Impact of obesity on antiretroviral pharmacokinetics and immuno-virological response in HIV-infected patients: a case-control study

Therapeutic drug monitoring of antiretroviral therapy: current progresses and future directions

INTRODUCTION

The treatment of HIV infection has been revolutionized in recent years thanks to the advent of dual antiretroviral regimens, administered orally or as long-acting injectable formulations. Here, we provide an update on the usefulness of therapeutic drug monitoring (TDM) of antiretroviral drugs to optimize the management of people with HIV (PWH) in the current scenario.

AREAS COVERED

A MEDLINE PubMed search for articles published between January 2014 and January 2024 was completed matching the terms HIV, antiretrovirals and TDM. Moreover, additional studies were identified from the reference list of retrieved articles.

EXPERT OPINION

Available antiretroviral treatments achieve a response rate of 90%-95%, making the routine TDM of antiretroviral drugs of limited clinical value. However, there are still some important applications of TDM in selected clinical conditions, such as assessing patient compliance or suspected drug-drug interactions (DDIs). Indeed, we are increasingly having to deal with polypharmacy and DDIs in the context of an aging patient with comorbidities that may potentially alter the pharmacokinetics of antiretroviral drugs. Finally, the role of pharmacogenetics, which is closely related to TDM, in influencing both the disposition of antiretrovirals and the course of DDIs should also be considered.

Antiretroviral Drug Exposure and Response in Obese and Morbidly Obese People With Human Immunodeficiency Virus (HIV): A Study Combining Modelling and Swiss HIV Cohort Data

BACKGROUND

Obesity is increasingly prevalent among people with HIV (PWH) and can possibly result in suboptimal antiretroviral drug (ARV) exposure and response. However, this has not been thoroughly evaluated given that obese PWH are underrepresented in clinical trials. We performed virtual trials using physiologically based pharmacokinetic (PBPK) modelling combined with observed clinical data to provide ARV dosing guidance in obese individuals.

METHODS

Each trial included a cohort of virtual adults with a body mass index (BMI) between 18.5 and 60 kg/m2. Therapeutic drug-monitoring data from the Swiss HIV Cohort Study (SHCS) were used to verify the predictive performance of the model. Subsequently, the model was applied to predict the pharmacokinetics of ARVs for different obesity classes. The association between ARV plasma concentrations and virological response was investigated in obese and nonobese individuals.

RESULTS

The PBPK model predicted an average reduction in ARV exposure of ∼20% and trough concentrations of ∼6% in obese (BMI ≥30 kg/m2) compared with nonobese (BMI: 18.5-25 kg/m2) individuals, consistent with observed clinical data. Etravirine and rilpivirine were the most impacted, especially in individuals with BMI >40 kg/m2 whose trough concentrations were below the clinical target threshold. Obese PWH in the SHCS did not have a higher rate of unsuppressed viral load than nonobese PWH.

CONCLUSIONS

The concentrations of ARVs are modestly reduced in obese individuals, with no negative impact on the virological response. Our data provide reassurance that standard doses of ARVs are suitable in obese PWH, including those who gained substantial weight with some of the first-line ARVs.

Effect of obesity on dolutegravir exposure in Black Southern African adults living with HIV

Background

Dolutegravir, a component of the preferred first-line antiretroviral therapy regimen, has been associated with increased weight gain. South Africa has a high prevalence of obesity, especially among women. Understanding dolutegravir exposure in patients with obesity is important for dose optimisation.

Objectives

We compared the pharmacokinetic parameters of dolutegravir in Southern African adults living with HIV with and without obesity.

Method

Blood samples were collected at various time points over a 24 h-period for dolutegravir assays. Non-compartmental analysis was conducted and geometric mean ratios (GMRs), with 90% confidence intervals (CIs), were generated to compare dolutegravir pharmacokinetic parameters between the groups. Regression analyses to assess predictors of dolutegravir exposure were done.

