Accumulation of integrase strand transfer inhibitor resistance mutations confers high-level resistance to dolutegravir in non-B subtype HIV-1 strains from patients failing raltegravir in Uganda

Dolutegravir based therapy showed CD4+ T cell count recovery and viral load suppression among ART naïve people living with HIV AIDS: a pilot evaluation

Recently, dolutegravir (DTG)-based combined therapy, a more effective and safer first-line antiretroviral therapy (ART), has been recommended by the World Health Organization for the treatment of Human Immunodeficiency Virus (HIV) since July 2018. However, its effectiveness in CD4+ T-cells count recovery and viral load suppression has not been studied yet in Ethiopia, where HIV is endemic. Therefore, we aimed to conduct a pilot assessment on the effect of DTG-based therapy on CD4+ T-cell count and viral load count among people living with HIV (PLWH) in Ethiopia. A longitudinal prospective cohort study was conducted from July 2020 to February 2021. 109 PLWH who are ART naive but plan to initiate DTG-based therapy were recruited. HIV viral ribonucleic acid (RNA) copies were determined using polymerase chain reaction. To compute the difference in viral load and CD4+ T-cell counts between the baseline, 3rd, and 6th months, a Friedman test was used. The study included 109 PLWH who had never received antiretroviral medication. Participants taking DTG-based treatment showed significantly decreasing median (IQR) values of viral load count (copies/mL) from 446,812 (237649.5-732994.5) at baseline to 34 (23.5-46) at 3 months and 0.0 (0-19) at 6 months of treatment follow-up. Although the treatment increases the proportion of participants with HIV-1 RNA 50 copies/mL from 0 (0% at baseline) to 87 (79.8%) and 100 (91.7%) at the 3rd and 6th months of treatment, respectively, On the other hand, the CD4+ T-cell count increased significantly during treatment: median (IQR): 209 (81.5-417.5) versus 291 (132-522) versus 378 (181-632.5) cells/L at baseline, the 3rd and 6th months of the treatment follow-up period, respectively. We found dolutegravir-based therapy was a promising option with high virological suppression rates and CD4+ T-cell count recovery, demonstrating a restoration of cellular immunity. Moreover, Viral load suppression rates were high after the initiation of the treatment. We recommend further research should be conducted with a larger number of participants to acquire greater awareness of the treatment outcomes.

Comprehensive Analysis of HIV-1 Integrase Resistance-Related Mutations in African Countries

The growing emergence of non-nucleoside reverse transcriptase inhibitor (NNRTI) HIV drug resistance in sub-Saharan Africa (SSA) led to the World Health Organization (WHO) recommending, in 2018, a transition to dolutegravir (DTG) as a first-line antiretroviral therapy (ART) in SSA. The broad HIV-1 genetic diversity in SSA could shape DTG effectiveness and the pattern of drug resistance mutations (DRMs) in this region. This study evaluated HIV-1 integrase (IN) DRMs and conserved regions among published groups M, N, O, and P HIV-1 sequences spanning forty years of the HIV epidemic during the transition of DTG-based ART. Overall, we found low levels of integrase strand transfer inhibitor (INSTI)-DRMs (<1%) across HIV groups between the years 1983 and 2023; however, it was unexpected to detect DRMs at statistically significantly higher frequencies in pre-INSTI (1983-2007) than in the INSTI (2008-2023) era. The variability of accessory INSTI-DRMs depended on the HIV subtypes, with implications for susceptibility to DTG. Our findings provide new perspectives on the molecular epidemiology and drug resistance profiles of INSTIs in SSA, emphasizing the need for ongoing surveillance and customized treatment approaches to address the continent's varied HIV subtypes and changing resistance patterns.

New antiretroviral inhibitors and HIV-1 drug resistance: more focus on 90% HIV-1 isolates?

Combined HIV antiretroviral therapy (cART) has been effective except if drug resistance emerges. As cART has been rolled out in low-income countries, drug resistance has emerged at higher rates than observed in high income countries due to factors including initial use of these less tolerated cART regimens, intermittent disruptions in drug supply, and insufficient treatment monitoring. These socioeconomic factors impacting drug resistance are compounded by viral mechanistic differences by divergent HIV-1 non-B subtypes compared to HIV-1 subtype B that largely infects the high-income countries (just 10% of 37 million infected). This review compares the inhibition and resistance of diverse HIV-1 subtypes and strains to the various approved drugs as well as novel inhibitors in clinical trials. Initial sequence variations and differences in replicative fitness between HIV-1 subtypes pushes strains through different fitness landscapes to escape from drug selective pressure. The discussions here provide insight to patient care givers and policy makers on how best to use currently approved ART options and reduce the emergence of drug resistance in ∼33 million individuals infected with HIV-1 subtype A, C, D, G, and recombinants forms. Unfortunately, over 98% of the literature on cART resistance relates to HIV-1 subtype B.

