Failure of Dolutegravir First-Line ART with Selection of Virus Carrying R263K and G118R

Development and Optimization of Oligonucleotide Ligation Assay (OLA) Probes for Detection of HIV-1 Resistance to Dolutegravir

The WHO currently recommends dolutegravir (DTG)-based ART for persons living with HIV infection in resource-limited-settings (RLS). To expand access to testing for HIV drug resistance (DR) to DTG in RLS, we developed probes for use in the oligonucleotide ligation assay (OLA)-Simple, a near-point of care HIV DR kit. Genotypic data from clinical trials and case reports were used to determine the mutations in HIV-1 integrase critical to identifying individuals with DTG-resistance at virologic failure of DTG-based ART. Probes to detect G118R, Q148H/K/R, N155H and R263K in HIV-1 subtypes A, B, C, D and CRF01_AE were designed using sequence alignments from the Los Alamos database and validated using 61 clinical samples of HIV-1 subtypes A, B, C, D, CRF01_AE genotyped by PacBio (n = 15) or Sanger (n = 46). Initial OLA probes failed to ligate for 16/244 (6.5%) codons (9 at G118R and 7 at Q148H/K/R). Probes revised to accommodate polymorphisms interfering with ligation at codons G118R and Q148R reduced indeterminates to 3.7% (5 at G118R and 4 at Q148H/K/R) and detected DTG-mutations with a sensitivity of 96.5% and 100% specificity. These OLA DTG resistance probes appear highly sensitive and specific across HIV-1 subtypes common in RLS with high burden of HIV infection.

HIV transmission dynamics and population-wide drug resistance in rural South Africa

Despite expanded antiretroviral therapy (ART) in South Africa, HIV-1 transmission persists. Integrase strand transfer inhibitors (INSTI) and long-acting injectables offer potential for superior viral suppression, but pre-existing drug resistance could threaten their effectiveness. In a community-based study in rural KwaZulu-Natal, prior to widespread INSTI usage, we enroled 18,025 individuals to characterise HIV-1 drug resistance and transmission networks to inform public health strategies. HIV testing and reflex viral load quantification were performed, with deep sequencing (20% variant threshold) used to detect resistance mutations. Phylogenetic and geospatial analyses characterised transmission clusters. One-third of participants were HIV-positive, with 21.7% having detectable viral loads; 62.1% of those with detectable viral loads were ART-naïve. Resistance to older reverse transcriptase (RT)-targeting drugs was found, but INSTI resistance remained low (<1%). Non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance, particularly to rilpivirine (RPV) even in ART-naïve individuals, was concerning. Twenty percent of sequenced individuals belonged to transmission clusters, with geographic analysis highlighting higher clustering in peripheral and rural areas. Our findings suggest promise for INSTI-based strategies in this setting but underscore the need for RPV resistance screening before implementing long-acting cabotegravir (CAB) + RPV. The significant clustering emphasises the importance of geographically targeted interventions to effectively curb HIV-1 transmission.

The Phenomenon of Antiretroviral Drug Resistance in the Context of Human Immunodeficiency Virus Treatment: Dynamic and Ever Evolving Subject Matter

Human immunodeficiency virus (HIV) is a significant global health issue that affects a substantial number of individuals across the globe, with a total of 39 million individuals living with HIV/AIDS. ART has resulted in a reduction in HIV-related mortality. Nevertheless, the issue of medication resistance is a significant obstacle in the management of HIV/AIDS. The unique genetic composition of HIV enables it to undergo rapid mutations and adapt, leading to the emergence of drug-resistant forms. The development of drug resistance can be attributed to various circumstances, including noncompliance with treatment regimens, insufficient dosage, interactions between drugs, viral mutations, preexposure prophylactics, and transmission from mother to child. It is therefore essential to comprehend the molecular components of HIV and the mechanisms of antiretroviral medications to devise efficacious treatment options for HIV/AIDS.

N-Substituted Bicyclic Carbamoyl Pyridones: Integrase Strand Transfer Inhibitors that Potently Inhibit Drug-Resistant HIV-1 Integrase Mutants

HIV-1 integrase (IN) is an important molecular target for the development of anti-AIDS drugs. A recently FDA-approved second-generation integrase strand transfer inhibitor (INSTI) cabotegravir (CAB, 2021) is being marketed for use in long-duration antiviral formulations. However, missed doses during extended therapy can potentially result in persistent low levels of CAB that could select for resistant mutant forms of IN, leading to virological failure. We report a series of N-substituted bicyclic carbamoyl pyridones (BiCAPs) that are simplified analogs of CAB. Several of these potently inhibit wild-type HIV-1 in single-round infection assays in cultured cells and retain high inhibitory potencies against a panel of viral constructs carrying resistant mutant forms of IN. Our lead compound, 7c, proved to be more potent than CAB against the therapeutically important resistant double mutants E138K/Q148K (>12-fold relative to CAB) and G140S/Q148R (>36-fold relative to CAB). A significant number of the BiCAPs also potently inhibit the drug-resistant IN mutant R263K, which has proven to be problematic for the FDA-approved second-generation INSTIs.

Virological Findings and Treatment Outcomes of Cases That Developed Dolutegravir Resistance in Malawi's National HIV Treatment Program

Millions of Africans are on dolutegravir-based antiretroviral therapy (ART), but few detailed descriptions of dolutegravir resistance and its clinical management exist. We reviewed HIV drug resistance (HIVDR) testing application forms submitted between June 2019 and October 2022, data from the national HIVDR database, and genotypic test results. We obtained standardized ART outcomes and virological results of cases with dolutegravir resistance, and explored associations with dolutegravir resistance among individuals with successful integrase sequencing. All cases were on two nucleoside reverse transcriptase inhibitors (NRTIs)/dolutegravir, and had confirmed virological failure, generally with prolonged viremia. Among 89 samples with successful integrase sequencing, 24 showed dolutegravir resistance. Dolutegravir resistance-associated mutations included R263K (16/24), E138K (7/24), and G118R (6/24). In multivariable logistic regression analysis, older age and the presence of high-level NRTI resistance were significantly associated with dolutegravir resistance. After treatment modification recommendations, four individuals (17%) with dolutegravir resistance died, one self-discontinued ART, one defaulted, and one transferred out. Of the 17 remaining individuals, 12 had follow-up VL results, and 11 (92%) were <1000 copies/mL. Twenty-four cases with dolutegravir resistance among 89 individuals with confirmed virological failure suggests a considerable prevalence in the Malawi HIV program. Successful management of dolutegravir resistance was possible, but early mortality was high. More research on the management of treatment-experienced individuals with dolutegravir resistance is needed.