Results

Forty participants were enrolled, 26 were women and 10 had obesity. Dolutegravir area under the concentration-time curve to 24-h and the maximum concentrations were not statistically significantly lower in participants with obesity: GMR 0.91 (90% CI: 0.71-1.16) and GMR 0.86 (90% CI: 0.68-1.07), respectively. In a multivariate linear regression analysis adjusting for age, gender, body mass index, creatinine clearance and randomisation arm (tenofovir alafenamide or tenofovir disoproxil fumarate), a unit increase in body mass index was associated with 1.2% lower dolutegravir area under the concentration-time curve to 24-h (P = 0.035).

Conclusion

Dolutegravir exposure was marginally lower in participants with obesity, but this is not clinically significant. Our findings suggest that there is no need to dose adjust dolutegravir in people with obesity.

Evaluating Possible Mechanisms Linking Obesity to COVID-19: a Narrative Review

Currently, pneumonia caused by the coronavirus disease 2019 (COVID-19) is a pandemic. To date, there is no specific antiviral treatment for the disease, and universal access to the vaccine is a serious challenge. Some observational studies have shown that COVID-19 is more common in countries with a high prevalence of obesity and that people with COVID-19 have a higher body mass index. In these studies, obesity increased the risk of disease, as well as its severity and mortality. This study aimed to review the mechanisms that link obesity to COVID-19.

Contribution of Adipose Tissue to the Chronic Immune Activation and Inflammation Associated With HIV Infection and Its Treatment

White adipose tissue (AT) contributes significantly to inflammation – especially in the context of obesity. Several of AT’s intrinsic features favor its key role in local and systemic inflammation: (i) large distribution throughout the body, (ii) major endocrine activity, and (iii) presence of metabolic and immune cells in close proximity. In obesity, the concomitant pro-inflammatory signals produced by immune cells, adipocytes and adipose stem cells help to drive local inflammation in a vicious circle. Although the secretion of adipokines by AT is a prime contributor to systemic inflammation, the lipotoxicity associated with AT dysfunction might also be involved and could affect distant organs. In HIV-infected patients, the AT is targeted by both HIV infection and antiretroviral therapy (ART). During the primary phase of infection, the virus targets AT directly (by infecting AT CD4 T cells) and indirectly (via viral protein release, inflammatory signals, and gut disruption). The initiation of ART drastically changes the picture: ART reduces viral load, restores (at least partially) the CD4 T cell count, and dampens inflammatory processes on the whole-body level but also within the AT. However, ART induces AT dysfunction and metabolic side effects, which are highly dependent on the individual molecules and the combination used. First generation thymidine reverse transcriptase inhibitors predominantly target mitochondrial DNA and induce oxidative stress and adipocyte death. Protease inhibitors predominantly affect metabolic pathways (affecting adipogenesis and adipocyte homeostasis) resulting in insulin resistance. Recently marketed integrase strand transfer inhibitors induce both adipocyte adipogenesis, hypertrophy and fibrosis. It is challenging to distinguish between the respective effects of viral persistence, persistent immune defects and ART toxicity on the inflammatory profile present in ART-controlled HIV-infected patients. The host metabolic status, the size of the pre-established viral reservoir, the quality of the immune restoration, and the natural ageing with associated comorbidities may mitigate and/or reinforce the contribution of antiretrovirals (ARVs) toxicity to the development of low-grade inflammation in HIV-infected patients. Protecting AT functions appears highly relevant in ART-controlled HIV-infected patients. It requires lifestyle habits improvement in the absence of effective anti-inflammatory treatment. Besides, reducing ART toxicities remains a crucial therapeutic goal.

