Integrase strand-transfer inhibitor polymorphic and accessory resistance substitutions in patients with acute/recent HIV infection

Development of H51Y and E157Q mutations for integrase inhibitor resistance in a patient undergoing treatment for pulmonary tuberculosis: A case report

Background

Failure of first-line regimens with dolutegravir, a high genetic barrier antiretroviral of the integrase inhibitor class, although uncommon, tends to increase in prevalence due to broader use.

Objective

To describe the clinical case of an HIV/Tuberculosis coinfected patient who developed Human Immunodeficieny Virus (HIV) treatment failure during dolutegravir therapy.

Case report

Male, 29 years old, presented with a right cervical mass, dry cough, and hyporexia, which lasted 2 weeks. Diagnostic tests were positive for tuberculosis and HIV. The viral load was 437,927 cp/mL (Log = 5.64). Antiretroviral therapy was initiated with Tenofovir/Lamivudine and Dolutegravir (TDF/3TC and DTG), the latter at a dose of 50 mg/day, as was a regimen for tuberculosis. After 8 months, therapeutic failure was verified. Genotyping was requested, with detection of the H51Y and E157Q mutations in the integrase.

Conclusion

Attention when determining the antiretroviral therapy treatment regimen of HIV/TB coinfected patients is paramount. Poor adherence to antiretroviral therapy and follow-up may have contributed to treatment failure and resistance.

Prevalence of HIV-1 Natural Polymorphisms and Integrase-Resistance-Associated Mutations in African Children

Integrase inhibitors (INIs) are a potent option for HIV treatment. Limited data exist on INI resistance in West Africa, particularly in children living with HIV/AIDS. We determined the prevalence of integrase gene polymorphisms and the frequency of naturally occurring amino acid (aa) substitutions at positions associated with INI resistance. Dried blood spot (DBS) samples were obtained from one hundred and seven (107) HIV-1-infected children aged less than 15 years old in two West African countries, Benin and Mali. All children were naïve to INI treatment, 56 were naïve to anti-retroviral therapy (ART), and 51 had received ART. Genetic sequencing of HIV integrase was successful in 75 samples. The aa changes at integrase positions associated with INI resistance were examined according to the Stanford HIV Genotypic Resistance database. The median ages were 2.6 and 10 years for ART-naïve and -treated children, respectively. The most common subtypes observed were CRF02_AG (74.7%) followed by CRF06_cpx (20%). No major INI-resistance mutations at positions 66, 92, 121, 143, 147, 148, 155, and 263 were detected. The most prevalent INI accessory resistance mutations were: L74I/M (14/75, 18.6%) followed by E157Q (8/75, 10.6%), G163E/N/T/Q (5/75, 6.6%), Q95A/H/P (2/75, 2.6%), and T97A (4/75, 5.3%). Other substitutions observed were M50I/L/P, H51E/P/S/Q, I72V, T112V, V201I, and T206S. Polymorphisms at positions which may influence the genetic barrier and/or drive the selection of specific INI-resistance pathways were detected. However, no transmitted drug resistance (TDR) to INI was detected among samples of INI-naïve patients. These findings support the use of this treatment class for children with HIV-1, particularly in West Africa.

Virological and Immunological Outcomes of an Intensified Four-Drug versus a Standard Three-Drug Antiretroviral Regimen, Both Integrase Strand Transfer Inhibitor-Based, in Primary HIV Infection

