Ide Reverse Transcriptase Inhibitors Research Articles

Impact of point-of-care HIV viral load and targeted drug resistance mutation testing on viral suppression among Kenyan pregnant and postpartum women: results from a prospective cohort study (Opt4Mamas).

Lack of viral suppression (VS) among pregnant and breastfeeding women living with HIV poses challenges for maternal and infant health, and viral load (VL) monitoring via centralized laboratory systems faces many barriers. We aimed to determine the impact of point-of-care (POC) VL and targeted drug resistance mutation (DRM) testing in improving VS among pregnant and postpartum women on antiretroviral therapy. We conducted a pre/post-intervention prospective cohort study among 820 pregnant women accessing HIV care at five public-sector facilities in western Kenya from 2019 to 2022. The pre-intervention or "control" group consisted of standard-of-care (SOC) centralized VL testing every 6 months and the post-intervention or "intervention" group consisted of a combined strategy of POC VL every 3 months, targeted DRM testing, and clinical management support. The primary outcome was VS (VL ≤1000 copies/ml) at 6 months postpartum; secondary outcomes included uptake and turnaround times for VL testing and sustained VS. At 6 months postpartum, 321/328 (98%) of participants in the intervention group and 339/347 (98%) in the control group achieved VS (aRR 1.00, 95% confidence interval [CI] 0.98, 1.02). When assessing VS using a threshold of <40 copies/ml, VS proportions were lower overall (90-91%) but remained similar between groups. Among women with viraemia (VL>1000 copies/ml) who underwent successful DRM testing in the intervention group, all (46/46, 100%) had some DRMs and 20 (43%) had major DRMs (of which 80% were nucleos(t)ide reverse transcriptase inhibitor mutations). POC VL testing uptake was high (>89%) throughout pregnancy, delivery, and postpartum periods, with a median turnaround time of 1 day (IQR 1, 4) for POC VL in the intervention group and 7 days (IQR 5, 9) for SOC VL in the control group. Sustained VS throughout follow-up was similar between groups with either POC or SOC VL testing (90-91% for <1000 copies/ml, 62-70% for <40 copies/ml). Our combined strategy markedly decreased turnaround time but did not increase VS rates, which were already very high, or sustained VS among pregnant and postpartum women living with HIV. Further research on how best to utilize POC VL and DRM testing is needed to optimize sustained VS among this population.

Integrated analysis of viral blips, residual viremia, and associated factors in people with HIV: Results from a retrospective cohort study.

The etiology of viral blips is not yet fully elucidated. One of the hypotheses is that blips reflect variations in residual viremia (RV) near the detectability threshold. In this study, we evaluated whether RV is associated with viral blips and which factors are associated with RV. All treatment regimens in 2010-2020 consisting of two nucleos(-t)ide reverse transcriptase inhibitors and one anchor (integrase strand transfer inhibitor [INSTI], non-nucleoside reverse transcriptase inhibitor [NNRTI], or protease inhibitor [PI]) in people with HIV (PWH) were evaluated for RV (detectable viremia <50 cp/mL) and blips (isolated viral loads [VLs] 50-499 cp/mL between measurements <50 cp/mL). All medical records were reviewed and regimens in which a VL ≥ 50 cp/mL was deemed to result from non-adherence (based on the documented conclusion by the treating physician) were excluded. Factors associated with blips and RV were identified using generalized linear mixed models. In total, 24 518 VLs from 1658 PWH were analyzed. VLs were measured during INSTI- (n = 5119; 20.9%), PI- (n = 8935; 36.4%), and NNRTI-use (n = 10 464; 42.7%). VLs were categorized as blips in 1.4% (n = 332). The 24,186 non-blip VLs were RNAneg (no RV) (n = 15 326; 63.4%), 1-19 cp/mL (n = 6318; 26.1%), 20-49 cp/mL (n = 1620; 6.7%), or <50 cp/mL with an unknown RV level (n = 922; 3.8%). In 193/1658 PWH (11.6%), the RV level was RNAneg in all VLs assessed. RV 1-19 cp/mL and 20-49 cp/mL (vs. RNAneg ) were significantly associated with subsequent viral blips (respective odds ratio 2.66 and 4.90 [95% confidence intervals: 1.98-3.58 and 3.41-7.04]). Zenith VL and use of PIs (vs. INSTIs/NNRTIs) were associated with higher RV and blip odds. This large cohort study showed that blips were associated with higher preceding RV. Both the anchor type and factors previously linked to the latent viral reservoir were associated with RV, suggesting blips having a multifactorial origin.