Weight and Body Mass Index Change After Switching to Integrase Inhibitors or Tenofovir Alafenamide Among Women Living with HIV

Weight and body mass index (BMI) change was assessed among women after switch to integrase inhibitors (INSTIs) and/or tenofovir alafenamide (TAF). From 2006 to 2019, 1,458 women living with HIV enrolled in the Women's Interagency HIV Study and on antiretroviral therapy (ART) with ≥1 study visit before and after switching to INSTIs and/or TAF were included. Weight and BMI were compared pre- and postswitch to INSTI (by class and type) and/or TAF using multivariable linear mixed effects models; all models were also stratified by preswitch presence or absence of obesity (BMI ≥30 vs. <30 kg/m2). Mean age preswitch was 47 ± 6 years, 64% were black, mean CD4 = 475 ± 201 cells/mm3, 56% had HIV RNA <200 copies/mL, 36% switched to TAF but not INSTI, 60% to INSTI but not TAF, and 3.5% to TAF+INSTI. Time from pre- to postswitch was 12.8 ± 11.8 months. The INSTI-only group but not TAF groups had small but significant increases in weight and BMI: mean 79.2-80.6 kg and 30.2-30.7 kg/m2, p's < .001, respectively, with congruent findings by INSTI type (p's ≤ .01). In stratified (preswitch BMI) analyses, only nonobese subgroups experienced increases in weight and BMI across all ART treatment groups (p's < .05). Significant, although small-to-medium, increases in weight and BMI occurred among nonobese women who switched to INSTIs and/or TAF over short follow-up. Given long-term health consequences of obesity particularly as a low-grade inflammatory condition, identifying women at highest risk of ART-associated weight gain is imperative.

Intracellular Tenofovir and Emtricitabine Concentrations in Younger and Older Women with HIV Receiving Tenofovir Disoproxil Fumarate/Emtricitabine

The altered immune states of aging and HIV infection may affect intracellular metabolism of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC); increased cellular senescence decreases FTC-triphosphate (FTCtp) concentrations. The effects of age and inflammation on the ratio of intracellular metabolites (IMs; tenofovir diphosphate [TFVdp] and FTCtp) to their endogenous nucleotides (ENs; dATP and dCTP), a potential treatment efficacy marker, were assessed among participants of the Women's Interagency HIV Study (WIHS), who ranged from 25 to 75 years. Samples from women receiving TDF-FTC with viral loads of <200 copies/ml were dichotomized by age at collection into two groups (≤45 years and ≥60 years). IM/EN concentrations were measured in peripheral blood mononuclear cell (PBMC) pellets; interleukin-6 (IL-6) and sCD163 were measured in plasma; senescent CD8⁺ T cells were measured in viable PBMCs. The TFVdp:dATP and FTCtp:dCTP ratios had statistically significantly different distributions in older and younger women (log-rank test, P = 0.0023 and P = 0.032, respectively); in general, IM and EN concentrations were higher in the older women. After adjusting for potential confounders, these findings were not significant. In women aged ≤45 years, TFVdp was negatively associated with IL-6 and sCD163, while FTCtp was positively associated with sCD163 and IL-6 in women aged ≥60 years. Body mass index (BMI) was positively associated with IL-6 in both age groups and negatively associated with TFVdp in women aged ≤45 years. After adjustment, age remained significant for sCD163, while black race, BMI, and renal function remained significant for several IMs and ENs, suggesting that factors associated with aging, but not age itself, govern intracellular TDF-FTC pharmacology.