Alternative dolutegravir dosing strategies with concurrent rifapentine utilized for latent tuberculosis treatment

We present a case of a 53-year-old person living with human immunodeficiency virus and a new diagnosis of latent tuberculosis. The patient had baseline suppressed HIV viral load on fixed dose combination dolutegravir/abacavir/lamivudine when once-weekly rifapentine 900 mg/isoniazid 900 mg/pyridoxine 25 mg was initiated for 12 weeks. An additional 50 mg dolutegravir dose, administered in the evenings, was added to the daily antiretroviral regimen for treatment duration secondary to rifapentine uridine diphosphate glucuronsyl transferase induction. Dolutegravir trough concentrations decreased during concurrent therapy with noted slight HIV viral load rebound. Upon completion of rifapentine use, and a return to dolutegravir 50 mg daily dose, the trough concentrations increased with a return to an undetectable viral load. We provide suggested dolutegravir dosing considerations with concomitant rifapentine use, not currently addressed in recommended guidelines.

HIV transmission dynamics and population-wide drug resistance in rural South Africa

Despite the scale-up of antiretroviral therapy (ART) in South Africa, HIV-1 incidence remains high. The anticipated use of potent integrase strand transfer inhibitors and long-acting injectables aims to enhance viral suppression at the population level and diminish transmission. Nevertheless, pre-existing drug resistance could impede the efficacy of long-acting injectable ART combinations, such as rilpivirine (an NNRTI) and cabotegravir (an INSTI). Consequently, a thorough understanding of transmission networks and geospatial distributions is vital for tailored interventions, including pre-exposure prophylaxis with long-acting injectables. However, empirical data on background resistance and transmission networks remain limited. In a community-based study in rural KwaZulu-Natal (2018-2019), prior to the widespread use of integrase inhibitor-based first-line ART, we performed HIV testing with reflex HIV-1 RNA viral load quantification on 18,025 participants. From this cohort, 6,096 (33.9%) tested positive for HIV via ELISA, with 1,323 (21.7%) exhibiting detectable viral loads (> 40 copies/mL). Of those with detectable viral loads, 62.1% were ART-naïve, and the majority of the treated were on an efavirenz + cytosine analogue + tenofovir regimen. Deep sequencing analysis, with a variant abundance threshold of 20%, revealed NRTI resistance mutations such as M184V in 2% of ART-naïve and 32% of treated individuals. Tenofovir resistance mutations K65R and K70E were found in 12% and 5% of ART-experienced individuals, respectively, and in less than 1% of ART-naïve individuals. Integrase inhibitor resistance mutations were notably infrequent (< 1%). Prevalence of pre-treatment drug resistance to NNRTIs was 10%, predominantly consisting of the K103N mutation. Among those with viraemic ART, NNRTI resistance was 50%, with rilpivirine-associated mutations observed in 9% of treated and 6% of untreated individuals. Cluster analysis revealed that 20% (205/1,050) of those sequenced were part of a cluster. We identified 171 groups with at least two linked participants; three quarters of clusters had only two individuals, and a quarter had 3-6 individuals. Integrating phylogenetic with geospatial analyses, we revealed a complex transmission network with significant clustering in specific regions, notably peripheral and rural areas. These findings derived from population scale genomic analyses are encouraging in terms of the limited resistance to DTG, but indicate that transitioning to long-acting cabotegravir + rilpivirine for transmission reduction should be accompanied by prior screening for rilpivirine resistance. Whole HIV-1 genome sequencing allowed identification of significant proportions of clusters with multiple individuals, and geospatial analyses suggesting decentralised networks can inform targeting public health interventions to effectively curb HIV-1 transmission.

Treatment Emergent Dolutegravir Resistance Mutations in Individuals Naïve to HIV-1 Integrase Inhibitors: A Rapid Scoping Review

Background: Dolutegravir (DTG)-based antiretroviral therapy (ART) rarely leads to virological failure (VF) and drug resistance in integrase strand transfer inhibitor (INSTI)-naïve persons living with HIV (PLWH). As a result, limited data are available on INSTI-associated drug resistance mutations (DRMs) selected by DTG-containing ART regimens. Methods: We reviewed studies published through July 2023 to identify those reporting emergent major INSTI-associated DRMs in INSTI-naïve PLWH receiving DTG and those containing in vitro DTG susceptibility results using a standardized assay. Results: We identified 36 publications reporting 99 PLWH in whom major nonpolymorphic INSTI-associated DRMs developed on a DTG-containing regimen and 21 publications containing 269 in vitro DTG susceptibility results. DTG-selected DRMs clustered into four largely non-overlapping mutational pathways characterized by mutations at four signature positions: R263K, G118R, N155H, and Q148H/R/K. Eighty-two (82.8%) viruses contained just one signature DRM, including R263K (n = 40), G118R (n = 24), N155H (n = 9), and Q148H/R/K (n = 9). Nine (9.1%) contained ≥1 signature DRM, and eight (8.1%) contained just other DRMs. R263K and G118R were negatively associated with one another and with N155H and Q148H/K/R. R263K alone conferred a median 2.0-fold (IQR: 1.8-2.2) reduction in DTG susceptibility. G118R alone conferred a median 18.8-fold (IQR:14.2-23.4) reduction in DTG susceptibility. N155H alone conferred a median 1.4-fold (IQR: 1.2-1.6) reduction in DTG susceptibility. Q148H/R/K alone conferred a median 0.8-fold (IQR: 0.7-1.1) reduction in DTG susceptibility. Considerably higher levels of reduced susceptibility often occurred when signature DRMs occurred with additional INSTI-associated DRMs. Conclusions: Among INSTI-naïve PLWH with VF and treatment emergent INSTI-associated DRMs, most developed one of four signature DRMs, most commonly R263K or G118R. G118R was associated with a much greater reduction in DTG susceptibility than R263K.

