Exploring the impact of therapeutic advances in HIV-related mortality in the United States

Objectives

Mortality from HIV has significantly declined with the introduction of highly active antiretroviral therapy (HAART). This study sought to examine the longitudinal trends in mortality from HIV-related diseases by race, sex, geographical region, and over time as HAART trends changed.

Methods

We queried the Centers for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research database and performed serial cross-sectional analyses of national death certificate data for all-cause mortality with comorbid HIV from 1999 to 2020. HIV diseases (International Classification of Diseases, Tenth Revision codes B20-B24, O98.7, R75) were listed as the contributing cause of death. We calculated the age-adjusted mortality ratio (AAMR) per 1,000,000 individuals and determined mortality trends using the Joinpoint Regression Program. Subgroup analyses were performed by sex, race, region, and organ system. The study period was further stratified into three groups when specific drug regimens were more prevalent.

Results

In the 22-year study period, 251,759 all-cause mortalities with comorbid HIV were identified. The leading cause of death was infectious disease (84.0%, N = 211,438). Men recorded a higher AAMR than women (4.66 vs 1.65, P < 0.01). African American individuals had the highest AAMR (13.46) compared to White, American Indian, and Asian individuals (1.70 vs 1.65 vs 0.47). The South region had the highest AAMR (4.32) and urban areas had a higher AAMR compared to rural areas (1.77 vs 0.88).

Conclusions

More than 80% of deaths occurred because of infectious disease over the last 2 decades with a decreasing trend over time when stratified by race, sex, and geographical region. Despite advances in HAART, mortality disparities persist which emphasizes the need for targeted interventions in these populations.

Strategies in the Design and Development of Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

AIDS (acquired immunodeficiency syndrome) is a potentially life-threatening infectious disease caused by human immunodeficiency virus (HIV). To date, thousands of people have lost their lives annually due to HIV infection, and it continues to be a big public health issue globally. Since the discovery of the first drug, Zidovudine (AZT), a nucleoside reverse transcriptase inhibitor (NRTI), to date, 30 drugs have been approved by the FDA, primarily targeting reverse transcriptase, integrase, and/or protease enzymes. The majority of these drugs target the catalytic and allosteric sites of the HIV enzyme reverse transcriptase. Compared to the NRTI family of drugs, the diverse chemical class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) has special anti-HIV activity with high specificity and low toxicity. However, current clinical usage of NRTI and NNRTI drugs has limited therapeutic value due to their adverse drug reactions and the emergence of multidrug-resistant (MDR) strains. To overcome drug resistance and efficacy issues, combination therapy is widely prescribed for HIV patients. Combination antiretroviral therapy (cART) includes more than one antiretroviral agent targeting two or more enzymes in the life cycle of the virus. Medicinal chemistry researchers apply different optimization strategies including structure- and fragment-based drug design, prodrug approach, scaffold hopping, molecular/fragment hybridization, bioisosterism, high-throughput screening, covalent-binding, targeting highly hydrophobic channel, targeting dual site, and multi-target-directed ligand to identify and develop novel NNRTIs with high antiviral activity against wild-type (WT) and mutant strains. The formulation experts design various delivery systems with single or combination therapies and long-acting regimens of NNRTIs to improve pharmacokinetic profiles and provide sustained therapeutic effects.

A Combination of Novel HIV-1 Protease Inhibitor and Cytochrome P450 (CYP) Enzyme Inhibitor to Explore the Future Prospective of Antiviral Agents: Evotaz

Viruses belong to the class of micro-organisms that are well known for causing infections in the human body. Antiviral medications are given out to prevent the spread of disease-causing viruses. When the viruses are actively reproducing, these agents have their greatest impact. It is particularly challenging to develop virus-specific medications since viruses share the majority of the metabolic functions of the host cell. In the continuous search for better antiviral agents, the United States Food and Drug Administration (USFDA) approved a new drug named Evotaz on January 29, 2015 for the treatment of human immunodeficiency virus (HIV). Evotaz is a combined once-daily fixed drug, containing Atazanavir, an HIV protease inhibitor, and cobicistat, an inhibitor of the human liver cytochrome P450 (CYP) enzyme. The medication is created such that it can kill viruses by concurrently inhibiting protease and CYP enzymes. The medicine is still being studied for a number of criteria, but its usefulness in children under the age of 12 is currently unknown. The preclinical and clinical characteristics of Evotaz, as well as its safety and efficacy profiles and a comparison of the novel drug with antiviral medications presently available in the market, are the main topics of this review paper.

Longitudinal analysis of new-onset non-AIDS-defining diseases among people living with HIV: A real-world observational study

OBJECTIVES

We aimed to analyze the incidence rates of new-onset diabetes, hypertriglyceridemia, hypercholesterolemia, liver injury, and renal injury during antiretroviral therapy (ART) among people living with HIV (PLWH) and determine the associated risk factors.

METHODS

This study included PLWH enrolled from Beijing Ditan Hospital from November 11, 2004, to December 29, 2018. The incidence rates of new-onset diabetes, hypertriglyceridemia, hypercholesterolemia, liver injury, and renal injury were calculated and stratified based on ART regimen, CD4 count, and HIV-RNA. Risk factors were determined using Cox regression analysis.

RESULTS

Overall, 6747 participants were included. Moreover, 4.5%, 43.3%, 25.4%, 11.2%, and 6.2% of patients developed new-onset diabetes, hypertriglyceridemia, hypercholesterolemia, liver injury, and renal injury, respectively, with incidence rates of 1.7, 26.9, 10.2, 3.9, and 5.5 per 100 person-years, respectively. Longitudinally, the incidence rates and percentages of these outcomes were highest in the first year of ART. The percentage of dyslipidemia was significantly higher in protease inhibitor (PI)-based regimen than in non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen. However, the percentage of liver injury was significantly higher in NNRTI-based regimen than in PI-based regimen. In multivariate Cox regression analysis, low CD4 count (<200 cells/µL, adjusted hazard ratio [aHR] = 1.34, 95% confidence interval [CI] 1.15-1.57) and high HIV-RNA (>10⁵ copies/mL, aHR = 1.26, 95% CI 1.08-1.48) were risk factors for hypertriglyceridemia.

CONCLUSIONS

Clinical outcomes, including new-onset diabetes, dyslipidemia, and liver and renal injuries, are common in PLWH. Regular glucose, lipid, liver, and renal function monitoring is required during ART, especially in high-risk patients.