Effectiveness of second-generation integrase strand-transfer inhibitor-based regimens for antiretroviral-experienced people with HIV who had viral rebound.

Antiretroviral regimens containing a second-generation integrase strand-transfer inhibitor (INSTI) plus 2 nucleos(t)ide reverse-transcriptase inhibitors (NRTIs) are the recommended therapy for people with HIV (PWH) who are antiretroviral-naïve or on stable antiretroviral therapy (ART) with viral suppression. Real-world data on the virologic effectiveness of co-formulated bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) among PWH with virologic failure while receiving other ART remain sparse. We retrospectively reviewed the medical records of PWH who had viral rebound with plasma HIV RNA >1000 copies/mL and were switched to either dolutegravir combined with 2 NRTIs or BIC/FTC/TAF. The primary end point was re-achieving viral suppression within the first 48 weeks of switch. The association between NRTI-related resistance-associated mutations (RAMs) and virologic effectiveness was examined. Seventy-nine PWH with viral rebound while receiving other antiretroviral regimens were included. Within the first 48 weeks of switch, the overall probability of re-achieving viral suppression was 79.7% (82.5% [33/40] and 76.9% [30/39] for BIC/FTC/TAF and dolutegravir-based regimens, respectively, p=0.78). PWH with a higher CD4 lymphocyte count (adjusted odds ratio, per 100-cell/mm3 increase, 1.41; 95% confidence interval, 1.02-1.95) were more likely to re-achieve viral suppression. Among PWH switching to BIC/FTC/TAF who had pre-existing RAMs to NRTIs before switch, 14 of 15 (93.3%) successfully achieved viral suppression. Switching to BIC/FTC/TAF and dolutegravir-based regimens could re-achieve viral suppression in four-fifth of the PWH who experienced viral rebound during treatment with other antiretroviral regimens. Pre-existing NRTI-related RAMs did not have adverse impact on the effectiveness of dolutegravir combined with 2 NRTIs or BIC/FTC/TAF.

Chronic Hepatitis B Finite Treatment: Similar and Different Concerns With New Drug Classes.

Chronic hepatitis B, a major cause of liver disease and cancer, affects >250 million people worldwide. Currently there is no cure, only suppressive therapies. Efforts to develop finite curative hepatitis B virus (HBV) therapies are underway, consisting of combinations of multiple novel agents with or without nucleos(t)ide reverse-transcriptase inhibitors. The HBV Forum convened a webinar in July 2021, along with subsequent working group discussions to address how and when to stop finite therapy for demonstration of sustained off-treatment efficacy and safety responses. Participants included leading experts in academia, clinical practice, pharmaceutical companies, patient representatives, and regulatory agencies. This Viewpoints article outlines areas of consensus within our multistakeholder group for stopping finite therapies in chronic hepatitis B investigational studies, including trial design, patient selection, outcomes, biomarkers, predefined stopping criteria, predefined retreatment criteria, duration of investigational therapies, and follow-up after stopping therapy. Future research of unmet needs are discussed.

Adaption of an ongoing clinical trial to quickly respond to gaps in changing international recommendations: the experience of D2EFT

A rapidly changing landscape of antiretrovirals and their procurement at scale has permitted the evaluation of new optimised second-line antiretroviral therapy (ART) in low- and middle-income countries. D2EFT is an open-label randomised controlled non-inferiority phase IIIB/IV trial in people living with HIV-1 (PWH) whose first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART is failing. At inception, it compared a standard of care of boosted darunavir with two nucleos(t)ide reverse transcriptase inhibitors (NRTIs) to the novel NRTI-sparing regimen of boosted darunavir with dolutegravir. Implemented in 2017, participating sites were across Africa, Asia and Latin America. Around the time of implementation, the World Health Organization updated its treatment guidelines and recommended scaling up tenofovir disoproxil fumarate-lamivudine-dolutegravir (TLD). This situation pushed D2EFT investigators to consider the impact of the roll-out of TLD on the D2EFT research question. The protocol team agreed it was important to study TLD in second-line when an NNRTI regimen was failing, and focused on options to expedite the work by studying the question within the existing trial and network. All key issues (statistical, programmatic and financial) were reviewed to assess the benefits and risks of adding a third arm to the ongoing study, as opposed to developing a new randomised clinical trial with the same control arm and within the same network. The development of a new trial was deemed to be longer than adding a third arm, and to create a challenging situation with two competing clinical trials at the same sites which would slow down recruitment and impair both trials. On the other hand, adding a third arm would be demanding in terms of operationalisation, increased sample size and statistical biases to control. The optimal strategy was deemed to be the addition of a third arm, arriving retrospectively at a simplified multi-arm multi-stage clinical trial design to achieve statistical validity. The D2EFT study maintains additional value in a quickly evolving second-line ART strategy allowed by the progress in global access to ART.

