Evolution of Protease Inhibitor Resistance in Human Immunodeficiency Virus Type 1 Infected Patients Failing Protease Inhibitor Monotherapy as Second-line Therapy in Low-income Countries: An Observational Analysis Within the EARNEST Randomized Trial

Spectrum of Atazanavir-Selected Protease Inhibitor-Resistance Mutations

Ritonavir-boosted atazanavir is an option for second-line therapy in low- and middle-income countries (LMICs). We analyzed publicly available HIV-1 protease sequences from previously PI-naïve patients with virological failure (VF) following treatment with atazanavir. Overall, 1497 patient sequences were identified, including 740 reported in 27 published studies and 757 from datasets assembled for this analysis. A total of 63% of patients received boosted atazanavir. A total of 38% had non-subtype B viruses. A total of 264 (18%) sequences had a PI drug-resistance mutation (DRM) defined as having a Stanford HIV Drug Resistance Database mutation penalty score. Among sequences with a DRM, nine major DRMs had a prevalence >5%: I50L (34%), M46I (33%), V82A (22%), L90M (19%), I54V (16%), N88S (10%), M46L (8%), V32I (6%), and I84V (6%). Common accessory DRMs were L33F (21%), Q58E (16%), K20T (14%), G73S (12%), L10F (10%), F53L (10%), K43T (9%), and L24I (6%). A novel nonpolymorphic mutation, L89T occurred in 8.4% of non-subtype B, but in only 0.4% of subtype B sequences. The 264 sequences included 3 (1.1%) interpreted as causing high-level, 14 (5.3%) as causing intermediate, and 27 (10.2%) as causing low-level darunavir resistance. Atazanavir selects for nine major and eight accessory DRMs, and one novel nonpolymorphic mutation occurring primarily in non-B sequences. Atazanavir-selected mutations confer low-levels of darunavir cross resistance. Clinical studies, however, are required to determine the optimal boosted PI to use for second-line and potentially later line therapy in LMICs.

HIV-1 drug resistance in adults and adolescents on protease inhibitor-based antiretroviral treatment in KwaZulu-Natal Province, South Africa

BACKGROUND

In low- and middle-income countries, increasing levels of HIV drug resistance (HIVDR) on second-line protease inhibitor (PI)-based regimens are a cause for concern, given limited drug options for third-line antiretroviral therapy (ART).

OBJECTIVES

We conducted a retrospective analysis of routine HIV-1 genotyping laboratory data from KwaZulu-Natal, in South Africa, to describe the frequency and patterns of HIVDR mutations and their consequent impact on standardized third-line regimens.

METHODS

This was a cross-sectional analysis of all HIV-1 genotypic resistance tests conducted by the National Health Laboratory Service in KwaZulu-Natal, South Africa (Jan 2015 - Dec 2016), for adults and adolescents (age ≥10 years) on second-line PI-based ART with virological failure. We assigned a third-line regimen to each record, based on a national treatment algorithm and calculated the genotypic susceptibility score (GSS) for that regimen.

RESULTS

Of 348 samples analyzed, 287 (83%) had at least one drug resistance mutation (DRM) and 114 (33%) had at least one major PI DRM. Major PI resistance was associated with longer duration on second-line ART (aOR per 6-months, 1.11, 95% CI 1.04-1.19) and older age (aOR 1.03, 95% CI 1.01-1.05). Of 112 patients requiring third-line ART, 12 (11%) had a GSS of <2 for the algorithm-assigned third-line regimen.

CONCLUSIONS

One in three people failing second-line ART had significant PI DRMs. A subgroup of these individuals had extensive HIVDR, where the predicted activity of third-line ART was suboptimal, highlighting the need for continuous evaluation of outcomes on third-line regimens and close monitoring for emergent HIV-1 integrase-inhibitor resistance.

Deep sequencing analysis of M184V/I mutation at the switch and at the time of virological failure of boosted protease inhibitor plus lamivudine or boosted protease inhibitor maintenance strategy (substudy of the ANRS-MOBIDIP trial)

BACKGROUND

The ANRS12286/MOBIDIP trial showed that boosted protease inhibitor (bPI) plus lamivudine dual therapy was superior to bPI monotherapy as maintenance treatment in subjects with a history of M184V mutation.

OBJECTIVES

We aimed to deep analyse the detection of M184V/I variants at time of switch and at the time of virological failure (VF).

METHODS

Ultra-deep sequencing (UDS) was performed on proviral HIV-DNA at inclusion among 265 patients enrolled in the ANRS 12026/MOBIDIP trial, and on plasma from 31 patients experiencing VF. The proportion of M184V/I variants was described and the association between the M184V/I mutation at 1% of threshold and VF was explored with logistic regression models.

RESULTS

M184V and I mutations were detected in HIV-DNA for 173/252 (69%) and 31/252 (12%) of participants, respectively. Longer duration of first-line treatment, higher plasma viral load at first-line treatment failure and higher baseline HIV-DNA load were associated with the archived M184V. M184I mutation was always associated with a STOP codon, suggesting defective virus. The 48 week estimated probability of remaining free from VF was comparable with or without the M184V/I mutation for dual therapy. At failure, M184V and major PI mutations were detected in 1/17 and 5/15 patients in the bPI arm and in 2/2 and 0/3 in the bPI+lamivudine arm, respectively.