The G118R plus R263K Combination of Integrase Mutations Associated with Dolutegravir-Based Treatment Failure Reduces HIV-1 Replicative Capacity and Integration

Human immunodeficiency virus (HIV) treatment with antiretroviral regimens containing integrase strand transfer inhibitors such as dolutegravir (DTG) and bictegravir (BIC) offers high levels of protection against the development of drug resistance mutations. Despite this, resistance to DTG and BIC can occur through the development of the R263K integrase substitution. Failure with DTG has also been associated with the emergence of the G118R substitution. G118R and R263K are usually found separately but have been reported together in highly treatment-experienced persons who experienced treatment failure with DTG. We used cell-free strand transfer and DNA binding assays and cell-based infectivity, replicative capacity, and resistance assays to characterize the G118R plus R263K combination of integrase mutations. R263K reduced DTG and BIC susceptibility ~2-fold, in agreement with our previous work. Single-cycle infectivity assays showed that G118R and G118R plus R263K conferred ~10-fold resistance to DTG. G118R alone conferred low levels of resistance to BIC (3.9-fold). However, the G118R plus R263K combination conferred high levels of resistance to BIC (33.7-fold), likely precluding the use of BIC after DTG failure with the G118R plus R263K combination. DNA binding, viral infectivity, and replicative capacity of the double mutant were further impaired, compared to single mutants. We propose that impaired fitness helps to explain the scarcity of the G118R plus R263K combination of integrase substitutions in clinical settings and that immunodeficiency likely contributes to its development.

Predicted effects of the introduction of long-acting injectable cabotegravir pre-exposure prophylaxis in sub-Saharan Africa: a modelling study

BACKGROUND

Long-acting injectable cabotegravir pre-exposure prophylaxis (PrEP) is recommended by WHO as an additional option for HIV prevention in sub-Saharan Africa, but there is concern that its introduction could lead to an increase in integrase-inhibitor resistance undermining treatment programmes that rely on dolutegravir. We aimed to project the health benefits and risks of cabotegravir-PrEP introduction in settings in sub-Saharan Africa.

METHODS

With HIV Synthesis, an individual-based HIV model, we simulated 1000 setting-scenarios reflecting both variability and uncertainty about HIV epidemics in sub-Saharan Africa and compared outcomes for each with and without cabotegravir-PrEP introduction. PrEP use is assumed to be risk-informed and to be used only in 3-month periods (the time step for the model) when having condomless sex. We consider three groups at risk of integrase-inhibitor resistance emergence: people who start cabotegravir-PrEP after (unknowingly) being infected with HIV, those who seroconvert while on PrEP, and those with HIV who have residual cabotegravir drugs concentrations during the early tail period after recently stopping PrEP. We projected the outcomes of policies of cabotegravir-PrEP introduction and of no introduction in 2022 across 50 years. In 50% of setting-scenarios we considered that more sensitive nucleic-acid-based HIV diagnostic testing (NAT), rather than regular antibody-based HIV rapid testing, might be used to reduce resistance risk. For cost-effectiveness analysis we assumed in our base case a cost of cabotegravir-PrEP drug to be similar to oral PrEP, resulting in a total annual cost of USD$144 per year ($114 per year and $264 per year considered in sensitivity analyses), a cost-effectiveness threshold of $500 per disability-adjusted life years averted, and a discount rate of 3% per year.

FINDINGS

Reflecting our assumptions on the appeal of cabotegravir-PrEP, its introduction is predicted to lead to a substantial increase in PrEP use with approximately 2·6% of the adult population (and 46% of those with a current indication for PrEP) receiving PrEP compared with 1·5% (28%) without cabotegravir-PrEP introduction across 20 years. As a result, HIV incidence is expected to be lower by 29% (90% range across setting-scenarios 6-52%) across the same period compared with no introduction of cabotegravir-PrEP. In people initiating antiretroviral therapy, the proportion with integrase-inhibitor resistance after 20 years is projected to be 1·7% (0-6·4%) without cabotegravir-PrEP introduction but 13·1% (4·1-30·9%) with. Cabotegravir-PrEP introduction is predicted to lower the proportion of all people on antiretroviral therapy with viral loads less than 1000 copies per mL by 0·9% (-2·5% to 0·3%) at 20 years. For an adult population of 10 million an overall decrease in number of AIDS deaths of about 4540 per year (-13 000 to -300) across 50 years is predicted, with little discernible benefit with NAT when compared with standard antibody-based rapid testing. AIDS deaths are predicted to be averted with cabotegravir-PrEP introduction in 99% of setting-scenarios. Across the 50-year time horizon, overall HIV programme costs are predicted to be similar regardless of whether cabotegravir-PrEP is introduced (total mean discounted annual HIV programme costs per year across 50 years is $151·3 million vs $150·7 million), assuming the use of standard antibody testing. With antibody-based rapid HIV testing, the introduction of cabotegravir-PrEP is predicted to be cost-effective under an assumed threshold of $500 per disability-adjusted life year averted in 82% of setting-scenarios at the cost of $144 per year, in 52% at $264, and in 87% at $114.

INTERPRETATION

Despite leading to increases in integrase-inhibitor drug resistance, cabotegravir-PrEP introduction is likely to reduce AIDS deaths in addition to HIV incidence. Long-acting cabotegravir-PrEP is predicted to be cost-effective if delivered at similar cost to oral PrEP with antibody-based rapid HIV testing.

FUNDING

Bill & Melinda Gates Foundation, National Institute of Allergy and Infectious Diseases of the National Institutes of Health.

HIV-1 resistance against dolutegravir fluctuates rapidly alongside erratic treatment adherence: a case report

OBJECTIVES

We report a case of incomplete HIV-1 suppression on a dolutegravir, lamivudine, and abacavir single-tablet regimen with the emergence of the H51Y and G118R integrase resistance mutations.

METHODS

Integrase sequencing was performed retrospectively by Sanger and next-generation sequencing. Rates of emergence and decline of resistance mutations were calculated using next-generation sequencing data. Dolutegravir plasma concentrations were measured by ultra-performance liquid chromatography-tandem mass spectrometry. The effects of H51Y and G118R on infectivity, fitness, and susceptibility to dolutegravir were quantified using cell-based assays.

