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

Durability of doravirine with dolutegravir dual regimen compared with other dolutegravir-based dual combinations

OBJECTIVES

The availability of doravirine (DOR) allowed clinicians to prescribe a dolutegravir (DTG)-based two-drug regimen (2DR) in individuals not eligible to receive lamivudine (3TC) or rilpivirine (RPV). The aims of this study were to describe the durability of DTG + DOR compared with DTG/3TC and DTG/RPV and the rate of virological failure and target not-detected maintenance over time.

METHODS

This retrospective, monocentric analysis included all subjects who started a DTG-based 2DR from 2018 to 2022 as a simplification. Descriptive statistics and non-parametric tests to describe and compare the groups were applied. Kaplan-Meier probability curves and Cox regression models for regimens durability were used.

RESULTS

The study enrolled 710 individuals: 499 treated with DTG/3TC, 140 with DTG/RPV, and 71 with DTG + DOR. A 2DR with DOR was prescribed to older subjects who had a longer infection, greater exposure to different antiretroviral regimens, a higher proportion of resistance-associated mutations, and a worse immune-virologic status. Over a cumulative follow-up of 68 152 weeks, 42 discontinuations were registered (5.9%). DTG + DOR had a risk of treatment interruption of 7.8% at 48 weeks and 9.8% at 96 weeks, significantly higher than the other 2DRs. In the multivariate Cox model, DTG + DOR and DTG/RPV were significantly associated with discontinuation. The maintenance of target not detected during follow-up was similar among groups. The rate of virological failure was higher for DTG + DOR through different event definitions.

CONCLUSIONS

DTG + DOR durability was high over a long follow-up albeit lower than for other 2DRs. This combination might be an effective option in people with HIV that has proven difficult to treat.

Switching to Dolutegravir/Lamivudine Two-Drug Regimen: Durability and Virologic Outcomes by Age, Sex, and Race in Routine US Clinical Care

Purpose

Two-drug regimens (2DR) may address drug-drug interactions and toxicity concerns. Dolutegravir/lamivudine (DTG/3TC) 2DR was approved in the US for both treatment-naïve and treatment-experienced individuals with a viral load <50 copies/mL. This study describes real-world DTG/3TC 2DR treatment outcomes among treatment-experienced individuals, stratified by age, sex, and race.

Methods

From the OPERA® cohort, people with HIV with a viral load <50 copies/mL who switched from a commonly used three-drug regimen to DTG/3TC 2DR as per the label between April 8, 2019 and April 30, 2021 were included. Incidence rates (Poisson regression) for loss of virologic control (first viral load ≥50 copies/mL), confirmed virologic failure (2 viral loads ≥200 copies/mL or discontinuation after 1 viral load ≥200 copies/mL), and DTG/3TC 2DR discontinuation were estimated overall and stratified by age, sex, and race.

Results

The 787 individuals included were followed for a median of 13.6 months (IQR: 8.2, 22.3). Confirmed virologic failure occurred in ≤5 individuals. Loss of virologic control occurred at a rate of 14.0 per 100 person-years (95% CI: 11.7, 16.8). DTG/3TC 2DR discontinuation occurred at a rate of 17.5 per 100 person-years (95% CI: 15.0, 20.3); 4% discontinued for treatment-related reasons (viremia, adverse diagnosis, side effect, lab abnormality). For all outcomes, incidence rates were comparable across strata of age, sex, and race.

Conclusion

This descriptive study demonstrates that DTG/3TC 2DR is an effective and well-tolerated treatment option for people with HIV with a viral load <50 copies/mL at switch, regardless of their age, sex, or race.

Human Immunodeficiency Virus-1 Drug Resistance Mutations in Iranian Treatment-experienced Individuals

BACKGROUND

Human immunodeficiency virus-1 infection still remains a global health threat. While antiretroviral therapy is the primary treatment option, concerns about the emergence of drug-resistance mutations and treatment failure in HIV-infected patients persist.

OBJECTIVE

In this study, we investigated the development of drug resistance in HIV-1-infected individuals receiving antiretroviral therapy for 6-10 years.

METHODS

In this cross-sectional study, we evaluated 144 people living with HIV-1 who had received antiretroviral therapy for at least 6 years. Plasma specimens were collected, and the HIV-1 viral load and drug-resistance mutations were assessed using molecular techniques.

RESULTS

The demographic and epidemiological characteristics of the participants were also analyzed: Twelve [8.3%) of the studied patients showed a viral load over 1000 copies per/mL, which indicates the suboptimal response to antiretroviral therapy. Significant correlations were found between viral load and CD4 count, as well as epidemiological factors, such as vertical transmission, history of imprisonment, and needle stick injuries. Drug resistance mutations were detected in 10 (83.3%) of patients who failed on antiretroviral therapy, with the most common mutations observed against nucleoside reverse transcriptase inhibitors (5 (41.7%)) and non-nucleoside reverse transcriptase inhibitors (9 (75%)). Phylogenetic analysis revealed that 12 patients who failed treatment were infected with CRF35_AD.