New designs for HIV-1 integrase inhibitors: a patent review (2018-present)

INTRODUCTION

Combination antiretroviral therapy (cART) has dramatically reduced morbidity and mortality of HIV-1-infected patients. Integrase strand transfer inhibitors (INSTIs) play an important role as a key drug in cART. The second-generation INSTIs are very potent, but due to the emergence of highly resistant viruses and the demand for more conveniently usable drugs, the development of 'third-generation' INSTIs and mechanistically different inhibitors is actively being pursued.

AREAS COVERED

This article reviews the patents (from 2018 to the present) for two classes of HIV-1 integrase inhibitors of INSTIs and integrase-LEDGF/p75 allosteric inhibitors (INLAIs).

EXPERT OPINION

Since the approval of the second-generation INSTI dolutegravir, the design of new INSTIs has been mostly focused on its scaffold, carbamoylpyridone (CAP). This CAP scaffold is used not only for HIV-1 INSTIs but also for drug discoveries targeting other viral enzymes. With the approval of cabotegravir as a regimen of long-acting injection in combination with rilpivirine, there is a growing need for longer-acting agents. INLAIs have been intensely studied by many groups but have yet to reach the market. However, INLAIs have recently been reported to also function as a latency promoting agent (LPA), indicating further development possibilities.

Pre-Treatment Integrase Inhibitor Resistance and Natural Polymorphisms among HIV-1 Subtype C Infected Patients in Ethiopia

Dolutegravir-based antiretroviral therapy (ART) has been scaled up in many developing countries, including Ethiopia. However, subtype-dependent polymorphic differences might influence the occurrence of HIV-drug-resistance mutations (HIVDRMs). We analyzed the prevalence of pre-treatment integrase strand transfer inhibitor (INSTI) HIVDRMs and naturally occurring polymorphisms (NOPs) of the integrase gene, using plasma samples collected as part of the national HIVDR survey in Ethiopia in 2017. We included a total of 460 HIV-1 integrase gene sequences from INSTI-naïve (n = 373 ART-naïve and n = 87 ART-experienced) patients. No dolutegravir-associated HIVDRMs were detected, regardless of previous exposure to ART. However, we found E92G in one ART-naïve patient specimen and accessory mutations in 20/460 (4.3%) of the specimens. Moreover, among the 288 integrase amino acid positions of the subtype C, 187/288 (64.9%) were conserved (<1.0% variability). Analysis of the genetic barrier showed that the Q148H/K/R dolutegravir resistance pathway was less selected in subtype C. Docking analysis of the dolutegravir showed that protease- and reverse-transcriptase-associated HIVDRMs did not affect the native structure of the HIV-1 integrase. Our results support the implementation of a wide scale-up of dolutegravir-based regimes. However, the detection of polymorphisms contributing to INSTI warrants the continuous surveillance of INSTI resistance.

Exploring the mechanisms behind HIV drug resistance in sub-Saharan Africa: conceptual mapping of a complex adaptive system based on multi-disciplinary expert insights

Background

HIV drug resistance (HIVDR) continues to threaten the effectiveness of worldwide antiretroviral therapy (ART). Emergence and transmission of HIVDR are driven by several interconnected factors. Though much has been done to uncover factors influencing HIVDR, overall interconnectedness between these factors remains unclear and African policy makers encounter difficulties setting priorities combating HIVDR. By viewing HIVDR as a complex adaptive system, through the eyes of multi-disciplinary HIVDR experts, we aimed to make a first attempt to linking different influencing factors and gaining a deeper understanding of the complexity of the system.

Methods

We designed a detailed systems map of factors influencing HIVDR based on semi-structured interviews with 15 international HIVDR experts from or with experience in sub-Saharan Africa, from different disciplinary backgrounds and affiliated with different types of institutions. The resulting detailed system map was conceptualized into three main HIVDR feedback loops and further strengthened with literature evidence.

Results

Factors influencing HIVDR in sub-Saharan Africa and their interactions were sorted in five categories: biology, individual, social context, healthcare system and ‘overarching’. We identified three causal loops cross-cutting these layers, which relate to three interconnected subsystems of mechanisms influencing HIVDR. The ‘adherence motivation’ subsystem concerns the interplay of factors influencing people living with HIV to alternate between adherence and non-adherence. The ‘healthcare burden’ subsystem is a reinforcing loop leading to an increase in HIVDR at local population level. The ‘ART overreliance’ subsystem is a balancing feedback loop leading to complacency among program managers when there is overreliance on ART with a perceived low risk to drug resistance. The three subsystems are interconnected at different levels.

Conclusions

Interconnectedness of the three subsystems underlines the need to act on the entire system of factors surrounding HIVDR in sub-Saharan Africa in order to target interventions and to prevent unwanted effects on other parts of the system. The three theories that emerged while studying HIVDR as a complex adaptive system form a starting point for further qualitative and quantitative investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12738-4.