RESULTS

During periods of non-adherence to treatment, mutations were retrospectively documented only by next-generation sequencing. Misdiagnosis by Sanger sequencing was caused by the rapid decline of mutant strains within the retroviral population. This observation was also true for a M184V lamivudine-resistant reverse transcriptase mutation found in association with integrase mutations on single HIV genomes. Resistance rebound upon treatment re-initiation was swift (>8000 copies per day). Next-generation sequencing indicated cumulative adherence to treatment. Compared to WT HIV-1, relative infectivity was 73%, 38%, and 43%; relative fitness was 100%, 35%, and 10% for H51Y, G118R, and H51Y+G118R viruses, respectively. H51Y did not change the susceptibility to dolutegravir, but G188R and H51Y+G118R conferred 7- and 28-fold resistance, respectively.

CONCLUSION

This case illustrates how poorly-fit drug-resistant viruses wax and wane alongside erratic treatment adherence and are easily misdiagnosed by Sanger sequencing. We recommend next-generation sequencing to improve the clinical management of incomplete virological suppression with dolutegravir.

Point-of-Care Tenofovir Urine Testing for the Prediction of Treatment Failure and Drug Resistance During Initial Treatment for Human Immunodeficiency Virus Type 1 (HIV-1) Infection

BACKGROUND

Viral rebound during antiretroviral treatment (ART) is most often driven by suboptimal adherence in the absence of drug resistance. We assessed the diagnostic performance of point-of-care (POC) tenofovir (TFV) detection in urine for the prediction of viral rebound and drug resistance during ART.

METHODS

We performed a nested case-control study within the ADVANCE randomized clinical trial (NCT03122262) in Johannesburg, South Africa. Adults with human immunodeficiency virus (HIV) and newly initiating ART were randomized to receive either dolutegravir or efavirenz, tenofovir disoproxil fumarate or alafenamide, and emtricitabine. All participants with rebound ≥200 copies/mL between 24 and 96 weeks of follow-up were selected as cases and matched to controls with virological suppression <50 copies/mL. Rapid POC urine-TFV detection was performed retrospectively.

RESULTS

We included 281 samples from 198 participants. Urine-TFV was detectable in 30.7% (70/228) of cases and in 100% (53/53) of controls. Undetectable urine-TFV predicted rebound with a sensitivity of 69% [95% confidence interval {CI}: 63-75] and specificity of 100% [93-100]. In cases with virological failure and sequencing data (n = 42), NRTI drug resistance was detected in 50% (10/20) of cases with detectable urine-TFV versus in 8.3% (2/24) of cases with undetectable urine-TFV. Detectable urine-TFV predicted NRTI resistance (odds ratio [OR] 10.4 [1.8-114.4] P = .005) with a sensitivity of 83% [52-98] and specificity of 69% [50-84].

CONCLUSIONS

POC objective adherence testing using a urine-TFV test predicted viral rebound with high specificity. In participants with rebound, urine-TFV testing predicted the selection of drug resistance. Objective adherence testing may be used to rapidly provide insight into adherence, suppression, and drug resistance during ART.

Brief Report: Efficacy and Safety of Efavirenz, Raltegravir, and Dolutegravir in HIV-1/TB Coinfection. A Multicenter Retrospective Cohort Study in France

BACKGROUND

There are limited data comparing the efficacy and safety of raltegravir and dolutegravir to that of efavirenz in HIV-1/tuberculosis (TB) coinfected patients.

METHODS

We conducted a 10-year retrospective study in 4 centers in France. We included all HIV-1/tuberculosis coinfected patients starting antiretroviral therapy with a rifampicin-based regimen, with a plasma HIV RNA level (VL) > 1000 copies/mL. The primary endpoint was the proportion of patients with virological success that is, with VL <50 copies/mL at W48 using an Intention-To-Treat analysis, using last-observation-carried-forward to impute missing data. We also assessed antiretroviral therapy safety, analyzing treatment discontinuation for adverse events.

RESULTS

Between 2010 and 2020, 117 patients were included. Thirty-nine (33.3%) were treated with raltegravir and 2 nucleoside reverse transcriptase inhibitors (NRTIs), 19 (16.2%) with dolutegravir (and 2 NRTIs) and 59 (50.4%) with efavirenz (and 2 NRTIs). At W48, the primary endpoint was achieved in 24 patients (61.5%) in the raltegravir group, in 12 (63.2%) in the dolutegravir group, and in 41 (69.5%) in the efavirenz group using an Intention-To-Treat analysis ( P = 0.68). Emergence of drug resistance in patients with virological failure, defined as a VL >50 copies/mL, was observed in 3 patients with efavirenz and one patient with raltegravir. Rate of treatment discontinuation for drug-related adverse events was 10.3%, 10.6%, 16.9% for raltegravir, dolutegravir and efavirenz respectively ( P = 0.67).

CONCLUSIONS

In this retrospective cohort study, raltegravir and dolutegravir yielded similar efficacy and safety results to efavirenz for the treatment of HIV-1/TB coinfected patients.

Forgiveness of INSTI-Containing Regimens at Drug Concentrations Simulating Variable Adherence In Vitro

The integrase strand transfer inhibitor (INSTI)-based regimens bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF), dolutegravir (DTG)+FTC/TAF, DTG/lamivudine (3TC), and DTG/rilpivirine (RPV) are all approved for treatment of HIV-infected patients, with various limitations. Here, time to in vitro viral breakthrough (VB) and resistance barrier using simulated human drug exposures at either full or suboptimal treatment adherence to each regimen were compared. At drug concentrations corresponding to full adherence and 1 missed dose (Cmin and Cmin-1), no VB occurred with any regimen. At Cmin-2, VB occurred only with DTG+3TC, with emergent resistance to both drugs. At Cmin-3, VB occurred with all regimens: 100% of DTG+3TC cultures had VB by day 12, and <15% of BIC+FTC+TAF, DTG+FTC+TAF, and DTG+RPV cultures had VB. Emergent reverse transcriptase (RT) or integrase (IN) resistance was seen with DTG+RPV and DTG+3TC but not with BIC+FTC+TAF or DTG+FTC+TAF. At Cmin-4, 100% VB occurred with DTG+3TC and DTG+FTC+TAF by day 12, while 94% VB occurred with DTG+RPV by day 25 and only 50% VB occurred with BIC+FTC+TAF by day 35. Emergent Cmin-4 drug resistance was seen with all regimens but at differing frequencies; DTG+RPV had the most cultures with resistance. Emergent resistance was consistent with clinical observations. Overall, under high adherence conditions, no in vitro VB or resistance development occurred with these INSTI-based regimens. However, when multiple missed doses were simulated in vitro, BIC+FTC+TAF had the highest forgiveness and barrier to resistance of all tested regimens. Compared to DTG+3TC and DTG+FTC+TAF, DTG+RPV had higher forgiveness but lower resistance barrier after several simulated missed doses.

