Comparative Clinical Pharmacokinetics and Pharmacodynamics of HIV-1 Integrase Strand Transfer Inhibitors

Dolutegravir-based Antiretroviral Therapy in People With HIV With Solid Organ Transplantation: A Single-arm Pilot Clinical Trial (DTG-SOT)

Background

This study assessed the pharmacokinetic interactions between dolutegravir (DTG)-based antiretroviral therapy (ART) and immunosuppressants in solid organ transplantation (SOT) recipients with HIV and ART safety.

Methods

A phase IV, single-center, open-label, single-arm clinical trial (DTG-SOT, NCT03360682) including adult SOT recipients with HIV conducted between 2017 and 2019. People with HIV with plasma viral load <50 copies/mL during ≥12 months and receiving stable raltegravir-based ART during ≥6 months were switched to tenofovir disoproxil fumarate/emtricitabine or lamivudine/abacavir + DTG and followed up for 48 weeks. Immunosuppressant pharmacokinetic parameters were compared before and 2 weeks after ART switch (primary outcome). Efficacy and safety were analyzed at 48 weeks by intention-to-treat analysis.

Results

Nineteen consecutive participants (median, 57 years; interquartile range, 51-60), mostly liver recipients (63.2%), received DTG/lamivudine/abacavir (63.2%) and DTG + emtricitabine/tenofovir disoproxil fumarate (36.8%). Pharmacokinetic parameters changed, albeit not significantly, before and after ART, for mycophenolic acid (maximum [Cmax] +63%, trough [Cmin] +53%, area under the curve [AUC] +16%; n = 7) and cyclosporine A (Cmax -64%, Cmin +14%, AUC -47%; n = 2), with smaller changes for tacrolimus (Cmax +14%, Cmin -29%, AUC -9%; n = 7). No participants experienced acute rejection or virological failure and CD4+ cell counts and percentages remained unchanged during follow-up. Three (15.8%) discontinued treatment because of adverse events. Estimated glomerular filtration rate decreased (P = 0.0015) and creatinine increased (P = 0.0001) slightly.

Conclusions

DTG-based ART lacked clinically significant drug-drug interactions with tacrolimus and mycophenolic acid. Switching to DTG-based ART was effective in people with HIV SOT recipients. More studies are needed to evaluate DTG safety in this setting.

Twice-Daily Dolutegravir-Based Antiretroviral Therapy With 1 Month of Daily Rifapentine and Isoniazid for Tuberculosis Prevention

BACKGROUND

One month of daily rifapentine + isoniazid (1HP) is an effective, ultrashort option for tuberculosis prevention in people with human immunodeficiency virus (HIV). However, rifapentine may decrease antiretroviral drug concentrations and increase the risk of virologic failure. AIDS Clinical Trials Group A5372 evaluated the effect of 1HP on the pharmacokinetics of twice-daily dolutegravir.

METHODS

A5372 was a multicenter, pharmacokinetic study in people with HIV (≥18 years) already on dolutegravir-containing antiretroviral therapy with HIV RNA <50 copies/mL. Participants received daily rifapentine/isoniazid (600 mg/300 mg) for 28 days as part of 1HP. Dolutegravir was increased to 50 mg twice daily during 1HP, and intensive pharmacokinetic sampling was performed on day 0 (before 1HP) and on the final day of 1HP treatment.

RESULTS

Thirty-two participants (41% female; 66% Black/African; median [Q1, Q3] age, 42 [34, 49] years) were included in the pharmacokinetic analysis; 31 had HIV RNA <50 copies/mL at the end of 1HP dosing. One participant had an HIV RNA of 160 copies/mL at day 28, with HIV RNA <50 copies/mL upon repeat testing on day 42. The median (Q1, Q3) dolutegravir trough concentration was 1751 ng/mL (1195, 2542) on day 0 versus 1987 ng/mL (1331, 2278) on day 28 (day 28:day 0 geometric mean ratio, 1.05 [90% confidence interval, .93-1.2]; P = .43). No serious adverse events were reported.

CONCLUSIONS

Dolutegravir trough concentrations with 50 mg twice-daily dosing during 1HP treatment were greater than those with standard-dose dolutegravir once daily without 1HP. These pharmacokinetic, virologic, and safety data provide support for twice-daily dolutegravir use in combination with 1HP for tuberculosis prevention.

CLINICAL TRIALS REGISTRATION

NCT04272242.

Clinical outcomes of liver transplantation in human immunodeficiency virus/hepatitis B virus coinfected patients in China

BACKGROUND

Highly active antiretroviral therapy (HAART) has been able to improve the immune system function and survival of human immunodeficiency virus (HIV) patients. However, Patients coinfected with HIV and hepatitis B virus (HBV) are more likely to develop end-stage liver disease (ESLD) than those infected with HBV alone. Consequently, liver transplantation is often required for these patients. This study evaluates the outcomes of orthotopic liver transplantation (OLT) of HIV-HBV coinfected patients in China.

METHODS

We conducted a retrospective analysis on all HIV-HBV coinfected patients that underwent OLT from April 1, 2019 to December 31, 2021 and their outcomes were compared to all HBV monoinfected patients undergoing OLT during the same period. Patient outcomes were determined, including cumulative survival, viral load, CD4 T-cell count and postoperative complications.

RESULTS

The median follow-up of HIV recipients was 36 months after OLT (interquartile range 12-39 months). Almost all patients had stable CD4 T-cell count (> 200 copies/ul), undetectable HBV DNA levels, and undetectable HIV RNA load during follow-up. The 1-, 2-, and 3-year posttransplant survival rates were 85.7% for the HIV group (unchanged from 1 to 3 years) versus 82.2%, 81.2%, and 78.8% for the non-HIV group. Cumulative survival among HIV-HBV coinfected recipients was not significantly different from the HBV monoinfected recipients (log-rank test P = 0.692). The percentage of deaths attributed to infection was comparable between the HIV and non-HIV groups (14.3% vs. 9.32%, P = 0.665). Post OLT, there was no significant difference in acute rejection, cytomegalovirus infection, bacteremia, pulmonary infection, acute kidney injury, de novo tumor and vascular and biliary complications.

CONCLUSIONS

Liver transplantation in patients with HIV-HBV coinfection yields excellent outcomes in terms of intermediate- or long-term survival rate and low incidence of postoperative complications in China. These findings suggest that OLT is safe and feasible for HIV-HBV coinfected patients with ESLD.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2300067631), registered 11 January 2023.

Efficacy, safety, and tolerability of dolutegravir-based ART regimen in Durban, South Africa: a cohort study

BACKGROUND

Dolutegravir is an integrase strand transfer inhibitor that has been recommended for use in first-line antiretroviral regimens by the World Health Organisation and is currently being rolled out globally. There has been safety concerns with dolutegravir which has caused concern about its use in the general population. Dolutegravir first-line regimens have been used in South Africa since early 2020. Therefore, the aim of the present study was to assess the efficacy, safety, and tolerability of first-line dolutegravir-based antiretrovirals amongst adults living with HIV in Durban, South Africa.

METHODS

This was a mixed-methods study, which comprised a cross-sectional survey and longitudinal retrospective follow-up of medical records. The study was conducted between October 2020 and January 2022. Data were described using descriptive and summary statistics. Bivariate logistic regression was applied to socio-demographic and clinical variables and crude odds ratios with a 95% confidence interval was calculated. Pearson chi-square tests, paired sample T-tests, and cross-tabulations were performed on selected variables.

RESULTS

A total of 461 participants were enrolled in the study. There was a significant change in immunological outcomes (p < 0.001) after dolutegravir initiation. Furthermore, an assessment of laboratory parameters showed that there was a significant decrease in cholesterol (p < 0.001) and increase in creatinine (p < 0.001) levels. Increased weight was shown by 60.7% of the participants but was not associated with age, gender, CD4 counts, and previous antiretroviral usage. The study found that 43.6% of the participants experienced at least one side-effect. A total of 21.6% and 23.2% of the participants experienced neuropsychiatric and central nervous system side-effects, respectively. In the bivariate analyses, only gender was shown to be associated with side-effects, and only 1.7% of the participants discontinued the study due to side-effects.

CONCLUSION

Our results suggest that dolutegravir is effective, safe, and well tolerated in the study population.

