Emergence of compensatory mutations reveal the importance of electrostatic interactions between HIV-1 integrase and genomic RNA

Independent of its catalytic activity, HIV-1 integrase (IN) enzyme regulates proper particle maturation by binding to and packaging the viral RNA genome (gRNA) inside the mature capsid lattice. Allosteric integrase inhibitors (ALLINIs) and class II IN substitutions inhibit the binding of IN to the gRNA and cause the formation of non-infectious virions characterized by mislocalization of the viral ribonucleoprotein complexes between the translucent conical capsid lattice and the viral lipid envelope. To gain insight into the molecular nature of IN-gRNA interactions, we have isolated compensatory substitutions in the background of a class II IN (R269A/K273A) variant that directly inhibits IN binding to the gRNA. We found that additional D256N and D270N substitutions in the C-terminal domain (CTD) of IN restored its ability to bind gRNA and led to the formation of infectious particles with correctly matured morphology. Furthermore, reinstating the overall positive electrostatic potential of the CTD through individual D256R or D256K substitutions was sufficient to restore IN-RNA binding and infectivity for the R269A/K273A as well as the R262A/R263A class II IN mutants. The compensatory mutations did not impact functional IN oligomerization, suggesting that they directly contributed to IN binding to the gRNA. Interestingly, HIV-1 IN R269A/K273A, but not IN R262A/R263A, bearing compensatory mutations was more sensitive to ALLINIs providing key genetic evidence that specific IN residues required for RNA binding also influence ALLINI activity. Structural modeling provided further insight into the molecular nature of IN-gRNA interactions and ALLINI mechanism of action. Taken together, our findings highlight an essential role of IN-gRNA interactions for proper virion maturation and reveal the importance of electrostatic interactions between the IN CTD and the gRNA.

Excess weight gain with integrase inhibitors and tenofovir alafenamide: what is the mechanism and does it matter?

Numerous studies have detected a greater likelihood of excess weight gain with specific antiretrovirals (ARV’s), particularly tenofovir alafenamide and integrase inhibitors, as compared to other agents and classes. The long-term implications and potential reversibility for individuals who have experienced substantial ARV-associated weight accumulation remain poorly understood. Furthermore, the underlying mechanism remains controversial: is the explanation mitochondrial toxicity and weight suppression from the older agents or direct effects of the newer drugs on appetite, adipocytes, or other unintended targets? This review discusses proposed mechanisms and evidence to date and argues that the question about mechanism is highly clinically relevant because it carries significant implications for ARV management. The existing literature suggests that older ARV’s, such as tenofovir disoproxil fumarate and efavirenz, suppress weight gain, but also that integrase inhibitors may stimulate excess weight gain through several pausible biologic pathways. Confirming the mechanisms of ARV-associated excess weight gain should be high priority for future research.

Absence of Resistance Mutations in the Integrase Coding Region among ART-Experienced Patients in the Republic of the Congo

Background: HIV infects around one hundred thousand patients in the Republic of the Congo. Approximately 25% of them receive an antiretroviral treatment; current first-line regimens include two NRTIs and one NNRTI, reverse transcriptase inhibitors. Recently, protease inhibitors (PIs) were also introduced as second-line therapy upon clinical signs of treatment failure. Due to the limited number of molecular characterizations and amount of drug resistance data available in the Republic of the Congo, this study aims to evaluate the prevalence of circulating resistance mutations within the pol region. Methods: HIV-positive, ART-experienced patients have been enrolled in four semi-urban localities in the Republic of the Congo. Plasma samples were collected, and viral RNA was extracted. The viral load for each patient was evaluated by RT-qPCR, following the general diagnostic procedures of the University Hospital of Bordeaux. Finally, drug resistance genotyping and phylogenetic analysis were conducted following Sanger sequencing of the pol region. Results: A high diversity of HIV-1 strains was observed with many recombinant forms. Drug resistance mutations in RT and PR genes were determined and correlated to HAART. Because integrase inhibitors are rarely included in treatments in the Republic of the Congo, the prevalence of integrase drug resistance mutations before treatment was also determined. Interestingly, very few mutations were observed. Conclusions: We confirmed a high diversity of HIV-1 in the Republic of the Congo. Most patients presented an accumulation of mutations conferring resistance against NRTIs, NNRTIs and PIs. Nonetheless, the absence of integrase mutations associated with drug resistance suggests that the introduction of integrase inhibitors into therapy will be highly beneficial to patients in the Republic of the Congo.