Dolutegravir resistance in Malawi’s national HIV treatment program

Dolutegravir HIV drug resistance (HIVDR) data from Africa remain sparse. We reviewed HIVDR results of Malawians on dolutegravir-based antiretroviral therapy (November 2020–September 2021). Of 6462 eligible clients, 33 samples were submitted to South Africa, 27 were sequenced successfully, and 8 (30%) had dolutegravir HIVDR. Malawi urgently requires adequate HIVDR testing capacity.

Pre-Treatment Integrase Inhibitor Resistance and Natural Polymorphisms among HIV-1 Subtype C Infected Patients in Ethiopia

Dolutegravir-based antiretroviral therapy (ART) has been scaled up in many developing countries, including Ethiopia. However, subtype-dependent polymorphic differences might influence the occurrence of HIV-drug-resistance mutations (HIVDRMs). We analyzed the prevalence of pre-treatment integrase strand transfer inhibitor (INSTI) HIVDRMs and naturally occurring polymorphisms (NOPs) of the integrase gene, using plasma samples collected as part of the national HIVDR survey in Ethiopia in 2017. We included a total of 460 HIV-1 integrase gene sequences from INSTI-naïve (n = 373 ART-naïve and n = 87 ART-experienced) patients. No dolutegravir-associated HIVDRMs were detected, regardless of previous exposure to ART. However, we found E92G in one ART-naïve patient specimen and accessory mutations in 20/460 (4.3%) of the specimens. Moreover, among the 288 integrase amino acid positions of the subtype C, 187/288 (64.9%) were conserved (<1.0% variability). Analysis of the genetic barrier showed that the Q148H/K/R dolutegravir resistance pathway was less selected in subtype C. Docking analysis of the dolutegravir showed that protease- and reverse-transcriptase-associated HIVDRMs did not affect the native structure of the HIV-1 integrase. Our results support the implementation of a wide scale-up of dolutegravir-based regimes. However, the detection of polymorphisms contributing to INSTI warrants the continuous surveillance of INSTI resistance.

Exploring the mechanisms behind HIV drug resistance in sub-Saharan Africa: conceptual mapping of a complex adaptive system based on multi-disciplinary expert insights

BACKGROUND

HIV drug resistance (HIVDR) continues to threaten the effectiveness of worldwide antiretroviral therapy (ART). Emergence and transmission of HIVDR are driven by several interconnected factors. Though much has been done to uncover factors influencing HIVDR, overall interconnectedness between these factors remains unclear and African policy makers encounter difficulties setting priorities combating HIVDR. By viewing HIVDR as a complex adaptive system, through the eyes of multi-disciplinary HIVDR experts, we aimed to make a first attempt to linking different influencing factors and gaining a deeper understanding of the complexity of the system.

METHODS

We designed a detailed systems map of factors influencing HIVDR based on semi-structured interviews with 15 international HIVDR experts from or with experience in sub-Saharan Africa, from different disciplinary backgrounds and affiliated with different types of institutions. The resulting detailed system map was conceptualized into three main HIVDR feedback loops and further strengthened with literature evidence.

RESULTS

Factors influencing HIVDR in sub-Saharan Africa and their interactions were sorted in five categories: biology, individual, social context, healthcare system and 'overarching'. We identified three causal loops cross-cutting these layers, which relate to three interconnected subsystems of mechanisms influencing HIVDR. The 'adherence motivation' subsystem concerns the interplay of factors influencing people living with HIV to alternate between adherence and non-adherence. The 'healthcare burden' subsystem is a reinforcing loop leading to an increase in HIVDR at local population level. The 'ART overreliance' subsystem is a balancing feedback loop leading to complacency among program managers when there is overreliance on ART with a perceived low risk to drug resistance. The three subsystems are interconnected at different levels.

CONCLUSIONS

Interconnectedness of the three subsystems underlines the need to act on the entire system of factors surrounding HIVDR in sub-Saharan Africa in order to target interventions and to prevent unwanted effects on other parts of the system. The three theories that emerged while studying HIVDR as a complex adaptive system form a starting point for further qualitative and quantitative investigation.

Antiretroviral Imprints and Genomic Plasticity of HIV-1 pol in Non-clade B: Implications for Treatment

Combinational antiretroviral therapy (cART) is the most effective tool to prevent and control HIV-1 infection without an effective vaccine. However, HIV-1 drug resistance mutations (DRMs) and naturally occurring polymorphisms (NOPs) can abrogate cART efficacy. Here, we aimed to characterize the HIV-1 pol mutation landscape in Cameroon, where highly diverse HIV clades circulate, and identify novel treatment-associated mutations that can potentially affect cART efficacy. More than 8,000 functional Cameroonian HIV-1 pol sequences from 1987 to 2020 were studied for DRMs and NOPs. Site-specific amino acid frequencies and quaternary structural features were determined and compared between periods before (≤2003) and after (2004-2020) regional implementation of cART. cART usage in Cameroon induced deep mutation imprints in reverse transcriptase (RT) and to a lower extent in protease (PR) and integrase (IN), according to their relative usage. In the predominant circulating recombinant form (CRF) 02_AG (CRF02_AG), 27 canonical DRMs and 29 NOPs significantly increased or decreased in RT during cART scale-up, whereas in IN, no DRM and only seven NOPs significantly changed. The profound genomic imprints and higher prevalence of DRMs in RT compared to PR and IN mirror the dominant use of reverse transcriptase inhibitors (RTIs) in sub-Saharan Africa and the predominantly integrase strand transfer inhibitor (InSTI)-naïve study population. Our results support the potential of InSTIs for antiretroviral treatment in Cameroon; however, close surveillance of IN mutations will be required to identify emerging resistance patterns, as observed in RT and PR. Population-wide genomic analyses help reveal the presence of selective pressures and viral adaptation processes to guide strategies to bypass resistance and reinstate effective treatment.

An up-to-date evaluation of dolutegravir/abacavir/lamivudine for the treatment of HIV

INTRODUCTION

There are more than 30 agents available for the treatment of HIV with guidelines shifting toward integrase strand transfer inhibitors (INSTIs) as part of first line therapy. The fixed dose combination of dolutegravir (DTG), abacavir (ABC), and lamivudine (3TC) is a convenient, well tolerated, and highly effective option for treating HIV infection and remains a first line therapy across several prominent guidelines.

