New antiretroviral drugs: a review of the efficacy, safety, pharmacokinetics, and resistance profile of tipranavir, darunavir, etravirine, rilpivirine, maraviroc, and raltegravir

Drug-drug interactions between gender-affirming hormone therapy and antiretrovirals for treatment/prevention of HIV

Transgender persons face a greater burden of HIV compared to cisgender counterparts. Concerns around drug-drug interactions (DDIs) have been cited as reasons for lower engagement in HIV care and lower pre-exposure prophylaxis (PrEP) uptake among transgender populations. It is therefore imperative for hormone therapy, PrEP and antiretroviral therapy providers to understand the DDI potential between these therapies. Studies of tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) PrEP with feminizing hormone therapies (FHTs) show reduced plasma tenofovir concentrations, but intracellular concentrations of tenofovir-diphosphate are not reduced. Efficacy of PrEP is expected to be maintained despite this interaction. Masculinizing hormone therapies have no effect on tenofovir concentrations but may increase FTC to a nonclinically relevant extent. No interactions between FHT and cabotegravir or tenofovir alafenamide have been demonstrated. Administration of TDF/FTC PrEP has no effect on hormone levels in transmen or transwomen. PrEP is expected to be effective and safe in transpersons and should be provided to high-risk individuals regardless of gender affirming hormone use. Enzyme inducing/inhibiting antiretroviral therapy may decrease or increase, respectively, the concentrations of FHT and masculinizing hormone therapy. Unboosted integrase inhibitors or enzyme neutral non-nucleoside reverse transcriptase inhibitors are not expected to affect and are not affected by gender affirming hormones and can be considered in transmen and transwomen. Overlapping toxicities including weight gain, dyslipidaemia, cardiovascular disease and bone density effects should be considered, and antiretroviral modifications can be made to minimize toxicities. Interactions between supportive care medications should be assessed to avoid chelation interactions and hyperkalaemia.

The Phenomenon of Antiretroviral Drug Resistance in the Context of Human Immunodeficiency Virus Treatment: Dynamic and Ever Evolving Subject Matter

Human immunodeficiency virus (HIV) is a significant global health issue that affects a substantial number of individuals across the globe, with a total of 39 million individuals living with HIV/AIDS. ART has resulted in a reduction in HIV-related mortality. Nevertheless, the issue of medication resistance is a significant obstacle in the management of HIV/AIDS. The unique genetic composition of HIV enables it to undergo rapid mutations and adapt, leading to the emergence of drug-resistant forms. The development of drug resistance can be attributed to various circumstances, including noncompliance with treatment regimens, insufficient dosage, interactions between drugs, viral mutations, preexposure prophylactics, and transmission from mother to child. It is therefore essential to comprehend the molecular components of HIV and the mechanisms of antiretroviral medications to devise efficacious treatment options for HIV/AIDS.

Sequential Methods for Di- and Tetrahydro-Pyranone Synthesis Enable Concise Access to Tuscolid δ-Lactone

Two novel tandem sequences for stereoselective synthesis of elaborate hydropyranones are reported. The first one relies on an aldol-lactonization procedure of a chiral enolate with an unprotected aldehyde, while the second one is based on a challenging dienolate ketone addition with concomitant cyclization and substrate controlled reduction. Both approaches proceed with high efficiency and stereoselectivity and enable very short accesses to the authentic pyranone subunit of the complex polyketide tuscolid and will be important to develop a first total synthesis of this structurally unique macrolide and to evaluate the tuscolid-tuscoron rearrangement.

Paired Electrolysis for Decarboxylative Cyanation: 4-CN-Pyridine, a Versatile Nitrile Source

A decarboxylative cyanation of amino acids under paired electrochemical reaction conditions has been developed. 4-CN-pyridine was found to be a new and effective cyanation reagent under catalyst-free conditions. Mechanistic studies support a nucleophilic reaction pathway, and the cyanation protocol can be applied to diverse substrates including N,N-dialkyl aniline and indole derivatives.

Estimating the minimum antiretroviral adherence required for plasma HIV-1 RNA viral load suppression among people living with HIV who use unregulated drugs

OBJECTIVES

Owing to advances in antiretroviral therapy (ART), we re-examined minimum ART adherence levels necessary to achieve sustained HIV-1 viral load (VL) suppression among people with HIV who use drugs (PHIV-PWUD).

DESIGN AND METHODS

We used data from ACCESS, a community-recruited prospective cohort of PHIV-PWUD in Vancouver, Canada. We calculated adherence using the proportion of days of ART dispensed in the year before each VL measurement. We used generalized linear mixed-effects models to identify adherence- and ART regimen-related correlates of VL suppression (<200 copies/ml). We employed probit regression models and generated dose-response curves to estimate the minimum adherence level needed to produce VL suppression in 90% of measures, stratified by regimen and calendar-year.

RESULTS

Among 837 ART-exposed PHIV-PWUD recruited between 1996 and 2017, the overall estimated adherence level necessary to achieve 90% VL suppression was 93% (95% confidence interval [CI]: 90-96). This differed by regimen: 69% (95% CI: 45-92) for integrase inhibitor (INSTI)-, 96% (95% CI: 92-100) for boosted protease inhibitor (bPI)-, and 98% (95% CI: 91-100) for non-nucleoside reverse transcriptase inhibitor-based regimens. In multivariable analysis, INSTI-based regimens were positively associated with VL suppression (vs. bPIs), while un-boosted PIs and other regimens were negatively associated. We observed a decreasing temporal trend of estimated adherence necessary for 90% VL suppression, dropping to 64% (95% CI: 50-77) during 2016-2017.