The pathogenesis of obesity in people living with HIV

PURPOSE OF REVIEW

The public health challenge of overweight and obesity increasingly affects people living with HIV (PWH). These effects have also accelerated as the prevalence of antiretroviral therapy (ART) use has increased among PWH. It is therefore also critical that we examine and understand the pathogenesis of obesity among PWH.This review will aim to summarize relevant and recent literature related to the risks of weight gain and obesity associated with HIV disease progression, cardiometabolic disease, and multimorbidity among PWH. Further, we will discuss adipose tissue changes associated with weight gain and obesity and how these changes relate to metabolic complications.

RECENT FINDINGS

Several observational and experimental studies in recent years have evaluated the role of contemporary ART regimens, particularly integrase strand transfer inhibitors (INSTIs) and tenofovir alafenamide (TAF), as contributors to weight gain, obesity, and cardiometabolic disease, though the mechanisms remain unclear. Metabolic dysregulation has also been linked to ectopic fat deposition and alterations in innate and adaptive immune cell populations in adipose tissue that accompany HIV and obesity. These factors continue to contribute to an increasing burden of metabolic diseases in an aging HIV population.

SUMMARY

Obesity accompanies an increasing burden of metabolic disease among PWH, and understanding the role of fat partitioning and HIV and ART-related adipose tissue dysfunction may guide prevention and treatment strategies.

Inhibition of lipid synthesis by the HIV integrase strand transfer inhibitor elvitegravir in primary rat oligodendrocyte cultures

Combined antiretroviral therapy (cART) has greatly decreased mortality and morbidity among persons with HIV; however, neurologic impairments remain prevalent, in particular HIV-associated neurocognitive disorders (HANDs). White matter damage persists in cART-treated persons with HIV and may contribute to neurocognitive dysfunction as the lipid-rich myelin membrane of oligodendrocytes is essential for efficient nerve conduction. Because of the importance of lipids to proper myelination, we examined the regulation of lipid synthesis in oligodendrocyte cultures exposed to the integrase strand transfer inhibitor elvitegravir (EVG), which is administered to persons with HIV as part of their initial regimen. We show that protein levels of genes involved in the fatty acid pathway were reduced, which correlated with greatly diminished de novo levels of fatty acid synthesis. In addition, major regulators of cellular lipid metabolism, the sterol regulatory element-binding proteins (SREBP) 1 and 2, were strikingly altered following exposure to EVG. Impaired oligodendrocyte differentiation manifested as a marked reduction in mature oligodendrocytes. Interestingly, most of these deleterious effects could be prevented by adding serum albumin, a clinically approved neuroprotectant. These new findings, together with our previous study, strengthen the possibility that antiretroviral therapy, at least partially through lipid dysregulation, may contribute to the persistence of white matter changes observed in persons with HIV and that some antiretrovirals may be preferable as life-long therapy.

Preswitch Regimens Influence the Rate of Weight Gain After Switch to Tenofovir Disoproxil Fumarate, Lamivudine, and Dolutegravir (TLD): Study From an East African Cohort

Background

Switching from non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens to dolutegravir (DTG) has been associated with greater weight gain.

Methods

We conducted our analysis using a longitudinal cohort of people with HIV (PWH) in Western Kenya. We evaluated changes in the rate of weight gain among treatment-experienced, virally suppressed PWH who switched from NNRTI to tenofovir disoproxil fumarate, lamivudine, and dolutegravir (TLD). We modeled the weights pre- and postswitch using a 2-phase model with linear trend preswitch and an inverted exponential function postswitch. We estimated an 18-month excess weight gain by comparing the projected weight with that expected using the preswitch rate.

Results

A total of 18 662 individuals were included in our analysis, with 55% switching from efavirenz (EFV) and 45% from nevirapine (NVP). Of the studied individuals, 51% were female, and the median age and body mass index (BMI) were 51 years and 22 kg/m2, respectively. For the overall population, the rate of weight gain increased from 0.47 kg/year preswitch to 0.77 kg/year, with higher increases for females (0.57 kg/year to 0.96 kg/year) than males (0.34 kg/year to 0.62 kg/year). The rate of weight gain for individuals switching from EFV-based regimens significantly increased from 0.57 kg/year preswitch to 1.11 kg/year postswitch but remained stable at 0.35 kg/year preswitch vs 0.32 kg/year postswitch for individuals switching from NVP-based regimens.

Conclusions

Switching from NNRTI-based regimens to TLD is associated with a modest increase in the rate of weight gain, with the preswitch NNRTI being the key determinant of the amount of weight gain experienced postswitch.

Effect of Integrase Strand Transfer Inhibitor Use on Time to HIV Viral Suppression before Delivery

OBJECTIVES

We sought to determine whether pregnant individuals with human immunodeficiency virus (HIV) prescribed integrase strand transfer inhibitor (INSTI) antiretrovirals (ARVs) achieve viral suppression faster than individuals taking non-INSTI regimens and to determine whether there were differences in viral suppression at delivery among INSTI ARVs.

METHODS

This is a retrospective cohort study of pregnant individuals with HIV who delivered a live infant during the study period (January 1, 2009-December 31, 2020). Patients' ARV therapy (ART) was classified as including INSTI or non-INSTI. We compared the proportion of individuals with viral suppression at delivery by group and individual INSTI ARVs using χ2 and Fisher exact tests. A log rank test was used to compare time to viral suppression on ARVs.

RESULTS

During the study period, 168 individuals delivered a live infant. Most of the patients were diagnosed as having HIV before pregnancy and had taken ARVs before conception (76%), but fewer than half had an undetectable viral load at the first antenatal visit (45%). During pregnancy, 46% were prescribed INSTI and 54% were prescribed non-INSTI ARVs. Most had an undetectable HIV RNA viral load at delivery (75% INSTI and 72% non-INSTI, P = 0.7). The time to viral suppression was similar between groups (log rank test P = 0.43). Viral suppression at delivery was similar among INSTI ARVs: raltegravir (53%), elvitegravir (88%), dolutegravir (73%), and bictegravir (88%) (P = 0.13).

CONCLUSIONS

Despite recommendations to prescribe INSTI in pregnancy for rapid viral suppression, we did not find a significant difference in time to viral suppression when pregnant individuals were taking non-INSTI ARVs. We did not find that one INSTI ARV was superior for viral suppression.

A computational overview of integrase strand transfer inhibitors (INSTIs) against emerging and evolving drug-resistant HIV-1 integrase mutants

AIDS (Acquired immunodeficiency syndrome) is one of the chronic and potentially life-threatening epidemics across the world. Hitherto, the non-existence of definitive drugs that could completely cure the Human immunodeficiency virus (HIV) implies an urgent necessity for the discovery of novel anti-HIV agents. Since integration is the most crucial stage in retroviral replication, hindering it can inhibit overall viral transmission. The 5 FDA-approved integrase inhibitors were computationally investigated, especially owing to the rising multiple mutations against their susceptibility. This comparative study will open new possibilities to guide the rational design of novel lead compounds for antiretroviral therapies (ARTs), more specifically the structure-based design of novel Integrase strand transfer inhibitors (INSTIs) that may possess a better resistance profile than present drugs. Further, we have discussed potent anti-HIV natural compounds and their interactions as an alternative approach, recommending the urgent need to tap into the rich vein of indigenous knowledge for reverse pharmacology. Moreover, herein, we discuss existing evidence that might change in the near future.

Adipocyte differentiation of 3T3-L1 cells under tenofovir alafenamide, tenofovir disoproxil fumarate, and integrase strand transfer inhibitors selective challenge: an in-vitro model

OBJECTIVE

Integrase strand transfer inhibitors (INSTIs) are a class of antiretroviral therapy (ART) medications with a good tolerability profile and a high genetic barrier to HIV drug resistance. However, several studies report significant weight gain among persons receiving INSTI-based ART regimens compared with other regimens.

DESIGN

In-vitro model of adipogenesis.

METHODS

We used 3T3-L1 cells to investigate the effects of the nucleoside reverse transcriptase inhibitors (NRTIs) tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), alone or in combination with INSTIs: raltegravir (RAL), elvitegravir (ELV), dolutegravir (DTG), and bictegravir (BIC) on adipose differentiation. To monitor adipocyte differentiation, expression levels of PPARɣ and C/EBPα and the intracellular lipid accumulation by Red Oil staining were used. Furthermore, we evaluated the immunohistochemical expression of ER-TR7, a fibroblastic marker, after INSTIs treatment.