High-level resistance to non-nucleos(t)ide reverse transcriptase inhibitor based first-line antiretroviral therapy in Ghana; A 2017 study.

Expanding access to effective antiretroviral therapy (ART) is a major tool for management of Human Immunodeficiency Virus (HIV) infection. However, rising levels of HIV drug-resistance have significantly hampered the anticipated success of ART in persons living with HIV (PLWH), particularly those from Africa. Though great strides have been made in Ghana toward achieving the UNAIDS “95-95-95” target, a substantial number of PLWH receiving ART have not attained viral suppression. This study investigated patterns of drug resistance mutations in ART naïve as well as ART-experienced PLWH receiving first-line regimen drugs from Ghana. In a cross-sectional study, blood samples were collected from HIV-1 infected adults (≥18 years) attending HIV/AIDS clinic at the Eastern Regional Hospital, Koforidua, Ghana from September to October 2017. Viral RNA isolated from plasma were subjected to genotypic drug resistance testing for Protease Inhibitors (PI), Reverse Transcriptase Inhibitors (RTI), and Integrase Strand Transfer Inhibitors (INSTI). A total of 95 (84 ART experienced, 11 ART naïve) HIV-1 infected participants were sampled in this study. Sixty percent (50/84) of the ART-experienced participants were controlling viremia (viral load < 1,000 copies/ml). Of the 95 patient samples, 32, 34, and 33 were successfully sequenced for protease, reverse-transcriptase, and integrase regions, respectively. The dominant HIV-1 subtypes detected were CRF02_AG (70%), and A3 (10%). Major drug resistance associated mutations were only detected for reverse transcriptase inhibitors. The predominant drug resistance mutations were against nucleos(t)ide reverse transcriptase inhibitors (NRTI)—M184V/I and non-nucleos(t)ide reverse transcriptase inhibitors (NNRTI)—K103N. In the ART-experienced group, M184V/I and K103N were detected in 54% (15/28) and 46% (13/28) of individuals, respectively. Both mutations were each detected in 33% (2/6) of ART naïve individuals. Multiclass resistance to NRTI and NNRTI was detected in 57% of ART-experienced individuals and two ART naïve individuals. This study reports high-level resistance to NNRTI-based antiretroviral therapy in PLWH in Ghana. However, the absence of major PI and INSTI associated-mutations is a good signal that the current WHO recommendation of Dolutegravir in combination with an NRTI backbone will yield maximum benefits as first-line regimen for PLWH in Ghana.

From the Editor’s Desk…

From the Editor’s Desk…

Impact of preexisting nucleos(t)ide reverse transcriptase inhibitor resistance on the effectiveness of bictegravir/emtricitabine/tenofovir alafenamide in treatment experience patients.

Few clinical trials and cohort studies have evaluated the efficacy of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in people with HIV (PWH) with preexisting M184V/I or other nucleos(t)ide reverse transcriptase inhibitor (NRTI) resistance-associated mutations (RAMs). Real-world data are also scarce. Retrospective review of treatment-experienced patients who started B/F/TAF in a cohort of PWH. HIV-RNA less than 50 copies/ml was analyzed at 48 weeks in an intention-to-treat (ITT) analysis (missing=failure) and per protocol analysis (patients with missing data or changes for reasons other than virological failure were excluded). Results were compared in patients with and without previous NRTI-RAMs. Five hundred and six PWH were included (16.2% women). Median age and time with HIV infection were 52.3 and 18.9 years, respectively. At baseline, viral load was less than 50 copies/ml in 440 patients (86.6%). Overall, 69 (13.6%) participants had documented preexisting NRTI-RAMs: 57 (11.2%) M184V/I and 30 (5.9%) tenofovir RAMs. In the ITT analysis, 83% (420/506) had HIV-RNA less than 50 copies/ml [82.2% (359/437) and 88.4% (61/69) in persons without and with NRTI-RAMs, respectively ( P = 0.2)]. In the per protocol analysis 94.2% (420/445) had HIV-RNA less than 50 copies/ml [94.4% (359/380) vs. 93.8% (61/65); P = 0.2]. A total of 61 participants were excluded from the per protocol analysis (23 missing data, 19 discontinued B/F/TAF because of toxicity, 13 for other reasons, and 6 died). Switching to B/F/TAF is well tolerated and effective in the real-world setting, even in patients with preexisting NRTI RAMs, such as M184V and RAMs conferring resistance to tenofovir. These results confirm the robustness of this combination.