The optimal therapeutic approach for primary HIV infection (PHI) is still debated. We aimed to compare the viroimmunological response to a four- versus a three-drug regimen, both INSTI-based, in patients with PHI. This was a monocentric, prospective, observational study including all patients diagnosed with PHI from December 2014 to April 2018. Antiretroviral therapy (ART) was started, before genotype resistance test results, with tenofovir/emtricitabine and either raltegravir plus boosted darunavir or dolutegravir. Cumulative probability of virological suppression [VS] (HIV-1 RNA< 40 cp/mL), low-level HIV-1 DNA [LL-HIVDNA] (HIV-1 DNA < 200 copies/106PBMC), and CD4/CD8 ratio ≥1 were estimated using Kaplan−Meier curves. Factors associated with the achievement of VS, LL-HIVDNA, and CD4/CD8 ≥ 1 were assessed by a Cox regression model. We enrolled 144 patients (95.8% male, median age 34 years): 110 (76%) started a four-drug-based therapy, and 34 (24%) a three-drug regimen. Both treatment groups showed a comparable high probability of achieving VS and a similar probability of reaching LL-HIVDNA and a CD4/CD8 ratio ≥1 after 48 weeks from ART initiation. Higher baseline HIV-1 RNA and HIV-1 DNA levels lowered the chance of VS, whereas a better preserved immunocompetence increased that chance. Not statistically significant factors associated with LL-HIVDNA achievement were found, whereas a higher baseline CD4/CD8 ratio predicted the achievement of immune recovery. In PHI patients, the rapid initiation of either an intensified four-drug or a standard three-drug INSTI-based regimen showed comparable responses in terms of VS, viral reservoir size, and immunological recovery.

Real-life experience with bictegravir/emtricitabine/tenofovir alafenamide in a large reference clinical centre

BACKGROUND

The use of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) is mainly based on robust, pivotal clinical trials.

OBJECTIVES

To provide data on clinical use of BIC/FTC/TAF in real life.

PATIENTS AND METHODS

This was an observational, retrospective and single-centre study. We included all adult, treatment-naive (TN) and treatment-experienced (TE) people living with HIV (PLWH) starting BIC/FTC/TAF from 8 June 2018. We evaluated effectiveness [on treatment (OT), modified intention-to-treat (mITT) and intention-to-treat (ITT)], tolerability and safety in those patients who reached 6 months of follow-up (M6).

RESULTS

We included 1584 PLWH [213 TN (13%) and 1371 TE (87%)]. The median (IQR) follow-up was 16 (7-21) months, with 81% and 53% of PLWH reaching M6 and M12, respectively. By OT, mITT and ITT, HIV-RNA <50 copies/mL was 77%, 70% and 62% at M6 and 92%, 77% and 63% at M12 for TN PLWH and 94%, 89% and 83% at M6 and 93%, 85% and 78% at M12 for TE PLWH, respectively. In PLWH carrying an M184V/I substitution, OT RNA <50 copies/mL was 89.5% at M6. The median CD4 cell count increased from 329 to 511/μL in TN PLWH and from 630 to 683/μL in TE PLWH at M6. Of the total, 1148 (88%) PLWH continued on BIC/FTC/TAF at M6. The most frequent known reason for discontinuation was toxicity [42 (69%) cases]; only 7 cases were considered virological failures (0.6% of the total OT cohort at M6), with no emerging resistance substitutions.

CONCLUSIONS

In real life, BIC/FTC/TAF showed high rates of virological suppression and also in PLWH carrying lamivudine/emtricitabine resistance substitutions. The tolerability and safety of BIC/FTC/TAF were good, with high persistence observed for patients on this regimen at M6.

High prevalence of HIV-1 transmitted drug resistance and factors associated with time to virological failure and viral suppression in Taiwan

BACKGROUND

Integrase strand transfer inhibitor (InSTI)-based regimens have become the major first-line treatment for HIV-1-infected patients in Taiwan. Transmitted drug resistance (TDR) and several clinical characteristics are associated with time to virological failure or viral suppression; however, these have not been investigated in Taiwan.

OBJECTIVES

To determine the impact of several factors on treatment outcomes in HIV-1-infected patients in Taiwan.

METHODS

The cohort included 164 HIV-1 treatment-naive patients in Taiwan from 2018 to 2020. Blood specimens were collected to determine the genotypic drug resistance using the Stanford University HIV drug resistance database. Cox proportional hazards models were used to identify factors associated with time to virological failure or viral suppression.