CONCLUSION

Our study provides important insights into the characteristics and development of drug resistance in HIV-1-infected individuals receiving long-term antiretroviral therapy in Iran. The findings underline the need for regular viral load monitoring, individualized treatment selection, and targeted interventions to optimize treatment outcomes and prevent the further spread of drug-resistant strains.

Effects of the androgen receptor inhibitor enzalutamide on the pharmacokinetics of dolutegravir and tenofovir: a case report

ABSTRACT

Enzalutamide is an androgen receptor inhibitor used for the treatment of prostate cancer. Although enzalutamide causes a favorable adverse effect profile, it might cause drug-drug interactions with some antiretrovirals. No major differences on the main dolutegravir and tenofovir pharmokinetocs were observed in this case report when comparing baseline assessments with those following the introduction of enzalutamide, also when given at higher doses, in a 63-year-old male living with HIV and prostate cancer.

In-vivo pharmacokinetic studies of Dolutegravir loaded spray dried Chitosan nanoparticles as milk admixture for paediatrics infected with HIV

Dolutegravir (DTG) is an antiretroviral drug approved in the year 2013, and being categorized as a BCS-II molecule, it possesses solubility issues. In order to enhance the solubility and improve its bioavailability, DTG-loaded Chitosan nanoparticles (NPs) were synthesized utilizing spray drying technology. The developed nanoformulation was characterized for its physicochemical properties and investigated for the feasibility of its administration through an oral route along with milk/food as an admixture for paediatric antiretroviral therapy. The in vivo oral bioavailability studies were conducted in Balb-C mice, where the animals were treated with the selected formulation of DTG-loaded Chitosan NPs and compared to pure DTG. The NPs exhibited 2.5-fold increase in the C_max (77.54 ± 7.93 μg/mL) when compared to the pure DTG (30.15 ± 8.06 μg/mL). This phenomenon was further reflected by the improved bioavailability of DTG (AUC: 678.3 ± 10.07 μg/h/mL) in the NPs administered to mice when compared to the AUC of animals administered with pure DTG (405.29 ± 7 μg/h/mL). Altogether, the research findings showed that Chitosan-based NPs were ideal carriers for oral administration of DTG along with milk and exhibited great potential to enhance the bioavailability of the drug and treatment adherence for paediatric HIV patients.

Role of islatravir in HIV treatment and prevention: an update

PURPOSE OF REVIEW

To summarize recent updates on the potential role of islatravir for HIV treatment and prevention.

RECENT FINDINGS

Islatravir is an investigational antiretroviral agent with unique pharmacologic properties that facilitate flexible dosing regimens. Islatravir has demonstrated potent antiviral activity and a high barrier to resistance when combined with doravirine and lamivudine. A simplified two-drug HIV treatment regimen of islatravir combined with doravirine has also demonstrated comparable efficacy to standard of care three-drug regimens. The long half-life and high potency of islatravir's active metabolite may support its use as a long-acting option for HIV preexposure prophylaxis (PrEP). A once monthly oral dose of islatravir maintains effective concentrations of its active metabolite over the entire dosing interval. Furthermore, an investigational implantable formulation has been projected to provide efficacious concentrations for at least a year and exhibits comparable distribution into vaginal and rectal tissues making it a promising PrEP option for male and female individuals. Islatravir has minimal risks of drug interactions as it is not a substrate, inducer, or inhibitor of major drug metabolizers and transporters. Finally, clinical trials demonstrate islatravir's favorable safety profile revealing only mild and transient adverse events.

SUMMARY

Leveraging the unique pharmacological properties of islatravir offers opportunities for simplified HIV treatment regimens and long-acting PrEP making it a valuable addition to the antiretroviral arsenal.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

An up-to-date evaluation of dolutegravir/abacavir/lamivudine for the treatment of HIV

INTRODUCTION

There are more than 30 agents available for the treatment of HIV with guidelines shifting toward integrase strand transfer inhibitors (INSTIs) as part of first line therapy. The fixed dose combination of dolutegravir (DTG), abacavir (ABC), and lamivudine (3TC) is a convenient, well tolerated, and highly effective option for treating HIV infection and remains a first line therapy across several prominent guidelines.

AREAS COVERED

In this drug evaluation, the authors provide a comprehensive overview of DTG/ABC/3TC for the treatment of HIV including the pharmacokinetics, pharmacodynamics, efficacy, safety, and tolerability. The authors also provide the reader with their expert perspectives on this particular treatment strategy.

EXPERT OPINION

While DTG/ABC/3TC remains a valuable HIV treatment option, newer combination regimens have entered the market. Bictegravir with tenofovir alafenamide and emtricitabine offers the benefit of same day initiation and efficacy in hepatitis B co-infection, while new two-drug regimens enhance the simplicity of HIV treatment. Continued study is required into the mechanisms and optimal management strategies for weight gain for many regimens, including DTG/ABC/3TC.