Phosphonates and Phosphonate Prodrugs in Medicinal Chemistry: Past Successes and Future Prospects

Compounds with a phosphonate group, i.e., -P(O)(OH)₂ group attached directly to the molecule via a P-C bond serve as suitable non-hydrolyzable phosphate mimics in various biomedical applications. In principle, they often inhibit enzymes utilizing various phosphates as substrates. In this review we focus mainly on biologically active phosphonates that originated from our institute (Institute of Organic Chemistry and Biochemistry in Prague); i.e., acyclic nucleoside phosphonates (ANPs, e.g., adefovir, tenofovir, and cidofovir) and derivatives of non-nucleoside phosphonates such as 2-(phosphonomethyl) pentanedioic acid (2-PMPA). Principal strategies of their syntheses and modifications to prodrugs is reported. Besides clinically used ANP antivirals, a special attention is paid to new biologically active molecules with respect to emerging infections and arising resistance of many pathogens against standard treatments. These new structures include 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidines or so-called "open-ring" derivatives, acyclic nucleoside phosphonates with 5-azacytosine as a base moiety, side-chain fluorinated ANPs, aza/deazapurine ANPs. When transformed into an appropriate prodrug by derivatizing their charged functionalities, all these compounds show promising potential to become drug candidates for the treatment of viral infections. ANP prodrugs with suitable pharmacokinetics include amino acid phosphoramidates, pivaloyloxymethyl (POM) and isopropoxycarbonyloxymethyl (POC) esters, alkyl and alkoxyalkyl esters, salicylic esters, (methyl-2-oxo-1,3-dioxol-4-yl) methyl (ODOL) esters and peptidomimetic prodrugs. We also focus on the story of cytostatics related to 9-[2-(phosphonomethoxy)ethyl]guanine and its prodrugs which eventually led to development of the veterinary drug rabacfosadine. Various new ANP structures are also currently investigated as antiparasitics, especially antimalarial agents e.g., guanine and hypoxanthine derivatives with 2-(phosphonoethoxy)ethyl moiety, their thia-analogues and N-branched derivatives. In addition to ANPs and their analogs, we also describe prodrugs of 2-(phosphonomethyl)pentanedioic acid (2-PMPA), a potent inhibitor of the enzyme glutamate carboxypeptidase II (GCPII), also known as prostate-specific membrane antigen (PSMA). Glutamate carboxypeptidase II inhibitors, including 2-PMPA have been found efficacious in various preclinical models of neurological disorders which are caused by glutamatergic excitotoxicity. Unfortunately its highly polar character and hence low bioavailability severely limits its potential for clinical use. To overcome this problem, various prodrug strategies have been used to mask carboxylates and/or phosphonate functionalities with pivaloyloxymethyl, POC, ODOL and alkyl esters. Chemistry and biological characterization led to identification of prodrugs with 44-80 fold greater oral bioavailability (tetra-ODOL-2-PMPA).

The New NNRTI ACC007 Combined with Lamivudine and Tenofovir Disoproxil Fumarate Show Synergy Anti-HIV Activity In Vitro

BACKGROUND

Acquired immunodeficiency syndrome can hardly be cured currently and people with human immunodeficiency virus (HIV) need lifelong treatment that may result in the emergence of drug resistance which leads to failed treatment. Thus, the development of new anti- HIV drugs and new treatment regimens are necessary.

OBJECTIVE

The aim of this study is to analyze the combined anti-HIV activity of tenofovir disoproxil fumarate, lamivudine and ACC007, a new non-nucleoside reverse transcriptase inhibitor.

METHODS

The antiviral activity of tenofovir disoproxil fumarate, lamivudine and ACC007 alone or in combination against different HIV-1 strains was determined by the detection of HIV-1 p24 level through enzyme-linked immunosorbent assay.

RESULT

ACC007 showed EC50 of nanomolar range (from 3.03 nM to 252.59 nM) against all HIV-1 strains used in this study except the HIV-1A17, with EC50 of 1.57 μM. The combined antiviral activity of ACC007, lamivudine and tenofovir disoproxil fumarate showed synergy antiviral activity against all HIV-1 strains used in this study. The three-drug combination showed moderate synergism against HIV-1A17, HIV-14755-5, HIV-1K103N and HIV-1V106M, with a combination index value ranging from 0.71 to 0.87, and showed synergism against the other HIV-1 strains with combination index value from 0.35 to 0.67. The combination with ACC007 significantly increases the dose reduction index value of lamivudine and tenofovir disoproxil fumarate, compared with two-drug combination.

CONCLUSION

ACC007 exhibits potent antiviral activity alone or with 3TC and TDF, and exerts synergistic effect against all HIV strains used in our investigation in vitro.

Mass Spectrometry Imaging Demonstrates the Regional Brain Distribution Patterns of Three First-Line Antiretroviral Drugs

HIV in the central nervous system (CNS) contributes to the development of HIV-associated neurological disorders (HAND), even with chronic antiretroviral therapy. In order for antiretroviral therapy to be effective in protecting the CNS, these drugs should have the ability to localize in brain areas known to be affected by HIV. Consequently, this study aimed to investigate the localization patterns of three first-line antiretroviral drugs, namely, efavirenz, tenofovir, and emtricitabine, in the rat brain. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) were utilized to assess the pharmacokinetics and brain spatial distribution of the three drugs. Each drug was administered (50 mg/kg) to healthy female Sprague-Dawley rats via intraperitoneal administration. LC-MS/MS results showed that all three drugs could be delivered into the brain, although they varied in blood-brain barrier permeability. MALDI-MSI showed a high degree of efavirenz localization across the entire brain, while tenofovir localized mainly in the cortex. Emtricitabine distributed heterogeneously mainly in the thalamus, corpus callosum, and hypothalamus. This study showed that efavirenz, tenofovir, and emtricitabine might be a potential drug combination antiretroviral therapy for CNS protection against HAND.

Karacoline, identified by network pharmacology, reduces degradation of the extracellular matrix in intervertebral disc degeneration via the NF-κB signaling pathway

Karacoline is a compound found in the plant Aconitum kusnezoffii Reichb. Although Aconitum kusnezoffii Reichb is widely used for the treatment of pain, very few studies have been carried out on the use of karacoline due to its potential toxicity. In this study, we selected key matrix metalloproteinases (MMPs), collagen II, and aggrecan as targets due to their association with intervertebral disc degeneration (IDD). Using these targets, we then used network pharmacology to predict a series of molecules that might exert therapeutic effects on IDD. Of these molecules, karacoline was predicted to have the best effect. Tumor necrosis factor (TNF)-α is known to promote the degeneration of the extracellular matrix in IDD. We therefore applied different concentrations of karacoline (0, 1.25, or 12.88 μM) along with 100 ng/mL TNF-α to rat nucleus pulposus cells and found that karacoline reduced the expression of MMP-14 in IDD by inhibiting the nuclear factor (NF)-κB pathway, while collagen II and aggrecan expression was increased. This suggested that extracellular matrix degradation was inhibited by karacoline (P < 0.05). Our data therefore reveal a new clinical application of karacoline and provide support for the use of network pharmacology in predicting novel drugs.

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The first study to demonstrate that karacoline can delay IDD by inhibiting extracellular matrix degradation.

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The study explores the possibility of using network pharmacology to predict new therapeutic drugs for some diseases.

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This study can lay the basic of using network pharmacology to construct a Chinese herbal compound for targeted therapy.

Pattern of and reasons for antiretroviral therapy regimen change among adult HIV/AIDS patients at regional hospital in Eastern Ethiopia: A 10-year retrospective study

Objectives

Despite the successes of treatment with antiretroviral therapy in reducing morbidity and mortality among HIV-infected patients, long-term sustainability of the initial regimen has become challenging. Therefore, this study is aimed to address pattern of and reasons for change of antiretroviral therapy regimens among HIV/AIDS patients at Jugel Hospital, Eastern Ethiopia.