RESULTS

The prevalence of TDR in Taiwan was 27.4% and an increasing trend was seen from 2018 to 2020. TDR mutations related to NNRTIs were the most prevalent (21%) while TDR to InSTIs remained at a relatively low level (1.3%). A baseline HIV-1 viral load of ≥100 000 copies/mL was associated with a shorter time to virological failure [multivariate hazard ratio (mHR) 7.84; P = 0.018] and longer time to viral suppression (mHR 0.46; P < 0.001). Time to viral suppression was shorter in patients receiving InSTI-based regimens (mHR 2.18; P = 0.006). Different InSTI-based regimens as initial treatment did not affect the treatment outcomes.

CONCLUSIONS

This study found an increasing trend of HIV-1 TDR prevalence from 2018 to 2020 in Taiwan. Baseline HIV-1 viral load and receiving InSTI-based regimens are important factors associated with time to virological failure or viral suppression.

Primary resistance to integrase strand transfer inhibitors in Spain using ultrasensitive HIV-1 genotyping

BACKGROUND

Transmission of resistance mutations to integrase strand transfer inhibitors (INSTIs) in HIV-infected patients may compromise the efficacy of first-line antiretroviral regimens currently recommended worldwide. Continued surveillance of transmitted drug resistance (TDR) is thus warranted.

OBJECTIVES

We evaluated the rates and effects on virological outcomes of TDR in a 96 week prospective multicentre cohort study of ART-naive HIV-1-infected subjects initiating INSTI-based ART in Spain between April 2015 and December 2016.

METHODS

Pre-ART plasma samples were genotyped for integrase, protease and reverse transcriptase resistance using Sanger population sequencing or MiSeq™ using a ≥ 20% mutant sensitivity cut-off. Those present at 1%-19% of the virus population were considered to be low-frequency variants.

RESULTS

From a total of 214 available samples, 173 (80.8%), 210 (98.1%) and 214 (100.0%) were successfully amplified for integrase, reverse transcriptase and protease genes, respectively. Using a Sanger-like cut-off, the overall prevalence of any TDR, INSTI-, NRTI-, NNRTI- and protease inhibitor (PI)-associated mutations was 13.1%, 1.7%, 3.8%, 7.1% and 0.9%, respectively. Only three (1.7%) subjects had INSTI TDR (R263K, E138K and G163R), while minority variants with integrase TDR were detected in 9.6% of subjects. There were no virological failures during 96 weeks of follow-up in subjects harbouring TDR as majority variants.

CONCLUSIONS

Transmitted INSTI resistance remains rare in Spain and, to date, is not associated with virological failure to first-line INSTI-based regimens.

Immunological and virological efficacy of different antiretroviral regimens initiated during acute/recent HIV infection

OBJECTIVES

Antiretroviral treatment (ART) during acute/recent HIV infection decreases transmission and optimizes immune recovery but the optimal ART-regimen in this setting is unknown. The objectives were to analyze the virological efficacy, immunological reconstitution and tolerability of different ART-regimens at 3 years after starting ART during acute/recent HIV infection.

DESIGN

Retrospective cohort study of consecutive acutely/recently infected patients who started ART within 6 months postinfection.

METHODS

We compared regimens based on protease-inhibitors (N = 28), integrase-strand-transfer-inhibitors (InSTI, N = 87) and nonnucleoside-reverse-transcriptase-inhibitors (N = 22). Virological suppression (viral load <50 copies/ml), immune reconstitution (CD4 T-cell count >900 cells/μl and CD4/CD8 ratio >1) and adverse events leading to ART discontinuation at 1 and 3 years were compared.