RESULTS

Compared with control, INSTIs were able to increase adipogenesis, especially RAL and ELV. TAF and TDF inhibited adipogenesis alone and in combination with INSTIs. This ability was more evident when TAF was used in combination with DTG and BIC. Finally, INSTIs increased the expression of ER-TR7 compared with control and cells treated with TAF or TDF.

CONCLUSION

Our data support the evidence that in-vitro challenge of 3T3-L1 cells with INSTIs is able to increase adipocytic differentiation and to drive a number of these cells toward the expression of fibroblastic features, with a different degree according to the various drugs used whereas TAF and TDF have an antagonistic role on this phenomenon.

Diabetes in HIV: the Link to Weight Gain

PURPOSE OF REVIEW

The burden of metabolic diseases, including type 2 diabetes mellitus (T2DM), is rising among persons with HIV (PWH) on antiretroviral therapy (ART). This increase coincides with an aging population and a greater proportion who are overweight/obese. This review summarizes the changing epidemic of T2DM on contemporary ART, the role of weight gain, and therapeutic options.

RECENT FINDINGS

Recent studies confirm that PWH face an epidemic of obesity and T2DM, similar to the general population. Contemporary ART is associated with greater weight gain and may contribute to the risk of T2DM. Recent advances in medical weight loss therapy offer a way forward in the prevention and treatment of weight-associated T2DM. Weight gain is one of the biggest contributors to T2DM in PWH. Future studies on the role of adipose tissue distribution, adipose tissue function and clinical use of effective weight loss medications may change the paradigm of care for PWH.

Weight Gain Among Treatment-Naïve Persons With HIV Receiving Dolutegravir in Kenya

BACKGROUND

Several recent studies have linked integrase strand transfer inhibitors (INSTI) with increased weight gain.

SETTING

The effects of sex on weight gain with dolutegravir (DTG)-based antiretroviral therapy (ART) among treatment-naïve participants in a lower-income, sub-Saharan population with high rates of pre-ART underweight and tuberculosis (TB) coinfection are unknown.

METHODS

Our analysis included treatment-naïve participants in Kenya and starting their first treatment regimen between January 1, 2015, and September 30, 2018. Participants were grouped into 2 cohorts based on the initial treatment regimen [DTG vs. nonnucleoside reverse transcriptase inhibitors (NNRTI)]. We modelled weight changes over time using a multivariable nonlinear mixed-effect model, with participant as a random effect. Logistic regression models were constructed to evaluate the association between different variables with extreme increase in body mass index (≥10% increase).

RESULTS

Seventeen thousand forty-four participants met our inclusion criteria. Sixty-two percent of participants were women, 6% were receiving active TB therapy, and 97% were on NNRTI-based regimens. Participants starting DTG-based regimens were more likely to gain weight when compared with participants starting NNRTI-based regimens. Female participants starting DTG-based regimens experienced the highest weight gain compared with other participants (mean gain of 6.1 kgs at 18 months). Female participants receiving DTG-based regimens, along with participants with lower CD4 cell counts, underweight at baseline, and those receiving active TB therapy were also at higher risk for extreme body mass index increase.

CONCLUSIONS

Our study in a lower-income sub-Saharan African population confirms higher weight gain with DTG-based regimens compared with traditional ART for treatment-naïve patients.

HIV-1 Integrase Strand Transfer Inhibitors and Neurodevelopment

Children born to mothers, with or at risk, of human immunodeficiency virus type-1 (HIV-1) infection are on the rise due to affordable access of antiretroviral therapy (ART) to pregnant women or those of childbearing age. Each year, up to 1.3 million HIV-1-infected women on ART have given birth with recorded mother-to-child HIV-1 transmission rates of less than 1%. Despite this benefit, the outcomes of children exposed to antiretroviral drugs during pregnancy, especially pre- and post- natal neurodevelopment remain incompletely understood. This is due, in part, to the fact that pregnant women are underrepresented in clinical trials. This is underscored by any potential risks of neural tube defects (NTDs) linked, in measure, to periconceptional usage of dolutegravir (DTG). A potential association between DTG and NTDs was first described in Botswana in 2018. Incidence studies of neurodevelopmental outcomes associated with DTG, and other integrase strand transfer inhibitors (INSTIs) are limited as widespread use of INSTIs has begun only recently in pregnant women. Therefore, any associations between INSTI use during pregnancy, and neurodevelopmental abnormalities remain to be explored. Herein, United States Food and Drug Administration approved ARVs and their use during pregnancy are discussed. We provide updates on INSTI pharmacokinetics and adverse events during pregnancy together with underlying mechanisms which could affect fetal neurodevelopment. Overall, this review seeks to educate both clinical and basic scientists on potential consequences of INSTIs on fetal outcomes as a foundation for future scientific investigations.

Drug-drug interactions of Integrase Strand Transfer Inhibitors among older people living with HIV: Interazioni farmacologiche degli inibitori delle integrase tra le persone anziane che vivono con HIV

The advancement of Human Immunodeficiency Virus (HIV) treatment improves the life expectancy of HIV-positive individuals. People living with HIV have more polypharmacy and drug-drug interactions than those without HIV. Integrase strand transfer inhibitors (INSTIs) are the newest class commonly used for HIV treatment. There are five INSTIs currently approved by the Food and Drug Administration, including raltegravir, elvitegravir, dolutegravir, bictegravir, and cabotegravir. INSTIs class contributes to better safety and efficacy profile, making them the preferred or recommended antiretroviral regimens in HIV treatment guidelines worldwide. Despite the shared mechanism of action, INSTIs differ in pharmacokinetics, contributing to different drug-drug interactions. This review summarized the potential drug interactions of INSTIs and the management of the drug interactions in clinical practice.

Effectiveness of integrase strand transfer inhibitors in HIV-infected treatment-experienced individuals across Europe

OBJECTIVES

To explore the effectiveness and durability of integrase strand transfer inhibitor (INSTI)-based regimens in pre-treated subjects.

METHODS

Treatment-experienced individuals starting an INSTI-based regimen during 2012-2019 were selected from the INTEGRATE collaborative study. The time to virological failure [VF: one measurement of viral load (VL) ≥ 1000 copies/mL or two ≥ 50 copies/ml or one VL measurement ≥ 50 copies/mL followed by treatment change] and to INSTI discontinuation were evaluated.

RESULTS

Of 13 560 treatments analysed, 4284 were from INSTI-naïve, non-viraemic (IN-NV) individuals, 1465 were from INSTI-naïve, viraemic (IN-V) individuals, 6016 were from INSTI-experienced, non-viraemic (IE-NV) individuals and 1795 were from INSTI-experienced, viraemic (IE-V) individuals. Major INSTI drug resistance mutations (DRMs) were previously detected in 4/519 (0.8%) IN-NV, 3/394 (0.8%) IN-V, 7/1510 (0.5%) IE-NV and 25/935 (2.7%) IE-V individuals. The 1-year estimated probabilities of VF were 3.1% [95% confidence interval (CI): 2.5-3.8] in IN-NV, 18.4% (95% CI: 15.8-21.2) in IN-V, 4.2% (95% CI: 3.6-4.9) in IE-NV and 23.9% (95% CI: 20.9-26.9) in IE-V subjects. The 1-year estimated probabilities of INSTI discontinuation were 12.1% (95% CI: 11.1-13.0) in IN-NV, 19.6% (95% CI: 17.5-21.6) in IN-V, 10.8% (95% CI: 10.0-11.6) in IE-NV and 21.7% (95% CI: 19.7-23.5) in IE-V subjects.

CONCLUSIONS

Both VF and INSTI discontinuation occur at substantial rates in viraemic subjects. Detection of DRMs in a proportion of INSTI-experienced individuals makes INSTI resistance testing mandatory after failure.

Pharmacokinetic drug interactions of integrase strand transfer inhibitors

The integrase strand transfer inhibitor (INSTI)-containing regimens are currently considered as the first-line treatment of human immunodeficiency virus (HIV) infection. Although possessing a common mechanism of action to inhibit HIV integrase irreversibly to stop HIV replication cycle, the INSTIs, including raltegravir, elvitegravir, dolutegravir, and bictegravir, differ in pharmacokinetic characteristics. While raltegravir undergoes biotransformation by the UDP-glucuronosyltransferases (UGTs), elvitegravir is primarily metabolized by cytochrome P450 (CYP) 3A4 and co-formulated with cobicistat to increase its plasma exposure. The metabolism pathways of dolutegravir and bictegravir are similar, both including CYP3A and UGT1A1, and both agents are substrates to different drug transporters. Because of their differences in metabolism, INSTIs interact with other medications differently through CYP enzymes and transporters as inducers or inhibitors. These drug interactions may become an important consideration in the long-term clinical use because the life expectancy of people with HIV (PWH) approaches to that of the general population. Also, common geriatric challenges such as multimorbidity and polypharmacy have been increasingly recognized in PWH. This review provides a summary of pharmacokinetic interactions with INSTIs and future perspectives in implications of INSTI drug interactions.