CONCLUSION

Although high levels of ART adherence were necessary to achieve consistent VL suppression, the minimum necessary adherence levels decreased over time. Overall, INSTI-based regimens performed the best, suggesting that they should be preferentially prescribed to PHIV-PWUD.

Styryl Group, a Friend or Foe in Medicinal Chemistry

The styryl (Ph-CH=CH-R) group is widely represented in medicinally important compounds, including drugs, clinical candidates, and molecular probes as it positively impacts the lipophilicity, oral absorption, and biological activity. The analysis of matched molecular pairs (styryl vs. phenethyl, phenyl, methyl, H) for the biological activity indicates the superiority aspect of styryl compounds. However, the Michael acceptor site in the styryl group makes it amenable to the nucleophilic attack by biological nucleophiles and transformation to the toxic metabolites. One of the downsides of styryl compounds is isomerization that impacts the molecular conformation and directly affects biological activity. The impact of cis-trans isomerism and isosteric replacements on biological activity is exemplified. We also discuss the styryl group-bearing drugs, clinical candidates, and fluorescent probes. Overall, the present review reveals the utility of the styryl group in medicinal chemistry and drug discovery.

Adherence after treatment switch from a multiple tablet antiretroviral regimen to a single tablet antiretroviral regimen

OBJECTIVES

To evaluate adherence after treatment switch from a multiple-tablet regimen (MTR) to a single-tablet regimen (STR) in a national cohort of human immunodeficiency virus (HIV) patients.

METHODS

This retrospective observational cohort, with data spanning January 1, 2000 to March 1, 2019, consisted of HIV infected patients receiving treatment from the Veterans Affairs (VA) health system. Patients were required to have a complete MTR regimen after January 1, 2006 and before December 31, 2018 with at least 60 days of treatment. Medical and pharmacy data were analyzed from the Veterans Affairs Informatics and Computing Infrastructure (VINCI) database. Statistical analyses examined differences in adherence when patients switched to a STR. Patients who switched to a STR were propensity score matched to those who never switched. Descriptive statistics and multivariable linear mixed effects models were utilized to evaluate differences in adherence between MTR and STR treatment in both the matched and unmatched samples.

RESULTS

A total of 5021 patients met the study criteria, 3906 patients in the MTR only cohort and 1115 patients in the switch to STR cohort. The unmatched cohorts were similar in terms of sex, index year, drug/alcohol abuse, and viral load but differed in terms of race, Charlson comorbidity and mental health conditions. The one to one propensity score matched cohort included 2230 patients, 1115 patients in each cohort. Among patients that switched from a MTR to STR, adherence increased on average from 65.9% to 78.12%. We find overall adherence is higher with STRs than with MTR HIV regimens in both the matched and unmatched sample and adherence declines with time for both STR and MTR regimens.

CONCLUSIONS

Switching to a STR is associated with higher adherence compared to MTR among patients with HIV treated with antiretrovirals. However, adherence declines over time with both STR and MTR regimens.

Comorbidity patterns among people living with HIV: a hierarchical clustering approach through integrated electronic health records data in South Carolina

Comorbidity among people living with HIV (PLWH) is understudied although identifying its patterns and socio-demographic predictors would be beneficial for comorbidity management. Using electronic health records (EHR) data, 8,490 PLWH diagnosed between January 2005 and December 2016 in South Carolina were included in the current study. An initial list of 86 individual diagnoses of chronic conditions was extracted in the EHR data. After grouping individual diagnoses with a pathophysiological similarity, 24 diagnosis groups were generated. Hierarchical cluster analysis was applied to these 24 diagnosis groups and yielded four comorbidity clusters: "substance use and mental disorder" (e.g., alcohol use, depression, and illicit drug use); "metabolic disorder" (e.g., hypothyroidism, diabetes, hypertension, and chronic kidney disease); "liver disease and cancer" (e.g., hepatitis B, chronic liver disease, and non-AIDS defining cancers); and "cerebrovascular disease" (e.g., stroke and dementia). Multivariable logistic regression was conducted to investigate the association between socio-demographic factors and multimorbidity (defined as concurrence of ≥ 2 comorbidity clusters). The multivariable logistic regression showed that age, gender, transmission risk, race, initial CD4 counts, and viral load were significant factors associated with multimorbidity. The results suggested the importance of integrated clinical care that addresses the complexities of multiple, and potentially interacting comorbidities among PLWH.

Pharmacokinetic Parameters of HIV-1 Protease Inhibitors

Since the beginning of the HIV epidemic, research has been carried out to control the virus. Understanding the mechanisms of replication has given access to the various classes of drugs that over time have transformed AIDS into a manageable chronic disease. The class of protease inhibitors (PIs) gained notice in anti-retroviral therapy, once it was found that peptidomimetic molecules act by blocking the active catalytic center of the aspartic protease, which is directly related to HIV maturation. However, mutations in enzymatic internal residues are the biggest issue for these drugs, because a small change in biochemical interaction can generate resistance. Low plasma concentrations of PIs favor viral natural selection; high concentrations can inhibit even partially resistant enzymes. Food-drug/drug-drug interactions can decrease the bioavailability of PIs and are related to many side effects. Therefore, this review summarizes the pharmacokinetic properties of current PIs, the changes when pharmacological boosters are used and also lists the major mutations to help understanding of how long the continuous treatment can ensure a low viral load in patients.

Antiretroviral Adherence Level Necessary for HIV Viral Suppression Using Real-World Data

BACKGROUND

A benchmark of near-perfect adherence (≥95%) to antiretroviral therapy (ART) is often cited as necessary for HIV viral suppression. However, given newer, more effective ART medications, the threshold for viral suppression may be lower. We estimated the minimum ART adherence level necessary to achieve viral suppression.