RESULTS

Baseline characteristics were comparable among groups. Overall viral suppression at 1 (96%) and 3 years (99%) was comparable in all ART regimens and, InSTI group, comparable for dolutegravir and elvitegravir within InSTIs. CD4 T-cell counts at 1 year were comparable in all ART regimens. Overall proportion of patients reaching CD4 cell count more than 900 cells/μl and CD4/CD8 ratio more than 1 was 36% and 40% and 46% and 63% at 1 and 3 years, respectively with no differences among ART regimens. Starting ART during the earliest Fiebig stages (I-V vs. VI) was associated with higher rates of CD4 cell count more than 900 cells/μl at 3 years (P = 0.027). Discontinuation due to adverse events was more frequent with nonnucleoside-reverse-transcriptase-inhibitors compared with other ART classes.

CONCLUSION

Viral suppression and immunological recovery were excellent, with no differences between ART regimens. Earlier ART initiation was associated with a higher proportion of long-term immunological recovery.

Predictors of virological failure and time to viral suppression of first line integrase inhibitor based antiretroviral treatment

Background

Integrase strand transfer inhibitors (InSTIs) are recommended for first-line treatment of persons with human immunodeficiency virus (HIV). We identified risk factors, including baseline minor InSTI resistance mutations, for treatment failure of InSTI-based regimens.

Methods

We studied time-to-treatment failure and time to viral suppression among 1419 drug-naive patients in the Swiss HIV Cohort Study. We performed Cox regression models adjusted for demographic factors, baseline HIV RNA/CD4 cell counts, AIDS-defining events, and the type of InSTI. In 646 patients with a baseline genotypic resistance test of the integrase, we studied the impact of minor integrase resistance mutations.

Results

We observed 121 virological failures during 18 447 person-years of follow-up. A baseline viral load ≥100 000 copies/mL (multivariable hazard ratio [mHR], 2.2; 95% confidence interval [CI], 1.3–3.6) and an AIDS-defining event (mHR, 1.8; 95% CI. 1.1–3.0) were associated with treatment failure. CD4 counts between 200 and 500 cells/µL (mHR, 0.5; 95% CI, .3–.8) and >500 cells/µL (mHR, 0.4; 95% CI, .2–.7) were protective. Time to suppression was shorter in lower viral load strata (mHR, 0.7; 95% CI, .6–.8) and in dolutegravir-based therapy (mHR, 1.2; 95% CI, 1.0–1.4). Minor resistance mutations were found at baseline in 104 of 646 (16%) patients with no effect on treatment outcome.

Conclusions

Factors associated with treatment failure on InSTI-based first-line regimen remained similar to those of older treatments, in particular high viral load and low CD4 counts.

Presence of V72I, G123S and R127K Integrase Inhibitor polymorphisms could reduce ART effectiveness: a retrospective longitudinal study

Objectives: Structural aspects of HIV-1 integrase complex and role of integrase minor mutations and polymorphisms in ART effectiveness is still unknown. The objective of this study was to assess the 24 and 48 weeks (W) effectiveness of ART regimens in patients with Integrase Inhibitors (InSTI) minor mutations and polymorphisms receiving InSTI-based regimens.Methods: We enrolled all ART-naïve or InSTI-naïve HIV-infected patients, with a baseline InSTI genotypic resistances test between 2011 and 2016. We analyzed integrase resistance mutations using the Stanford University HIV Drug Resistance Database (HIVdb Program, version 6.3.0). The outcome was virological response at 24 and 48 W of follow up (FU) according to snapshot analysis. We defined virological failure as two consecutive HIV-RNA > 50 copies/ml, or one >1000 copies/ml. Patients were divided in those presenting InSTI minor mutations (Group 1), and those with only polymorphisms or wild type (Group 2).Results: We enrolled 83 patients. 81 patients reached 24 W of FU: 2/20 (10%) and 4/61 (6.5%) showed virological failure in Group 1 and 2 respectively. 66 patients reached 48 W of FU: 0/17 (0%) and 2/49 (4%) showed virological failure in Group 1 and 2 respectively. Interestingly, patients with polymorphisms G123S and R127K had higher risk of failure at 24 W (respectively, relative risk - RR - 36, IQR 2.1-613, p = 0.01; RR 36, IQR 2.1-613, p = 0.01) and patients with V72I had an higher risk of failure both at 24 W (RR 6.52, IQR 1.29-32.9, p = 0.02) and 48 W (RR 21.1, IQR 1.07-414, p = 0.04).Conclusions: Our study showed that the presence of V72I, G123S and R127K polymorphisms could play a role in reducing InSTI effectiveness.