Structural insight into the binding interactions of NTPs and nucleotide analogues to RNA dependent RNA polymerase of SARS-CoV-2

RNA dependent RNA polymerase (RdRP) from positive-stranded RNA viruses has always been a hot target for designing of new drugs. Major class of drugs that are targeted against RdRP are nucleotide analogues. Extensive docking and molecular dynamics study describing the binding of natural nucleotides (NTPs) and its analogues leading to significant structural variation in the RdRP has been presented here. RdRP simulations in its apo, NTP-bound, and analogue-bound form have been performed. Nucleotide analogues included in this study were, favipiravir, galidesivir, lamivudine, ribavirin, remdesivir and sofosbuvir. The conformational flexibility of the RdRP molecule has been explored using principal component (PCA) and Markov state modeling (MSM) analysis. PCA inferred the presence of correlated motions among the conserved motifs of RdRP. Inter-domain distances between the finger and thumb subdomain flanking the nascent RNA template entry site sampled open and closed conformations. The ligand and template binding motifs F and G showed negatively correlated motions. K551, R553, and R555, a part of motif F appear to form strong interactions with the ligand molecules. R836, a primer binding residue was observed to strongly bind to the analogues. MSM analysis helped to extract statistically distinct conformations explored by the RdRP. Ensemble docking of the ligands on the Markov states also suggested the involvement of the above residues in ligand interactions. Markov states obtained clearly demarcated the open/closed conformations of the template entry site. These observations on residues from the conserved motifs involved in binding to the ligands may provide an insight into designing new inhibitors.Communicated by Ramaswamy H. Sarma.

Risks and benefits of reducing the number of drugs to treat HIV-1 infection

Introduction: Despite the efficacy and safety of antiretroviral therapy, new treatment options are needed to address the concerns of patients and physicians regarding long-term toxicities, costs, and convenience of lifelong antiretroviral therapy. To achieve this goal, one strategy is to reduce the number of drugs in the antiretroviral regimen.Areas covered: We review the recent evidence on the efficacy and safety of reduced drug regimens and their potential risks and benefits. There is currently strong evidence showing that some two-drug regimens have a comparable efficacy and short-term safety compared to standard three-drug regimens. The fixed-dose combination of dolutegravir/lamivudine is already an alternative for many treatment-naïve and virologically suppressed HIV-1 infected adults supported by large randomized clinical trials. The co-formulation dolutegravir plus rilpivirine is also a switch strategy for maintenance therapy. Long-acting injectable cabotegravir plus rilpivirine has already regulatory approval, and islatravir plus doravirine is an expected option in the near future. Some two-drug regimens have not been as successful.Expert opinion: Long-term safety issues of these two-drug regimens remain to be determined, but with the overwhelming evidence available in virological control and short-term safety, the potential benefits of some of these two-drug regimens appear to outweigh the risks.

Doing More With Less: Review of Dolutegravir-Lamivudine, a Novel Single-Tablet Regimen for Antiretroviral-Naïve Adults With HIV-1 Infection

OBJECTIVE

To review data on efficacy and safety of dolutegravir (DTG) and lamivudine (3TC) in treatment-naïve adults with HIV-1 infection.

DATA SOURCES

Phase III clinical trials and review articles were identified through PubMed (1996 to March 2020) and ClinicalTrials.gov (2000 to May 2020) using the keywords dolutegravir, lamivudine, and HIV.

STUDY SELECTION AND DATA EXTRACTION

Relevant clinical trials and review articles available in English evaluating efficacy and safety of DTG and 3TC were included.

DATA SYNTHESIS

The once-daily, single-tablet regimen of DTG/3TC is the first dual antiretroviral therapy (ART) recommended for initial therapy in treatment-naïve adults with HIV-1 infection. DTG and 3TC were compared with a regimen of DTG and tenofovir disoproxil fumarate/emtricitabine in the GEMINI studies and demonstrated noninferiority for the primary end point of virological suppression at up to 96 weeks. No treatment-emergent resistance mutations were identified in a small group of participants who did not reach virological suppression. The regimen is well tolerated, and the most common adverse events reported in trials include headache, diarrhea, nausea, insomnia, and fatigue.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This dual-ART regimen is a favorable treatment option for ART-naïve patients with HIV-1 RNA <500 000 copies/mL, absence of hepatitis B virus, and no resistance to DTG or 3TC. Benefits of dual ART include reduction in treatment-related adverse events and toxicities, drug interactions, and cost. In addition, the once-daily, single-tablet formulation promotes adherence.

CONCLUSIONS

DTG/3TC has demonstrated efficacy in maintaining virological suppression in ART-naïve patients at up to 96 weeks while minimizing treatment-related adverse events and toxicities.

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.