Major Drug Resistance Mutations Research Articles

Prevalence of HIV Drug Resistance Mutations among Treatment-Naive People Living with HIV in a Tertiary Care Center in India.

India has the third-largest number of people living with HIV (PLHIV) in the world. A national program provides free access to standard uniform antiretroviral therapy. However, the program is not monitored by comprehensive drug resistance surveys. The aim of this study was to determine the prevalence of HIV drug resistance mutations (DRMs) among treatment-naive PLHIV in a large antiretroviral treatment center of the national program. This cross-sectional study was done in 2017 and involved 200 consecutive treatment-naive PLHIV. A target fragment of 1,306 bp in the reverse transcriptase and protease regions was amplified. Identification of mutations and drug resistance interpretation was done by HIV Genotypic Resistance Interpretation and International Antiviral Society-USA list. Sequencing was successful in 177 samples. The majority (98.8%; 175/177) belonged to subtype C. Nineteen of 177 patients (10.7%; 95% CI: 6.2%-15.3%) had at least one major DRM. The prevalence of non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations was 10.2% (18/177). The most frequent mutations were E138A/K, A98G, K103N, V179D, and K101H/E. The prevalence of nucleoside reverse transcriptase inhibitor (NRTI) mutations was 1.1% (2/177). None of the samples had major protease inhibitor resistance mutations. The prevalence of NNRTI mutations in this study was >10%, crossing the threshold recommended by the WHO to change the NNRTI-based first-line regimen to non-NNRTI based. In 2021, the national program replaced efavirenz with dolutegravir in the first-line regimen of tenofovir, lamivudine, and efavirenz. As the majority (64%) of PLHIV in India are accessing free ART from the national program, this study highlights the need for regular nationally representative drug resistance surveys for optimizing antiretroviral regimens in the program.

High prevalence of pre-treatment and acquired HIV-1 drug resistance mutations among non-citizens living with HIV in Botswana.

Approximately 30,000 non-citizens are living with HIV in Botswana, all of whom as of 2020 are eligible to receive free antiretroviral treatment (ART) within the country. We assessed the prevalence of HIV-1 mutational profiles [pre-treatment drug resistance (PDR) and acquired drug resistance (ADR)] among treatment-experienced (TE) and treatment-naïve (TN) non-citizens living with HIV in Botswana. A total of 152 non-citizens living with HIV were enrolled from a migrant HIV clinic at Independence Surgery, a private practice in Botswana from 2019-2021. Viral RNA isolated from plasma samples were genotyped for HIV drug resistance (HIVDR) using Sanger sequencing. Major known HIV drug resistance mutations (DRMs) in the pol region were determined using the Stanford HIV Drug Resistance Database. The proportions of HIV DRMs amongst TE and TN non-citizens were estimated with 95% confidence intervals (95% CI) and compared between the two groups. A total of 60/152 (39.5%) participants had a detectable viral load (VL) >40 copies/mL and these were included in the subsequent analyses. The median age at enrollment was 43 years (Q1, Q3: 38-48). Among individuals with VL > 40 copies/mL, 60% (36/60) were treatment-experienced with 53% (19/36) of them on Atripla. Genotyping had a 62% (37/60) success rate - 24 were TE, and 13 were TN. A total of 29 participants (78.4, 95% CI: 0.12-0.35) had major HIV DRMs, including at least one non-nucleoside reverse transcriptase inhibitor (NNRTI) associated DRM. In TE individuals, ADR to any antiretroviral drug was 83.3% (20/24), while for PDR was 69.2% (9/13). The most frequent DRMs were nucleoside reverse transcriptase inhibitors (NRTIs) M184V (62.1%, 18/29), NNRTIs V106M (41.4%, 12/29), and K103N (34.4%, 10/29). No integrase strand transfer inhibitor-associated DRMs were reported. We report high rates of PDR and ADR in ART-experienced and ART-naïve non-citizens, respectively, in Botswana. Given the uncertainty of time of HIV acquisition and treatment adherence levels in this population, routine HIV-1C VL monitoring coupled with HIVDR genotyping is crucial for long-term ART success.

Current Resistance of HIV-1 Strains Isolated in Volunteer Blood Donors in Gabon.