SETTINGS

The Patient-centered HIV Care Model demonstration project.

METHODS

Adherence to ART was calculated using the proportion of days covered measure for the 365-day period before each viral load test result, and grouped into 5 categories (<50%, 50% to <80%, 80% to <85%, 85% to <90%, and ≥90%). Binomial regression analyses were conducted to determine factors associated with viral suppression (HIV RNA <200 copies/mL); demographics, proportion of days covered category, and ART regimen type were explanatory variables. Generalized estimating equations with an exchangeable working correlation matrix accounted for correlation within subjects. In addition, probit regression models were used to estimate adherence levels required to achieve viral suppression in 90% of HIV viral load tests.

RESULTS

The adjusted odds of viral suppression did not differ between persons with an adherence level of 80% to <85% or 85% to <90% and those with an adherence level of ≥90%. In addition, the overall estimated adherence level necessary to achieve viral suppression in 90% of viral load tests was 82% and varied by regimen type; integrase inhibitor- and nonnucleoside reverse transcriptase inhibitor-based regimens achieved 90% viral suppression with adherence levels of 75% and 78%, respectively.

CONCLUSIONS

The ART adherence level necessary to reach HIV viral suppression may be lower than previously thought and may be regimen-dependent.

Maintenance of virologic suppression and improvement in comorbidities after simplification to raltegravir plus boosted darunavir among treatment-experienced HIV-infected patients

The use of two potent, well-tolerated, drugs could permit the maintenance of virologic suppression even in heavily pretreated people living with HIV. In this retrospective, multicenter, simplification study (NCT03348449), we included those patients with virologic suppression who switched to raltegravir (RAL) plus boosted darunavir (b/DRV). Overall, 345 patients (75 females, 25%) were included. Patients were largely pretreated (mean, 9.4 regimens), suppressed for a median of 41.1 months. Fifty patients had ≥1 mutation against DRV. At 96 weeks, the efficacy by intention-to-treat analysis (snapshot) was 73% (95%CI, 68.4–77.8%), but 97.1% (95%CI, 95.4–98.9) excluding changes due to non-virologic reasons, and virologic failure was rare (0.9%; 95%CI, 0.1–1.2%). Median CD4/CD8 ratio increased from 0.59 to 0.62 (p < 0.01), CD4+ cell count by +90 cells/µl (p < 0.01), and mean estimated glomerular filtration rate (eGFR) increased from 85.2 to 88.5 ml/min at 96 weeks, greater for patients receiving tenofovir disoproxil fumarate (eGFR, +3.6 ml/min, p = 0.04; serum phosphate +0.33 mg/dl; p < 0.01). There was a continued and significant improvement in the total cholesterol/high-density lipoprotein-cholesterol ratio. In conclusion, the simplification to a dual regimen with the combination of RAL and b/DRV is associated with maintenance of virologic suppression, even in largely pretreated patients, with improvements in CD4+ cell count, CD4/CD8 ratio, and in renal and lipid parameters.

Multimorbidity Among Persons Living with Human Immunodeficiency Virus in the United States

Background

Age-associated conditions are increasingly common among persons living with human immunodeficiency virus (HIV) (PLWH). A longitudinal investigation of their accrual is needed given their implications on clinical care complexity. We examined trends in the co-occurrence of age-associated conditions among PLWH receiving clinical care, and differences in their prevalence by demographic subgroup.

Methods

This cohort study was nested within the North American AIDS Cohort Collaboration on Research and Design. Participants from HIV outpatient clinics were antiretroviral therapy-exposed PLWH receiving clinical care (ie, ≥1 CD4 count) in the United States during 2000-2009. Multimorbidity was irreversible, defined as having ≥2: hypertension, diabetes mellitus, chronic kidney disease, hypercholesterolemia, end-stage liver disease, or non-AIDS-related cancer. Adjusted prevalence ratios (aPR) and 95% confidence intervals (CIs) comparing demographic subgroups were obtained by Poisson regression with robust error variance, using generalized estimating equations for repeated measures.

Results

Among 22969 adults, 79% were male, 36% were black, and the median baseline age was 40 years (interquartile range, 34-46 years). Between 2000 and 2009, multimorbidity prevalence increased from 8.2% to 22.4% (Ptrend < .001). Adjusting for age, this trend was still significant (P < .001). There was no difference by sex, but blacks were less likely than whites to have multimorbidity (aPR, 0.87; 95% CI, .77-.99). Multimorbidity was the highest among heterosexuals, relative to men who have sex with men (aPR, 1.16; 95% CI, 1.01-1.34). Hypertension and hypercholesterolemia most commonly co-occurred.

Conclusions

Multimorbidity prevalence has increased among PLWH. Comorbidity prevention and multisubspecialty management of increasingly complex healthcare needs will be vital to ensuring that they receive needed care.