Comparative Clinical Pharmacokinetics and Pharmacodynamics of HIV-1 Integrase Strand Transfer Inhibitors: An Updated Review

Bictegravir, cabotegravir, dolutegravir, elvitegravir, and raltegravir are members of the latest class of antiretrovirals available to treat human immunodeficiency virus (HIV) infection, the integrase strand transfer inhibitors. Integrase strand transfer inhibitors are potent inhibitors of the HIV integrase enzyme with IC_90/95 values in the low nanogram per milliliter range and they retain antiviral activity against strains of HIV with acquired resistance to other classes of antiretrovirals. Each of the integrase strand transfer inhibitors have unique pharmacokinetic/pharmacodynamic properties, influencing their role in clinical use in specific subsets of patients. Cabotegravir, approved for use in Canada but not yet by the US Food and Drug Administration, is formulated in both oral and intramuscular formulations; the latter of which has shown efficacy as a long-acting extended-release formulation. Cabotegravir, raltegravir, and dolutegravir have minimal drug-drug interaction profiles, as their metabolism has minimal cytochrome P450 involvement. Conversely, elvitegravir metabolism occurs primarily via cytochrome P450 3A4 and requires pharmacokinetic boosting to achieve systemic exposures amenable to once-daily dosing. Bictegravir metabolism has similar contributions from both cytochrome P450 3A4 and uridine 5'-diphospho-glucuronosyltransferase 1A1. Bictegravir, dolutegravir, and raltegravir are recommended components of initial regimens for most people with HIV in the US adult and adolescent HIV treatment guidelines. This review summarizes and compares the pharmacokinetics and pharmacodynamics of the integrase strand transfer inhibitor agents, and describes specific pharmacokinetic considerations for persons with hepatic impairment, renal dysfunction, pregnancy, and co-infections.

Clinical Safety Considerations of Integrase Strand Transfer Inhibitors in the Older Population Living with HIV

There are approximately 40 million people living with HIV globally, and 21% (7.9 million) are older adults (aged > 50 years) as of 2019. The average age of HIV-positive patients is predicted to increase to 58 by 2035. The favorable clinical efficacy of integrase strand transfer inhibitors has led to high rates of viral suppression and have now become the preferred agents by the AIDS guideline when initiating antiretroviral therapy. There are concerns of increasing adverse effects from HIV medications, such as integrase strand transfer inhibitors, as a result of changes in pharmacodynamic and pharmacokinetic parameters within the older population. The authors aim to describe the safety concerns of the current integrase strand transfer inhibitors based upon a narrative literature review, including recommendations for drug-drug interactions, and relevant comorbidities to consider for selection of the most appropriate integrase strand transfer inhibitor for older people living with HIV. Raltegravir is a well-tolerated option with minor adverse events; however, adherence to a twice-daily regimen may be difficult in older patients who are also taking many other medications for various comorbidities. Elvitegravir is also well tolerated with limited adverse effects, but has many drug-drug interactions that may pose problems for older patients with polypharmacy. Dolutegravir has been associated with more frequent adverse events, such as neuropsychiatric disorders.

A Gut Reaction to SIV and SHIV Infection: Lower Dysregulation of Mucosal T Cells during Acute Infection Is Associated with Greater Viral Suppression during cART

Selection of a pre-clinical non-human primate (NHP) model is essential when evaluating therapeutic vaccine and treatment strategies for HIV. SIV and SHIV-infected NHPs exhibit a range of viral burdens, pathologies, and responses to combinatorial antiretroviral therapy (cART) regimens and the choice of the NHP model for AIDS could influence outcomes in studies investigating interventions. Previously, in rhesus macaques (RMs) we showed that maintenance of mucosal Th17/Treg homeostasis during SIV infection correlated with a better virological response to cART. Here, in RMs we compared viral kinetics and dysregulation of gut homeostasis, defined by T cell subset disruption, during highly pathogenic SIVΔB670 compared to SHIV-1157ipd3N4 infection. SHIV infection resulted in lower acute viremia and less disruption to gut CD4 T-cell homeostasis. Additionally, 24/24 SHIV-infected versus 10/19 SIV-infected animals had sustained viral suppression <100 copies/mL of plasma after 5 months of cART. Significantly, the more profound viral suppression during cART in a subset of SIV and all SHIV-infected RMs corresponded with less gut immune dysregulation during acute SIV/SHIV infection, defined by maintenance of the Th17/Treg ratio. These results highlight significant differences in viral control during cART and gut dysregulation in NHP AIDS models and suggest that selection of a model may impact the evaluation of candidate therapeutic interventions for HIV treatment and cure strategies.

Bictegravir/emtricitabine/tenofovir alafenamide combination in the management of kidney transplant patients with HIV receiving immunosuppressants

We report here a drug-drug interaction with tacrolimus in a HIV-positive patient with renal transplant, after switch from highly active antiretroviral therapy with boosted protease inhibitors to the combination bictegravir/emtricitabine/tenofovir alafenamide. Although the tacrolimus doses were adapted to take account of the pharmacokinetic interactions with protease inhibitors, a tacrolimus overdosage occurred in the patient nonetheless. Through this case report, we highlight the need to consider a sufficient timeframe of withdrawal of protease inhibitors, which induce a prolonged drug-drug interaction with tacrolimus. To conclude, we purport that the combination bictegravir/emtricitabine/tenofovir alafenamide could be an attractive alternative in the context of transplantation provided a discontinuation of boosted protease inhibitors for more than 48 hours before introducing tacrolimus.

Therapeutic Drug Monitoring of HIV Antiretroviral Drugs in Pregnancy: A Narrative Review

To date, therapeutic drug monitoring (TDM) has played an important role in the management of pregnant HIV patients on highly active antiretroviral therapy. Historically, in pregnant women living with HIV, the third agent in triple therapy has been either non-nucleoside reverse transcriptase inhibitors or protease inhibitors (PIs). PIs have been the preferred agents because of their robustness from the perspective of viral resistance and the dominant drug class for the management of HIV during pregnancy for the previous decade. As with many drugs used during pregnancy, pharmacokinetic changes decrease exposure to these agents as the pregnancy progresses. This can lead to viral escape at the time of pregnancy and ultimately increase the risk of mother-to-child transmission (MTCT) of HIV. TDM has been well-established for this class of highly active antiretroviral therapy, and appropriate dose adjustment studies have been performed. At present, there is a shift from the traditional treatment paradigm in pregnancy to a new drug class, integrase strand transfer inhibitors (INSTIs). Although INSTIs are affected by pharmacokinetic changes during pregnancy, they do not harbor the same issues with viral escape as seen with PIs at birth and in general eliminate the need for boosting with additional agents like ritonavir (r) and cobicistat (c) [bar elvitegravir (EVG)] that can lead to interactions with treatment of other common infections in HIV, including tuberculosis. Furthermore, INSTIs are the most successful medication for rapidly reducing the viral load (VL) in HIV patients, a useful factor where VL may be unknown, or in late presenters. These merits make INSTIs the best choice in pregnancy, although their use has been hindered in recent years by a report of neural tube defects from a large African study with dolutegravir (DTG). New data from Botswana and Brazil indicate that this risk is less significant than previously reported, necessitating further data to shed light on this critical issue. Current international guidelines including DHHS, EACS, WHO, and BHIVA (for patients with VLs >100,000 copies/mL or late presenters) now recommend INSTIs as first-line agents. The role of TDM in INSTIs shifts to cases of insufficient viral suppression with standard adherence measures, cases of drug-drug interactions, or cases where EVG/c is continued throughout pregnancy, and thus remains an important aspect of HIV care in pregnancy.

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

BACKGROUND

The treatment of HIV infection has evolved significantly since the advent of highly active antiretroviral therapy. As a result, a response rate of 90%-95% now represents a realistically achievable target. Given this background, it is difficult to imagine the additional benefits that therapeutic drug monitoring (TDM) could provide in the management of HIV infection.