Comparison of the Effects of Three Dual-Nucleos(t)ide Reverse Transcriptase Inhibitor Backbones on Placenta Mitochondria Toxicity and Oxidative Stress Using a Mouse Pregnancy Model.

Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) are the backbone of HIV antiretroviral therapy (ART). ART use in pregnancy has been associated with adverse birth outcomes, in part due to NRTI-induced mitochondrial toxicity. Direct comparison on the effects of commonly used dual-NRTI regimens on placental mitochondria toxicity in pregnancy is lacking. We compared zidovudine/lamivudine, abacavir/lamivudine, and tenofovir/emtricitabine using a mouse model and examined markers of placental mitochondrial function and oxidative stress. Zidovudine/lamivudine and abacavir/lamivudine were associated with lower fetal and placental weights compared to controls, whereas tenofovir/emtricitabine was associated with the least fetal and placental weight reduction, as well as lower resorption rates. Placental mitochondrial DNA content, as well as placental expression of cytochrome c-oxidase subunit-II, DNA polymerase gamma, and citrate synthase, was higher in tenofovir/emtricitabine-treated mice compared to other groups. Zidovudine/lamivudine-treated mice had elevated malondialdehyde levels (oxidative stress marker) compared to other groups and lower mRNA levels of manganese superoxide dismutase and peroxisome proliferator-activated receptor gamma coactivator 1-alpha in the placenta compared to tenofovir/emtricitabine-treated mice. We observed differences in effects between NRTI regimens on placental mitochondrial function and birth outcomes. Tenofovir/emtricitabine was associated with larger fetuses, increased mtDNA content, and higher expression of mitochondrial-specific antioxidant enzymes and mitochondrial biogenesis enzymes, whereas zidovudine/lamivudine was associated with markers of placental oxidative stress.

Doravirine and Islatravir Have Complementary Resistance Profiles and Create a Combination with a High Barrier to Resistance.

Doravirine (DOR), a non-nucleoside reverse transcriptase inhibitor (NNRTI), was approved for treatment of HIV-1 infection in 2018. In the pivotal phase 3 trials, DRIVE-FORWARD and DRIVE-AHEAD, 7 out of 747 (0.9%) treatment-naive participants treated with DOR plus two nucleos(t)ide reverse transcriptase inhibitors (NRTIs) met protocol-defined virologic failure criteria and showed phenotypic resistance to DOR at week 48. The most common DOR resistance-associated mutation (RAM) detected in 5 of the 7 resistant isolates was F227C. Six isolates bearing NRTI RAMs (M184V and/or K65R) were resistant to lamivudine (3TC) and emtricitabine (FTC) but not to other approved NRTIs. All DOR-resistant isolates were susceptible or hypersusceptible (fold change of <0.25) to islatravir (ISL), a nucleoside reverse transcriptase translocation inhibitor (NRTTI). Isolate hypersusceptibility to ISL required F227C, in contrast to zidovudine, an NRTI, which required M184V. Based on the frequent emergence of F227C, we hypothesized that DOR and ISL would create a combination (DOR/ISL) with a high barrier to resistance. In de novo resistance selection studies in MT4-GFP cells (MT4 cells engineered to express green fluorescent protein), DOR/ISL synergistically prevented viral breakthrough at a threshold of 2× the half-maximal inhibitory concentration (IC50). DOR/ISL exhibited a higher barrier to resistance than DOR/3TC and dolutegravir (DTG)/3TC. Resistance analysis showed no emergence of substitutions at F227, an observation consistent with its ability to confer hypersusceptibility to ISL. Overall, the data demonstrate that DOR/ISL creates a 2-drug combination with a higher barrier to resistance, consistent with the reported clinical activity.

HTLV-1 Transmission and HIV Pre-exposure Prophylaxis: A Scoping Review.