Effect of rilpivirine on the pharmacokinetics of methadone in HIV-Infected Chinese patients

Background: The combination of rilpivirine with methadone may result in complex interactions secondary to the induction of oxidative metabolism by rilpivirine. Research design and methods: TMC278IFD4007 was a single-center, prospective, open-label, multiple-dose study with 12 HIV-infected Chinese participants. The objective was to evaluate the potential effect of rilpivirine on the pharmacokinetics of methadone. The participants received a daily dose of 25 mg rilpivirine for 11 days with individualized methadone ranging from 25 to 100 mg. Pharmacokinetic studies of methadone were conducted on day 1 and 11. Opiate withdrawal symptoms were evaluated. Results: A large inter-subject variability was noted in methadone pharmacokinetics. Rilpivirine increased methadone minimum and maximum plasma concentrations (Cmin; Cmax) and area under the plasma concentration-time curve versus methadone alone (least-square mean ratio; 90% confidence interval) by 5% (1.05; 0.46, 2.39), 5% (1.05; 0.73, 1.52), and 6% (0.75; 0.74, 1.50) as measured in S-methadone, and 5% (1.05; 0.50, 2.22), 5% (1.05; 0.74, 1.50), and 5% (1.05; 0.76, 1.46) as measured in R-methadone, respectively. No opioid withdrawal symptoms or methadone dose adjustments were reported. Co-administration was well tolerated without serious adverse effects or discontinuations. Conclusion: Concomitant administration of rilpivirine was unlikely to have significant effects on the pharmacokinetics of methadone.

What is the effect of pill burden on adherence to HIV antiretroviral therapy?

Antiretroviral therapy (ART) is a combination treatment involving three or more antiretroviral agents for patients with HIV. ART has reduced HIV-related morbidity and mortality via single-tablet or multiple-tablet regimens. Single-tablet regimens, with their lower pill burdens, have demonstrated higher adherence rates, improved viral suppression, and reduced resource use compared with multiple-tablet regimens. In addition, select newer ARTs do not require the high levels of adherence for viral load suppression required by older ART formulations.

Survival of HIV-positive patients starting antiretroviral therapy between 1996 and 2013: a collaborative analysis of cohort studies

Background

Health care for people living with HIV has improved substantially in the past two decades. Robust estimates of how these improvements have affected prognosis and life expectancy are of utmost importance to patients, clinicians, and health-care planners. We examined changes in 3 year survival and life expectancy of patients starting combination antiretroviral therapy (ART) between 1996 and 2013.

Methods

We analysed data from 18 European and North American HIV-1 cohorts. Patients (aged ≥16 years) were eligible for this analysis if they had started ART with three or more drugs between 1996 and 2010 and had at least 3 years of potential follow-up. We estimated adjusted (for age, sex, AIDS, risk group, CD4 cell count, and HIV-1 RNA at start of ART) all-cause and cause-specific mortality hazard ratios (HRs) for the first year after ART initiation and the second and third years after ART initiation in four calendar periods (1996–99, 2000–03 [comparator], 2004–07, 2008–10). We estimated life expectancy by calendar period of initiation of ART.

Findings

88 504 patients were included in our analyses, of whom 2106 died during the first year of ART and 2302 died during the second or third year of ART. Patients starting ART in 2008–10 had lower all-cause mortality in the first year after ART initiation than did patients starting ART in 2000–03 (adjusted HR 0·71, 95% CI 0·61–0·83). All-cause mortality in the second and third years after initiation of ART was also lower in patients who started ART in 2008–10 than in those who started in 2000–03 (0·57, 0·49–0·67); this decrease was not fully explained by viral load and CD4 cell count at 1 year. Rates of non-AIDS deaths were lower in patients who started ART in 2008–10 (vs 2000–03) in the first year (0·48, 0·34–0·67) and second and third years (0·29, 0·21–0·40) after initiation of ART. Between 1996 and 2010, life expectancy in 20-year-old patients starting ART increased by about 9 years in women and 10 years in men.

Interpretation

Even in the late ART era, survival during the first 3 years of ART continues to improve, which probably reflects transition to less toxic antiretroviral drugs, improved adherence, prophylactic measures, and management of comorbidity. Prognostic models and life expectancy estimates should be updated to account for these improvements.

Funding

UK Medical Research Council, UK Department for International Development, EU EDCTP2 programme.

Acute Care Management of the HIV-Infected Patient: A Report from the HIV Practice and Research Network of the American College of Clinical Pharmacy

OBJECTIVE

Patients infected with human immunodeficiency virus (HIV) admitted to the hospital have complex antiretroviral therapy (ART) regimens with an increased medication error rate upon admission. This report provides a resource for clinicians managing HIV-infected patients and ART in the inpatient setting.

METHODS

A survey of the authors was conducted to evaluate common issues that arise during an acute hospitalization for HIV-infected patients. After a group consensus, a review of the medical literature was performed to determine the supporting evidence for the following HIV-associated hospital queries: admission/discharge orders, antiretroviral hospital formularies, laboratory monitoring, altered hepatic/renal function, drug-drug interactions (DDIs), enteral administration, and therapeutic drug monitoring.

RESULTS

With any hospital admission for an HIV-infected patient, a specific set of procedures should be followed including a thorough admission medication history and communication with the ambulatory HIV provider to avoid omissions or substitutions in the ART regimen. DDIs are common and should be reviewed at all transitions of care during the hospital admission. ART may be continued if enteral nutrition with a feeding tube is deemed necessary, but the entire regimen should be discontinued if no oral access is available for a prolonged period. Therapeutic drug monitoring is not generally recommended but, if available, should be considered in unique clinical scenarios where antiretroviral pharmacokinetics are difficult to predict. ART may need adjustment if hepatic or renal insufficiency ensues.

CONCLUSIONS

Treatment of hospitalized patients with HIV is highly complex. HIV-infected patients are at high risk for medication errors during various transitions of care. Baseline knowledge of the principles of antiretroviral pharmacotherapy is necessary for clinicians managing acutely ill HIV-infected patients to avoid medication errors, identify DDIs, and correctly dose medications if organ dysfunction arises. Timely ambulatory follow-up is essential to prevent readmissions and facilitate improved transitions of care.

