Low-frequency drug-resistant HIV-1 and risk of virological failure to first-line NNRTI-based ART: a multicohort European case-control study using centralized ultrasensitive 454 pyrosequencing

Objectives It is still debated if pre-existing minority drug-resistant HIV-1 variants (MVs) affect the virological outcomes of first-line NNRTI-containing ART. Methods This Europe-wide case-control study included ART-naive subjects infected with drug-susceptible HIV-1 as revealed by population sequencing, who achieved virological suppression on first-line ART including one NNRTI. Cases experienced virological failure and controls were subjects from the same cohort whose viraemia remained suppressed at a matched time since initiation of ART. Blinded, centralized 454 pyrosequencing with parallel bioinformatic analysis in two laboratories was used to identify MVs in the 1%-25% frequency range. ORs of virological failure according to MV detection were estimated by logistic regression. Results Two hundred and sixty samples (76 cases and 184 controls), mostly subtype B (73.5%), were used for the analysis. Identical MVs were detected in the two laboratories. 31.6% of cases and 16.8% of controls harboured pre-existing MVs. Detection of at least one MV versus no MVs was associated with an increased risk of virological failure (OR = 2.75, 95% CI = 1.35-5.60, P = 0.005); similar associations were observed for at least one MV versus no NRTI MVs (OR = 2.27, 95% CI = 0.76-6.77, P = 0.140) and at least one MV versus no NNRTI MVs (OR = 2.41, 95% CI = 1.12-5.18, P = 0.024). A dose-effect relationship between virological failure and mutational load was found. Conclusions Pre-existing MVs more than double the risk of virological failure to first-line NNRTI-based AR

A Novel Substrate-Based HIV-1 Protease Inhibitor Drug Resistance Mechanism

BACKGROUND: HIV protease inhibitor (PI) therapy results in the rapid selection of drug resistant viral variants harbouring one or two substitutions in the viral protease. To combat PI resistance development, two approaches have been developed. The first is to increase the level of PI in the plasma of the patient, and the second is to develop novel PI with high potency against the known PI-resistant HIV protease variants. Both approaches share the requirement for a considerable increase in the number of protease mutations to lead to clinical resistance, thereby increasing the genetic barrier. We investigated whether HIV could yet again find a way to become less susceptible to these novel inhibitors. METHODS AND FINDINGS: We have performed in vitro selection experiments using a novel PI with an increased genetic barrier (RO033-4649) and demonstrated selection of three viruses 4- to 8-fold resistant to all PI compared to wild type. These PI-resistant viruses did not have a single substitution in the viral protease. Full genomic sequencing revealed the presence of NC/p1 cleavage site substitutions in the viral Gag polyprotein (K436E and/or I437T/V) in all three resistant viruses. These changes, when introduced in a reference strain, conferred PI resistance. The mechanism leading to PI resistance is enhancement of the processing efficiency of the altered substrate by wild-type protease. Analysis of genotypic and phenotypic resistance profiles of 28,000 clinical isolates demonstrated the presence of these NC/p1 cleavage site mutations in some clinical samples (codon 431 substitutions in 13%, codon 436 substitutions in 8%, and codon 437 substitutions in 10%). Moreover, these cleavage site substitutions were highly significantly associated with reduced susceptibility to PI in clinical isolates lacking primary protease mutations. Furthermore, we used data from a clinical trial (NARVAL, ANRS 088) to demonstrate that these NC/p1 cleavage site changes are associated with virological failure during PI therapy. CONCLUSIONS: HIV can use an alternative mechanism to become resistant to PI by changing the substrate instead of the protease. Further studies are required to determine to what extent cleavage site mutations may explain virological failure during PI therapy

Modalites de prescription de la mesure de la charge virale (ARN VI plasmatique) chez les personnes atteintes par le VIH et ses consequen es en matiere de suivi et de strategie therapeutique

SIGLEAvailable at La Documentation francaise (FR) Number :96-4-0010 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Improved Sensitivity of Human Immunodeficiency Virus Type 2 Subtype B Plasma Viral Load Assay

We developed a new assay for human immunodeficiency virus type 2 plasma RNA quantification based on a previous format. The new version performed significantly better than the original regarding the detection of subtype B, allowing the detection of 14 out of 36 plasma RNAs in the subtype B-infected patients not detected with the original version

Recherches, dans le cadre des Hopitaux de Paris, sur les diverses formes d'infection par les virus HIV

SIGLEINIST AR 13455 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Low-frequency drug-resistant HIV-1 and risk of virological failure to first-line NNRTI-based ART: a multicohort European case–control study using centralized ultrasensitive 454 pyrosequencing

Objectives: It is still debated if pre-existing minority drug-resistant HIV-1 variants (MVs) affect the virological outcomes of first-line NNRTI-containing ART. Methods: This Europe-wide case–control study included ART-naive subjects infected with drug-susceptible HIV-1 as revealed by population sequencing, who achieved virological suppression on first-line ART including one NNRTI. Cases experienced virological failure and controls were subjects from the same cohort whose viraemia remained suppressed at a matched time since initiation of ART. Blinded, centralized 454 pyrosequencing with parallel bioinformatic analysis in two laboratories was used to identify MVs in the 1%–25% frequency range. ORs of virological failure according to MV detection were estimated by logistic regression. Results: Two hundred and sixty samples (76 cases and 184 controls), mostly subtype B (73.5%),were used for the analysis. Identical MVs were detected in the two laboratories. 31.6% of cases and 16.8% of controls harboured pre-existing MVs. Detection of at least one MV versus no MVs was associated with an increased risk of virological failure (OR¼2.75, 95% CI¼1.35–5.60, P¼0.005); similar associations were observed for at least one MV versus no NRTIMVs (OR¼2.27, 95% CI¼0.76–6.77, P¼0.140) and at least oneMV versus no NNRTIMVs (OR¼2.41, 95% CI¼1.12–5.18, P¼0.024). A dose–effect relationship between virological failure and mutational loadwas found. Conclusions: Pre-existing MVs more than double the risk of virological failure to first-line NNRTI-based ART

Analysis of Gag Polyprotein Processing

<p>Western blot analysis of cell lysates (left panel) or virus particles (right panel) obtained by ultracentrifugation of cell culture supernatants from 293T cells transfected with the respective recombinant virus plasmids in the absence of inhibitor or in the presence of 50 or 500 nM of RO033-4649. Molecular mass standards are depicted on the left, Gag-derived proteins are identified on the right. Protein detection was performed following incubation with a specific antibody against NC.</p

Schematic Representation of the Viral Frameshift Region and Investigation of Frameshift Efficiency

<div><p>The RNA structure of the frameshift stimulatory signal is represented here [<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040036#pmed-0040036-b030" target="_blank">30</a>,<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0040036#pmed-0040036-b051" target="_blank">51</a>]. The nucleotide and amino acid changes (between brackets) as observed in our in vitro selection experiments are indicated.</p> <p>(A) The relative frameshift efficiency of wild-type HIV (HXB2) and the p1 constructs of IVS-1 (436E+437T), IVS-32 (437V), and IVS-34 (437T). The values of the frameshift efficiency are the means of four independent experiments, with bars representing the standard errors.</p> <p>(B) Analysis of differences in levels of HIV GagPol products (RT, p66, and p51) as compared to HIV Gag products (CA, p24) by Western blot analysis.</p></div