clinical relevance of drug interaction was grouped into four levels according to seriously and probability of occurrence. Results: Global, 546 different references were retrieved and 243 were selected. In addition 11 further manuscripts were identified in the references of the included articles. Overall, 935 pairs of drug interactions were identified, 95.7% pharmacokinetic (823 by enzyme induction or inhibition and 67 by changes in bioavailability). Of the 935 pairs of drug interactions, 402(43%) were classified as levels 1 or 2. Conclusions: The most clinically relevant antiretroviral drug interactions are due to pharmacokinetic mechanism, mainly induction or enzyme inhibition, according to previous reviews, the protease inhibitors remain as the antiretrovirals with the highest number of clinical relevant interactions.

Objetivo: Actualizar información sobre interacciones medicamentosas en pacientes con VIH/SIDA. Métodos: Revisión estructurada en MEDLINE/PubMed utilizando los términos Mesh: Anti-retroviral agents and drug interactions or herb-drug interactions or food-drug interactions, entre mayo de 2009 y diciembre de 2014. Publicaciones sobre interacciones medicamentosas, en humanos, en inglés o español y con acceso a texto completo fueron seleccionadas. Además, se incluyeron referencias de artículos considerados relevantes. La inclusión de los artículos fue evaluada por tres investigadores independientes y, en caso de requerirlo, por consenso entre ellos. La relevancia clínica se estableció en cuatro niveles, acorde con la gravedad y probabilidad de ocurrencia de la interacción. Resultados: Se identificaron 546 artículos, de los cuales se seleccionaron 273; además, se incluyeron 11 referencias relevantes. Se identificaron 935 parejas de interacciones medicamentosas, 95,7% farmacocinéticas. De este grupo, 823 mediadas por inducción o inhibición enzimática y 67 por cambios en la biodisponibilidad. De las 935 parejas de interacciones, 402 (43%) fueron relevantes clínicamente (niveles 1 o 2). Conclusiones: Las interacciones medicamentosas con anti-retrovirales de mayor relevancia clínica se deben a mecanismos farmacocinéticos, principalmente inducción o inhibición enzimática. Acorde con revisiones previas, los inhibidores de proteasa continúan siendo los anti-retrovirales con mayor número de interacciones relevantes.

High efficacy of first-line ART in a West African cohort, assessed by dried blood spot virological and pharmacological measurements.

OBJECTIVES: The objectives of this study were to determine the rate of viral success in HIV-infected patients on first-line ART by the assessment of dried blood spot (DBS) viral load (VL) and to assess the performance of DBS sampling for VL measurement, genotypic resistance and antiretroviral concentration determinations. METHODS: HIV-infected patients treated for >1 year with first-line ART in Niamey, Niger were included. VL based on nucleic acid sequence-based amplification (NASBA) assay (limit of quantification <800 copies/mL) was measured on DBS capillary samples. Resistance genotype was assessed for all detectable VLs (limit of detection >100 copies/mL); antiretroviral concentrations were interpreted using standard plasma cut-offs after extrapolation of blood to plasma results. Median (IQR) results are presented. RESULTS: Two hundred and eighteen patients (61% women), aged 41 (34-46) years, with 138 (56-235) CD4 cells/mm3 at baseline were included. After 4 (2-6) years of follow-up under therapy, CD4 gain was +197 (98-372) cells/mm3; 81% had VL <800 copies/mL. Antiretroviral concentrations were adequate in 87% of patients and nevirapine/efavirenz concentrations were related to viral success (P < 0.001). DBS genotypic resistance amplification succeeded in 71% of failing patients: NRTI drug resistance mutations were identified in 73% including resistance to lamivudine/emtricitabine (67%), abacavir (30%) and tenofovir (21%); and NNRTI drug resistance mutations were identified in 82% including resistance to rilpivirine (39%) and etravirine (15%). CONCLUSIONS: This study demonstrated a good response after 4 years of first-line ART in Niger. Adherence was high, according to antiretroviral concentrations, and the majority of failures were explained by selection of drug resistance mutations detected in the DBS genotype. Using DBS might improve the assessment of ART failure in HIV-infected patients in low-income countries.

Effect of mid-dose efavirenz concentrations and CYP2B6 genotype on viral suppression in patients on first-line antiretroviral therapy.

The therapeutic range for efavirenz plasma concentrations is unclear and some studies found no correlation with viral non-suppression. Efavirenz concentrations are variable, driven in part by polymorphisms in CYP2B6. We hypothesised that efavirenz mid-dosing concentrations, together with CYP2B6 metaboliser genotype, could predict viral non-suppression. Participants starting first-line efavirenz-based antiretroviral therapy were monitored for 48 weeks. HIV-RNA and efavirenz mid-dose interval concentrations were determined at Weeks 16 and 48. CYP2B6 metaboliser genotype status was determined by 516G→T and 983T→C polymorphisms. Cox proportional hazards modelling was used to predict viral non-suppression and to determine the most predictive efavirenz mid-dosing concentration threshold. In total, 180 participants were included. Median efavirenz concentrations were 2.3 mg/L (IQR 1.6-4.6 mg/L) and 2.2 mg/L (IQR 1.5-3.9 mg/L) at Weeks 16 and 48, respectively. Moreover, 49 (27.2%), 84 (46.7%) and 39 (21.7%) participants had extensive, intermediate or slow CYP2B6 metaboliser genotype, respectively. Log2 efavirenz concentrations [adjusted hazard ratio (aHR) = 0.77, 95% CI 0.67-0.89] and baseline CD4 cell count (aHR = 0.994, 95% CI 0.989-0.998), but not CYP2B6 genotype, were predictive of viral non-suppression. For every doubling of efavirenz concentration there was a 23% decrease in the hazard of non-suppression. A threshold of 0.7 mg/L was found to be the efavirenz mid-dosing concentration that was most predictive of non-suppression. Mid-dosing efavirenz concentrations are predictive of viral non-suppression, but the currently recommended lower therapeutic limit (1 mg/L) is higher than our finding. Knowledge of CYP2B6 metaboliser genotype is not required for prediction of virological outcomes.