Odds of Viral Suppression by Single-Tablet Regimens, Multiple-Tablet Regimens, and Adherence Level in HIV/AIDS Patients Receiving Antiretroviral Therapy

STUDY OBJECTIVE

To evaluate the odds of achieving viral suppression in human immunodeficiency virus (HIV) patients using antiretroviral therapy as a single-tablet regimen (STR) or multiple-tablet regimen (MTR).

DESIGN

Retrospective cohort study.

DATA SOURCES

South Carolina Medicaid medical and pharmacy paid claims data were obtained from the South Carolina Revenue and Fiscal Affairs Office; laboratory data were obtained from the South Carolina Department of Health and Environmental Control.

PATIENTS

A total of 1536 patients who were dispensed a complete STR (477 patients) or MTR (1059 patients) regimen lasting at least 60 days between January 1, 2006, and December 31, 2013.

MEASUREMENTS AND MAIN RESULTS

The analysis examined adherence levels and regimen type on odds of viral load suppression. Regimen adherence levels (90-94%, 85-89%, 80-84%, and less than 80%) were compared with the gold standard adherence for HIV of 95% or greater. Patients were followed from index date until the earliest date of regimen discontinuation, treatment switch, end of study period, last date of eligibility, or death. Differences in outcomes were evaluated by χ² , Wilcoxon rank sum statistical tests, and multivariate regression models controlling for covariates. For STR regimens we find that, when compared with 95% or greater adherence, there is no statistical difference in the odds of viral suppression with adherence levels greater than or equal to 80%. However, adherence levels greater than or equal to 95% were associated with a greater odds of viral suppression when compared with less than 80% STR adherence (odds ratio [OR] 2.57, Dunnett 95% confidence interval [CI] 1.04-6.32). For MTR regimens, there was no statistical difference in the odds of viral suppression for the adherence level 90-94% compared with the 95% or greater adherence (OR 3.59, Dunnett 95% CI 0.805-16.043). However, the 95% or greater adherence has greater odds of viral suppression compared with all other MTR adherence levels. In addition, no difference was found in the odds of viral suppression between STR and MTR for all adherence levels.

CONCLUSIONS

Compared with 95% or greater adherence, STR regimens achieve viral suppression with adherence levels of 80% or greater, whereas MTR regimens require adherence levels of 90% or greater to achieve viral suppression in South Carolina Medicaid patients with HIV/AIDS.

Mechanism of selective C–H cyanation of 2-phenylpyridine with benzyl nitrile catalyzed by CuBr: a DFT investigation

The mechanism of C–H cyanation of 2-phenylpyridine with 2-phenylacetonitrile catalyzed by the CuBr catalyst was elaborated based on DFT calculations.

Copper(ii)-mediated formation of oxazole-4-carbonitrile from acetophenone and coordinated cyanide anion via a radical coupling

A protocol for the direct synthesis of 4-aryloxazole-5-carbonitrile from acetophenone was first described.

Greater carotid intima media thickness at a younger age in HIV-infected patients compared with reference values for an uninfected cohort

OBJECTIVES

In contrast to the general population, no decline in cardiovascular disease (CVD) has been noted in HIV-infected patients over the last 10 years. We compared the carotid artery intima media thickness (CIMT) of HIV-infected patients to that of age- and gender-matched reference values and determined the relationship between CVD risk factors and CIMT.

METHODS

A total of 292 HIV-infected patients were enrolled in the study. Data collected included vascular screening data, data obtained using a questionnaire, data obtained from laboratory assessments and CIMT measurement. Using linear regression (adjusted for age/gender/known HIV), the association between HIV-specific and classical cardiovascular risk factors and CIMT was evaluated.

RESULTS

The cohort comprised for 91% of male patients, aged 49.4 ± 10.5 years, with a known duration of HIV infection of 8.8 ± 6.7 years. The mean with standard deviation (mean ± SD) CIMT was 0.77 ± 0.19 mm, compared with 0.58 ± 0.05 mm in the controls. A steeper increase of CIMT per age was seen in the HIV-infected patients. A significant relationship between CIMT and hypertension, diabetes mellitus, smoking, systolic blood pressure, HbA1c (glycated hemoglobin) and ankle brachial index was found. Of the HIV-specific variables, only a relationship between CIMT and length of cART use and between CIMT and (inversely) current cART use was seen.

CONCLUSIONS

A greater CIMT was found in HIV-infected patients compared with controls. In contrast to HIV-specific variables, classical CVD risk factors were associated with a greater CIMT and should therefore be the focus of preventive measures.

Antiretroviral drug toxicity in relation to pharmacokinetics, metabolic profile and pharmacogenetics

INTRODUCTION

Besides therapeutic effectiveness, drug tolerability is a key issue for treatments that must be taken indefinitely. Given the high prevalence of toxicity in HIV therapy, the factors implicated in drug-induced morbidities should be identified in order to improve the safety, tolerability and adherence to the treatments. Current approaches have focused almost exclusively on parent drug concentrations; whereas recent evidence suggests that drug metabolites resulting from complex genetic and environmental influences can also contribute to treatment outcome. Pharmacogenetic variations have shown to play a relevant role in the variability observed in antiretroviral drug exposure, clinical response and sometimes toxicity. The integration of pharmacokinetic, pharmacogenetic and metabolic determinants will more probably address current therapeutic needs in patients.

AREAS COVERED

This review offers a concise description of three classes of antiretroviral drugs. The review looks at the metabolic profile of these drugs and gives a comprehensive summary of the existing literature on the influence of pharmacogenetics on their pharmacokinetics and metabolic pathways, and the associated drug or metabolite toxicity.