HIV pre-exposure prophylaxis (HIV-PrEP) is effective in reducing the likelihood of HIV acquisition in HIV-negative people at high risk of exposure. Guidelines recommend testing for sexually transmitted infections (STIs) before starting, and periodically on PrEP, including bacterial infections, HIV, hepatitis C virus, and, for those who are non-immune, hepatitis B virus. Diagnosed infections can be promptly treated to reduce onward transmission. HTLV-1 is not mentioned; however, it is predominantly sexually transmitted, causes adult T-cell leukaemia/lymphoma (ATL) or myelopathy in 10% of those infected, and is associated with an increased risk of death in those without any classically HTLV-associated condition. The 2021 WHO Technical Report on HTLV-1 called for the strengthening of global public health measures against its spread. In this scoping review, we, therefore, (1) discuss the epidemiological context of HIV-PrEP and HTLV-1 transmission; (2) present current knowledge of antiretrovirals in relation to HTLV-1 transmission prevention, including nucleos(t)ide reverse transcriptase inhibitors (NRTIs) and integrase strand transfer inhibitors (INSTIs); and (3) identify knowledge gaps where data are urgently required to inform global public health measures to protect HIV-PrEP users from HTLV-1 acquisition. We suggest that systematic seroprevalence studies among PrEP-using groups, including men who have sex with men (MSM), people who inject drugs (PWIDs), and female sex workers (FSWs), are needed. Further data are required to evaluate antiretroviral efficacy in preventing HTLV-1 transmission from in vitro studies, animal models, and clinical cohorts. PrEP delivery programmes should consider prioritizing the long-acting injectable INSTI, cabotegravir, in HTLV-1 endemic settings.

Lower Incidence of HIV-1 Blips Observed During Integrase Inhibitor-Based Combination Antiretroviral Therapy.

As the nature of viral blips remains unclear, their occurrence often leads to uncertainty. This study compares blip incidence rates during treatment with different combination antiretroviral therapy anchors. Retrospective cohort study in a tertiary hospital. All antiretroviral regimens between 2010 and 2020 containing 2 nucleos(-t)ide reverse transcriptase inhibitors and 1 anchor in virologically suppressed people living with HIV (PLWH) from our center were evaluated for the occurrence of blips [isolated viral loads (VLs) 50-499 copies/mL between measurements <50 copies/mL]. Factors associated with blips were identified using multivariable generalized estimating equation-based negative binomial models. The relationship between blips and either persistent low-level viremia (consecutive VLs ≥ 50 copies/mL not classified as failure) or virologic failure (consecutive VLs ≥ 200 or 1 VL ≥ 500 copies/mL) was also evaluated. In total, 308 blips occurred during 3405 treatment courses in 1661 PLWH. Compared with a non-nucleoside reverse transcriptase inhibitor anchor, blip incidence was higher for protease inhibitors (incidence rate ratio 1.37; 95% confidence interval 1.05 to 1.78) and lower for integrase inhibitors (INSTIs) (incidence rate ratio 0.64; 95% confidence interval: 0.43 to 0.96). In addition, blips were associated with higher zenith VL, higher VL test frequency, and shorter time since antiretroviral therapy initiation. PLWH experiencing blips were more likely to demonstrate persistent low-level viremia but not virologic failure. Blips led to extra consultations and measurements. INSTI-based regimens display a low number of blips. Although we found no correlation with virologic failure, the occurrence of blips led to an increased clinical burden. Further research is needed to elucidate the implications and underlying mechanisms of these findings.

Predictors of low-level HIV viraemia and virological failure in the era of integrase inhibitors: A Spanish nationwide cohort.

To pinpoint factors associated with low-level viraemia (LLV) and virological failure (VF) in people living with HIV in the era of high-efficacy antiretroviral treatment (ART) and widespread use of integrase strand transfer inhibitor (INSTIs)-based ART. We included adults aged >18years starting their first ART between 2015 and 2018 in the Spanish HIV/AIDS Research Network National Cohort (CoRIS). Low-level viraemia was defined as plasma viral load (pVL) of 50-199 copies/mL at weeks 48 and 72 and VF was defined as pVL ≥50 copies/mL at week 48 and pVL ≥200 copies/mL at week 72. Multivariable logistic regression models assessed the impact on LLV and VF of baseline CD4 T-cell count, CD4/CD8 T-cell ratio and pVL, initial ART classes, age at ART initiation, time between HIV diagnosis and ART initiation, gender and transmission route. Out of 4186 participants, 3120 (76.0%) started INSTIs, 455 (11.1%) started boosted protease inhibitors (bPIs) and 443 (10.8%) started nonnucleoside reverse transcriptase inhibitors (NNRTIs), either of them with two nucleos(t)ide reverse transcriptase inhibitors (NRTIs). Low-level viraemia was met in 2.5% of participants and VF in 4.3%. There were no significant differences throughout the years for both virological outcomes. Baseline HIV-1 RNA >5log10 copies/mL was the only consistent predictor of higher risk of LLV [adjusted odds ratio (aOR) = 9.8, 95% confidence interval (CI): 2.0-48.3] and VF (aOR = 5.4, 95%CI: 1.9-15.1), even in participants treated with INSTIs. The rates of LLV and VF were low but remained steady throughout the years. Baseline HIV-1 RNA >5log10 copies/mL showed a persistent association with LLV and VF even in participants receiving INSTIs.