889. Early Discontinuations and Adverse Events Among Treatment-Naïve Patients Initiating Integrase Inhibitors in a Real-world Setting

Background Cohort studies suggest higher rates of discontinuations (DCs) and adverse events (AEs) with integrase inhibitors (INSTIs) than is reported in clinical trials. Here, we assess DC of different INSTIs in combination with one of two tenofovir prodrugs in the first year following initiation defined as “early DC” in a real-world cohort of treatment-naïve patients. Methods This analysis evaluated treatment-naïve patients at a single center initiating raltegravir (RAL), elvitegravir/cobicistat (EVG/c), dolutegravir (DTG) or bictegravir (BIC) in combination with emtricitabine/tenofovir alafenamide (F/TAF) or emtricitabine/tenofovir disoproxil fumarate (F/TDF) between 10/2007-1/2020. Eligible patients had a minimum follow-up of 1 year. The primary endpoint was incidence of early INSTI DC. Secondary endpoints included AEs and risk factors for early INSTI DC and treatment-related AEs. Results 331 patients were included. Median age was 32 years, 89% were male, 43% were non-White, 8% started RAL-based therapy, 46% started EVG/c-based therapy, 22% started DTG-based therapy and 24% started BIC/F/TAF. 36 discontinued INSTI-based therapy early yielding an incidence rate of 0.17 DCs per person-years (PPY) among RAL patients, 0.14 DCs PPY among EVG/c patients, 0.22 DCs PPY among DTG patients, and 0 DCs PPY among BIC patients, p=0.006. Treatment-related AEs occurred in 27% of RAL patients, 42% of EVG/c patients, 50% of DTG patients, and 43% of BIC patients p=0.607; and were responsible for early DC rates of 0.022 in 3 EVG/c patients and 0.075 in 5 DTG patients. No treatment-related early DCs occurred among RAL or BIC patients. No evaluated factor was significantly associated with early INSTI DC, however DTG use was significantly associated with treatment-related AEs (aOR 3.46, 95% confidence interval: [1.20; 10.82]). Table 1. Risk factors for early integrase inhibitor discontinuation and treatment-related adverse events Conclusion In this cohort, early DCs occurred in 11% initiating INSTI-based therapy, however of these only 2% were treatment-related. These data support use of INSTI-based regimens as preferred options for treatment-naïve patients living with HIV due to their favorable safety and tolerability profiles. Disclosures Charlotte-Paige M. Rolle, MD MPH, Gilead Sciences (Grant/Research Support, Scientific Research Study Investigator, Speaker’s Bureau)Janssen Infectious Disease (Scientific Research Study Investigator, Advisor or Review Panel member)ViiV Healthcare (Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau) Kiran Patel, PharmD, Gilead Sciences (Employee) Federico Hinestrosa, MD, AbbVie (Speaker’s Bureau)Gilead Sciences (Advisor or Review Panel member, Speaker’s Bureau)Theratechonologies (Advisor or Review Panel member)ViiV Healthcare (Advisor or Review Panel member, Speaker’s Bureau) Edwin DeJesus, MD, Gilead Sciences (Scientific Research Study Investigator, Advisor or Review Panel member)

890. Evaluation of Association Among Integrase Inhibitors for HIV Treatment, Weight Gain, and Body Image

Background Integrase inhibitors (INSTIs) are preferred antiretroviral agents for people living with HIV (PLWH). Recent studies suggest that INSTIs may contribute to weight gain and the development of metabolic syndrome. A lack of knowledge remains about how INSTIs affect metabolic parameters that contribute to weight gain as well as the impact of weight gain on medication adherence and body image in PLWH. Methods We conducted a retrospective chart review along with a real time survey of PLWH who are receiving HIV care at UConn Health. Participants who were switched to or added an INSTI to their ART regimen between 2012 - 2020 were included (n=204). Patient weight was recorded in 3-month intervals for two years prior to and two years after INSTI initiation. Lipid profile parameters and hemoglobin A1c were noted pre and post INSTI switch. A survey was administered to rate perception of weight gain, body appearance, and medication adherence on a five-point Likert scale. Statistical methods included Chi-square test and Fisher’s Exact test for categorical data, and T-test or Kruskal-Wallis test for continuous data. Results Patients started on or switched to any INSTI regimen experienced a mean weight gain of 5 and 7 pounds at 12 and 24 months, respectively (p < 0.001). Weight gain was greatest with raltegravir and elvitegravir (Figure 1,2). Bictegravir regimens resulted in a 4 pound weight loss at 24 months. An INSTI switch increased cholesterol by a mean of of 7.9mg/dL (p=0.05), with no effect on other parameters. A switch to Bictegravir increased HDL by 4mg/dL (p=0.04) and decreased triglycerides by 35mg/dL (p=0.04). Survey results showed that 100% of patients denied missing ART doses despite 69% mentioning weight gain due to ART. 97% of patients were satisfied with their ART regimen, with the majority disagreeing that their body image was negatively affected. Conclusion We demonstrate a link between INSTI use and weight gain up to two years following INSTI initiation, with the most weight gained within the first 12 months. Elvitegravir and raltegravir are associated with greater weight gain whereas bictegravir demonstrates weight loss and beneficial effects on lipid profile. Despite weight gain, most patients remained adherent and satisfied with their medication and denied negative perceptions of body image. Disclosures All Authors: No reported disclosures