Detection of drug resistance mutations (DRMs) and HIV-1 subtypes ensures effective therapeutic management for HIV-infected individuals. In Gabon, data on DRMs are very little available in the population of people living with HIV and also among voluntary HIV-positive blood donors. This study aimed to study subtypes and DRMs in HIV-1-positive volunteer blood donors in Gabon. A cross-sectional study was carried out at the National Blood Transfusion Center of Gabon. A purposive sampling method was used to collect 128 HIV-1 seropositive blood samples. Viral RNA was extracted on real-time PCR (Abbott 2000®), and sequencing was performed on ABI 3500 (Hitachi®). SPSS version 21.0 software was used for statistical analysis. Of the 128 seropositive volunteer donors included, men and the 29-39-age group were more representative at 78.9% and 49.2%, respectively. Eighty-two samples were sequenced. The majority strains identified were subtype A, subtype F, subtype G, CRF02_AG, and CRF45_cpx. The resistance mutations identified were K103N, L210W, E138G, V179D, V179T, and M46L. The prevalence of resistant subtypes was 25.6%. CRF02_AG strains exhibited high-level resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs), including efavirenz and nevirapine. The study identified major DRMs in reverse transcriptase and protease that confer high-level resistance to most NNRTIs, nucleoside reverse transcriptase inhibitors, and protease inhibitors. CRF02_AG was more predominant, and the frequency of resistant subtypes was high. However, these data will contribute to the therapeutic choice during the initiation of antiretroviral treatment in treatment-naive patients in Gabon.

Performance characteristics of Allele-Specific PCR (ASPCR) in detecting drug resistance mutations among non-B HIV-1 Variants

Allele-Specific Polymerase Chain Reaction (ASPCR) is an affordable point-mutation assay whose validation could improve the detection of HIV-1 drug resistance mutations (DRMs) in resource-limited settings (RLS). We assessed the performance of ASPCR onforty-four non-B HIV-1 plasma samples from patients who were ARV treated in failure in N’Djamena-Chad. Viral RNA was reverse-transcribed and amplified using LightCycler® FastStart DNA MasterPLUS SYBR Green I. Detection of six major DRMs (K70R, K103N, Y181C, M184V, T215F, T215Y) was evaluated on Roche LightCycler®480 automated system (with dilutions 0.01–100%). ASPCR-results were compared to Sanger-sequencing (gold-standard). Correlations of mutation curves were excellent (R2 >0.97); all DRMs were detected with desirable mutant/wild-type threshold differences (ΔCt≥9) except K70R(ΔCtK70R=6; ΔCtK103N=13; ΔCtM184V=9; ΔCtT215F=12; ΔCtT215Y=12; ΔCtY181C=9) and positive controls were below required thresholds. Also, ASPCR reproducibility on DRMs was assessed by using dilutions of intra-assay and inter-assay coefficient of variations respectively with a threshold of less than 50(i.e.<0.50 variation) which are;: K70R (0.02–0.28 vs. 0.12–0.37), K103N (0.08–0.42 vs. 0.12–0.37), Y181C (0.12–0.39 vs. 0.31–0.37), M184V (0.13–0.39 vs. 0.23–0.42), T215F (0.05–0.43 vs. 0.04–0.45) and T215Y (0.13–0.41 vs. 0.19–0.41). DRM detection-rate by ASPCR vs Sanger was respectively: M184V (63.6% vs. 38.6%); T215F (18.1% vs. 9.1%); T215Y (6.8% vs. 2.3%); K70R (4.5% vs. 2.3%). K103N (22.7% vs. 13.6%); Y181C (13.6% vs. 11.4%). Correlations of mutation curves were excellent (R2 >0.97); all DRMs were detected with desirable mutant/wild-type threshold differences (ΔCt≥9) except K70R(ΔCtK70R=6; ΔCtK103N=13; ΔCtM184V=9; ΔCtT215F=12; ΔCtT215Y=12; ΔCtY181C=9) and positive controls were below required thresholds. Also, ASPCR reproducibility on DRMs was assessed by using dilutions of intra-assay and inter-assay coefficient of variations respectively with a threshold of less than 50(i.e.<0.50 variation) which are;: K70R (0.02–0.28 vs. 0.12–0.37), K103N (0.08–0.42 vs. 0.12–0.37), Y181C (0.12–0.39 vs. 0.31–0.37), M184V (0.13–0.39 vs. 0.23–0.42), T215F (0.05–0.43 vs. 0.04–0.45) and T215Y (0.13–0.41 vs. 0.19–0.41). DRM detection-rate by ASPCR vs Sanger was respectively: M184V (63.6% vs. 38.6%); T215F (18.1% vs. 9.1%); T215Y (6.8% vs. 2.3%); K70R (4.5% vs. 2.3%). K103N (22.7% vs. 13.6%); Y181C (13.6% vs. 11.4%). ASPCR appears more efficient for detecting DRMs on diverse HIV-1 non-B circulating in RLS like Chad.

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.

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.