METHODS

This article is not intended to provide a systematic literature review on TDM of antiretroviral agents; rather, the authors aim to discuss the potential added value of TDM in the optimal management of people living with HIV (PLWH) in selected real-life clinical scenarios based on data collected over 10 years by their TDM service.

RESULTS

Some clinical situations, in which the selection of the optimal antiretroviral therapy is challenging, have been identified. These include poorly compliant patients, suboptimal antiretroviral therapies (in terms of both efficacy and toxicity), polypharmacy with a high risk of drug-drug interactions, and different patient populations, such as pregnant women.

CONCLUSIONS

The transformation of HIV infection from a near-universally fatal illness to a lifelong chronic disease has resulted in an HIV population that is growing and aging, placing new and increasing demands on public programs and health services. Increasingly, the management of comorbidities, polypharmacy, and drug-drug interaction, and their impact on antiretroviral therapy will have to be undertaken. These clinical settings represent some of the new frontiers for the use of TDM with the goal of achieving optimal prescription and outcome for PLWH.

Total and Unbound Bictegravir Concentrations and Viral Suppression in Cerebrospinal Fluid of Human Immunodeficiency Virus-Infected Patients (Spanish HIV/AIDS Research Network, PreEC/RIS 56)

We determined total and unbound concentrations of bictegravir (BIC) in cerebrospinal fluid (CSF) in 15 asymptomatic, virologically suppressed patients. The median plasma and CSF total BIC concentrations were 1837.1 ng/mL (interquartile range [IQR], 1237.2-2586.7) and 6.9 (IQR, 4.8-10.9), respectively. Median unbound BIC concentration was 2.48 ng/mL (IQR, 1.6-3.7). Total and unbound BIC CSF concentrations were above the half-maximal effective concentration value in all patients, and all subjects had human immunodeficiency virus viral suppression in plasma and CSF. Bictegravir may contribute to inhibit viral replication in this compartment.

Elvitegravir-Cobicistat-Emtricitabine-Tenofovir Alafenamide Single-tablet Regimen for Human Immunodeficiency Virus Postexposure Prophylaxis

We evaluated an elvitegravir-cobicistat-emtricitabine-tenofovir alafenamide single-tablet regimen for human immunodeficiency virus postexposure prophylaxis. The completion rate and adherence were good, and the tolerance was acceptable; no seroconversion was observed. We confirm that this regimen could be appropriate for postexposure prophylaxis.

CLINICAL TRIALS REGISTRATION

NCT02998320.

Antiviral Classification

Over the past 60 years, more than 100 antiviral drugs or their combinations have been approved for clinical use. Antiviral drugs can be classified according to their chemical nature (e.g., small-molecules, peptides, biologics) or mechanisms of drug actions against specific viral proteins (e.g., polymerase inhibitors, protease inhibitors, glycoprotein inhibitors). This article provides an overview of antiviral classifications in 10 important human viruses: hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), human cytomegalovirus (HCMV), herpes simplex virus (HSV), variola virus (human smallpox), varicella zoster virus (VZV), influenza virus, respiratory syncytial virus (RSV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

New insights into application of nanoparticles in the diagnosis and screening of novel coronavirus (SARS-CoV-2)

Novel coronavirus disease 2019 (COVID-19) is by far the worst pandemic disease in the current millennium. The first human-to-human transmission was observed in December 2019 in China and is caused by the highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has infected millions of people within months across the globe. SARS-CoV-2 is a spike protein enveloped virus with particle-like characteristics and a diameter of 60-140 nm. Real-time PCR, reverse transcriptase PCR, isothermal PCR, immunological-based detection technique and nano-based diagnostic system have been explained for the identification and differentiation of different types of virus including SARS-COV-2. Synthetic nanoparticles can closely mimic the virus and interact strongly with its virulent proteins due to their morphological similarities. Some of the antiviral nanomaterials are also discussed, for example zinc oxide nanoparticle is an antiviral agent with a tetrapod morphology that mimics the cell surface by interacting with the viral capsid. It suppressed the viral proteins upon UV radiation due to reaction caused by photocatalysis. Hence, nanoparticle-based strategies for tackling viruses have immense potential. The second part of the review points to the latest in vitro and in vivo procedures for screening viral particles and the usage of nanoparticles in diagnostic and therapeutics. This would be beneficial for early detection and assists for the safe and effective therapeutic management of COVID-19.

Dolutegravir-Based Antiretroviral Regimens for HIV Liver Transplant Patients in Real-Life Settings

Background and Objectives

Liver transplantation is now considered a safe procedure in patients with HIV because of the advent of potent antiretroviral therapies (ART).

Objective

We aimed to describe the use of dolutegravir-based maintenance ART in patients with HIV and liver transplant regularly followed in our hospital.

Methods

We searched the database of our Department of Infectious Diseases for liver transplant recipients receiving calcineurin inhibitor-based maintenance immunosuppression concomitantly treated with dolutegravir for at least 1 month.

Results

Ten HIV-positive liver transplant recipients were identified. At 4.6 ± 3.5 years post-transplant, all the patients were switched to dolutegravir-based therapies for treatment simplification. However, at 1 year after the switch, five of the ten patients returned to their previous ART regimens because of increased serum transaminases (n = 1), reversible increased serum creatinine (n = 4), repeated episodes of nausea/vomiting (n = 1) and variable out-of-range concentrations of tacrolimus or cyclosporine (n = 2). However, it should be recognized that these events cannot be unequivocally ascribed to dolutegravir and, in the case of increased serum creatinine, are predictable.

Conclusions

The management of HIV-positive liver transplant recipients in clinical practice is a complex task, where possibility of simplifying antiretroviral regimens must be balanced with the need to guarantee optimal immunosuppression and the finest treatment tolerability. A multidisciplinary approach involving physicians and clinical pharmacologists/pharmacists could help achieve this goal.

Placental transfer of the integrase strand inhibitors cabotegravir and bictegravir in the ex-vivo human cotyledon perfusion model

: Data on placental transfer is lacking for the recent HIV integrase inhibitors, bictegravir and cabotegravir, although their future use in pregnancy is to be expected. The objective of this study was to determine their transplacental pharmacokinetics. Maternal-to-fetal transfer was investigated using the open-circuit ex-vivo dually perfused human cotyledon model. Cabotegravir or bictegravir was added to a maternal perfusate containing 2 g/l of human albumin and antipyrine, a marker to validate the cotyledon's viability, and cotyledons were dually perfused for up to 90 min. For cabotegravir, in five experiments, the median (IQR 25-75) concentrations in the maternal and in the fetal compartments were, respectively, 550 ng/ml (344-788) and 48 ng/ml (37-54), with a maternal-to-fetal ratio of 10% (5-16) and a clearance index (in comparison with antipyrine transfer) of 22% (19-28). The median cotyledon accumulation index was 10% (2-21). For bictegravir, in six experiments, the median (IQR 25-75) concentrations in the maternal and in the fetal compartments were, respectively, 1650 ng/ml (1455-1960) and 126 ng/ml (112-142), with a maternal-to-fetal ratio of 7% (6-9.5) and a clearance index (in comparison with antipyrine transfer) of 21% (17-29). The median cotyledon accumulation index was 4% (3-5). Placental transfer of cabotegravir and bictegravir were low. This may not only limit the potential for fetal toxicities but also be a limit to their usefulness at the time of labor and delivery to reduce the risk of vertical HIV transmission. The safety and efficacy of these new integrase inhibitors in pregnancy require more investigation.

Characteristics of Dolutegravir and Bictegravir Plasma Protein Binding: a First Approach for the Study of Pharmacologic Sanctuaries

This study aimed to characterize in vitro dolutegravir (DTG) and bictegravir (BIC) binding. They had a preferential binding to human serum albumin (HSA) with two classes of albumin sites. Human alpha-1-acid glycoprotein (HAAG) binding of DTG and BIC showed an atypical nonlinear binding. The low-affinity site on HSA, the main plasma binding protein, suggests that the high protein binding rate should not impair passive diffusion.