EXPERT OPINION

Due to the high prevalence of toxicity and the related risk of low adherence to the treatments, association of kinetic, genetic and metabolic markers predictive of therapeutic or toxicity outcomes could represent a more complete approach for optimizing antiretroviral therapy.

Natural history and treatment of HCV/HIV coinfection: Is it time to change paradigms?

Evidence over the past decades have shown that HIV/HCV coinfected patients did not respond as well to HCV therapy as HCV mono-infected patients. However, these paradigms are being recently reassessed with the improvements of care for HIV and HCV patients. This article reviews these original paradigms and how the new data is impacting upon them. Treatment efficacy now appears comparable for HIV/HCV coinfected and HCV mono-infected patients, while liver fibrosis progression is increasingly similar in optimally managed patients. Additional importance of therapy is directed to drug-drug interactions and the impact of HCV reinfection, as well as the possibility of transmitted drug resistance.

Adherence and HIV RNA Suppression in the Current Era of Highly Active Antiretroviral Therapy

BACKGROUND

We examined trends in adherence to highly active antiretroviral therapy (HAART) and HIV RNA suppression and estimated the minimum cutoff of adherence to newer HAART formulations needed for HIV RNA suppression by regimen type.

METHODS

We used Veterans Affairs pharmacy dispensing data from the Veterans Aging Cohort Study Virtual Cohort between October 2000 and September 2010 and defined adherence as the duration of time the patient had the medications available, relative to the total number of days between refills for all antiretrovirals in a year. Temporal trends in adherence and viral load suppression were examined by the patient's most frequently used HAART regimen in the year. The minimum needed adherence was defined as the level at which the odds of suppression was not significantly different than that observed with ≥ 95% adherence using repeated-measures logistic regression.

RESULTS

A total of 21,865 HAART users contributed 82,217 person-years of follow-up. There was a significant increase (P(trend) < 0.001) in the proportion virally suppressed even among those with <95% adherence (2001: 38% to 2010: 84%), and the trend was similar when restricting to their first HAART regimen. For nonnucleoside reverse transcriptase inhibitor multi-pill users, the odds of suppression did not differ for 85%-89% adherence compared to those with ≥ 95% adherence [odds ratios: 0.82 (0.64-1.04)], but for protease inhibitor users, the odds of suppression significantly differed if adherence levels were <95% compared to ≥ 95% adherence.

CONCLUSIONS

Although all HIV-infected persons should be instructed to achieve perfect adherence, concerns of slightly lower adherence should not hinder prescribing new HAART regimens early in HIV infection.

Drug use patterns associated with risk of non-adherence to antiretroviral therapy among HIV-positive illicit drug users in a Canadian setting: a longitudinal analysis

BACKGROUND

Among people living with HIV/AIDS, illicit drug use is a risk for sub-optimal treatment outcomes. However, few studies have examined the relative contributions of different patterns of drug use on adherence to antiretroviral therapy (ART). We sought to estimate the effect of different types of illicit drug use on adherence in a setting of universal free HIV/AIDS treatment and care.

METHODS

Using data from ongoing prospective cohorts of HIV-positive illicit drug users linked to comprehensive pharmacy dispensation records in Vancouver, Canada, we examined factors associated with ≥95% prescription refill adherence using generalized estimating equations (GEE) logistic regression.

RESULTS

Between 1996 and 2013, 692 ART-exposed individuals were followed for a median of 42.7 months (Interquartile Range: 29.1-71.7). In multivariable GEE analyses, heroin injection (Adjusted Odds Ratio [AOR] = 0.75, 95% Confidence Interval [CI]: 0.66-0.85) as well as cocaine injection (AOR = 0.80, 95% CI: 0.72-0.90) were associated with lower likelihoods of optimal adherence. Methadone maintenance therapy (AOR = 1.88, 95% CI: 1.68-2.11) was associated with a greater likelihood of adherence.

CONCLUSIONS

Periods of heroin and cocaine injection appeared to have the most deleterious impact upon antiretroviral adherence. The findings point to the need for improved access to treatment for heroin use disorder, particularly methadone, and highlight the need to identify strategies to support ART adherence among cocaine injectors.

Level of adherence and HIV RNA suppression in the current era of highly active antiretroviral therapy (HAART)

The need to achieve ≥95 % adherence to HAART for treatment effectiveness may be a barrier for universal initiation at early stages of HIV. Using longitudinal data collected from 2006 to 2011 from cohort studies of MSM (MACS) and IDUs (ALIVE study), we estimated the minimum adherence needed to achieve HIV RNA suppression (<50 copies/mL), defined as the level at which at least 80 % were virally suppressed, and the odds of suppression was not significantly different than that observed with ≥95 % adherence. In the MACS, ≥80 % suppression was observed with 80-84 % adherence and the odds ratio for suppression (vs. ≥95 % adherence) was 1.43 (0.61, 3.33). In the ALIVE study where <35 % were on newer drugs, only 71.4 % were suppressed among those who reported ≥95 % adherence. Although IDUs on older HAART regimens may need to be ≥95 % adherent, concerns related to non-adherence may be less of a barrier to initiation of modern HAART regimens.