Naturally Occurring Mutations in HIV-1 Protease Gene Among People Living With HIV

The emergence of resistance to antiretroviral drugs is the main problem in their long-term efficacy and by considering the wide use of protease inhibitors (PIs), monitoring drug resistance mutations is necessary. Therefore, this study aimed to investigate the PIs drug resistance mutations in Iranian patients as well as subtyping using bioinformatics analysis. Fifteen Iranian patients living with Human Immunodeficiency Virus (HIV) (PLWH) were examined. RNA was used to amplify and sequence the HIV protease gene; also, HIV viral load was determined for all samples. The sequencing results were analyzed by several strong bioinformatics tools to determine the drug-resistance mutations and HIV subtypes. Some polymorphisms in the protease gene were recognized; however, there was no significant rate of major or minor drug resistance mutations in our studied patients. Subtyping analysis revealed the new subtype (D) and the previously reported ones, A and CRF-AD 35, in patients. This study confirmed that the resistance mutations and genetic polymorphisms of the protease region are rare in Iranian-infected patients that can be concluded that prescribing protease inhibitor class in HIV-infected patients is promising in controlling HIV in Iran. In addition, conducting periodic studies to determine the new mutations and the rate of drug resistance to PIs in Iranian individuals highlights the importance of WHO guidelines that recommends monitoring of genotypic-resistance testing and investigation of mutations in HIV-related genes.

Subtype Distribution and Drug Resistance Patterns Among HIV-1 Strains Prevalent in Makassar, Indonesia.

Human immunodeficiency virus type 1 (HIV-1) is characterized by a large degree of genetic variability because of high rates of recombination and mutation, sizable population sizes, and rapid replication. Therefore, this study investigated HIV-1 subtype distribution and the appearance of drug resistance mutations (DRMs) in viruses that are prevalent in Makassar, South Sulawesi, Indonesia. The HIV-1 pol, env, and gag genes were amplified from 63 infected individuals and sequenced for a subtyping analysis. CRF01_AE was identified as the predominant HIV-1 circulating recombinant form (CRF) in Makassar, South Sulawesi, Indonesia. Subtype B and recombinant viruses containing CRF01_AE, CRF02_AG, and/or subtype B gene fragments were also detected. Several major DRMs against non-nucleoside reverse transcriptase inhibitors were found among antiretroviral therapy (ART)-experienced subjects, whereas ART-naive subjects did not possess any transmitted drug resistance. The prevalence of DRMs was very high among ART-experienced subjects; therefore, further surveillance is required in this region.

Emerging integrase strand transfer inhibitor drug resistance mutations among children and adults on ART in Tanzania: findings from a national representative HIV drug resistance survey.

Despite the scale-up of ART and the rollout in Tanzania of dolutegravir, an integrase strand transfer inhibitor (INSTI), treatment success has not been fully realized. HIV drug resistance (HIVDR), including dolutegravir resistance, could be implicated in the notable suboptimal viral load (VL) suppression among HIV patients. To determine the prevalence and patterns of acquired drug resistance mutations (DRMs) among children and adults in Tanzania. A national cross-sectional HIVDR survey was conducted among 866 children and 1173 adults. Genotyping was done on dried blood spot and/or plasma of participants with high HIV VL (≥1000 copies/mL). HIV genes (reverse transcriptase, protease and integrase) were amplified by PCR and directly sequenced. The Stanford HIVDR Database was used for HIVDR interpretation. HIVDR genotyping was performed on blood samples from 137 participants (92 children and 45 adults) with VL ≥ 1000 copies/mL. The overall prevalence of HIV DRMs was 71.5%, with DRMs present in 78.3% of children and 57.8% of adults. Importantly, 5.8% of participants had INSTI DRMs including major DRMs: Q148K, E138K, G118R, G140A, T66A and R263K. NNRTI, NRTI and PI DRMs were also detected in 62.8%, 44.5% and 8% of participants, respectively. All the participants with major INSTI DRMs harboured DRMs targeting NRTI backbone drugs. More than 7 in 10 patients with high HIV viraemia in Tanzania have DRMs. The early emergence of dolutegravir resistance is of concern for the efficacy of the Tanzanian ART programme.

Primary resistance to integrase inhibitors in Shenzhen.