HIV-1 pretreatment drug resistance negatively impacts outcomes of first-line antiretroviral treatment.

Pretreatment drug resistance (PDR) prevalence in sub-Saharan Africa is rising, but evidence of its impact on efavirenz (EFV)-based antiretroviral treatment (ART) is inconclusive. We determined the impact of PDR on outcomes of EFV-based ART in a subanalysis of a randomized clinical trial comparing different ART monitoring strategies implemented at a rural treatment facility in Limpopo, South Africa. Participants initiating EFV-based first-line ART (2015-2017) were enrolled and received 96 weeks follow-up. Resistance to nucleos(t)ide reverse transcriptase inhibitors (NRTIs) and non-NRTI's (NNRTIs) was retrospectively assessed by population-based sequencing. Virological failure was defined as a viral load of at least 1000 copies/ml after at least 24 weeks of ART. A total of 207 participants were included, 60.4% (125/207) of whom were female. Median age was 38.8 (interquartile range: 31.4-46.7) years. Median CD4+ cell count was 191 (interquartile range: 70-355) cells/μl. PDR was detected in 12.9% (25/194) of participants with available sequencing results; 19 had NNRTI-resistance, and six had NRTI- and NNRTI-resistance. 26.0% of participants (40/154) with sequencing results and virological follow-up developed virological failure. PDR was independently associated with failure (adjusted hazard ratio: 3.7 [95% confidence interval: 1.68.5], P = 0.002). At failure, 87.5% (7/8) of participants with PDR harboured dual-class resistant virus, versus 16.7% (4/24) of participants without PDR (P = 0.0007). Virological resuppression after failure on first-line ART occurred in 57.7% (15/26) of participants without PDR versus 14.3% (1/7) of participants with PDR (P = 0.09). PDR was detected in 13% of study participants. PDR significantly increased the risk of virological failure of EFV-based ART. Accumulation of resistance at failure and inability to achieve virological resuppression illustrates the profound impact of PDR on treatment outcomes.

Diversity of HIV-1 Subtypes and Transmitted Drug-resistance Mutations Among Minority HIV-1 Variants in a Turkish Cohort.

The World Health Organization (WHO) recommends the surveillance of transmitted drug resistance mutations (TDRMs) to ensure the effectiveness and sustainability of HIV treatment programs. Our aim was to determine the TDRMs and evaluate the distribution of HIV-1 subtypes using and compared next-generation sequencing (NGS) and Sanger-based sequencing (SBS) in a cohort of 44 antiretroviral treatment-naïve patients. All samples that were referred to the microbiology laboratory for HIV drug resistance analysis between December 2016 and February 2018 were included in the study. After exclusions, 44 treatment-naive adult patients with a viral load of >1000 copies/mL were analyzed. DNA sequencing for reverse transcriptase and protease regions was performed using both DeepChek ABL single round kit and Sanger-based ViroSeq HIV-1 Genotyping System. The mutations and HIV-1 subtypes were analyzed using the Stanford HIVdb version 8.6.1 Genotypic Resistance software, and TDRMs were assessed using the WHO surveillance drug-resistance mutation database. HIV-1 subtypes were confirmed by constructing a maximum-likelihood phylogenetic tree using Los Alamos IQ-Tree software. NGS identified nucleos(t)ide reverse transcriptase inhibitor (NRTI)-TDRMs in 9.1 % of the patients, non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI)-TDRMs in 6.8 % of the patients, and protease inhibitor (PI)-TDRMs in 18.2 % of the patients at a detection threshold of ≥ 1 %. Using SBS, 2.3 % and 6.8 % of the patients were found to have NRTI- and NNRTI-TDRMs, respectively, but no major PI mutations were detected. M41L, L74I, K65R, M184V, and M184I related to NRTI, K103N to NNRTI, and N83D, M46I, I84V, V82A, L24I, L90M, I54V to the PI sites were identified using NGS. Most mutations were found in low-abundance (frequency range: 1.0 % - 4.7 %) HIV-1 variants, except M41L and K103N. The subtypes of the isolates were found as follows; 61.4 % subtype B, 18.2 % subtype B/CRF02_AG recombinant, 13.6 % subtype A, 4.5 % CRF43_ 02G, and 2.3 % CRF02_AG. All TDRMs, except K65R, were detected in HIV-1 subtype B isolates. The high diversity of protease site TDRMs in the minority HIV-1 variants and prevalence of CRFs were remarkable in this study. All minority HIV-1 variants were missed by conventional sequencing. TDRM prevalence among minority variants appears to be decreasing over time at our center.