Structure and function of retroviral integrase

A hallmark of retroviral replication is establishment of the proviral state, wherein a DNA copy of the viral RNA genome is stably incorporated into a host cell chromosome. Integrase is the viral enzyme responsible for the catalytic steps involved in this process, and integrase strand transfer inhibitors are widely used to treat people living with HIV. Over the past decade, a series of X-ray crystallography and cryogenic electron microscopy studies have revealed the structural basis of retroviral DNA integration. A variable number of integrase molecules congregate on viral DNA ends to assemble a conserved intasome core machine that facilitates integration. The structures additionally informed on the modes of integrase inhibitor action and the means by which HIV acquires drug resistance. Recent years have witnessed the development of allosteric integrase inhibitors, a highly promising class of small molecules that antagonize viral morphogenesis. In this Review, we explore recent insights into the organization and mechanism of the retroviral integration machinery and highlight open questions as well as new directions in the field.

HIV-1 integrase resistance associated mutations and the use of dolutegravir in Sub-Saharan Africa: A systematic review and meta-analysis

As sub-Saharan Africa (SSA) countries are transitioning to dolutegravir (DTG)-based ART, baseline data are required for optimal monitoring of therapeutic response. In this frame, we sought to generate up-to-date evidence on the use of integrase-strand transfer inhibitors (INSTI) and associated drug resistance mutations (DRMs) within SSA. In this systematic review and meta-analysis, we included randomized and non-randomized trials, cohort-studies, cross-sectional studies, and case-reports published on INSTI or integrase DRMs in SSA. We included studies of patients exposed to DTG, raltegravir (RAL) or elvitegravir (EVG). Primary outcomes were "the rate of virological control (VC:<50copies/ml)" and "the presence of DRMs" on INSTI-based regimens among patients in SSA. We synthesised extracted data using subgroup analysis, and random effect models were used where appropriate. Additional analyses were conducted to assess study heterogeneity. We identified 1,916 articles/citations through database searches, of which 26 were included in the analysis pertaining to 5,444 patients (mean age: 37±13 years), with 67.62% (3681/5444) female. Specifically, 46.15% (12/26) studies focused on DTG, 26.92% (7/26) on RAL, 23.08% (6/26) on both DTG and RAL, and 3.85% (1/26) on EVG. We found an increasing use of DTG overtime (0% before 2018 to 100% in 2021). Median treatment duration under INSTI-based regimens was 12 [9-36] months. Overall, the rate of VC was 88.51% [95%CI: 73.83-97.80] with DTG vs. 82.49% [95%CI: 55.76-99.45] and 96.55% [95%CI: 85.7-100.00] with RAL and EVG, respectively. In univariate analysis, VC with DTG-containing vs. other INSTI-regimens was significantly higher (OR = 1.44 [95%CI: 1.15-1.79], p = 0.0014). Among reported DRMs at failure, the only DTG resistance-mutations were G118R and R263K. In SSA, DTG presents a superiority effect in VC compared to other INSTIs. Nonetheless, the early detection of INSTI-DRMs calls for sentinel surveillance for a successful transition and a sustained efficacy of DTG in SSA. PROSPERO Registration Number: CRD42019122424.

High-level resistance to bictegravir and cabotegravir in subtype A- and D-infected HIV-1 patients failing raltegravir with multiple resistance mutations

OBJECTIVES

The second-generation integrase strand transfer inhibitor (INSTI) bictegravir is becoming accessible in low- and middle-income countries (LMICs), and another INSTI, cabotegravir, has recently been approved as a long-acting injectable. Data on bictegravir and cabotegravir susceptibility in raltegravir-experienced HIV-1 subtype A- and D-infected patients carrying drug resistance mutations (DRMs) remain very scarce in LMICs.

PATIENTS AND METHODS

HIV-1 integrase (IN)-recombinant viruses from eight patients failing raltegravir-based third-line therapy in Uganda were genotypically and phenotypically tested for susceptibility to bictegravir and cabotegravir. Ability of these viruses to integrate into human genomes was assessed in MT-4 cells.

RESULTS

HIV-1 IN-recombinant viruses harbouring single primary mutations (N155H or Y143R/S) or in combination with secondary INSTI mutations (T97A, M50I, L74IM, E157Q, G163R or V151I) were susceptible to both bictegravir and cabotegravir. However, combinations of primary INSTI-resistance mutations such as E138A/G140A/G163R/Q148R or E138K/G140A/S147G/Q148K led to decreased susceptibility to both cabotegravir (fold change in EC50 values from 429 to 1000×) and bictegravir (60 to 100×), exhibiting a high degree of cross-resistance. However, these same IN-recombinant viruses showed impaired integration capacity (14% to 48%) relative to the WT HIV-1 NL4-3 strain in the absence of drug.

CONCLUSIONS

Though not currently widely accessible in most LMICs, bictegravir and cabotegravir offer a valid alternative to HIV-infected individuals harbouring subtype A and D HIV-1 variants with reduced susceptibility to first-generation INSTIs but previous exposure to raltegravir may reduce efficacy, more so with cabotegravir.