E157Q integrase strand-transfer inhibitor substitution in patients with acute/recent HIV infection

OBJECTIVES

Integrase strand-transfer inhibitor (InSTI)-based regimens are the preferred combinations for naïve HIV-infected individuals. Polymorphic substitutions that reduce InSTIs activity have been described, with E157Q being one of the most frequently found. This study aimed to evaluate the prevalence of E157Q substitution in newly diagnosed acute/recent HIV cases and the presence of transmission clusters.

DESIGN

Prospective cohort study in patients with acute/recent HIV infection.

METHODS

Genotypic drug resistance tests were performed in all consecutive patients prospectively enrolled with a documented infection of less than 6 months from May 2015 to May 2017. Sequences were obtained by ultra-deep sequencing. Phylogenetic inferences were performed using maximum likelihood trees constructed with Mega 6.06. Bootstrap values of 75% or greater were defined for cluster assignment. Follow-up was, at least, 1 year.

RESULTS

In six out of 67 consecutive patients (8.95%, 95% confidence interval 4.17-18.19) with acute/recent HIV infection, strains carrying the E157Q InSTI substitution were detected. All cases were MSM patients infected with subtype B strains. No other resistance substitutions were detected in these cases. Median viral load was 5.33 (interquartile range: 4.54-5.71) log10 copies/ml and, in all cases, the mutational viral load was high (>95%). Three cases were included in transmission clusters. Three cases responded to dolutegravir-based regimens; nonnucleoside reverse transcriptase inhibitor-based regimens were used for the other case(s).

CONCLUSION

E157Q substitution, reducing raltegravir and elvitegravir activity, was frequently found in acute/recent HIV cases. All cases were infected with subtype B, and some were included in clusters. Cases treated with dolutegravir-based regimens had good virological response.

Impact of genotypic susceptibility score on cART outcomes during primary HIV infection

To assess the impact of genotypic susceptibility score (GSS) on combined antiretroviral therapy (cART) outcomes during primary HIV infection (PHI) we retrospectively enrolled patients with PHI diagnosed between 2008 and 2015 at 9/24 Italian Network ACuTe HIV InfectiON centers. One hundred-seventy-six patients were enrolled. Of these, 55 (32.9%) patients started with more than three drugs and 11 (7.2%) started with a GSS < 3. Regimen's GSS (per 1 point increase) (adjusted odds ratio [aOR], 4.82; 95% confidence interval [CI], 1.62-14.28; P = .005) and baseline HIV-RNA (per 1 log10 increase) (aOR, 2.02; 95% CI, 1.09-3.73; P = .025) resulted associated with early cART initiation. In conclusion, regimen's GSS resulted to be associated to the time to cART initiation during PHI.

Phenotypic analysis of HIV-1 E157Q integrase polymorphism and impact on virological outcome in patients initiating an integrase inhibitor-based regimen

Objectives

To assess the phenotypic susceptibility of the E157Q polymorphism in HIV-1 integrase (IN) and the virological outcome of patients infected with E157Q-mutated virus initiating an IN inhibitor (INI)-based regimen.

Methods

This was a multicentre study assessing IN sequences from INI-naive patients among 17 French HIV clinical centres. E157Q site-directed mutants in pNL4.3 and pCRF02_AG contexts were assessed in a recombinant phenotypic assay.