Design, Synthesis and Docking Studies of Thioimidazolyl Diketoacid Derivatives Targeting HIV-1 Integrase

Background: Integrase enzyme is a validated drug target to discover novel structures as anti-HIV-1 agents. Objective: Novel series of thioimidazolyl diketo acid derivatives characterizing various substituents at N-1 and 2-thio positions of central ring were developed as HIV-1 integrase inhibitors. Results: The obtained molecules were evaluated in the enzyme assay, displaying promising integrase inhibitory activity with IC50 values ranging from 0.9 to 7.7 M. The synthesized compounds were also tested for antiviral activity and cytotoxicity using HeLa cells infected by the single-cycle replicable HIV-1 NL4-3. Conclusion: The most potent compound was 18i with EC50=19 µM, IC50 0.9 µM and SI= 10.5. Docking studies indicated that the binding mode of the active molecule is well aligned with the known HIV-1 integrase inhibitors.

Anti-HIV Integrase Inhibitors as New Candidates for the Treatment of COVID-19: A Narrative Literature Review

Background: The initial reports of a contagious novel Severe Acute Respiratory Syndrome – Coronavirus-2 (SARS-CoV-2) were proclaimed by Wuhan, Hubei province, China. This pathogen quickly became a health concern due to the World Health Organization's (WHO) alarm of its pandemic essence. Hence, there is an urgent need for efficacious and curative therapy against COVID-19. Objective: Theoretically, repurposing anti-viral drugs, specifically HIV treatments, could help the urgent need for treating COVID-19 due to the structural similarities of their critical enzyme substrates. Integrase inhibitors are a category of anti-HIV drugs that inhibit integrase strand transfer. In this review, we investigate the binding affinity and stability of raltegravir, dolutegravir, bictegravir, and elvitegravir in interactions with crucial enzymes of coronavirus. Methods: A literature search was conducted using scientific databases such as Web of Science, Medline (PubMed), Scopus, Google Scholar, and Embase from commencement to September 2020. The most relevant articles regarding the potential effects of integrase inhibitors against COVID-19 were gathered. Ultimately, ten original articles related to the searched terms were selected for this narrative review. Results: Apparently, in addition to the recent drugs prescribed to cure SARS-CoV-2, integrase inhibitors are promising drugs for repurposing in COVID-19 treatment. Several studies on raltegravir, dolutegravir, bictegravir and elvitegravir were conducted using virtual screening to guess either they are effective or not. Encouraging results were mostly reported for raltegravir and dolutegravir. Nevertheless, bictegravir and elvitegravir need more investigations. Conclusion: Further experimental and clinical studies of antiviral drugs are necessary to introduce appropriate treatment options for COVID-19.

Efficacy, effectiveness, and safety of integrase inhibitors in the treatment of HIV/AIDS in patients with tuberculosis: A systematic review and meta-analysis

Aims: To evaluate the efficacy, effectiveness, and safety of integrase inhibitors in the treatment of HIV/AIDS in patients coinfected with tuberculosis (TB). Methods: Clinical trials or observational studies were included. The searches were performed in the MEDLINE, EMBASE, LILACS, COCHRANE, Web of Science, Scopus, and CINAHL databases using the terms “HIV”, “AIDS”, “tuberculosis”, “raltegravir potassium”, “dolutegravir”, “elvitegravir”, “bictegravir”, “integrase inhibitor”, and their respective synonyms. The methodological quality of the studies was independently assessed using the Cochrane risk of bias and Newcastle Ottawa scales. Results: Reports from three randomised clinical trials and a historical cohort were included. Patients coinfected with TB and HIV/AIDS showed a good response to TB treatment, which was above 85% in all arms of the evaluated studies. As a primary outcome, the HIV viral load suppression rates at week 48 were greater than 60% in all arms. The therapies evaluated in patients coinfected with TB and HIV/AIDS were also proven to be safe. However, there was no statistically significant difference in the efficacy outcomes between the efavirenz and integrase inhibitor arms, and regarding safety outcomes, there were few events compared with the total. Furthermore, the certainty of the evidence of the outcomes assessed was low, indicating that future research is likely to have an important impact on this estimate. Conclusion: Integrase inhibitors are effective and well tolerated, being an alternative to efavirenz in clinical protocols. However, more studies with high quality evidence are needed on the use of this treatment in health systems.