In recent years, integrase strand transfer inhibitor (INSTI)-containing regimens have been increasingly adopted in treatment for HIV/AIDS and promoted as non-occupational post-exposure prophylaxis in China. This study aims to describe the prevalence of resistance to integrase and drug resistance mutations (DRMs) among ART-naive patients in Shenzhen, China. Serum samples and demographic information were collected from newly reported ART-naive patients in Shenzhen in 2020. The study sequenced the coding sequence of the HIV-1 integrase gene and determined the DRMs.​. In this study, 1682 newly reported cases were included and 1071 of them were successfully sequenced finally. The prevalence of primary drug resistance was 1.77%, with 19 samples showing varying degrees of resistance to INSTIs. The study detected six major DRMs in 16 individuals and eight accessory DRMs in 24 individuals. The prevalence of transmitted drug resistance (TDR) mutations was 1.21%, with five transmitted mutations detected in 13 individuals. The prevalence of drug resistance to raltegravir and elvitegravir was statistically higher than to bictegravir, cabotegravir and dolutegravir. The prevalence of INSTI resistance in Shenzhen in 2020 was relatively high. ​Continued surveillance for resistance to INSTIs is recommended and treatment regimens should be adopted based on the pattern of resistance to INSTIs. ​Dolutegravir or bictegravir is first recommended when considering INSTIs as treatment regimens.

HIV-1C in-House RNA-Based Genotyping Assay for Detection of Drug Resistance Mutations in Samples with Low-Level Viral Loads.

Monitoring HIV-1 drug resistance mutations (DRM) in treated patients on combination antiretroviral therapy (cART) with a detectable HIV-1 viral load (VL) is important for the selection of appropriate cART. Currently, there is limited data on HIV DRM at low-level viremia (LLV) (VL 401-999 copies/mL) due to the use of a threshold of VL ≥1000 copies/mL for HIV DRM testing. We here assess the performance of an in-house HIV drug resistance genotyping assay using plasma for the detection of DRM at LLV. We used a total of 96 HIV plasma samples from the population-based Botswana Combination Prevention Project (BCPP). The samples were stratified by VL groups: 50 samples had LLV, defined as 401-999 copies/mL, and 46 had ≥1000 copies/mL. HIV pol (PR and RT) region was amplified and sequenced using an in-house genotyping assay with BigDye sequencing chemistry. Known HIV DRMs were identified using the Stanford HIV Drug Resistance Database. Genotyping success rate between the two groups was estimated and compared using the comparison of proportions test. The overall genotyping success rate was 79% (76/96). For VL groups, the genotyping success was 72% (36/50) at LLV and 87% (40/46) at VL ≥1000 copies/mL. Among generated sequences, the overall prevalence of individuals with at least 1 major or intermediate-associated DRM was 24% (18/76). The proportions of NNRTI-, NRTI- and PI-associated resistance mutations were 28%, 24%, and 0%, respectively. The most predominant mutations detected were K103N (18%) and M184V (12%) in NNRTI- and NRTI-associated mutations, respectively. The prevalence of DRM was 17% (6/36) at LLV and 30% (12/40) at VL ≥1000 copies/mL. The in-house HIV genotyping assay successfully genotyped 72% of LLV samples and was able to detect 17% of DRM amongst them. Our results highlight the possibility and clinical significance of genotyping HIV among individuals with LLV.

Drug resistance in children and adolescents with HIV in Panama.

The inadequacy of resistance monitoring in Latin America leads to circulation of HIV strains with drug resistance mutations (DRMs), compromising ART effectiveness. This study describes the DRM prevalence in HIV-infected paediatric patients in Panama. During 2018-19, plasma was collected from 76 HIV-infected children/adolescents (5 ART-naive, 71 treated) in Panama for HIV-1 DRM pol analysis, predicted antiretroviral (ARV) susceptibility by Stanford, and HIV-1 variant phylogenetic characterization. HIV-1 pol sequences were recovered from 67 (88.2%) of 76 children/adolescents (median age 12 years), carrying 65 subtype B, 1 subtype G and 1 unique recombinant URF_A1B. Five were ART-naive and 62 ART-treated under virological failure (viraemia >50 copies/mL) with previous exposure to NRTIs, (100%), NNRTIs (45.2%), PIs (95.2%) and integrase strand transfer inhibitors (INSTIs, 17.7%). Among the treated patients, 34 (54.8%) carried resistant strains, with major DRMs to one (40.3%), two (9.7%) or three (4.8%) ARV families. Most of them harboured DRMs to NRTIs (58.5%) or NNRTIs (39%), but also major DRMs to PIs (4.9%) and INSTIs (6.5%). We also found dual-class NRTI + NNRTI (12.2%) and NNRTI + PI (2.6%) resistance. Two naive subjects carried viruses with DRMs to NRTIs and NRTI + NNRTI, respectively. Sequenced viruses presented high/intermediate resistance mainly to emtricitabine/lamivudine (48.9% each) and efavirenz/nevirapine (33.3% each). Most participants were susceptible to PIs (91.3%) and INSTIs (88.1%). The high DRM prevalence to NRTIs and NNRTIs observed among treated HIV-infected children/adolescents in Panama justifies the need for routine resistance monitoring for optimal rescue therapy selection in this vulnerable population.