Impact of nucleos(t)ide reverse transcriptase inhibitor resistance on dolutegravir and protease-inhibitor-based regimens in children and adolescents in Kenya.

We assessed the impact of using dolutegravir or a protease inhibitor with an inactive nucleoside-reverse transcriptase inhibitor (NRTI) in children and adolescents. We observed high-levels of viral suppression among those on tenofovir-lamivudine-dolutegravir even in presence of an inactive NRTI backbone but lower levels among those on protease inhibitors, especially those retained on an inactive abacavir. Although tenofovir may be recycled with dolutegravir, more studies are needed to determine if abacavir can be reused with dolutegravir or protease inhibitors.

Evolution of Hepatitis B Virus (HBV) Serologic Markers Among Antiretroviral-Naive Young People Living With Human Immunodeficiency Virus Who Had Undergone Neonatal HBV Vaccination and Initiated Antiretroviral Therapy.

With initiation of antiretroviral therapy (ART) containing nucleos(t)ide reverse-transcriptase inhibitors (NRTIs) with anti-hepatitis B virus (HBV) activity, the evolution of HBV serologic markers among people living with human immunodeficiency virus (PLWH) who were born in the era of nationwide neonatal HBV vaccination is rarely investigated. This retrospective cohort study evaluated the changes of HBV serologic markers (hepatitis B surface antigen [HBsAg], antibody to hepatitis B surface antigen [anti-HBs], and antibody to hepatitis B core antigen [anti-HBc]) of PLWH who had undergone neonatal HBV vaccination. Clinical characteristics were analyzed and the incidences of evolution of HBV serologic markers were estimated. Between 2004 and 2020, 608 PLWH (mean age, 24 years) were included and 62.0% initiated tenofovir-containing ART: 13 (2.1%) were HBsAg-positive, 312 (51.3%) tested triple-negative, 209 (34.4%) had vaccine-induced seroprotection against HBV, and 74 (12.2%) tested positive for anti-HBc with or without anti-HBs. Among 492 PLWH who received a median follow-up of 2.8 years, 4 cases of incident HBV infection occurred (0.59 per 100 person-years of follow-up [PYFU]) in PLWH testing triple-negative at baseline despite ART containing NRTIs with anti-HBV activity. Of PLWH with seroprotection against HBV at baseline, 38 subsequently lost anti-HBs (4.46 per 100 PYFU) and 4 cases of incident HBV infection occurred (0.47 per 100 PYFU). PLWH with an anti-HBs antibody titer ≥100 mIU/mL at baseline (adjusted hazard ratio [aHR], 0.10 [95% confidence interval {CI}: .02-.42]) and CD4 ≥500 cells/µL during follow-up (aHR, 0.51 [95% CI: .30-1.00]) were less likely to lose HBV seroprotection. Among young PLWH who had undergone neonatal HBV vaccination, evolution of HBV serologic markers and incident infections occurred despite ART containing NRTIs with anti-HBV activity.

626. The Efficacy and Safety of Maintenance with Doravirine Plus Two NRTIs after Initial Suppression in Adults with HIV-1 in the DRIVE-FORWARD Clinical Trial: Results from the Study Extension through 192 Weeks