Evaluation of the concentrations of psychotropic drugs in HIV-infected versus HIV-negative patients: Potential implications for clinical practice

Objectives: The management of psychiatric illness in HIV-infected patients is clinically challenging because of the risk of potential drug-drug interactions. Here, we aimed to measure the antidepressant and/or antipsychotic drug concentrations in HIV-infected patients during routine outpatient visits.Methods: Six hundred HIV-infected patients were screened during the first 15 months after the introduction of our outpatient polytherapy management service in a search for subjects treated with psychotropic drugs for at least 3 months. The distribution of psychotropic drug concentrations in HIV-infected patients was compared with that observed in a control group of HIV-negative patients monitored over the same period.Results: The search identified 82 HIV-infected patients concomitantly receiving antiretroviral and psychotropic drug treatment, 55% of whom had plasma psychotropic drug concentrations that were below minimum effective levels. The same result was found in only 26% of the samples taken from HIV-negative patients. These results were not affected by patients' gender, age, adherence to therapies or drug-drug interactions.Conclusions: A higher rate of sub-therapeutic antidepressant and/or antipsychotic drugs concentrations were found in HIV-infected patients. The creation of multidiscliplinary specialist teams may contribute to improving the management of such complex patients.

Differential effects of integrase strand transfer inhibitors, elvitegravir and raltegravir, on oligodendrocyte maturation: A role for the integrated stress response

Regardless of adherence to combined antiretroviral therapy, white matter and myelin pathologies persist in patients with HIV-associated neurocognitive disorders, a spectrum of cognitive, motor, and behavioral impairments. We hypothesized that antiretroviral therapy alters the maturation of oligodendrocytes which synthesize myelin. We tested whether specific frontline integrase strand transfer inhibitors would alter oligodendrocyte differentiation and myelination. To model the effect of antiretrovirals on oligodendrocytes, we stimulated primary rat oligodendrocyte precursor cells to differentiate into mature oligodendrocytes in vitro in the presence of therapeutically relevant concentrations of elvitegravir or raltegravir and then assessed differentiation with lineage specific markers. To examine the effect of antiretrovirals on myelination, we treated mice with the demyelinating compound cuprizone, for 5 weeks. This was followed by 3 weeks of recovery in absence of cuprizone, during which time some mice received a daily intrajugular injection of elvitegravir. Brains were harvested, sectioned and processed by immunohistochemistry to examine oligodendrocyte maturation and myelination. Elvitegravir inhibited oligodendrocyte differentiation in vitro in a concentration-dependent manner, while raltegravir had no effect. Following cuprizone demyelination, administration of elvitegravir to adult mice reduced remyelination compared with control animals. Elvitegravir treatment activated the integrated stress response in oligodendrocytes in vitro, an effect which was completely blocked by pretreatment with the integrated stress response inhibitor Trans-ISRIB, preventing elvitegravir-mediated inhibition of oligodendrocyte maturation. These studies demonstrate that elvitegravir impairs oligodendrocyte maturation and remyelination and that the integrated stress response mediates this effect and may be a possible therapeutic target.

Population pharmacokinetics of dolutegravir: influence of drug-drug interactions in a real-life setting

OBJECTIVES

Dolutegravir is widely prescribed owing to its potent antiviral activity, high genetic barrier and good tolerability. The aim of this study was to characterize dolutegravir's pharmacokinetic profile and variability in a real-life setting and to identify individual factors and co-medications affecting dolutegravir disposition.

METHODS

A population pharmacokinetic model was developed using NONMEM®. Relevant demographic factors, clinical factors and co-medications were tested as potential covariates. Simulations based on the final model served to compare expected dolutegravir concentrations under standard and alternative dosage regimens in the case of drug-drug interactions.

RESULTS

A total of 620 dolutegravir plasma concentrations were collected from 521 HIV-infected individuals under steady-state conditions. A one-compartment model with first-order absorption and elimination best characterized dolutegravir pharmacokinetics. Typical dolutegravir apparent clearance (CL/F) was 0.93 L/h with 32% between-subject variability, the apparent volume of distribution was 20.2 L and the absorption rate constant was fixed to 2.24 h-1. Older age, higher body weight and current smoking were associated with higher CL/F. Atazanavir co-administration decreased dolutegravir CL/F by 38%, while darunavir modestly increased CL/F by 14%. Rifampicin co-administration showed the largest impact on CL/F. Simulations suggest that average dolutegravir trough concentrations are 63% lower after 50 mg/12h with rifampicin compared with a standard dosage of 50 mg/24h without rifampicin. Average trough concentrations after 100 mg/24h and 100 mg/12h with rifampicin are 92% and 25% lower than the standard dosage without rifampicin, respectively.

CONCLUSIONS

Patients co-treated with dolutegravir and rifampicin might benefit from therapeutic drug monitoring and individualized dosage increase, up to 100 mg/12 h in some cases.

Nothing is perfect: the safety issues of integrase inhibitor regimens

INTRODUCTION

Since the administration of the first integrase strand transfer inhibitor (INSTI) in 2007, most international treatment guidelines consider INSTI-based regimens to be the preferred antiretroviral combinations for HIV-1-infected patients as a result of their safety and efficacy profile. INSTIs are generally well tolerated, and reported rates of discontinuation due to drug-related adverse events (AEs) have been very low to date. However, recent reports indicate that physicians should be aware of potential INSTI-related AEs to ensure good clinical practice.

AREAS COVERED

The authors performed a critical review of the safety issues affecting INSTIs based on published evidence from original studies and new data from researchers.

EXPERT OPINION

Almost all antiretroviral drugs, including INSTIs, are associated with undesirable AEs. Dolutegravir in particular has been associated with more frequent AEs such as neuropsychiatric disorders, neural tube defect in newborns, and weight gain. Data with bictegravir in routine practice are still scarce. While this association and its clinical relevance are not clear, physicians should be alert to the appearance of the aforementioned AEs and others in the future. In the meantime, INSTIs continue to be the preferred option in guidelines on antiretroviral therapy.

Weight gain among treatment-naïve persons with HIV starting integrase inhibitors compared to non-nucleoside reverse transcriptase inhibitors or protease inhibitors in a large observational cohort in the United States and Canada

INTRODUCTION

Weight gain following antiretroviral therapy (ART) initiation is common, potentially predisposing some persons with HIV (PWH) to cardio-metabolic disease. We assessed relationships between ART drug class and weight change among treatment-naïve PWH initiating ART in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD).

METHODS

Adult, treatment-naïve PWH in NA-ACCORD initiating integrase strand transfer inhibitor (INSTI), protease inhibitor (PI) or non-nucleoside reverse-transcriptase inhibitor (NNRTI)-based ART on/after 1 January 2007 were followed through 31 December 2016. Multivariate linear mixed effects models estimated weight up to five years after ART initiation, adjusting for age, sex, race, cohort site, HIV acquisition mode, treatment year, and baseline weight, plasma HIV-1 RNA level and CD4+ cell count. Due to shorter follow-up for PWH receiving newer INSTI drugs, weights for specific INSTIs were estimated at two years. Secondary analyses using logistic regression and all covariates from primary analyses assessed factors associated with >10% weight gain at two and five years.

RESULTS

Among 22,972 participants, 87% were male, and 41% were white. 49% started NNRTI-, 31% started PI- and 20% started INSTI-based regimens (1624 raltegravir (RAL), 2085 elvitegravir (EVG) and 929 dolutegravir (DTG)). PWH starting INSTI-based regimens had mean estimated five-year weight change of +5.9kg, compared to +3.7kg for NNRTI and +5.5kg for PI. Among PWH starting INSTI drugs, mean estimated two-year weight change was +7.2kg for DTG, +5.8kg for RAL and +4.1kg for EVG. Women, persons with lower baseline CD4+ cell counts, and those initiating INSTI-based regimens had higher odds of >10% body weight increase at two years (adjusted odds ratio = 1.37, 95% confidence interval: 1.20 to 1.56 vs. NNRTI).

CONCLUSIONS

PWH initiating INSTI-based regimens gained, on average, more weight compared to NNRTI-based regimens. This phenomenon may reflect heterogeneous effects of ART agents on body weight regulation that require further exploration.

Obesity and Weight Gain in Persons with HIV

PURPOSE OF REVIEW

The proportion of overweight and obese persons with HIV (PWH) has increased since the introduction of antiretroviral therapy (ART). We aim to summarize recent literature on risks of weight gain, discuss adipose tissue changes in HIV and obesity, and synthesize current understanding of how excess adiposity and HIV contribute to metabolic complications.

RECENT FINDINGS

Recent studies have implicated contemporary ART regimens, including use of integrase strand transfer inhibitors and tenofovir alafenamide, as a contributor to weight gain, though the mechanisms are unclear. Metabolic dysregulation is linked to ectopic fat and alterations in adipose immune cell populations that accompany HIV and obesity. These factors contribute to an increasing burden of metabolic diseases in the aging HIV population. Obesity compounds an increasing burden of metabolic disease among PWH, and understanding the role of fat partitioning and HIV- and ART-related adipose tissue dysfunction may guide prevention and treatment strategies.