Methods

A retrospective cross-sectional study was conducted to review medical records of 220 patients who had been on treatment and experienced regimen change at least once from September 2006 to August 2016. Structured data abstraction format was customized from World Health Organization guideline. Data were entered in Epi-data version 3.1, and exported to and analyzed with Statistical Package for Social Sciences version 20. Following descriptive statistics, binary logistic regression was run to determine the association between selected variables and second-time regimen change.

Results

The mean age of patients was 37.6 (±8.9) years and 62.3% of them were female. Majority of the patients were presented to the hospital with World Health Organization clinical stage III (59.1%) and CD4 count below 200 cells/mm³ (68.6%). The mean duration of stay on initial regimen was found to be 3.26 (±1.92) years. The average number of initial regimen changes per year was 22 (±11.28). In two-thirds (66.36%) of the patients, their initial regimen was changed to tenofovir disproxil fumarate-based alternatives. The most-frequent reason for initial regimen change was toxicity (32.3%). Among those who experienced the regimen change for the first time, the prevalence of second-time regimen change was found to be 18.18%. Patients who had been taking tuberculosis treatment along with antiretroviral therapy were more likely to get their regimen changed for the second-time compared to those who were not infected with tuberculosis (adjusted odds ratio: 3.40; 95% confidence interval: 1.87-6.47). Besides, patients who were on zidovudine-based (adjusted odds ratio: 0.26; 95% confidence interval: 0.33-0.47) and tenofovir disoproxil fumarate-based regimens (adjusted odds ratio: 0.03; 95% confidence interval: 0.01-0.12) were less likely to get their regimen changed for the second-time compared to those who were on stavudine-based regimens.

Conclusion

The majority of the patients had their treatment regimen changed because of drug-related toxicities, treatment failure, and comorbid conditions. Some regimen changes might be attributable to failure of either hospital supply system or patient-related factors which would have been prevented considering limited number of treatment options. There must be consideration of risks and benefits prior to changing a particular regimen.

Appropriateness of Cotrimoxazole Prophylactic Therapy Among HIV/AIDS Patients in Public Hospitals in Eastern Ethiopia: A Retrospective Evaluation of Clinical Practice

Background: Cotrimoxazole prophylactic therapy (CPT) is a feasible, cost-effective, and safe way of using cotrimoxazole intervention to reduce HIV/AIDS related morbidities and mortalities associated with opportunistic infections. Despite its effectiveness in reducing the incidence of opportunistic infections, the actual drug utilization process has been shown to deviate from World Health Organization (WHO) guideline in Ethiopia. This study, therefore, aims to evaluate CPT among HIV/AIDS patients in Jugel Hospital (JH), Harar and Dilchora Referral Hospital (DRH), Dire Dawa, Eastern Ethiopia.

Methods: A cross sectional study was conducted to evaluate the use of cotrimoxazole as prophylactic therapy. In this study, 556 medical records (305 in JH and 251 in DRH) of HIV/AIDS patients who had been taking CPT within September 2015–August 2016 were reviewed. Systematic random sampling was employed to obtain medical records from the sampling frame. Data were abstracted from the patient medical records using structured checklist customized from the WHO guideline. The data were entered into Epi-data 3.1 and exported to and analyzed with statistical Package for Social Sciences (SPSS) version 20. The finding was evaluated against the WHO guideline on the use of cotrimoxazole prophylaxis in HIV/AIDS patients. Descriptive statistics was used to present the data in tables, figures and pie chart.

Results: Majority of the HIV/AIDS patients who had been taking CPT were adults (95.9%), female (61.2%), married (43.7%), Orthodox Christian (54.3%), and attended primary school (40.1%). At the initiation of CPT, most of the patients were at WHO clinical stage III (40.8%). The major comorbid illnesses identified were tuberculosis and pneumocystis-jiroveci pneumonia. Initially, majority of the patients were at CD₄ count of less than 350 cells/mm³ (n = 504, 90.6%). Greater proportion of patients started CPT prior to initiating antiretroviral therapy (ART). Most of the patients took CPT for greater than 6 months. The primary reasons for premature discontinuation of CPT were CD4 greater than 350 cells/mm³, severe sulfa allergy and first trimester of pregnancy. Generally, the use of cotrimoxazole prophylaxis was consistent with the WHO guideline for indication to start (n = 519, 93.3%) and dose (n = 552, 99.28%), despite the presence of contraindication in 6.65% patients.

Conclusion: In reference to the WHO guideline, the use of CPT was found to be fully appropriate in nearly two-thirds of HIV/AIDS patients. For the rest patients, inappropriate use of cotrimoxazole was observed based on the WHO criteria for initiation, discontinuation, continuation and dose with rate of discontinuation being the dominant one. Such practice may lead to adverse health outcomes including adverse drug reactions and negative treatment outcome.

Histomorphological changes in the pancreas and kidney and histopathological changes in the liver in male Wistar rats on antiretroviral therapy and melatonin treatment

Combination antiretroviral therapy (cART) has shown to cause inflammation, cellular injury and oxidative stress, whereas melatonin has been successful in reducing these effects. The aim of the study was to determine potential morphometric changes caused by cART in combination with melatonin supplementation in human immunodeficiency virus (HIV)-free rats. Tissue samples (N = 40) of the pancreas, liver and kidney from a control (C/ART-/M-), cART group (C/ART + ), melatonin (C/M + ) and experimental group (ART+/M + ) were collected and stained with haematoxylin and eosin (H&E) and evaluated for histopathology. The pancreata were labelled with anti-insulin and anti-glucagon to determine α- and β-cell regions. Kidneys were stained with periodic acid Schiff (PAS) to measure the area, perimeter, diameter and radius of renal corpuscles, glomeruli and proximal convoluted tubules (PCTs). Blood tests were conducted to determine hepatotoxicity. No significant changes in histopathology were seen. Melatonin stimulated pancreatic islet abundance, as the number of islets per mm² was significantly higher in the C/M+ than in the C/ART-/M- and ART+/M+. Parameters of the renal corpuscle, glomeruli, renal space and PCTs were significantly lower in the C/ART+ compared to the other groups, thus cART may have caused tubular dysfunction or cellular damage. A significant increase in serum haemoglobin was observed in the C/ART+ compared to the C/ART-, which showed cART increases serum haemoglobin in the absence of immune deficiency. Serum lipids were significantly decreased in the C/M+ compared to the C/ART-, possibly due to the effect of melatonin on the decrease of lipolysis, decreasing effect on cholesterol absorption and stimulation of lipoprotein lipase (LPL) activity. In conclusion, we have demonstrated that melatonin stimulated α-cell production, increased the number of pancreatic islets and caused a decrease in total lipids, whereas cART increased serum haemoglobin and decreased various parameters of the nephron in an HIV-free rat model, suggestive of tubular dysfunction.

Inhibitors of HIV-1 Attachment: The Discovery and Development of Temsavir and its Prodrug Fostemsavir

Human immunodeficiency virus-1 (HIV-1) infection currently requires lifelong therapy with drugs that are used in combination to control viremia. The indole-3-glyoxamide 6 was discovered as an inhibitor of HIV-1 infectivity using a phenotypic screen and derivatives of this compound were found to interfere with the HIV-1 entry process by stabilizing a conformation of the virus gp120 protein not recognized by the host cell CD4 receptor. An extensive optimization program led to the identification of temsavir (31), which exhibited an improved antiviral and pharmacokinetic profile compared to 6 and was explored in phase 3 clinical trials as the phosphonooxymethyl derivative fostemsavir (35), a prodrug designed to address dissolution- and solubility-limited absorption issues. In this drug annotation, we summarize the structure-activity and structure-liability studies leading to the discovery of 31 and the clinical studies conducted with 35 that entailed the development of an extended release formulation suitable for phase 3 clinical trials.