Results

Prevalence of the E157Q polymorphism was 2.7% among 8528 IN sequences from INI-naive patients and its distribution was 1.7%, 5.6% and 2.2% in B, CRF02_AG and various non-B subtypes, respectively. Thirty-nine INI-naive patients with E157Q-mutated virus initiated an INI-based regimen. Among them, 15 had a viral load (VL) <50 copies/mL at initiation and virological suppression was maintained during the first year of follow-up in all but two exhibiting a viral blip. Twenty-four patients had a VL > 50 copies/mL at the time of INI-based regimen initiation. Among them eight were receiving a first-line regimen and the only two patients who did not reach VL < 50 copies/mL at week 24 were receiving elvitegravir. The 16 remaining patients were ART experienced in virological failure with drug-resistant viruses displaying several virological outcomes independently of the genotypic susceptibility score. Phenotypic analyses showed a fold change in EC50 of 0.6, 0.9 and 1.9 for raltegravir, dolutegravir and elvitegravir, respectively, in a subtype B context, and 1.1, 1.9 and 2.4 for raltegravir, dolutegravir and elvitegravir, respectively, in a CRF02_AG context.

Conclusions

Assessment of virological response in 39 patients initiating an INI-based regimen with E157Q-mutated virus, in combination with phenotypic analysis, suggests that particular attention should be paid to antiretroviral-naive patients and dolutegravir should be preferentially used in these patients.

Predicted antiviral activity of tenofovir versus abacavir in combination with a cytosine analogue and the integrase inhibitor dolutegravir in HIV-1-infected South African patients initiating or failing first-line ART

Objectives

The WHO recently recommended the use of a new first-line ART containing dolutegravir. We investigated the efficacy of NRTI backbones (tenofovir or abacavir with a cytosine analogue) in low- and middle-income countries where there is significant prior exposure to antiretrovirals and drug resistance to NRTIs.

Methods

Within the treatment-as-prevention study in South Africa, we selected participants with available next-generation sequencing (NGS) data for the HIV-1 pol gene at trial entry; they were either ART initiators (n = 1193) or already established on ART (n = 94). NGS of the HIV-1 pol gene was carried out using MiSeq technology; reverse transcriptase drug resistance mutations (DRMs) were detected at 5% (DRM5%) and 20% (DRM20%) for all 1287 participants. Genotypic susceptibility was assessed using the Stanford HIVDB resistance interpretation algorithm.

Results

NRTI DRM20% and DRM5% were detected among 5/1193 (0.4%) and 9/1193 (0.8%) of ART initiators, respectively. There was tenofovir exposure in 73/94 (77.7%) of those established on ART, with full susceptibility to abacavir in 57/94 (60.6%) and 56/94 (59.6%) for DRM20% and DRM5%, respectively, while 67/94 (71.3%) and 64/94 (68.1%) were fully susceptible to tenofovir, respectively. The differences between tenofovir and abacavir were not statistically significant at the 20% or 5% variant level (P = 0.16 and 0.29, respectively). NGS detection of variants at the 5% level increased detection of K65R in both naive and treated groups. One of 607 integrase sequences carried a DRM20% (Q148R).

Conclusions

Dolutegravir with a cytosine analogue plus tenofovir or abacavir appears to have similar efficacy in South Africans naive to ART. NGS should be considered in HIV drug resistance surveillance.

Relationship between HIV integrase polymorphisms and integrase inhibitor susceptibility: An in silico analysis

Integrase (IN) plays an essential role in HIV-1 replication, by mediating integration of the viral genome into the host cell genome. IN is a potential target of antiretroviral (ARV) therapeutic drugs such as ALLINI, Raltegravir (RAL), and Elvitegravir (EVG). The effect of IN polymorphisms on its structure and binding affinity to the integrase inhibitors (INIs) is not well understood. The goal of this study was to examine the effect of IN polymorphisms on its tertiary structure and binding affinities to INIs using computational approaches. HIV genomes were isolated from patient blood and the IN gene was sequenced to identify polymorphisms. Protein structures were derived using FoldX and the binding affinity of IN for ALLINI, RAL, and EVG was evaluated using a molecular docking method. The binding affinities of ALLINI and EVG for wild-type IN were lower as compared to an IN variant; in contrast, the binding affinity of RAL for the IN variant was lower as compared to wild-type IN. These results suggested that IN variant interacts with ALLINI and EVG more efficiently as compared to the wildtype, which may not cause resistent to the drugs. In vitro and in vivo studies should be done to validate the findings of this study.