CONCLUSIONS

Using UDS evidenced that archiving of M184V in HIV-DNA is heterogeneous despite past historical M184V in 96% of cases. The antiviral efficacy of lamivudine-based dual therapy regimens is mainly due to the residual lamivudine activity.

In Vivo Emergence of a Novel Protease Inhibitor Resistance Signature in HIV-1 Matrix

Protease inhibitors (PIs) are the second- and last-line therapy for the majority of HIV-infected patients worldwide. Only around 20% of individuals who fail PI regimens develop major resistance mutations in protease. We sought to explore the role of mutations in gag-pro genotypic and phenotypic changes in viruses from six Nigerian patients who failed PI-based regimens without known drug resistance-associated protease mutations in order to identify novel determinants of PI resistance. Target enrichment and next-generation sequencing (NGS) with the Illumina MiSeq system were followed by haplotype reconstruction. Full-length Gag-protease gene regions were amplified from baseline (pre-PI) and virologic failure (VF) samples, sequenced, and used to construct gag-pro-pseudotyped viruses. Phylogenetic analysis was performed using maximum-likelihood methods. Susceptibility to lopinavir (LPV) and darunavir (DRV) was measured using a single-cycle replication assay. Western blotting was used to analyze Gag cleavage. In one of six participants (subtype CRF02_AG), we found 4-fold-lower LPV susceptibility in viral clones during failure of second-line treatment. A combination of four mutations (S126del, H127del, T122A, and G123E) in the p17 matrix of baseline virus generated a similar 4-fold decrease in susceptibility to LPV but not darunavir. These four amino acid changes were also able to confer LPV resistance to a subtype B Gag-protease backbone. Western blotting demonstrated significant Gag cleavage differences between sensitive and resistant isolates in the presence of drug. Resistant viruses had around 2-fold-lower infectivity than sensitive clones in the absence of drug. NGS combined with haplotype reconstruction revealed that resistant, less fit clones emerged from a minority population at baseline and thereafter persisted alongside sensitive fitter viruses. We used a multipronged genotypic and phenotypic approach to document emergence and temporal dynamics of a novel protease inhibitor resistance signature in HIV-1 matrix, revealing the interplay between Gag-associated resistance and fitness.

Major drug resistance mutations to HIV-1 protease inhibitors (PI) among patients exposed to PI class failing antiretroviral therapy in São Paulo State, Brazil

Background

Protease inhibitors (PI) are especially important in salvage therapy. Previous treatment failure with a PI containing regimen may elicit resistance mutations, reducing PI susceptibility and limiting treatment options. The aim of this study was to describe major PI mutations among patients exposed to at least one PI to evaluate predictors of mutation emergence and the impact of subtypes on resistance.

Methodology

Partial HIV-1 pol sequences (Sanger Sequencing) from patients exposed to PI with virological failure were genotyped from January 2014 to December 2017. Drug resistance mutations (DRM), antiretroviral susceptibility (GSS) and subtypes, along clinical and laboratory parameters, were evaluated using logistic regression to access the predictors of mutation emergence.

Results

In 27.5% (466/1696) of the cases at least one major PI mutations was identified, most commonly M46 (14.7%), V82 (13.8%) and I54 (13.3%). Mutations to NRTI and NNRTI were observed in 69.6% and 59.9%, respectively, of the 1696 sequences. Full activity to darunavir was predicted in 88% (1496/1696), but was only 57% among those with at least one PI-DRM. Subtype C sequences had less major PI-DRMs (10%, 9/87) compared to B (28%, 338/1216) or F (35%, 58/168) (p <0.001) but adjusted analysis suggested that this association is not independent from a shorter treatment time and fewer regimens (OR 0.59, Confidence Interval 95: 0.2–2.5, p = 0.48). Subtype F, together with NRTI mutations and longer time on treatment was associated to presence of PI-DRM, to a lower darunavir GSS and to mutations at codon I50.

Conclusions

Among patients with PI-DRM, full activity to darunavir was compromised in almost half of the cases and efforts to detect failure at earlier time are warranted, particularly for HIV-1 subtype F that showed association to the emergence of resistance, with potential impact in protease inhibitors sequencing. Furthermore, NRTI mutations may serve as an indicative of sufficient adherence to allow PI-DRM emergence.

G2-S16 sulfonate dendrimer as new therapy for treatment failure in HIV-1 entry inhibitors

Aim: Polyanionic carbosilane dendrimers have been shown to be safe and block human immunodeficiency virus type 1 (HIV-1) infection in a multifunctional manner. The aim of this study is to evaluate the appearance of HIV-1 resistance mutations after treatment with polyanionic carbosilane dendrimers. Materials & methods: A resistance mutation assay was performed on MT2 cells, viral quantity was measured by ELISA HIVp24^gag and titration was carried out on TZM.bl. Next generation sequencing for HIV-1 Env was performed on G1-S4 or G2-S16 dendrimers supernatants. Results: Data showed the appearance of mutation resistance to G1-S4 treatment, inducing three significant mutations. G2-S16 did not generate any mutations and, furthermore, inhibited G1-S4-resistant viruses. Conclusion: G1-S4 treatment generates significant mutations in HIV-1_NL4.3. G2-S16 does not generate resistance-associated mutation, suggesting that G2-S16 is safe as a HIV-entry inhibitor.