Newly approved integrase inhibitors for clinical treatment of AIDS

The current therapy for the human immunodeficiency virus (HIV) infection is a combination of anti-HIV drugs targeting multiple steps of virus replication. The drugs for the acquired immunodeficiency syndrome (AIDS) treatment include reverse transcriptase inhibitors, protease inhibitors, fusion inhibitors, co-receptor inhibitor and the newly added integrase inhibitors. Raltegravir, elvitegravir and dolutegravir are the three Food and Drug Administration (FDA) approved integrase strand transfer inhibitors for clinical treatment of HIV infection. The addition of these integrase inhibitors benefits a lot to HIV infected patients. Although it is only seven years from the first integrase inhibitor, which was approved by FDA to now, multiple drug resistant HIV strains have emerged in clinical treatment. Most of the drug resistant virus strains are against raltegravir. Some are cross-resistant to elvitegravir. Dolutegravir is effective for suppression of the current drug resistant viruses. A number of clinical trials have been performed on the three integrase inhibitors. In this study, the application of the three integrase inhibitors in clinical treatment and the findings of drug resistance to integrase inhibitors are summarized.

Two-year Carcinogenicity Study in Rats with a Nonnucleoside Reverse Transcriptase Inhibitor

Administration of lersivirine, a nonnucleotide reverse transcriptase inhibitor, daily by oral gavage to Sprague-Dawley rats for up to 2 yr was associated with decreased survival, decreased body weights, and an increase in neoplasms and related proliferative lesions in the liver, thyroid, kidney, and urinary bladder. Thyroid follicular adenoma and carcinoma, the associated thyroid follicular hypertrophy/hyperplasia, hepatocellular adenoma/adenocarcinoma, altered cell foci, and hepatocellular hypertrophy were consistent with lersivirine-related induction of hepatic microsomal enzymes. Renal tubular adenoma and renal tubular hyperplasia were attributed to the lersivirine-related exacerbation of chronic progressive nephropathy (CPN), while urinary bladder hyperplasia and transitional cell carcinoma in the renal pelvis and urinary bladder were attributed to urinary calculi. Renal tubular neoplasms associated with increased incidence and severity of CPN, neoplasms of transitional epithelium attributed to crystalluria, and thyroid follicular and hepatocellular neoplasms related to hepatic enzyme induction have low relevance for human risk assessment.

Reduction of the HIV protease inhibitor-induced ER stress and inflammatory response by raltegravir in macrophages

BACKGROUND

HIV protease inhibitor (PI), the core component of highly active antiretroviral treatment (HAART) for HIV infection, has been implicated in HAART-associated cardiovascular complications. Our previous studies have demonstrated that activation of endoplasmic reticulum (ER) stress is linked to HIV PI-induced inflammation and foam cell formation in macrophages. Raltegravir is a first-in-its-class HIV integrase inhibitor, the newest class of anti-HIV agents. We have recently reported that raltegravir has less hepatic toxicity and could prevent HIV PI-induced dysregulation of hepatic lipid metabolism by inhibiting ER stress. However, little information is available as to whether raltegravir would also prevent HIV PI-induced inflammatory response and foam cell formation in macrophages.

METHODOLOGY AND PRINCIPAL FINDINGS

In this study, we examined the effect of raltegravir on ER stress activation and lipid accumulation in cultured mouse macrophages (J774A.1), primary mouse macrophages, and human THP-1-derived macrophages, and further determined whether the combination of raltegravir with existing HIV PIs would potentially exacerbate or prevent the previously observed activation of inflammatory response and foam cell formation. The results indicated that raltegravir did not induce ER stress and inflammatory response in macrophages. Even more interestingly, HIV PI-induced ER stress, oxidative stress, inflammatory response and foam cell formation were significantly reduced by raltegravir. High performance liquid chromatography (HPLC) analysis further demonstrated that raltegravir did not affect the uptake of HIV PIs in macrophages.

CONCLUSION AND SIGNIFICANCE

Raltegravir could prevent HIV PI-induced inflammatory response and foam cell formation by inhibiting ER stress. These results suggest that incorporation of this HIV integrase inhibitor may reduce the cardiovascular complications associated with current HAART.

Molecular basis of human immunodeficiency virus type 1 drug resistance: overview and recent developments

The introduction of potent combination therapies in the mid-90s had a tremendous effect on AIDS mortality. However, drug resistance has been a major factor contributing to antiretroviral therapy failure. Currently, there are 26 drugs approved for treating human immunodeficiency virus (HIV) infections, although some of them are no longer prescribed. Most of the available antiretroviral drugs target HIV genome replication (i.e. reverse transcriptase inhibitors) and viral maturation (i.e. viral protease inhibitors). Other drugs in clinical use include a viral coreceptor antagonist (maraviroc), a fusion inhibitor (enfuvirtide) and two viral integrase inhibitors (raltegravir and elvitegravir). Elvitegravir and the nonnucleoside reverse transcriptase inhibitor rilpivirine have been the most recent additions to the antiretroviral drug armamentarium. An overview of the molecular mechanisms involved in antiretroviral drug resistance and the role of drug resistance-associated mutations was previously presented (Menéndez-Arias, L., 2010. Molecular basis of human immunodeficiency virus drug resistance: an update. Antiviral Res. 85, 210-231). This article provides now an updated review that covers currently approved drugs, new experimental agents (e.g. neutralizing antibodies) and selected drugs in preclinical or early clinical development (e.g. experimental integrase inhibitors). Special attention is dedicated to recent research on resistance to reverse transcriptase and integrase inhibitors. In addition, recently discovered interactions between HIV and host proteins and novel strategies to block HIV assembly or viral entry emerge as promising alternatives for the development of effective antiretroviral treatments.