Antiretroviral Drugs for Treatment and Prevention of HIV Infection in Adults: 2018 Recommendations of the International Antiviral Society-USA Panel

Importance

Antiretroviral therapy (ART) is the cornerstone of prevention and management of HIV infection.

Objective

To evaluate new data and treatments and incorporate this information into updated recommendations for initiating therapy, monitoring individuals starting therapy, changing regimens, and preventing HIV infection for individuals at risk.

Evidence Review

New evidence collected since the International Antiviral Society-USA 2016 recommendations via monthly PubMed and EMBASE literature searches up to April 2018; data presented at peer-reviewed scientific conferences. A volunteer panel of experts in HIV research and patient care considered these data and updated previous recommendations.

Findings

ART is recommended for virtually all HIV-infected individuals, as soon as possible after HIV diagnosis. Immediate initiation (eg, rapid start), if clinically appropriate, requires adequate staffing, specialized services, and careful selection of medical therapy. An integrase strand transfer inhibitor (InSTI) plus 2 nucleoside reverse transcriptase inhibitors (NRTIs) is generally recommended for initial therapy, with unique patient circumstances (eg, concomitant diseases and conditions, potential for pregnancy, cost) guiding the treatment choice. CD4 cell count, HIV RNA level, genotype, and other laboratory tests for general health and co-infections are recommended at specified points before and during ART. If a regimen switch is indicated, treatment history, tolerability, adherence, and drug resistance history should first be assessed; 2 or 3 active drugs are recommended for a new regimen. HIV testing is recommended at least once for anyone who has ever been sexually active and more often for individuals at ongoing risk for infection. Preexposure prophylaxis with tenofovir disoproxil fumarate/emtricitabine and appropriate monitoring is recommended for individuals at risk for HIV.

Conclusions and Relevance

Advances in HIV prevention and treatment with antiretroviral drugs continue to improve clinical management and outcomes for individuals at risk for and living with HIV.

Resistance to HIV Integrase Inhibitors: About R263K and E157Q Mutations

The use of integrase inhibitors (INI) is increasing in antiretroviral therapies (ART) and INI are not all equal regarding genetic barrier to resistance. The aim of this manuscript was to review main in vivo and in vitro knowledge about two particular integrase resistance-associated mutations: R263K and E157Q. The R263K mutation was the first mutation rarely found selected at time of virological failure in patients failing a first-line dolutegravir-based treatment. Further in vitro studies on R263K mutants showed a moderate increase in phenotypic resistance level and a drastic reduction in viral replicative capacity. No compensatory mutations were evidenced. The E157Q mutation is polymorphic, found between 1.7% and 5.6% of viral sequences issued from ART-naïve patients depending on the viral subtype; as well as acquired resistance emerging at failure of a raltegravir-based regimen in two case reports. We reported data on phenotypic resistance level of E157Q mutants and virological response of patients harboring a E157Q virus initiating an INI-based regimen, showing that dolutegravir might be the most recommended INI in such patients. These findings show that there is still a need for a better understanding of resistance mechanisms to INI and emphasized the importance of genotypic background in viral evolution under drug pressure.

The HIV-1 integrase E157Q polymorphism per se does not alter susceptibility to raltegravir and dolutegravir in vitro

: The HIV-1 integrase E157Q natural polymorphism has been reported to cause one case of raltegravir (RAL) and dolutegravir (DTG) failure. Six recombinant viruses were constructed containing integrase from clinical HIV-1 isolates found to harbour E157Q as the only integrase strand inhibitor (INSTI) resistance-related mutation. Phenotypic analysis showed that E157Q results in minimal changes in RAL and DTG susceptibility. Together with data retrieved from the Stanford HIV database, our results indicate that E157Q is not a relevant INSTI resistance mutation per se. The previously reported case of E157Q-based resistance must have resulted from combined as yet unidentified integrase polymorphisms.

