We need to use the best antiretroviral drugs worldwide to prevent HIV drug resistance

Structure of a HIV-1 IN-Allosteric inhibitor complex at 2.93 Å resolution: Routes to inhibitor optimization

HIV integrase (IN) inserts viral DNA into the host genome and is the target of the strand transfer inhibitors (STIs), a class of small molecules currently in clinical use. Another potent class of antivirals is the allosteric inhibitors of integrase, or ALLINIs. ALLINIs promote IN aggregation by stabilizing an interaction between the catalytic core domain (CCD) and carboxy-terminal domain (CTD) that undermines viral particle formation in late replication. Ongoing challenges with inhibitor potency, toxicity, and viral resistance motivate research to understand their mechanism. Here, we report a 2.93 Å X-ray crystal structure of the minimal ternary complex between CCD, CTD, and the ALLINI BI-224436. This structure reveals an asymmetric ternary complex with a prominent network of π-mediated interactions that suggest specific avenues for future ALLINI development and optimization.

Hollow mesoporous structured molecularly imprinted polymer as adsorbent in pipette-tip solid-phase extraction for the determination of antiretrovirals from plasma of HIV-infected patients

In this work a hollow mesoporous structured molecularly imprinted polymer was synthetized and used as adsorbent in pipette-tip solid-phase extraction for the determination of lamivudine (3TC), zidovudine (AZT) and efavirenz (EFZ) from plasma of human immunodeficiency virus (HIV) infected patients by high-performance liquid chromatography (HPLC). All parameters that influence the recovery of the pipette tip based on hollow mesoporous molecularly imprinted polymer solid-phase extraction (PT-HM-MIP-SPE) method were systematically studied and discussed in detail. The adsorbent material was prepared using methacrylic acid and 4-vinylpyridine as functional monomers, ethylene glycol dimethacrylate as crosslinker, acetonitrile as solvent, 4,4'-azobis(4-cyanovaleric acid) as radical initiator, benzalkonium chloride as surfactant, 3TC, and AZT as templates. The simultaneous separation of 3TC, AZT and EFZ by HPLC-UV was performed using a Gemini C18 Phenomenex® column (250 mm × 4.6 mm, 5 μm) and mobile phase consisting of acetonitrile: water pH 3.2 (68:32, v/v), flow rate of 1.0 mL/min and λ = 260 nm. The method was linear over the concentration range from 0.25 to 10 μg/mL for 3TC and EFZ, and 0.05 to 2.0 μg mL^-1 for AZT, with correlation coefficients larger than 0.99 for all analytes. Recovery ± relative standard deviations (RSDs %) were 41.99 ± 2.38%, 82.29 ± 1.63%, and 83.72 ± 7.52% for 3TC, AZT, and EFZ, respectively. The RSDs and relative errors (REs) were lower than 15% for intra and interday assays. The method has been successfully applied for monitoring HIV-infected patients outside the therapeutic dosage.

The anti-caspase inhibitor Q-VD-OPH prevents AIDS disease progression in SIV-infected rhesus macaques

Apoptosis has been proposed as a key mechanism responsible for CD4+ T cell depletion and immune dysfunction during HIV infection. We demonstrated that Q-VD-OPH, a caspase inhibitor, inhibits spontaneous and activation-induced death of T cells from SIV-infected rhesus macaques (RMs). When administered during the acute phase of infection, Q-VD-OPH was associated with (a) reduced levels of T cell death, (b) preservation of CD4+/CD8+ T cell ratio in lymphoid organs and in the gut, (c) maintenance of memory CD4+ T cells, and (d) increased specific CD4+ T cell response associated with the expression of cytotoxic molecules. Although therapy was limited to the acute phase of infection, Q-VD-OPH-treated RMs showed lower levels of both viral load and cell-associated SIV DNA as compared with control SIV-infected RMs throughout the chronic phase of infection, and prevented the development of AIDS. Overall, our data demonstrate that Q-VD-OPH injection in SIV-infected RMs may represent an adjunctive therapeutic agent to control HIV infection and delaying disease progression to AIDS.