Optimizing concentrations of concomitant antiretrovirals by reducing etravirine doses: two case reports of complex drug-drug interactions

We report the cases of two treatment-experienced HIV-infected patients with complex antiretroviral regimens that showed significant drug-drug interactions with etravirine. Unexpectedly high etravirine concentrations likely caused subtherapeutic levels of darunavir, elvitegravir and dolutegravir through concentration-dependent metabolic induction. Therapeutic drug monitoring allowed safe etravirine dose decreases to manage these interactions.

Dolutegravir plus lamivudine for the treatment of HIV-1 infection

Introduction: Recent data on the 2-drug regimen (2DR) with dolutegravir (DTG) plus lamivudine (3TC) have shown high efficacy and tolerability both in treatment-naïve and experienced HIV-positive patients. Current guidelines recommend DTG+3TC as an alternative to triple antiretroviral therapy (ART) in selected patients to reduce long-term toxicity and costs.Areas covered: This review is intended to provide insight about the efficacy, safety, and tolerability of a 2DR with DTG+3TC in naïve and treatment-experienced patients.Expert opinion: Data from clinical trials and from real-life show that DTG+3TC is an effective and safe switch option for the treatment of experienced patients. In treatment-naïve patients, DTG+3TC has shown non-inferiority compared to standard 3-drug regimens but is less effective in severely immunocompromised naïve patients (i.e. with a CD4+ cell count below 200 cell/mm3); furthermore, current guidelines have upgraded this dual regimen to recommended first-line strategy, but indicate that it should not be used without genotypic resistance results. Moreover, this regimen is not feasible for HBV-coinfected individuals and should not be used during pregnancy. Currently, out of 2-drug regimens, DTG+3TC is one of clinicians' preferred option as it requires no pharmacokinetic booster, has a low risk of drug interaction, and does not require food intake.

Genetic influence of ABCG2, UGT1A1 and NR1I2 on dolutegravir plasma pharmacokinetics

Objectives

Dolutegravir has replaced efavirenz as first-line treatment in universal HIV guidelines. We sought to ascertain the contributory effect of SNPs in four key genes linked to dolutegravir disposition (UGT1A1, ABCG2, CYP3A and NR1I2) on plasma dolutegravir pharmacokinetics.

Methods

Paired pharmacogenetic/pharmacokinetic data from 93 subjects were analysed for association using multivariate linear regression.

Results

Co-occurring UGT1*28 and NR1I2 c.63396C&gt;T homozygosity was associated with a 79% increase in AUC0–24 (P = 0.001; 27% if analysed individually), whilst combined ABCG2 c.421C&gt;A and NR1I2 c.63396C&gt;T variants were associated with a 43% increase in Cmax (P = 0.002) and a 39% increase in AUC0–24 (P = 0.002). When analysed individually, homozygosity for the NR1I2 c.63396C&gt;T variant alleles was associated with a 28% increase in Cmax (P = 0.033) and homozygosity for the ABCG2 c.421C&gt;A variant alleles was associated with a 28% increase in Cmax (P = 0.047). The UGT1A1*28 (rs8175347) poor metabolizer status (*28/*28; *28/*37; *37/*37) was individually associated with a 27% increase in AUC0–24 (P = 0.020). The combination of UGT1A1*28 poor metabolizer and UGT1A1*6 intermediate metabolizer statuses correlated with a 43% increase in AUC0–24 (P = 0.023).

Conclusions

This study showed a pharmacogenetic association between dolutegravir pharmacokinetics and variants in the ABCG2, UGT1A1 and NR1I2 genes, particularly when combined. Further research is warranted to confirm these associations in population-specific studies and to investigate their putative relationship with dolutegravir pharmacodynamics.

Pharmacokinetics of Coencapsulated Antiretrovirals with Ingestible Sensors

We investigated the use of a system with an ingestible sensor (Proteus Digital Health Feedback system) coencapsulated with antiretrovirals (ARVs) to measure real-time adherence. To assess the safety and impact, if any, coencapsulation might have on ARV concentrations, we evaluated the pharmacokinetics of ARVs coencapsulated with an ingestible sensor for eight commonly used fixed-dose combination ARVs: emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF); FTC/tenofovir alafenamide (TAF); efavirenz (EFV)/FTC/TDF; abacavir (ABC)/lamivudine (3TC); dolutegravir (DTG)/ABC/3TC; rilpivirine (RPV)/TAF/FTC; elvitegravir (EVG)/cobicistat (COBI)/FTC/TAF; and bictegravir (BIC)/FTC/TAF. The steady-state apparent peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) were determined from plasma concentrations measured at predose, 1, 2, 4, and 6 h postdose, and compared with literature values. A total of 49 unique patients on stable regimens for at least 12 weeks with undetectable viral loads were recruited. Cmax and AUC values were not statistically significantly different from literature values for all of the formulations except the Cmax of FTC/TDF, Cmax of BIC, and the Cmax of RPV. In a subsequent evaluation of FTC/TDF and BIC/FTC/TAF using a crossover design, the geometric mean ratio (GMR) between the coencapsulated and the unencapsulated formulations for FTC/TDF were the following: FTC, 84.6% (90% confidence interval [CI] 66.6-107.4) for AUC and 77.5% (60.1-99.9) for Cmax. For tenofovir (TFV), the GMR was 96.2% (90% CI 89.2-103.8) for AUC and 87.3% (64.2-118.7) for Cmax. The GMR for BIC (from the BIC/FTC/TAF formulation) was 98.0% (90% CI 84.5-113.5) for AUC and 89.9% (84.5-95.7) for Cmax. The observed deviation in FTC/TDF (Truvada) may be due to participant characteristics, fasted/fed conditions, and/or random variation and may warrant further investigations with a larger sample size. These findings provide assurance for use of coencapsulated ARVs for future HIV treatment-adherence research.

Pharmacokinetics and Pharmacodynamics of Cabotegravir, a Long-Acting HIV Integrase Strand Transfer Inhibitor

Available antiretroviral drugs have demonstrated effectiveness in both pre-exposure prophylaxis and treatment of HIV infection. However, some concerns still persist regarding these therapies, mainly related to patient adherence, drug toxicity and dosing convenience. Cabotegravir is a potent integrase strand transfer inhibitor with a chemical structure similar to dolutegravir that is under clinical evaluation both as oral and long-acting injectable (LAI) formulations for both the prevention or treatment of HIV infection. Indeed, preclinical and clinical studies have consistently shown that LAI cabotegravir is readily absorbed following intramuscular and subcutaneous administration, with an elimination half-life of approximately 40 days, permitting infrequent dosing, possibly once every 1 or 2 months (eventually combined with rilpivirine). Here, we reviewed the existing literature on the preclinical and clinical pharmacokinetics and pharmacodynamics of LAI cabotegravir, with emphasis on the actual pharmacokinetic challenges of this novel formulation, as well as its potential to act as a victim or perpetrator of drug-drug interactions.

Dolutegravir And Lamivudine Combination For The Treatment Of HIV-1 Infection

There have been remarkable advances in drug development for the treatment of HIV-1 infection. From the co-formulation of combination antiretroviral therapy (cART) into single-tablet regimens to the development of long-acting antiretroviral (ARV) drug formulations, the treatment of HIV has and will become much more tolerable and less complicated for patients. In addition, and appropriately, there is a focus on reducing short- and long-term toxicities of treatment while maintaining robust efficacy. One of such approaches includes 2-drug regimen constructs that contain and retain effective ARV compounds while excluding components that have relatively unfavorable toxicity profiles. The first-ever 2-drug regimen approved for the treatment of HIV-1 infection for treatment-naive people living with HIV (PLWH), consisting of the integrase inhibitor dolutegravir (DTG) and the nucleoside reverse transcriptase inhibitor (NRTI) lamivudine (3TC), is reviewed in this paper. The chemical composition and properties, pharmacokinetic and pharmacodynamics profile, and clinical trial data on efficacy and safety of DTG/3TC are presented. An expert opinion aims to highlight important considerations for the use of DTG/3TC in the context of existing and emerging ARV options.