Drug resistance in B and non-B subtypes amongst subjects recently diagnosed as primary/recent or chronic HIV-infected over the period 2013-2016: Impact on susceptibility to first-line strategies including integrase strand-transfer inhibitors

OBJECTIVES

To characterize the prevalence of transmitted drug resistance mutations (TDRMs) by plasma analysis of 750 patients at the time of HIV diagnosis from January 1, 2013 to November 16, 2016 in the Veneto region (Italy), where all drugs included in the recommended first line therapies were prescribed, included integrase strand transfer inhibitors (InNSTI).

METHODS

TDRMs were defined according to the Stanford HIV database algorithm.

RESULTS

Subtype B was the most prevalent HIV clade (67.3%). A total of 92 patients (12.3%) were expected to be resistant to one drug at least, most with a single class mutation (60/68-88.2% in subtype B infected subjectsand 23/24-95.8% in non-B subjects) and affecting mainly NNRTIs. No significant differences were observed between the prevalence rates of TDRMs involving one or more drugs, except for the presence of E138A quite only in patients with B subtype and other NNRTI in subjects with non-B infection. The diagnosis of primary/recent infection was made in 73 patients (9.7%): they had almost only TDRMs involving a single class. Resistance to InSTI was studied in 484 subjects (53 with primary-recent infection), one patient had 143C in 2016, a total of thirteen 157Q mutations were detected (only one in primary/recent infection).

CONCLUSIONS

Only one major InSTI-TDRM was identified but monitoring of TDRMs should continue in the light of continuing presence of NNRTI-related mutation amongst newly diagnosed subjects, sometime impacting also to modern NNRTI drugs recommended in first-line therapy.

Neurological involvement in patients with acute/recent HIV-1 infection. A case-control study

Primary HIV-1 infection is a relevant period for its virological and epidemiological consequences. Most patients present a symptomatic disease that can be potentially serious, but neurological involvement during primary HIV-1 infection has been poorly studied. The aim of this study was to describe the characteristics and outcomes of primary HIV-1 infection patients presenting neurological symptoms and to compare them with primary HIV-1 infection patients without neurological involvement. Retrospective case-control study (1:3) comparing primary HIV-1 infection patients with and without neurological involvement enrolled in the Acute/Recent Hospital Clinic PHI Cohort between 1997 and 2016. Matching criteria included age (±10 years), gender, year of diagnosis (±4 years), and Fiebig stage. The conditional logit model was used for comparisons. Fourteen out of 463 patients (3.02%) enrolled in the Acute/Recent Hospital Clinic PHI Cohort between 1997 and 2016 presented neurological symptoms. 28.5% of cases presented as meningitis and 71.5% as meningoencephalitis. Cerebrospinal fluid showed non-specific findings, including pleocytosis with lymphocyte predominance and increased protein levels. All cases required hospitalisation, whereas only 19% of the controls did. No other pathogen was identified in any case, but five patients initiated empirically antimicrobial treatment for other aetiologies until diagnosis was confirmed. CD4/CD8 ratio was significantly lower (p = 0.039) and plasmatic viral load significantly higher in the case group, compared to controls (p = 0.028). Risk factors, HIV-1 tropism, subtype distribution, and prescribed ART regimens were comparable between cases and controls. After 6 months on ART, 92% of cases had undetectable viral load, similar to controls, and CD4/CD8 ratio became also comparable between groups. All cases recovered rapidly with ART and were discharged without sequels. Neurological involvement during primary HIV-1 infection is unusual but serious, always requiring hospitalisation. Diagnosis is difficult because of the wide range of symptoms and similarities with other viral aetiologies. Neurological manifestations during primary HIV-1 infection are associated with a lower CD4/CD8 ratio and with a higher viral load than controls. Immediate ART initiation and rapid viral load decrease are required, allowing complete clinical recovery.