BackgroundDRIVE-FORWARD is a phase 3 trial with a completed double-blind period comparing doravirine (DOR) 100 mg with ritonavir-boosted darunavir (DRV/r) 800/100 mg, both administered with two nucleos(t)ide reverse transcriptase inhibitors (NRTIs; tenofovir and emtricitabine, or abacavir and lamivudine), and an ongoing open-label extension. At Week (W) 48, DOR demonstrated non-inferior efficacy to DRV/r, with a superior lipid profile. Those results were sustained at W96. Here we present efficacy and safety results through W192.MethodsParticipants who completed the 96-week double-blind phase and met inclusion criteria were eligible to receive open-label DOR plus two NRTIs in a 96-week extension. Efficacy and safety at W192 were assessed in two groups: participants initially randomized to DOR and maintained on DOR (n=259) and those who switched from DRV/r to DOR at W96 (n=233).ResultsHIV-1 RNA < 50 copies/mL were maintained through W192 in 81.1% of participants who continued DOR and 80.7% of those who switched from DRV/r to DOR. The mean increase in CD4 T-cell counts from W96 to W192 was similar for participants maintained on DOR (47 cells/mm3) and those switched from DRV/r (53 cells/mm3). Protocol-defined virologic failure occurred in 3.1% and 5.6% of participants maintained on DOR and switched from DRV/r, respectively, and development of genotypic resistance was low in both groups (Table 1). Discontinuation due to adverse events was also low (Table 1). Fasting LDL-cholesterol, non-HDL-cholesterol, and triglycerides showed minimal increase in participants maintained on DOR and were reduced in those switched from DRV/r to DOR (Table 1). Participants maintained on DOR had minimal weight gain after W96 (median 1 kg), and a small increase overall (median 1.9 kg, Day 1 through W192); participants who switched to DOR had a small increase after W96 (median 1.5 kg), similar to the median weight gain in the base study (DOR 1.8 kg; DRV/r 0.7 kg).ConclusionAmong participants who continued DOR in the DRIVE-FORWARD open-label extension, virologic suppression and favorable safety were maintained for an additional 96 weeks. Participants who switched from DRV/r to DOR maintained virologic suppression and demonstrated favorable safety for 96 weeks. Disclosures Pedro Cahn, MD, PHD, Merck (Advisor or Review Panel member)ViiV Healthcare (Grant/Research Support, Advisor or Review Panel member) Kathleen Squires, MD, Merck (Employee) Sushma Kumar, PhD, Merck (Employee) Hong Wan, PhD, Merck (Employee) Valerie Teal, MS, Merck (Employee) Ernest Asante-Appiah, PhD, Merck (Employee) Peter Sklar, MD, Merck (Employee) Elizabeth A. Martin, DO, MPH, MBA, Merck (Employee) Rima Lahoulou, n/a, Merck (Employee)

HIV-1 gp120 Antagonists Also Inhibit HIV-1 Reverse Transcriptase by Bridging the NNRTI and NRTI Sites.

HIV-1 infection is typically treated using ≥2 drugs, including at least one HIV-1 reverse transcriptase (RT) inhibitor. Drugs targeting RT comprise nucleos(t)ide RT inhibitors (NRTIs) and non-nucleoside RT inhibitors (NNRTIs). NRTI-triphosphates bind at the polymerase active site and, following incorporation, inhibit DNA elongation. NNRTIs bind at an allosteric pocket ∼10 Å away from the polymerase active site. This study focuses on compounds ("NBD derivatives") originally developed to bind to HIV-1 gp120, some of which inhibit RT. We have determined crystal structures of three NBD compounds in complex with HIV-1 RT, correlating with RT enzyme inhibition and antiviral activity, to develop structure-activity relationships. Intriguingly, these compounds bridge the dNTP and NNRTI-binding sites and inhibit the polymerase activity of RT in the enzymatic assays (IC50 < 5 μM). Two of the lead compounds, NBD-14189 and NBD-14270, show potent antiviral activity (EC50 < 200 nM), and NBD-14270 shows low cytotoxicity (CC50 > 100 μM).

Impact of HIV-1 Resistance-Associated Mutations on Susceptibility to Doravirine: Analysis of Real-World Clinical Isolates

ABSTRACTClinical management of human immunodeficiency virus type-1 (HIV-1) infection may be negatively impacted by either acquired or transmitted drug resistance. Here, we aim to extend our understanding of the impact of resistance-associated mutations (RAMs) on the susceptibility of clinical isolates to the nonnucleoside reverse transcriptase inhibitor (NNRTI) doravirine. Clinical isolates from people living with HIV-1 undergoing routine testing for susceptibility to doravirine and other approved NNRTIs (etravirine, rilpivirine, efavirenz, and nevirapine) were collected from August 2018 to August 2019. Susceptibility in the presence/absence of NNRTI and nucleos(t)ide reverse transcriptase inhibitor (NRTI) mutations was determined using cutoffs for relative fold change in inhibition (ratio of the 50% inhibitory concentration [IC50] of patient virus compared with the IC50 of a wild-type reference strain). Biological cutoffs of 3- to 15-fold change were investigated for doravirine, with preestablished cutoffs used for the other NNRTIs. Of 4,070 clinical isolates, 42.9% had ≥1 NNRTI RAM. More isolates were susceptible to doravirine (92.5–96.7%) than to etravirine (91.5%), rilpivirine (89.5%), efavirenz (81.5%), or nevirapine (77.5%). Based on a 3-fold cutoff, doravirine susceptibility was retained in 44.7–65.8% of isolates resistant to another NNRTI and 28.5% of isolates resistant to all other tested NNRTIs. The presence of NRTI RAMs, including thymidine analog mutations, was associated with doravirine hypersusceptibility in some isolates, particularly in the absence of NNRTI RAMs. These results support the favorable resistance profile of doravirine and are of particular importance given the challenge posed by both acquired and transmitted resistance.