AREAS COVERED

In this drug evaluation, the authors provide a comprehensive overview of DTG/ABC/3TC for the treatment of HIV including the pharmacokinetics, pharmacodynamics, efficacy, safety, and tolerability. The authors also provide the reader with their expert perspectives on this particular treatment strategy.

EXPERT OPINION

While DTG/ABC/3TC remains a valuable HIV treatment option, newer combination regimens have entered the market. Bictegravir with tenofovir alafenamide and emtricitabine offers the benefit of same day initiation and efficacy in hepatitis B co-infection, while new two-drug regimens enhance the simplicity of HIV treatment. Continued study is required into the mechanisms and optimal management strategies for weight gain for many regimens, including DTG/ABC/3TC.

Integrase Inhibitor Resistance Mechanisms and Structural Characteristics in Antiretroviral Therapy-Experienced, Integrase Inhibitor-Naive Adults with HIV-1 Infection Treated with Dolutegravir plus Two Nucleoside Reverse Transcriptase Inhibitors in the DAWNING Study

At week 48 in the phase IIIb DAWNING study, the integrase strand transfer inhibitor (INSTI) dolutegravir plus 2 nucleoside reverse transcriptase inhibitors demonstrated superiority to ritonavir-boosted lopinavir in achieving virologic suppression in adults with HIV-1 who failed first-line therapy. Here, we report emergent HIV-1 drug resistance and mechanistic underpinnings among dolutegravir-treated adults in DAWNING. Population viral genotyping, phenotyping, and clonal analyses were performed on participants meeting confirmed virologic withdrawal (CVW) criteria on dolutegravir-containing regimens. Dolutegravir binding to and structural changes in HIV-1 integrase-DNA complexes with INSTI resistance-associated substitutions were evaluated. Of participants who received dolutegravir through week 48 plus an additional 110 weeks for this assessment, 6 met CVW criteria with treatment-emergent INSTI resistance-associated substitutions and 1 had R263R/K at baseline but not at CVW. All 7 achieved HIV-1 RNA levels of <400 copies/mL (5 achieved <50 copies/mL) before CVW. Treatment-emergent G118R was detected in 5 participants, occurring with ≥2 other integrase substitutions, including R263R/K, in 3 participants and without other integrase substitutions in 2 participants. G118R or R263K increased the rate of dolutegravir dissociation from integrase-DNA complexes versus wild-type but retained prolonged binding. Overall, among treatment-experienced adults who received dolutegravir in DAWNING, 6 of 314 participants developed treatment-emergent INSTI resistance-associated substitutions, with a change in in vitro dolutegravir resistance of >10-fold and reduced viral replication capacity versus baseline levels. This study demonstrates that the pathway to dolutegravir resistance is a challenging balance between HIV-1 phenotypic change and associated loss of viral fitness. (This study has been registered at ClinicalTrials.gov under identifier NCT02227238.).

SARS-CoV-2 Evolution and Spike-Specific CD4+ T-Cell Response in Persistent COVID-19 with Severe HIV Immune Suppression

Intra-host evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported in cases with persistent coronavirus disease 2019 (COVID-19). In this study, we describe a severely immunosuppressed individual with HIV-1/SARS-CoV-2 coinfection with a long-term course of SARS-CoV-2 infection. A 28-year-old man was diagnosed with HIV-1 infection (CD4+ count: 3 cells/µL nd 563000 HIV-1 RNA copies/mL) and simultaneous Pneumocystis jirovecii pneumonia, disseminated Mycobacterium avium complex infection and SARS-CoV-2 infection. SARS-CoV-2 real-time reverse transcription polymerase chain reaction positivity from nasopharyngeal samples was prolonged for 15 weeks. SARS-CoV-2 was identified as variant Alpha (PANGO lineage B.1.1.7) with mutation S:E484K. Spike-specific T-cell response was similar to HIV-negative controls although enriched in IL-2, and showed disproportionately increased immunological exhaustion marker levels. Despite persistent SARS-CoV-2 infection, adaptive intra-host SARS-CoV-2 evolution, was not identified. Spike-specific T-cell response protected against a severe COVID-19 outcome and the increased immunological exhaustion marker levels might have favoured SARS-CoV-2 persistence.

Altered HIV-1 mRNA Splicing Due to Drug-Resistance-Associated Mutations in Exon 2/2b

The underlying molecular mechanism and their general effect on the replication capacity of HIV 1 drug-resistance-associated mutations is often poorly understood. To elucidate the effect of two such mutations located in a region with a high density of spicing regulatory elements on the HIV-1-splicing outcome, bioinformatic predictions were combined with transfection and infection experiments. Results show that the previously described R263K drug-resistance-associated integrase mutation has additionally a severe effect on the ESE2b splicing regulatory element (SRE) in exon 2b, which causes loss of SD2b recognition. This was confirmed by an R263R silent mutation with a similar predicted effect on the exon 2b SRE. In contrast, a V260I mutation and its silent counterpart with a lower effect on ESS2b did not exhibit any differences in the splicing pattern. Since HIV-1 highly relies on a balanced splicing reaction, changes in the splicing outcome can contribute to changes in viral replication and might add to the effect of escape mutations toward antiviral drugs. Thus, a classification of mutations purely addressing proteins is insufficient.

Retroviral integrase: Structure, mechanism, and inhibition

The retroviral protein Integrase (IN) catalyzes concerted integration of viral DNA into host chromatin to establish a permanent infection in the target cell. We learned a great deal about the mechanism of catalytic integration through structure/function studies over the previous four decades of IN research. As one of three essential retroviral enzymes, IN has also been targeted by antiretroviral drugs to treat HIV-infected individuals. Inhibitors blocking the catalytic integration reaction are now state-of-the-art drugs within the antiretroviral therapy toolkit. HIV-1 IN also performs intriguing non-catalytic functions that are relevant to the late stages of the viral replication cycle, yet this aspect remains poorly understood. There are also novel allosteric inhibitors targeting non-enzymatic functions of IN that induce a block in the late stages of the viral replication cycle. In this chapter, we will discuss the function, structure, and inhibition of retroviral IN proteins, highlighting remaining challenges and outstanding questions.