HIV and antiretroviral therapy-related fat alterations

Early in the HIV epidemic, lipodystrophy, characterized by subcutaneous fat loss (lipoatrophy), with or without central fat accumulation (lipohypertrophy), was recognized as a frequent condition among people living with HIV (PLWH) receiving combination antiretroviral therapy. The subsequent identification of thymidine analogue nucleoside reverse transcriptase inhibitors as the cause of lipoatrophy led to the development of newer antiretroviral agents; however, studies have demonstrated continued abnormalities in fat and/or lipid storage in PLWH treated with newer drugs (including integrase inhibitor-based regimens), with fat gain due to restoration to health in antiretroviral therapy-naive PLWH, which is compounded by the rising rates of obesity. The mechanisms of fat alterations in PLWH are complex, multifactorial and not fully understood, although they are known to result in part from the direct effects of HIV proteins and antiretroviral agents on adipocyte health, genetic factors, increased microbial translocation, changes in the adaptive immune milieu after infection, increased tissue inflammation and accelerated fibrosis. Management includes classical lifestyle alterations with a role for pharmacological therapies and surgery in some patients. Continued fat alterations in PLWH will have an important effect on lifespan, healthspan and quality of life as patients age worldwide, highlighting the need to investigate the critical uncertainties regarding pathophysiology, risk factors and management.

Immunologic and Virologic Outcomes of Obese and Nonobese Incarcerated Adults on Antiretroviral Therapy for HIV Infection

Background:

Obesity is common among patients with HIV. The objective of this study was to characterize response to antiretroviral therapy (ART) in a cohort of obese incarcerated adults compared to a nonobese cohort.

Methods:

A retrospective matched cohort study was conducted in an HIV telemedicine clinic. Patients with body mass index (BMI) >30 kg/m² who received the same ART with >95% adherence for at least 6 months were matched to nonobese patients by age, gender, ART, CD4 count, and viral load at baseline.

Results:

Twenty pairs were included, with an average BMI of 24 kg/m² in the nonobese cohort and 35 kg/m² in the obese cohort. No difference was observed in the proportion of patients who achieved virologic suppression or the change in CD4 count from baseline to 6 to 12 months.

Conclusion:

This study revealed no differences in immunologic recovery or virologic suppression between obese and nonobese patients in an adult correctional population.

Second-line HIV treatment failure in sub-Saharan Africa: A systematic review and meta-analysis

BACKGROUND

Increased second-line antiretroviral therapy (ART) failure rate narrows future options for HIV/AIDS treatment. It has critical implications in resource-limited settings; including sub-Saharan Africa (SSA) where the burden of HIV-infection is immense. Hence, pooled estimate for second-line HIV treatment failure is relevant to suggest valid recommendations that optimize ART outcomes in SSA.

METHODS

We retrieved literature systematically from PUBMED/MEDLINE, EMBASE, CINAHL, Google Scholar, and AJOL. The retrieved studies were screened and assessed for eligibility. We also assessed the eligible studies for their methodological quality using the Joanna Briggs Institute's appraisal checklist. The pooled estimates for second-line HIV treatment failure and its associated factors were determined using STATA, version 15.0 and MEDCALC, version 18.11.3, respectively. We assessed publication bias using Comprehensive Meta-analysis software, version 3. Detailed study protocol for this review/meta-analysis is registered and found on PROSPERO (ID: CRD42018118959).

RESULTS

A total of 33 studies with the overall 18,550 participants and 19,988.45 person-years (PYs) of follow-up were included in the review. The pooled second-line HIV treatment failure rate was 15.0 per 100 PYs (95% CI: 13.0-18.0). It was slightly higher at 12-18 months of follow-up (19.0/100 PYs; 95% CI: 15.0-22.0), in children (19.0/100 PYs; 95% CI: 14.0-23.0) and in southern SSA (18.0/100 PYs; 95% CI: 14.0-23.0). Baseline values (high viral load (OR: 5.67; 95% CI: 13.40-9.45); advanced clinical stage (OR: 3.27; 95% CI: 2.07-5.19); and low CD4 counts (OR: 2.80; 95% CI: 1.83-4.29)) and suboptimal adherence to therapy (OR: 1.92; 95% CI: 1.28-2.86) were the factors associated with increased failure rates.

CONCLUSION

Second-line HIV treatment failure has become highly prevalent in SSA with alarming rates during the 12-18 month period of treatment start; in children; and southern SSA. Therefore, the second-line HIV treatment approach in SSA should critically consider excellent adherence to therapy, aggressive viral load suppression, and rapid immune recovery.