Model Linking Plasma and Intracellular Tenofovir/Emtricitabine with Deoxynucleoside Triphosphates

The coformulation of the nucleos(t)ide analogs (NA) tenofovir (TFV) disoproxil fumarate (TDF) and emtricitabine (FTC) is approved for HIV-infection treatment and prevention. Plasma TFV and FTC undergo complicated hybrid processes to form, accumulate, and retain as their active intracellular anabolites: TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP). Such complexities manifest in nonlinear intracellular pharmacokinetics (PK). In target cells, TFV-DP/FTC-TP compete with endogenous deoxynucleoside triphosphates (dNTP) at the active site of HIV reverse transcriptase, underscoring the importance of analog:dNTP ratios for antiviral efficacy. However, NA such as TFV and FTC have the potential to disturb the dNTP pool, which could augment or reduce their efficacies. We conducted a pharmacokinetics-pharmacodynamics (PKPD) study among forty subjects receiving daily TDF/FTC (300 mg/200 mg) from the first-dose to pharmacological intracellular steady-state (30 days). TFV/FTC in plasma, TFV-DP/FTC-TP and dNTPs in peripheral blood mononuclear cells (PBMC) were quantified using validated LC/MS/MS methodologies. Concentration-time data were analyzed using nonlinear mixed effects modeling (NONMEM). Formations and the accumulation of intracellular TFV-DP/FTC-TP was driven by plasma TFV/FTC, which was described by a hybrid of first-order formation and saturation. An indirect response link model described the interplay between TFV-DP/FTC-TP and the dNTP pool change. The EC₅₀ (interindividual variability, (%CV)) of TFV-DP and FTC-TP on the inhibition of deoxyadenosine triphosphate (dATP) and deoxycytidine triphosphate (dCTP) production were 1020 fmol/10⁶ cells (130%) and 44.4 pmol/10⁶ cells (82.5%), resulting in (90% prediction interval) 11% (0.45%, 53%) and 14% (2.6%, 35%) reductions. Model simulations of analog:dNTP molar ratios using IPERGAY dosing suggested that FTC significantly contributes to the protective effect of preexposure prophylaxis (PrEP). Simulation-based intracellular operational multiple dosing half-lives of TFV-DP and FTC-TP were 6.7 days and 33 hours. This model described the formation of intracellular TFV-DP/FTC-TP and the interaction with dNTPs, and can be used to simulate analog:dNTP time course for various dosing strategies.

Challenges in oral drug delivery of antiretrovirals and the innovative strategies to overcome them

Development of novel drug delivery systems (DDS) represents a promising opportunity to overcome the various bottlenecks associated with the chronic antiretroviral (ARV) therapy of the human immunodeficiency virus (HIV) infection. Oral drug delivery is the most convenient and simplest route of drug administration that involves the swallowing of a pharmaceutical compound with the intention of releasing it into the gastrointestinal tract. In oral delivery, drugs can be formulated in such a way that they are protected from digestive enzymes, acids, etc. and released in different regions of the small intestine and/or the colon. Not surprisingly, with the exception of the subcutaneous enfuvirtide, all the marketed ARVs are administered orally. However, conventional (marketed) and innovative (under investigation) oral delivery systems must overcome numerous challenges, including the acidic gastric environment, and the poor aqueous solubility and physicochemical instability of many of the approved ARVs. In addition, the mucus barrier can prevent penetration and subsequent absorption of the released drug, a phenomenon that leads to lower oral bioavailability and therapeutic concentration in plasma. Moreover, the frequent administration of the cocktail (ARVs are administered at least once a day) favors treatment interruption. To improve the oral performance of ARVs, the design and development of more efficient oral drug delivery systems are called for. The present review highlights various innovative research strategies adopted to overcome the limitations of the present treatment regimens and to enhance the efficacy of the oral ARV therapy in HIV.

Rare emergence of drug resistance in HIV-1 treatment-naïve patients after 48 weeks of treatment with elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide

Tenofovir alafenamide (TAF), a novel prodrug of the NtRTI tenofovir (TFV), delivers TFV-diphosphate (TFV-DP) to target cells more efficiently than the current prodrug, tenofovir disoproxil fumarate (TDF), with a 90% reduction in TFV plasma exposure. TAF, within the fixed dose combination of elvitegravir /cobicistat / emtricitabine (FTC)/TAF (E/C/F/TAF), has been evaluated in one Phase 2 and two Phase 3 randomized, double-blinded studies in HIV-infected treatment-naive patients, comparing E/C/F/TAF to E/C/F/TDF. In these studies, the TAF-containing group demonstrated non-inferior efficacy to the TDF-containing comparator group with 91.9% of E/C/F/TAF patients having <50 copies/mL of HIV-1 RNA at week 48. An integrated resistance analysis across these three studies was conducted, including HIV-1 genotypic analysis at screening, and genotypic/phenotypic analysis for patients with HIV-1 RNA>400 copies/mL at virologic failure. Pre-existing primary resistance-associated mutations (RAMs) were observed at screening among the 1903 randomized and treated patients: 7.5% had NRTI-RAMs, 18.2% had NNRTI-RAMs, and 3.4% had primary PI-RAMs. Pre-treatment RAMs did not influence treatment response at Week 48. In the E/C/F/TAF group, resistance development was rare; seven patients (0.7%, 7/978) developed NRTI-RAMs, five of whom (0.5%, 5/978) also developed primary INSTI-RAMs. In the E/C/F/TDF group, resistance development was also rare; seven patients (0.8%, 7/925) developed NRTI-RAMs, four of whom (0.4%, 4/925) also developed primary INSTI-RAMs. An additional analysis by deep sequencing in virologic failures revealed minimal differences compared to population sequencing. Overall, resistance development was rare in E/C/F/TAF-treated patients, and the pattern of emergent mutations was similar to E/C/F/TDF.

Switching from a two-tablet regimen of tenofovir/emtricitabine and efavirenz to a one-tablet regimen may affect patients' perceptions and drug management

OBJECTIVES

Simplification of antiretroviral therapy enhances a patient's adherence but a new formulation could also lead to new adverse events and changes in daily routine. This study compared medication adherence, tolerance and satisfaction among subjects switching from a two-tablet tenofovir/emtricitabine/efavirenz regimen to a one-tablet regimen.

METHODS

Clinical and sociodemographic data were collected and three surveys were administered at month 0 (=switch), and then 1 and 4-6 months after the switch: the Beliefs about Medicines Questionnaire, the HIV-symptom index questionnaire, the Short HIV Treatment Satisfaction Questionnaire, the Swiss HIV Cohort Study (SHCS) two-item adherence questionnaire, and a questionnaire on daily combination antiretroviral therapy (cART) management. Medication adherence of a subgroup of subjects was routinely monitored using an electronic device (MEMS(™) ).