Sequence quality analysis tool for HIV type 1 protease and reverse transcriptase

Access to antiretroviral therapy is increasing globally and drug resistance evolution is anticipated. Currently, protease (PR) and reverse transcriptase (RT) sequence generation is increasing, including the use of in-house sequencing assays, and quality assessment prior to sequence analysis is essential. We created a computational HIV PR/RT Sequence Quality Analysis Tool (SQUAT) that runs in the R statistical environment. Sequence quality thresholds are calculated from a large dataset (46,802 PR and 44,432 RT sequences) from the published literature ( http://hivdb.Stanford.edu ). Nucleic acid sequences are read into SQUAT, identified, aligned, and translated. Nucleic acid sequences are flagged if with >five 1-2-base insertions; >one 3-base insertion; >one deletion; >six PR or >18 RT ambiguous bases; >three consecutive PR or >four RT nucleic acid mutations; >zero stop codons; >three PR or >six RT ambiguous amino acids; >three consecutive PR or >four RT amino acid mutations; >zero unique amino acids; or <0.5% or >15% genetic distance from another submitted sequence. Thresholds are user modifiable. SQUAT output includes a summary report with detailed comments for troubleshooting of flagged sequences, histograms of pairwise genetic distances, neighbor joining phylogenetic trees, and aligned nucleic and amino acid sequences. SQUAT is a stand-alone, free, web-independent tool to ensure use of high-quality HIV PR/RT sequences in interpretation and reporting of drug resistance, while increasing awareness and expertise and facilitating troubleshooting of potentially problematic sequences.

New option for management of HIV-1 infection in treatment-naive patients: once-daily, fixed-dose combination of rilpivirine-emtricitabine-tenofovir

Fixed-dose combination tablets have become an important therapy option for patients infected with the human immunodeficiency virus. Fixed-dose combination rilpivirine-tenofovir-emtricitabine is a recently approved therapy option that has been extensively studied within the treatment-naïve population. When compared with efavirenz-based therapy, improved tolerability with rilpivirine-based therapy was balanced by higher rates of virologic failure to provide similar overall efficacy rates within the intention-to-treat analysis. As a result, providers will need to balance the potential for improved tolerability with fixed-dose combination rilpivirine-tenofovir-emtricitabine against a higher potential for virologic failure, particularly among patients with baseline viral loads above 100,000 copies/mL. Current treatment guidelines have recommended that fixed-dose combination rilpivirine-tenofovir-emtricitabine be an alternative therapy option for treatment-naïve patients and advise caution in those patients with high viral loads at baseline. Similar to other non-nucleoside reverse transcriptase inhibitor-based regimens, there are a number of drug interaction concerns with fixed-dose combination rilpivirine-tenofovir-emtricitabine that will necessitate monitoring and, in some cases, appropriate management. Additionally, the emergence of drug resistance to fixed-dose combination rilpivirine-tenofovir-emtricitabine has been well documented in clinical studies and close attention will be necessary in order to protect current and future therapy options. Overall, fixed-dose combination rilpivirine-tenofovir-emtricitabine is poised to provide an important therapy option for patients when appropriately applied.

F18, a novel small-molecule nonnucleoside reverse transcriptase inhibitor, inhibits HIV-1 replication using distinct binding motifs as demonstrated by resistance selection and docking analysis

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are one of the key components of antiretroviral therapy drug regimen against human immunodeficiency virus type 1 (HIV-1) replication. We previously described a newly synthesized small molecule, 10-chloromethyl-11-demethyl-12-oxo-calanolide A (F18), a (+)-calanolide A analog, as a novel anti-HIV-1 NNRTI (H. Xue et al., J. Med. Chem. 53:1397-1401, 2010). Here, we further investigated its antiviral range, drug resistance profile, and underlying mechanism of action. F18 consistently displayed potent activity against primary HIV-1 isolates, including various subtypes of group M, circulating recombinant form (CRF) 01_AE, and laboratory-adapted drug-resistant viruses. Moreover, F18 displayed distinct profiles against 17 NNRTI-resistant pseudoviruses, with an excellent potency especially against one of the most prevalent strains with the Y181C mutation (50% effective concentration, 1.0 nM), which was in stark contrast to the extensively used NNRTIs nevirapine and efavirenz. Moreover, we induced F18-resistant viruses by in vitro serial passages and found that the mutation L100I appeared to be the dominant contributor to F18 resistance, further suggesting a binding motif different from that of nevirapine and efavirenz. F18 was nonantagonistic when used in combination with other antiretrovirals against both wild-type and drug-resistant viruses in infected peripheral blood mononuclear cells. Interestingly, F18 displayed a highly synergistic antiviral effect with nevirapine against nevirapine-resistant virus (Y181C). Furthermore, in silico docking analysis suggested that F18 may bind to the HIV-1 reverse transcriptase differently from other NNRTIs. This study presents F18 as a new potential drug for clinical use and also presents a new mechanism-based design for future NNRTI.

Antiretroviral drug interactions: overview of interactions involving new and investigational agents and the role of therapeutic drug monitoring for management

Antiretrovirals are prone to drug-drug and drug-food interactions that can result in subtherapeutic or supratherapeutic concentrations. Interactions between antiretrovirals and medications for other diseases are common due to shared metabolism through cytochrome P450 (CYP450) and uridine diphosphate glucuronosyltransferase (UGT) enzymes and transport by membrane proteins (e.g., p-glycoprotein, organic anion-transporting polypeptide). The clinical significance of antiretroviral drug interactions is reviewed, with a focus on new and investigational agents. An overview of the mechanistic basis for drug interactions and the effect of individual antiretrovirals on CYP450 and UGT isoforms are provided. Interactions between antiretrovirals and medications for other co-morbidities are summarized. The role of therapeutic drug monitoring in the detection and management of antiretroviral drug interactions is also briefly discussed.