Impact of pre-existing drug resistance on risk of virological failure in South Africa

OBJECTIVES

There is conflicting evidence on the impact of pre-existing HIV drug resistance mutations (DRMs) in patients infected with non-B subtype virus.

METHODS

We performed a case-cohort substudy of the AIDS Drug Resistance Surveillance Study, which enrolled South African patients initiating first-line efavirenz/emtricitabine/tenofovir. Pre-ART DRMs were detected by Illumina sequencing of HIV pol and DRMs present at <20% of the viral population were labelled as minority variants (MVs). Weighted Cox proportional hazards models estimated the association between pre-ART DRMs and risk of virological failure (VF), defined as confirmed HIV-1 RNA ≥1000 copies/mL after ≥5 months of ART.

RESULTS

The evaluable population included 178 participants from a randomly selected subcohort (16 with VF, 162 without VF) and 83 additional participants with VF. In the subcohort, 16% of participants harboured ≥1 majority DRM. The presence of any majority DRM was associated with a 3-fold greater risk of VF (P = 0.002), which increased to 9.2-fold (P < 0.001) in those with <2 active drugs. Thirteen percent of participants harboured MV DRMs in the absence of majority DRMs. Presence of MVs alone had no significant impact on the risk of VF. Inclusion of pre-ART MVs with majority DRMs improved the sensitivity but reduced the specificity of predicting VF.

CONCLUSIONS

In a South African cohort, the presence of majority DRMs increased the risk of VF, especially for participants receiving <2 active drugs. The detection of drug-resistant MVs alone did not predict an increased risk of VF, but their inclusion with majority DRMs affected the sensitivity/specificity of predicting VF.

HIV-1 integrase strand transfer inhibitors: a review of current drugs, recent advances and drug resistance

Antiretroviral therapy has been imperative in controlling the human immunodeficiency virus (HIV) epidemic. Most low- and middle-income countries have used nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors extensively in the treatment of HIV. However, integrase strand transfer inhibitors (INSTIs) are becoming more common. Since their identification as a promising therapeutic drug, significant progress has been made that has led to the approval of five INSTIs by the US Food and Drug Administration (FDA), i.e. dolutegravir (DTG), raltegravir (RAL), elvitegravir (EVG), bictegravir (BIC) and cabotegravir (CAB). INSTIs have been shown to effectively halt HIV-1 replication and are commended for having a higher genetic barrier to resistance compared with NRTIs and NNRTIs. More interestingly, DTG has shown a higher genetic barrier to resistance compared with RAL and EVG, and CAB is being used as the first long-acting agent in HIV-1 treatment. Considering the increasing interest in INSTIs for HIV-1 treatment, we focus our review on the retroviral integrase, development of INSTIs and their mode of action. We also discuss each of the INSTI drugs, including potential drug resistance and known side effects.

Standard dose raltegravir or efavirenz-based antiretroviral treatment for patients co-infected with HIV and tuberculosis (ANRS 12 300 Reflate TB 2): an open-label, non-inferiority, randomised, phase 3 trial

BACKGROUND

In patients co-infected with HIV and tuberculosis, antiretroviral therapy options are limited due to drug-drug interactions with rifampicin. A previous phase 2 trial indicated that raltegravir 400 mg twice a day or efavirenz 600 mg once a day might have similar virological efficacy in patients given rifampicin. In this phase 3 trial, we assessed the non-inferiority of raltegravir to efavirenz.

METHODS

We did a multicentre, open-label, non-inferiority, randomised, phase 3 trial at six sites in Côte d'Ivoire, Brazil, France, Mozambique, and Vietnam. We included antiretroviral therapy (ART)-naive adults (aged ≥18 years) with confirmed HIV-1 infection and bacteriologically confirmed or clinically diagnosed tuberculosis who had initiated rifampicin-containing tuberculosis treatment within the past 8 weeks. Using computerised random numbers, we randomly assigned participants (1:1; stratified by country) to receive raltegravir 400 mg twice daily or efavirenz 600 mg once daily, both in combination with tenofovir and lamivudine. The primary outcome was the proportion of patients with virological suppression at week 48 (defined as plasma HIV RNA concentration <50 copies per mL). The prespecified non-inferiority margin was 12%. The primary outcome was assessed in the intention-to-treat population, which included all randomly assigned patients (excluding two patients with HIV-2 infection and one patient with HIV-1 RNA concentration of <50 copies per mL at inclusion), and the on-treatment population, which included all patients in the intention-to-treat population who initiated treatment and were continuing allocated treatment at week 48, and patients who had discontinued allocated treatment due to death or virological failure. Safety was assessed in all patients who received at least one dose of the assigned treatment regimen. This study is registered with ClinicalTrials.gov, NCT02273765.

FINDINGS

Between Sept 28, 2015, and Jan 5, 2018, 460 participants were randomly assigned to raltegravir (n=230) or efavirenz (n=230), of whom 457 patients (230 patients in the raltegravir group; 227 patients in the efavirenz group) were included in the intention-to-treat analysis and 410 (206 patients in the raltegravir group; 204 patients in the efavirenz group) in the on-treatment analysis. At baseline, the median CD4 count was 103 cells per μL and median plasma HIV RNA concentration was 5·5 log₁₀ copies per mL (IQR 5·0-5·8). 310 (68%) of 457 participants had bacteriologically-confirmed tuberculosis. In the intention-to-treat population, at week 48, 140 (61%) of 230 participants in the raltegravir group and 150 (66%) of 227 patients in the efavirenz had achieved virological suppression (between-group difference -5·2% [95% CI -14·0 to 3·6]), thus raltegravir did not meet the predefined criterion for non-inferiority. The most frequent adverse events were HIV-associated non-AIDS illnesses (eight [3%] of 229 patients in the raltegravir group; 21 [9%] of 230 patients in the efavirenz group) and AIDS-defining illnesses (ten [4%] patients in the raltegravir group; 13 [6%] patients in the efavirenz group). 58 (25%) of 229 patients in raltegravir group and 66 (29%) of 230 patients in the efavirenz group had grade 3 or 4 adverse events. 26 (6%) of 457 patients died during follow-up: 14 in the efavirenz group and 12 in the raltegravir group.

INTERPRETATION

In patients with HIV given tuberculosis treatment, non-inferiority of raltegravir compared with efavirenz was not shown. Raltegravir was well tolerated and could be considered as an option, but only in selected patients.