RESULTS

Eighty-eight subjects gave informed consent to participate in the study. The subjects' back-switch rate was 7% (six of 88). Subjects who did not back-switch preferred the one-tablet regimen (median = 2; IQR = 1.3-2.5; on a -3 to 3 scale), but no change in adherence was found (10 of 46 nonadherent subjects; P = 1.00). The perception of treatment necessity score decreased (P = 0.004), the efavirenz blood level increased (14%; P = 0.04), and association/dissociation of cART with food intake evolved (P = 0.01) after the switch. Subjects listed equivalent numbers of symptoms during the three visits.

CONCLUSIONS

The one-tablet regimen was preferred but the number of back-switches was not negligible. The perception of treatment necessity score decreased with the simplification of the regimen from a two-tablet to a one-tablet formulation, which could negatively impact adherence. Switching is a sensitive time in a patient's treatment life and professionals should pay particular attention to patient's perceptions of treatment during such a transition.

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.

Meta-Analysis of Studies Comparing Single and Multi-Tablet Fixed Dose Combination HIV Treatment Regimens

Availability of a single source review of once-daily fixed-dose single tablet regimen (STR) and multiple tablet fixed-dose regimen (MTR) would optimally inform healthcare providers and policy makers involved in the management of population with human immunodeficiency virus (HIV).We conducted a meta-analysis of published literature to compare patient adherence, clinical, and cost outcomes of STR to MTR.Published literature in English between 2005 and 2014 was searched using Embase, PubMed (Medline in-process), and ClinicalTrials.Gov databases. Two-level screening was undertaken by 2 independent researchers to finalize articles for evidence synthesis. Adherence, efficacy, safety, tolerability, healthcare resource use (HRU), and costs were assessed comparing STR to MTR. A random-effects meta-analysis was performed and heterogeneity examined using meta-regression.Thirty-five articles were identified for qualitative evidence synthesis, of which 9 had quantifiable data for meta-analysis (4 randomized controlled trials and 5 observational studies). Patients on STR were significantly more adherent when compared to patients on MTR of any frequency (odds ratio [OR]: 2.37 [95% CI: 1.68, 3.35], P < 0.001; 4 studies), twice-daily MTR (OR: 2.53 [95% CI: 1.13, 5.66], P = 0.02; 2 studies), and once-daily MTR (OR: 1.81 [95% CI: 1.15, 2.84], P = 0.01; 2 studies). The relative risk (RR) for viral load suppression at 48 weeks was higher (RR: 1.09 [95% CI: 1.04, 1.15], P = .0003; 3 studies) while RR of grade 3 to 4 laboratory abnormalities was lower among patients on STR (RR: 0.68 [95% CI: 0.49, 0.94], P = 0.02; 2 studies). Changes in CD4 count at 48 weeks, any severe adverse events (SAEs), grade 3 to 4 AEs, mortality, and tolerability were found comparable between STR and MTR. Several studies reported significant reduction in HRU and costs among STR group versus MTR.Study depicted comparable tolerability, safety (All-SAE and Grade 3-4 AE), and mortality and fewer Grade 3 to 4 lab abnormalities and better viral load suppression and adherence among patients on FDC-containing STR versus MTR; literature depicted favorable HRU and costs for STRs.These findings may help decision makers especially in resource-poor settings to plan for optimal HIV disease management when the choice of both STRs and MTRs are available.

Molecular dynamics and density functional studies on the metabolic selectivity of antipsychotic thioridazine by cytochrome P450 2D6: Connection with crystallographic and metabolic results

CYP2D6, a cytochrome P450 isoform, significantly contributes to the metabolism of many clinically important drugs. Thioridazine (THD) is one of the phenothiazine-type antipsychotics, which exhibit dopamine D2 antagonistic activity. THD shows characteristic metabolic profiles compared to other phenothiazine-type antipsychotics such as chlorpromazine. The sulfur atom attached to the phenothiazine ring is preferentially oxidized mainly by CYP2D6, that is, the 2-sulfoxide is a major metabolite, and interestingly this metabolite shows more potent activity against dopamine D2 receptors than THD. On the other hand, the formation of this metabolite causes many serious problems for its clinical use. Wójcikowski et al. (Drug Metab. Dispos. 2006, 34, 471) reported a kinetic study of THD formed by CYP2D6. Recently, Wang et al. (J. Biol. Chem. 2012, 287, 10834 and J. Biol. Chem. 2015, 290, 5092) revealed the crystallographic structure of THD with CYP2D6. In the current study, the binding and reaction mechanisms at the atomic and electronic levels were computationally examined based on the assumption as to whether or not the different crystallographic binding poses correspond to the different metabolites. The binding and oxidative reaction steps in the whole metabolic process were investigated using molecular dynamics and density functional theory calculations, respectively. The current study demonstrated the essential importance of the orientation of the substrate in the reaction center of CYP2D6 for the metabolic reaction.

Drug-Drug Interactions Among Hepatitis C Virus (HCV) and Human Immunodeficiency Virus (HIV) Medications

One-fourth of individuals diagnosed with the human immunodeficiency virus concomitantly have the hepatitis C virus infection. Since the discovery of highly active antiretroviral therapy, liver complications have become the leading cause of morbidity and mortality in HIV-HCV coinfected individuals. Optimal treatment in this patient population is critical, as coinfection has been linked to deterioration of both disease states. The objective of this review article is to highlight the current literature on drug-drug interactions between HIV and HCV treatments. The management of the treatment of coinfection patients has been covered extensively in numerous other publications.

Efficacy of tenofovir and efavirenz in combination with lamivudine or emtricitabine in antiretroviral-naive patients in Europe

BACKGROUND

The combination of tenofovir and efavirenz with either lamivudine or emtricitabine (TELE) has proved to be highly effective in clinical trials for first-line treatment of HIV-1 infection. However, limited data are available on its efficacy in routine clinical practice.

METHODS

A multicentre cohort study was performed in therapy-naive patients initiating ART with TELE before July 2009. Efficacy was studied using ITT (missing or switch = failure) and on-treatment (OT) analyses. Genotypic susceptibility scores (GSSs) were determined using the Stanford HIVdb algorithm.

RESULTS

Efficacy analysis of 1608 patients showed virological suppression to <50 copies/mL at 48 weeks in 91.5% (OT) and 70.6% (ITT). Almost a quarter of all patients (22.9%) had discontinued TELE at week 48, mainly due to CNS toxicity. Virological failure within 48 weeks was rarely observed (3.3%, n = 53). In multilevel, multivariate analysis, infection with subtype B (P = 0.011), baseline CD4 count <200 cells/mm³ (P < 0.001), GSS <3 (P = 0.002) and use of lamivudine (P < 0.001) were associated with a higher risk of virological failure. After exclusion of patients using co-formulated compounds, virological failure was still more often observed with lamivudine. Following virological failure, three-quarters of patients switched to a PI-based regimen with GSS <3. After 1 year of second-line therapy, viral load was suppressed to <50 copies/mL in 73.5% (OT).

CONCLUSIONS

In clinical practice, treatment failure on TELE regimens is relatively frequent due to toxicity. Virological failure is rare and more often observed with lamivudine than with emtricitabine. Following virological failure on TELE, PI-based second-line therapy was often successful despite GSS <3.

Elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate single-tablet regimen (Stribild®): a review of its use in the management of HIV-1 infection in adults

A new single-tablet, fixed-dose formulation consisting of elvitegravir, an HIV-1 integrase strand transfer inhibitor (INSTI); cobicistat, a pharmacokinetic enhancer; emtricitabine, a nucleoside reverse transcriptase inhibitor; and tenofovir disoproxil fumarate (tenofovir DF), a nucleotide reverse transcriptase inhibitor (elvitegravir/cobicistat/emtricitabine/tenofovir DF 150 mg/150 mg/200 mg/300 mg; Stribild®) is available in some countries for the once-daily treatment of HIV-1 infection in antiretroviral therapy-naïve adults. Elvitegravir/cobicistat/emtricitabine/tenofovir DF is the first INSTI-based single-tablet regimen available for the complete initial treatment of adults with HIV-1 infection. In two large, randomized, double-blind, phase III trials, once-daily treatment with elvitegravir/cobicistat/emtricitabine/tenofovir DF was effective in reducing plasma HIV-1 RNA levels to <50 copies/mL at the week 48 assessment and showed virological efficacy noninferior to that of the efavirenz/emtricitabine/tenofovir DF single-tablet regimen or a once-daily regimen of atazanavir plus ritonavir (ritonavir-boosted atazanavir) plus the fixed-dose combination of emtricitabine/tenofovir DF. Elvitegravir/cobicistat/emtricitabine/tenofovir DF also showed durable efficacy in terms of achieving sustained suppression of HIV-1 RNA levels to <50 copies/mL for up to 144 weeks in both of the phase III trials. Elvitegravir/cobicistat/emtricitabine/tenofovir DF is an important addition to the group of simplified once-daily single-tablet regimens currently available for the effective treatment of HIV-1 infection in antiretroviral therapy-naïve patients and is among the preferred regimens recommended for use as initial treatment. It offers advantages over more complex multiple-tablet regimens that may impair treatment adherence, which is fundamental to the successful management of HIV-1 infection.

Effectiveness of antiretroviral therapy in individuals who for economic reasons were switched from a once-daily single-tablet regimen to a triple-tablet regimen

BACKGROUND

To assess the impact on virological outcomes of a switch from branded single-tablet regimen (STR) including tenofovir, efavirenz, and emtricitabine (STR-TEE) to generic triple-tablet regimen (TTR), including tenofovir, efavirenz, and lamivudine (TTR-TEL), which was implemented on April 1, 2011 to obtain economic savings.

METHODS AND FINDINGS

From the Capital Region of Denmark (covering two-thirds of the Danish HIV patients), we included combination antiretroviral therapy (cART)-naive patients who administered STR-TEE from April 1, 2010 to March 31, 2011 (n = 111) or TTR-TEL from April 1, 2011 to March 31, 2012 (n = 56) and cART-experienced HIV patients who were on STR-TEE from April 1, 2010 (n = 356) or were switched from STR-TEE to TTR-TEL after April 1, 2011 (n = 512). We estimated the fraction with detectable HIV-RNA, development of the 184V/I resistance mutations, and time to switch of cART. Approximately 96.2% of cART-experienced patients on STR-TEE were shifted to TTR-TEL after April 1, 2011. For the naive STR-TEE and TTR-TEL patients, the fractions with detectable HIV-RNA at week 48 were 7.0% and 8.3% and for the cART experienced 4.0% and 4.4%, respectively. The 184V/I resistance mutation was detected in 1 cART-experienced patient on TTR-TEL with virological failure. The risk of switch to a new cART regimen was slightly increased in the cART-experienced population (difference in 1-year risk: 1.5%; 95% confidence interval: -2.4% to 5.4%).

CONCLUSIONS

In settings comparable with the Danish health care system, the estimated economic savings from a switch from STR-TEE to TTR-TEL can be realized with negligible short-term risk of adverse outcomes.

Vitamin D deficiency aggravates nephrotoxicity, hypertension and dyslipidemia caused by tenofovir: role of oxidative stress and renin-angiotensin system

Vitamin D deficiency (VDD) is prevalent among HIV-infected individuals. Vitamin D has been associated with renal and cardiovascular diseases because of its effects on oxidative stress, lipid metabolism and renin-angiotensin-aldosterone system (RAAS). Tenofovir disoproxil fumarate (TDF), a widely used component of antiretroviral regimens for HIV treatment, can induce renal injury. The aim of this study was to investigate the effects of VDD on TDF-induced nephrotoxicity. Wistar rats were divided into four groups: control, receiving a standard diet for 60 days; VDD, receiving a vitamin D-free diet for 60 days; TDF, receiving a standard diet for 60 days with the addition of TDF (50 mg/kg food) for the last 30 days; and VDD+TDF receiving a vitamin D-free diet for 60 days with the addition of TDF for the last 30 days. TDF led to impaired renal function, hyperphosphaturia, hypophosphatemia, hypertension and increased renal vascular resistance due to downregulation of the sodium-phosphorus cotransporter and upregulation of angiotensin II and AT1 receptor. TDF also increased oxidative stress, as evidenced by higher TBARS and lower GSH levels, and induced dyslipidemia. Association of TDF and VDD aggravated renovascular effects and TDF-induced nephrotoxicity due to changes in the redox state and involvement of RAAS.

Single-Tablet Regimens in HIV Therapy

Combined antiretroviral therapy (cART) has evolved considerably over the past decades leading to a better control of human immunodeficiency virus replication. Recently, regimens have evolved so as to simplify dosing frequency and reduce pill burden to improve adherence. Several national and international guidelines suggest antiretroviral (ARV) regimen simplification as a method of improving adherence. Decreased cART adherence has been associated with both patient-related factors and regimen-related factors. Adherence rates are statistically higher when simpler, once-daily (OD) regimens are combined with smaller daily regimen pill burdens. The avoidance of selective non-adherence, where a patient takes part of a regimen but not the full regimen, is a further potential benefit offered by single-tablet regimens (STRs). Simplification of cART has been associated with a better quality of life (QoL). Although tempered by other factors, better adherence, higher QoL and patients' preferences are all key points which might combine to assure long-lasting efficacy and durability of cART. All studies underlined the favorable tolerability profile of newer STRs. Three STRs are currently available. Tenofovir (TDF) plus emtricitabine (FTC)/efavirenz (EFV) was the first OD complete ARV regimen available as a STR. TDF plus FTC/rilpivirine is a second-generation STR. The most recently approved STR, TDF plus FTC/cobicistat/elvitegravir, is the first non-nucleoside reverse transcriptase inhibitor-based STR. All of them have shown excellent efficacy; safety and tolerability have been improved by more recent formulations. Several other STRs are anticipated both combining completely different drugs, abacavir (ABC) plus lamivudine (3TC)/dolutegravir, utilizing innovative formulations of older drugs, tenofovir alafenamide fumarate, or taking advance of bioequivalent drugs, lamivudine (3TC) plus ABC/EFV. The future challenge would be to develop completely alternative STRs (including for example protease inhibitors or new molecules) to extend the advantages of simplicity to heavily pre-treated individuals.