Nanotechnology approaches for delivery of cytochrome P450 substrates in HIV treatment

Introduction: Antiretroviral therapy (ART) has led to a significant reduction in HIV-1 morbidity and mortality. Many antiretroviral drugs (ARVs) are metabolized by cytochrome P450 (CYP) pathway, and the majority of these drugs are also either CYP inhibitors or inducers and few possess both activities. These CYP substrates, when used for HIV treatment in the conventional dosage form, have limitations such as low systemic bioavailability, potential drug-drug interactions, and short half-lives. Thus, an alternative mode of delivery is needed in contrast to conventional ARVs. Areas covered: In this review, we summarized the limitations of conventional ARVs in HIV treatment, especially for ARVs which are CYP substrates. We also discussed the preclinical and clinical studies using the nanotechnology strategy to overcome the limitations of these CYP substrates. The preclinical studies and clinical studies published from 2000 to February 2019 were discussed. Expert opinion: Since preclinical and clinical studies for prevention and treatment of HIV using nanotechnology approaches have shown considerable promise in recent years, nanotechnology could become an alternative strategy for daily oral therapy as a future treatment.

Low plasmatic concentration of intensified antiretroviral therapy in a pregnant woman: a case report

Background

Identifying the most appropriate antiretroviral regimen for pregnant women with Human Immunodeficiency Virus (HIV-1) infection can be challenging, mainly due to pregnancy-related physiological alterations which can significantly reduce maternal drug plasma concentration. We would like to report our experience as it consists of an unusual case of low plasmatic concentration of antiretroviral drugs despite regimen intensification in a HIV-positive pregnant woman. It also underlines the need for accurate monitoring and treatment adjustment in pregnant women with Human Immunodeficiency Virus (HIV).

Case presentation

A 26-year-old Brazilian woman with HIV-1 infection attending our out-patient clinic presented with low plasmatic concentration of antiretroviral drugs and persistent detectable viral load despite regimen intensification during pregnancy.

Trough plasma concentrations of dolutegravir and darunavir were measured by validated liquid chromatography–mass spectrometry. At 23 weeks of gestation it showed a lower value than expected in non-pregnant adults, compared to a normal level of plasma concentration measured at 10 weeks after delivery. Our patient and the baby had no regimen-related adverse effects.

Conclusions

Physiological changes during pregnancy can affect pharmacokinetics and reduce a mother’s bioavailability of antiretroviral drugs, potentially altering their pharmacological activity. A personalized treatment and a careful follow-up are hence mandatory for this key population.

Maternal-Neonatal Raltegravir Population Pharmacokinetics Modeling: Implications for Initial Neonatal Dosing

Raltegravir readily crosses the placenta to the fetus with maternal use during pregnancy. After birth, neonatal raltegravir elimination is highly variable and often extremely prolonged, with some neonates demonstrating rising profiles after birth despite removal from the source of extrinsic raltegravir. To establish an appropriate dosing regimen, an integrated maternal–neonatal pharmacokinetics model was built to predict raltegravir plasma concentrations in neonates with in utero raltegravir exposure. Postnatal age and body weight were used as structural covariates. The model predicted rising or decreasing neonatal elimination profiles based on the time of maternal drug administration relative to time of birth and degree of in utero drug disposition into the central and peripheral compartments. Based on this model, it is recommended to delay the first oral dose of raltegravir until 1–2 days of age in those neonates born to mothers who received raltegravir during pregnancy, labor, and delivery.

Pharmacokinetics and Pharmacodynamics of Cabotegravir, a Long-Acting HIV Integrase Strand Transfer Inhibitor

Available antiretroviral drugs have demonstrated effectiveness in both pre-exposure prophylaxis and treatment of HIV infection. However, some concerns still persist regarding these therapies, mainly related to patient adherence, drug toxicity and dosing convenience. Cabotegravir is a potent integrase strand transfer inhibitor with a chemical structure similar to dolutegravir that is under clinical evaluation both as oral and long-acting injectable (LAI) formulations for both the prevention or treatment of HIV infection. Indeed, preclinical and clinical studies have consistently shown that LAI cabotegravir is readily absorbed following intramuscular and subcutaneous administration, with an elimination half-life of approximately 40 days, permitting infrequent dosing, possibly once every 1 or 2 months (eventually combined with rilpivirine). Here, we reviewed the existing literature on the preclinical and clinical pharmacokinetics and pharmacodynamics of LAI cabotegravir, with emphasis on the actual pharmacokinetic challenges of this novel formulation, as well as its potential to act as a victim or perpetrator of drug-drug interactions.

Pharmacotherapeutic management of HIV in transplant patients

INTRODUCTION

In the last two decades, an increasing number of people living with HIV (PLWH) have undergone solid-organ and hematopoietic cell transplantation as a treatment of end-stage organ and hematological diseases, respectively. Although transplant outcomes are more than satisfactory, transplantation in PLWH is still challenging for clinicians because of concerns regarding potentially higher rates of infective complications, higher risks of allograft rejection, and drug-drug interactions between antiretroviral drugs and immunosuppressive agents.

AREAS COVERED

This review provides an overview of transplantation in PLWH, with focus on the management of combination antiretroviral therapy in this population.

EXPERT OPINION

Solid-organ and hematopoietic cell transplantations should be proposed without any reservation to all PLWH who may benefit from them. Particular attention should be paid to possible drug-drug interactions between antiretrovirals and immunosuppressive agents; moreover, when feasible, integrase strand transfer inhibitor-based antiretroviral regimens should be preferred to protease and non-nucleoside reverse transcriptase inhibitors. Considering the worse prognosis in HIV/hepatitis C virus (HCV) transplant recipients, treatment of HCV with new direct-acting antivirals (DAAs) represents a key issue in the management of this population. However, the timing of treatment (before or early after transplant) should be individualized by considering short-term prognosis, access to transplant, and comorbidities.

A Phase 1 Study to Evaluate the Pharmacokinetics and Safety of Cabotegravir in Patients With Hepatic Impairment and Healthy Matched Controls

Cabotegravir is an investigational integrase inhibitor in development for the treatment and pre-exposure prophylaxis of HIV-1 infection. Liver disease is a major cause of morbidity and mortality in HIV-infected individuals and can impact the pharmacokinetics (PK) of HIV medications. This phase 1 study evaluated the PK of cabotegravir in individuals with moderate hepatic impairment (n = 8) versus healthy controls (n = 8). Participants received a single oral cabotegravir 30-mg tablet and underwent PK sampling to determine total and unbound plasma cabotegravir concentrations. Calculated geometric least-squares mean ratios (90% confidence intervals) for individuals with hepatic impairment versus healthy controls were 0.73 (0.50-1.06) for AUC_0-∞ , 0.69 (0.51-0.93) for C_max , 1.40 (0.80-2.46) for unbound concentration (CU) 2 hours postdose, 1.55 (0.82-2.94) for CU at 24 hours, 2.14 (1.57-2.90) for unbound fraction (FU) at 2 hours, and 1.90 (1.14-3.18) for FU at 24 hours. Adverse events (AEs) occurred in 2 individuals with hepatic impairment and 3 healthy controls and were grade 1/2 in severity. No participant discontinued because of AEs. Increased FU resulted in a modest decrease in total plasma exposure not considered clinically relevant. We conclude that cabotegravir may be administered without dose adjustment in patients with mild to moderate hepatic impairment.

Drug-drug interactions of a two-drug regimen of dolutegravir and lamivudine for HIV treatment

INTRODUCTION

The GEMINI trials have recently shown that a two-drug regimen of dolutegravir plus lamivudine was non-inferior to a three-drug regimen in HIV-infected naïve patients. Accordingly, it is important that physicians be aware and confident about the drug-drug interactions (DDIs) involving dolutegravir, lamivudine, and other medications. Areas covered: Here, we firstly update the available information on the pharmacokinetic features of dolutegravir and lamivudine; subsequently, the articles mainly deals with the predictable DDIs for both antiretroviral drugs, attempting to underline their clinical implications. This review focuses on the DDIs of dolutegravir/lamivudine combined regimen and, therefore, does not provide an exhaustive list of all the potential DDIs involving the two single agents. A MEDLINE Pubmed search for articles published from January 2000 to December 2018 was completed matching the terms dolutegravir or lamivudine with pharmacokinetics, DDIs, and pharmacology. Moreover, additional studies were identified from the reference list of retrieved articles. Expert opinion: The antiretroviral dual regimen of dolutegravir and lamivudine represents an attractive therapeutic option for HIV in terms of DDIs. This is particularly relevant considering that the population with HIV is aging and is increasingly experience age-related comorbidities, increasing pill burden, polypharmacy and the risk of DDIs.