HIV-1 strains belonging to large phylogenetic clusters show accelerated escape from integrase inhibitors in cell culture compared with viral isolates from singleton/small clusters

Objectives: Viral phylogenetics revealed two patterns of HIV-1 spread among MSM in Quebec. While most HIV-1 strains (n = 2011) were associated with singleton/small clusters (cluster size 1–4), 30 viral lineages formed large networks (cluster size 20–140), contributing to 42% of diagnoses between 2011 and 2015. Herein, tissue culture selections ascertained if large cluster lineages possessed higher replicative fitness than singleton/small cluster isolates, allowing for viral escape from integrase inhibitors.

Methods: Primary HIV-1 isolates from large 20+ cluster (n = 11) or singleton/small cluster (n = 6) networks were passagedin vitro in escalating concentrations of dolutegravir, elvitegravir and lamivudine for 24–36 weeks. Sanger and deep sequencing assessed genotypic changes under selective drug pressure.

Results: Large cluster HIV-1 isolates selected for resistance to dolutegravir, elvitegravir and lamivudine faster than HIV-1 strains forming small clusters. With dolutegravir, large cluster HIV-1 variants acquired solitary R263K (n = 7), S153Y (n = 1) or H51Y (n = 1) mutations as the dominant quasi-species within 8–12 weeks as compared with small cluster lineages where R263K (n = 1/6), S153Y (1/6) or WT species (4/6) were observed after 24 weeks. Interestingly, dolutegravir-associated mutations compromised viral replicative fitness, precluding escalations in concentrations beyond 5–10 nM. With elvitegravir, large cluster variants more rapidly acquired first mutations (T66I, A92G, N155H or S147G) by week 8 followed by sequential accumulation of multiple mutations leading to viral escape (>10 μM) by week 24.

Conclusions: Further studies are needed to understand virological features of large cluster viruses that may favour their transmissibility, replicative competence and potential to escape selective antiretroviral drug pressure.

Genotypic and Phylogenetic Insights on Prevention of the Spread of HIV-1 and Drug Resistance in "Real-World" Settings

HIV continues to spread among vulnerable heterosexual (HET), Men-having-Sex with Men (MSM) and intravenous drug user (IDU) populations, influenced by a complex array of biological, behavioral and societal factors. Phylogenetics analyses of large sequence datasets from national drug resistance testing programs reveal the evolutionary interrelationships of viral strains implicated in the dynamic spread of HIV in different regional settings. Viral phylogenetics can be combined with demographic and behavioral information to gain insights on epidemiological processes shaping transmission networks at the population-level. Drug resistance testing programs also reveal emergent mutational pathways leading to resistance to the 23 antiretroviral drugs used in HIV-1 management in low-, middle- and high-income settings. This article describes how genotypic and phylogenetic information from Quebec and elsewhere provide critical information on HIV transmission and resistance, Cumulative findings can be used to optimize public health strategies to tackle the challenges of HIV in “real-world” settings.

HIV drug resistance against strand transfer integrase inhibitors

Integrase strand transfer inhibitors (INSTIs) are the newest class of antiretroviral drugs to be approved for treatment and act by inhibiting the essential HIV protein integrase from inserting the viral DNA genome into the host cell’s chromatin. Three drugs of this class are currently approved for use in HIV-positive individuals: raltegravir (RAL), elvitegravir (EVG), and dolutegravir (DTG), while cabotegravir (CAB) and bictegravir (BIC) are currently in clinical trials. RAL and EVG have been successful in clinical settings but have relatively low genetic barriers to resistance. Furthermore, they share a high degree of cross-resistance, which necessitated the development of so-called second-generation drugs of this class (DTG, CAB, and BIC) that could retain activity against these resistant variants. In vitro selection experiments have been instrumental to the clinical development of INSTIs, however they cannot completely recapitulate the situation in an HIV-positive individual. This review summarizes and compares all the currently available information as it pertains to both in vitro and in vivo selections with all five INSTIs, and the measured fold-changes in resistance of resistant variants in in vitro assays. While the selection of resistance substitutions in response to RAL and EVG bears high similarity in patients as compared to laboratory studies, there is less concurrence regarding the “second-generation” drugs of this class. This highlights the unpredictability of HIV resistance to these inhibitors, which is of concern as CAB and BIC proceed in their clinical development.