Antiretroviral treatment in HIV-1 infected pediatric patients: focus on efavirenz

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI), used for the treatment of human immunodeficiency virus (HIV)-1 infection. Approved by the US Food and Drug Administration in 1998, its indication was recently extended to include children as young as 3 months of age. The World Health Organization and many national guidelines consider efavirenz to be the preferred NNRTI for first-line treatment of children over the age of 3 years. Clinical outcomes of patients on three-drug antiretroviral regimens which include efavirenz are as good as or better than those for patients on all other currently approved HIV medications. Efavirenz is dosed once daily and has pediatric-friendly formulations. It is usually well tolerated, with central nervous system side effects being of greatest concern. Efavirenz increases the risk of neural tube defects in nonhuman primates and therefore its use during the first trimester of pregnancy is limited in some settings. With minimal interactions with antituberculous drugs, efavirenz is preferred for use among patients with HIV/tuberculosis coinfection. Efavirenz can be rendered inactive by a single point mutation in the reverse transcriptase enzyme. Newer NNRTI drugs such as etravirine, not yet approved for use in children under the age of 6 years, may maintain their activity following development of efavirenz resistance. This review highlights key points from the existing literature regarding the use of efavirenz in children and suggests directions for future investigation.

Single-tablet regimens in HIV: does it really make a difference?

OBJECTIVES

Review of the available data on the currently available single-tablet regimens (STRs), from the analysis of efficacy and safety to the key points of value in terms of adherence, quality of life and pharmacoeconomic evaluation.

METHODS

For this narrative review, literature searches have been performed in PubMed, IndexRevMed and Cochrane, using the search terms HIV, single-tablet, one-pill, single dose, fixed-dose, and STR. These have been reviewed and complemented with the most recent publications of interest.

RESULTS

Fixed-dose combinations are a significant advance in antiretroviral treatment simplification, contributing to an increase in compliance with complex chronic therapies, thus improving patients' quality of life. Reducing the number of pills and daily doses is associated with higher adherence and better quality of life. As a fixed-dose combination tablet given once daily, EFV/FTC/TDF was the first available STR combining efficacy, tolerability and convenience, with the simplest dosing schedule and smallest numbers of pills of any ART combination therapy. The RPV/FTC/TDF is a next-generation NNRTI-based STR, a once daily complete ART regimen for the treatment of HIV-1 infection. Recently the combination of EVG/COBI/FTC/TDF was also approved by the European Commission, and is the first integrase inhibitor-based STR. Receiving antiretroviral therapy as once daily STR is associated with both clinical and economic benefits, which confirms previous research.

CONCLUSIONS

The associated benefits of STRs provide a valid strategy for the treatment of HIV-infected patients.

Direct monthly highly active antiretroviral therapy supply – a method to increase patient's adherence and outcome. Experience of one AIDS centre in Israel

In Israel, antiretroviral therapy (ART) is available (at local pharmacies) without cost. Nevertheless, poor adherence, especially of immigrants from Africa, leads to a high rate of treatment failures. Our study looked whether direct monthly ART supply in our AIDS centre has an effect on adherence and outcome. A total of 385 HIV (clade C) immigrants from Africa that were treated with ART for >2 years prior to the initiation of the study were evaluated. During the first 2 years, ART medications were supplied by local pharmacies. Thereafter (next 2 years), all patients received medications, monthly at our centre. Adherence, immunological (CD4) and virological (VL) outcome at the end of the two study periods were determined. At baseline, only 75% of the patients attended more than 90% of scheduled visits with 57% treatment adherence. Virological failure (VL >40 copies/ml) was observed in 53% of the patients. As a result of our intervention (2 years of direct monthly ART supply), visits and treatment adherence significantly increased (90% and 84%, respectively; p < 0.001). Concomitantly, virological failure rate significantly dropped to 28% ( p < 0.001). Direct monthly supply of ART is a relatively low-cost mode to improve patient's adherence and immunological/virological outcomes.

The impact of neurobehavioral features on medication adherence in HIV: evidence from longitudinal models

Effective antiretroviral therapy has led to substantial improvements in health-related outcomes among individuals with HIV. Despite advances in HIV pharmacotherapy, suboptimal medication adherence remains a significant barrier to successful treatment. Although several factors have been associated with medication adherence in the extant literature, study assessing the effects of some of the neurobehavioral features specific to HIV has been limited. Moreover, although there is a growing body of literature measuring medication adherence in HIV prospectively, few employ advanced statistical methodologies suited to handle advanced models with multiple predictors that would strengthen our understanding of medication adherence trajectories in HIV. This study sought to integrate traditionally assessed predictors of medication adherence with neurobehavioral features of HIV in a longitudinal study of medication adherence to combined antiretroviral therapy (cART). The current study used multilevel modeling to examine a wide arrangement of categories of factors - demographic, medication related, psychosocial, and neurobehavioral - on medication adherence. The sample consisted of 235 HIV+ individuals whose medication adherence was monitored over the course of six months using electronic monitoring devices. After controlling for the effects of demographic, medication, and psychosocial factors, neurobehavioral features added predictive validity to the model. In the final model, simultaneously controlling for the effects of each of the predictors within all the categories, age, self-efficacy, executive functioning, apathy, and frequency of stimulant use emerged as unique individual predictors of average medication adherence across the 6-month study. Self-efficacy and irritability predicted changes in medication adherence over time. Adherence behavior is multidetermined. Adequate assessment of these factors, combined with timely intervention, appears to be warranted in order to boost adherence rates.

Characterization of peripheral and mucosal immune responses in rhesus macaques on long-term tenofovir and emtricitabine combination antiretroviral therapy

BACKGROUND

The goal of antiretroviral therapy (ART) is to suppress virus replication to limit immune system damage. Some have proposed combining ART with immune therapies to boost antiviral immunity. For this to be successful, ART must not impair physiological immune function.

METHODS

We studied the impact of ART (tenofovir and emtricitabine) on systemic and mucosal immunity in uninfected and simian immunodeficiency (SIV)-infected Chinese rhesus macaques. Subcutaneous ART was initiated 2 weeks after tonsillar inoculation with SIVmac239.

RESULTS

There was no evidence of immune dysregulation as a result of ART in either infected or uninfected animals. Early virus-induced alterations in circulating immune cell populations (decreased central memory T cells and myeloid dendritic cells) were detected, but normalized shortly after ART initiation. ART-treated animals showed marginal SIV-specific T-cell responses during treatment, which increased after ART discontinuation. Elevated expression of CXCL10 in oral, rectal, and blood samples and APOBEC3G mRNA in oral and rectal tissues was observed during acute infection and was down regulated after starting ART. ART did not impact the ability of the animals to respond to tonsillar application of polyICLC with increased CXCL10 expression in oral fluids and CD80 expression on blood myeloid dendritic cells.

CONCLUSION

Early initiation of ART prevented virus-induced damage and did not impede mucosal or systemic immune functions.

Benzoxazole and benzothiazole amides as novel pharmacokinetic enhancers of HIV protease inhibitors

A new class of benzoxazole and benzothiazole amide derivatives exhibiting potent CYP3A4 inhibiting properties was identified. Extensive lead optimization was aimed at improving the CYP3A4 inhibitory properties as well as overall ADME profile of these amide derivatives. This led to the identification of thiazol-5-ylmethyl (2S,3R)-4-(2-(ethyl(methyl)amino)-N-isobutylbenzo[d]oxazole-6-carboxamido)-3-hydroxy-1-phenylbutan-2-ylcarbamate (C1) as a lead candidate for this class. This compound together with structurally similar analogues demonstrated excellent 'boosting' properties when tested in dogs. These findings warrant further evaluation of their properties in an effort to identify valuable alternatives to Ritonavir as pharmacokinetic enhancers.