FUNDING

National French Agency for AIDS Research, Ministry of Health in Brazil, Merck.

TRANSLATIONS

For the Portuguese and French translations of the abstract see Supplementary Materials section.

Integrase Strand Transfer Inhibitors Are Effective Anti-HIV Drugs

Integrase strand transfer inhibitors (INSTIs) are currently recommended for the first line treatment of human immunodeficiency virus type one (HIV-1) infection. The first-generation INSTIs are effective but can select for resistant viruses. Recent advances have led to several potent second-generation INSTIs that are effective against both wild-type (WT) HIV-1 integrase and many of the first-generation INSTI-resistant mutants. The emergence of resistance to these new second-generation INSTIs has been minimal, which has resulted in alternative treatment strategies for HIV-1 patients. Moreover, because of their high antiviral potencies and, in some cases, their bioavailability profiles, INSTIs will probably have prominent roles in pre-exposure prophylaxis (PrEP). Herein, we review the current state of the clinically relevant INSTIs and discuss the future outlook for this class of antiretrovirals.

Emergence of Resistance to Integrase Strand Transfer Inhibitors during Dolutegravir Containing Triple-Therapy in a Treatment-Experienced Patient with Pre-Existing M184V/I Mutation

With the current widespread use of dolutegravir in low-income countries, the understanding of the impact of nucleoside reverse transcriptase inhibitor (NRTI-) associated mutations on the efficacy of dolutegravir-containing antiretroviral therapy (ART) is of utmost importance. We describe a rare case of a patient with pre-existing M184V/I mutation and virological failure on a dolutegravir/lamivudine/abacavir regimen with the emergence of integrase strand transfer inhibitor resistance mutations. Additional risk factors, which may have triggered the virological failure, included suboptimal adherence and low nadir CD4+ cell count. This case illustrates that dolutegravir-containing triple-therapy should be prescribed with caution to patients with pre-existing M184V/I mutation and poor efficacy of the reverse transcriptase inhibitor backbone. In addition, this case highlights the need for viral load monitoring in patients on dolutegravir-containing regimens in settings with a high prevalence of the M184V/I mutation such as in low-income countries.

Occurrence of the S230R integrase strand inhibitor mutation in a treatment-naïve individual case report

RATIONALE

Transmitted resistance to integrase strand inhibitors (INSTI) has been uncommon, but is slowly becoming more prevalent among those living with HIV. In an era with 2-drug regimens for antiretroviral therapy, transmitted resistance for INSTI is alarming.

PATIENT CONCERNS

A 28-year-old African American female was recently diagnosed with HIV during a 30-week prenatal visit.

DIAGNOSIS

HIV 4th generation test was positive as well as confirmation. Genotype was performed using next generation sequencing.

INTERVENTIONS

Patient was initially rapidly started on a dolutegravir based regimen and changed to a protease inhibitor regimen once her genotype reported an S230R mutation.

OUTCOMES

Patient became virally suppressed on antiretroviral therapy and delivered an HIV negative baby.

LESSONS

INSTI resistance testing should be done for treatment-naïve and INSTI-naïve persons, particularly when considering 2 drug INSTI based regimens.

Case report: Emergence of dolutegravir resistance in a patient on second-line antiretroviral therapy

Introduction

The integrase strand transfer inhibitor dolutegravir (DTG) has a high genetic barrier to resistance. Only rare cases of resistance to DTG have been reported when it is used as a component of antiretroviral therapy regimens in treatment-experienced patients unless there was prior use of a first-generation integrase inhibitor.

Patient presentation

A 38-year-old woman diagnosed with tuberculosis was switched to a second-line antiretroviral regimen of zidovudine, lamivudine and dolutegravir 50 mg 12-hourly together with rifampicin-based TB treatment. Based on treatment history and a previous resistance test there was resistance to lamivudine but full susceptibility to zidovudine. The patient did not suppress her viral load on this regimen and later admitted to only taking dolutegravir 50 mg in the morning because of insomnia.

Management and outcome

A second resistance test was performed which showed intermediate level of resistance to dolutegravir. Her regimen was changed to tenofovir, emtricitabine and ritonavir-boosted atazanavir with rifabutin replacing rifampicin for the remainder of her TB treatment. She achieved viral suppression on this regimen.

Conclusion

To our knowledge this is the first case report from South Africa of emergent dolutegravir resistance in a treatment-experienced, integrase inhibitor-naïve patient. Factors that may have contributed to resistance emergence in this patient were that there was only one fully active nucleoside reverse transcriptase inhibitor in the regimen and lower exposure to dolutegravir because of the reduced dosing frequency while on rifampicin.

Emergent Resistance to Dolutegravir Among INSTI-Naïve Patients on First-line or Second-line Antiretroviral Therapy: A Review of Published Cases

None of the licensing studies of dolutegravir (DTG) reported any treatment-emergent resistance among DTG-treated individuals, though virological failure in treatment-naïve and treatment-experienced, integrase strand transfer inhibitor (INSTI)-naïve individuals has been reported in clinical practice. While the spectrum of dolutegravir-selected mutations and their effects on clinical outcome have been described, the clinical characteristics of these rare but important virological failure cases are often overlooked. In this perspective piece, we focus on key clinical aspects of emergent resistance to DTG among treatment-naïve and treatment-experienced INSTI-naïve patients, with an aim to inform clinical decision-making. Poor adherence and HIV disease factors contribute to emergent drug resistance, even in regimens with high resistance barriers. Patients with severe immunosuppression or poor adherence are under-represented in licensing studies, and these patients may be at higher risk of treatment failure with DTG resistance, which requires close clinical and laboratory follow-up.

Failure to bictegravir and development of resistance mutations in an antiretroviral-experienced patient

We present here one of the first cases of virological failure during treatment with bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). On March 2019, an antiretroviral-experienced HIV-infected patient was admitted to hospital because of cerebral toxoplasmosis. After undergoing treatment with sulfadiazine-pyrimethamine for two weeks, the patient initiated a BIC/FTC/TAF treatment, with 6.01 HIV RNA Log copies/mL, and 37 CD4 cells/μL. After two months under antiretroviral therapy (ART), acute neurologic deterioration with epilepsy, right hemiparesis and dysphagia occurred, leading to nasogastric nutrition and treatment. After several weeks, virological failure was confirmed with 4.01 HIV RNA Log copies/mL and R263K and M184V resistance mutations were detected.