Effect of efavirenz on UDP-glucuronosyltransferase 1A1, 1A4, 1A6, and 1A9 activities in human liver microsomes

Efavirenz is a non-nucleoside reverse transcriptase inhibitor used for the treatment of human immunodeficiency virus type 1 infections. Drug interactions of efavirenz have been reported due to in vitro inhibition of CYP2C9, CYP2C19, CYP3A4, and UDP-glucuronosyltransferase 2B7 (UGT2B7) and in vivo CYP3A4 induction. The inhibitory potentials of efavirenz on the enzyme activities of four major UDP-glucuronosyltransferases (UGTs), 1A1, 1A4, 1A6, and 1A9, in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. Efavirenz potently inhibited UGT1A4-mediated trifluoperazine N-glucuronidation and UGT1A9-mediated propofol glucuronidation, with K_i values of 2.0 and 9.4 μM, respectively. [I]/K_i ratios of efavirenz for trifluoperazine N-glucuronidation and propofol glucuronidation were 6.5 and 1.37, respectively. Efavirenz also moderately inhibited UGT1A1-mediated 17β-estradiol 3-glucuronidation, with a K_i value of 40.3 μM, but did not inhibit UGT1A6-mediated 1-naphthol glucuronidation. Those in vitro results suggest that efavirenz should be examined for potential pharmacokinetic drug interactions in vivo due to strong inhibition of UGT1A4 and UGT1A9.

[HIV infection]

The skin can be an indicator of decreased immunocompetence. Dermatological markers include new and extensive seborrheic eczema, psoriasis without a family history, widespread herpes zoster in young adults, oral hairy leucoplakia and mollusca in adults. In these cases an HIV test should be offered. During the last 15 years the clinical picture of HIV has changed dramatically. Almost every year new drugs with better efficacy, lower pill burden and less side effects have been approved. Life expectancy is close to normal in western countries. In spite of better treatment options, prevention is the key to stop the worldwide epidemic. Awareness campaigns have to account for the synergies between HIV and other sexually transmitted diseases. This poses a great challenge for dermatovenereology.

Comparative manufacture and cell-based delivery of antiretroviral nanoformulations

Nanoformulations of crystalline indinavir, ritonavir, atazanavir, and efavirenz were manufactured by wet milling, homogenization or sonication with a variety of excipients. The chemical, biological, immune, virological, and toxicological properties of these formulations were compared using an established monocyte-derived macrophage scoring indicator system. Measurements of drug uptake, retention, release, and antiretroviral activity demonstrated differences amongst preparation methods. Interestingly, for drug cell targeting and antiretroviral responses the most significant difference among the particles was the drug itself. We posit that the choice of drug and formulation composition may ultimately affect clinical utility.

Antiviral interactions of combinations of highly potent 2,4(1H,3H)-pyrimidinedione congeners and other anti-HIV agents

Structure-activity relationship evaluation of seventy-four 2,4(1H,3H)-pyrimidinedione derivatives identified seven lead compounds based on anti-HIV-1 potency, extended range of action to include HIV-2, virus entry inhibition, reverse transcriptase inhibition, and lack of cytotoxicity to human cells. The selected pyrimidinedione congeners are highly active inhibitors of HIV-1 with EC(50) values ranging from 0.6 to 2 nM in CEM-SS cells infected with laboratory derived viruses, 11-20 nM in fresh human PBMCs infected with subtype B (HT/92/599) virus, and 2-7 nM in PBMCs infected with the clinical subtype C (ZA/97/003) virus. Combination antiviral assays were performed using the laboratory adapted RF strain of HIV-1 in CEM-SS cells and with a clade B and C low passage clinical isolate in fresh human peripheral mononuclear cells and the compound interactions were analyzed using MacSynergy II. The seven pyrimidinedione compounds resulted in additive to synergistic interactions in combination with entry and fusion inhibitors, nonnucleoside and nucleoside reverse transcriptase inhibitors, and the protease inhibitors. No evidence of antagonistic antiviral activity or synergistic cytotoxicity was detected with the combinations of compounds tested. The dual mechanism of action of the pyrimidinediones resulting in inhibition of both virus entry and reverse transcription suggests excellent potential of these lead pyrimidinediones as candidates for combination therapy with other approved HIV inhibitors of varying mechanism of action.

Nephrotoxicity of HAART

Highly active antiretroviral therapy (HAART) and other medical therapies for HIV-related infections have been associated with toxicities. Antiretroviral therapy can contribute to renal dysfunction directly by inducing acute tubular necrosis, acute interstitial nephritis, crystal nephropathy, and renal tubular disorders or indirectly via drug interactions. With the increase in HAART use, clinicians must screen patients for the development of kidney disease especially if the regimen employed increases risk of kidney injury. It is also important that patients with chronic kidney disease (CKD) are not denied the best combinations, especially since most drugs can be adjusted based on the estimated GFR. Early detection of risk factors, systematic screening for chronic causes of CKD, and appropriate referrals for kidney disease management should be advocated for improved patient care. The interaction between immunosuppressive therapy and HAART in patients with kidney transplants and the recent endorsement of tenofovir/emtricitabine by the Centers for Disease Control (CDC) for preexposure prophylaxis bring a new dimension for nephrotoxicity vigilance. This paper summarizes the common antiretroviral drugs associated with nephrotoxicity with particular emphasis on tenofovir and protease inhibitors, their risk factors, and management as well as prevention strategies.

[Characteristics of antiretroviral drugs]

As of November 2010, a total of 22 antiretroviral agents are marketed in Spain. These agents are divided into 6 classes according to their mechanism of action: 1) nucleos(t)ide reverse transcriptase inhibitors (NRTI) (abacavir, didanosine, emtricitabine, stavudine, lamivudine, zidovudine, and tenofovir), 2) non-nucleoside reverse transcriptase inhibitors (NNRTI) (efavirenz, etravirine, and nevirapine), 3) protease inhibitors (PI) (atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, tipranavir), 4) entry inhibitors (enfuvirtide), 5) coreceptor CCR5 inhibitors (maraviroc), and 6) integrase inhibitors (raltegravir). All 22 agents are indicated for the treatment of HIV-1 infection in combination with other antiretroviral drugs. Most have also proven to be active against HIV-2 (except the NNRTIs, enfuvirtide, and maraviroc) and some are active against hepatitis B virus (lamivudine, emtricitabine, and tenofovir). The present article reviews the main characteristics of the different antiretroviral agents and classes, namely, commercial presentations, paediatric and adult dosages, dose adjustments in renal and hepatic insufficiency, pharmacokinetics and interactions, mechanism of action, treatment indications, resistance, adverse effects, and safety during pregnancy and breastfeeding. Some of the characteristics of antiretrovirals are class-specific and common to other agents of the same class, and others are individual and different from those of other drugs in the same class. Knowledge of these characteristics enables us to prepare efficacious therapeutic regimens according to the specific requirements of the patient (tolerability, simplicity, adaptability to lifestyle) and clinical setting (naive, simplification, rescue, resistance).