Drug Resistance to Integrase Strand-Transfer Inhibitors among HIV-1-Infected Adults in Guangdong, China.

Integrase strand-transfer inhibitor (INSTI)-containing regimens have gradually been administered in Guangdong Province, China beginning in 2016, and INSTI-related drug resistance (DR) may occur and should be monitored among HIV-1-infected patients. To investigate the prevalence of INSTI-related resistance among HIV-1-infected individuals in Guangdong and provide evidence for the optimal administration of INSTIs. This study recruited 1208 HIV-1-infected patients (including 404 ART-naive and 804 ART-experienced patients) between June 2021 and April 2022. The entire integrase gene was amplified from blood plasma. Demographic and epidemiological information were collected. INSTI mutations and susceptibility were interpreted using the Stanford HIV Drug Resistance Database HIVdb program. Of the 1208 enrolled individuals, 2.65% (32/1208) carried at least one INSTI major or accessory drug resistance mutation (DRM), with 1.49% (6/404) being from ART-naive individuals and 3.23% (26/804) from ART-experienced individuals. Among them, seven polymorphic major mutations were detected. Although no INSTI drug resistance was found among treatment-naive patients, seven ART-experienced patients (0.87%, 7/804) carried mutations conferring resistance to INSTIs. The overall prevalence of INSTI DRMs and DR was comparatively low among ART-naive and ART-treated populations in Guangdong; however, INSTI-related polymorphic mutations were observed. Surveillance should be reinforced before transfer to INSTI-containing regimens.

Point-of-care HIV viral load and targeted drug resistance mutation testing versus standard care for Kenyan children on antiretroviral therapy (Opt4Kids): an open-label, randomised controlled trial

Feasible, scalable, and cost-effective approaches to ensure virological suppression among children living with HIV are urgently needed. The aim of the Opt4Kids study was to determine the effect of point of care viral load and targeted drug resistance mutation testing in improving virological suppression among children on antiretroviral therapy (ART) in Kenya. In this open-label, individually randomised controlled trial, we enrolled children living with HIV aged 1-14 years and who were either newly initiating or already receiving ART at five study facilities in Kenya. Participants were randomly allocated 1:1 to receive the intervention of point-of-care viral load testing every 3 months, targeted drug resistance mutation testing, and clinical decision support (point-of-care testing) or to receive the standard care (control group), stratified by facility site and age groups (1-9 years vs 10-14 years). Investigators were masked to the randomised group. The primary efficacy outcome was virological suppression (defined as a viral load of <1000 copies per mL) by point-of-care viral load testing at 12 months after enrolment in all participants with an assessment. This study is registered with ClinicalTrials.gov, NCT03820323. Between March 7, 2019, and December 31, 2020, we enrolled 704 participants. Median age at enrolment was 9 years (IQR 7-12), 344 (49%) participants were female and 360 (51%) were male, and median time on ART was 5·8 years (IQR 3·1-8·6). 536 (76%) of 704 had documented virological suppression at enrolment. At 12 months after enrolment, the proportion of participants achieving virological suppression in the intervention group (283 [90%] of 313 participants with a 12 month point-of-care viral load test) did not differ from that in the control group (289 [92%] of 315; risk ratio [RR] 0·99, 95% CI 0·94-1·03; p=0·55). We identified 138 episodes of viraemia in intervention participants, of which 107 (89%) samples successfully underwent drug resistance mutation testing and 91 (85%) had major drug resistance mutations. The median turnaround time for viral load results was 1 day (IQR 0-1) in the intervention group and 15 days (10-21) in the control group. Point-of-care viral load testing decreased turnaround time and targeted drug resistance mutation testing identified a high prevalence of HIV drug resistance mutations in children living with HIV, but the combined approach did not increase rates of virological suppression. Further research in combination interventions, including point-of-care viral load and drug resistance mutation testing coupled with psychosocial support, is needed to optimise virological suppression for children living with HIV. National Institutes of Mental Health of the US National Institutes of Health, Thrasher Research Fund.

Spectrum of Atazanavir-Selected Protease Inhibitor-Resistance Mutations.

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

Pre-treatment and acquired antiretroviral drug resistance among people living with HIV in Tianjin, China.

This study investigated the prevalence and patterns of pre-treatment and acquired HIV drug resistance mutations among people living with HIV (PLWH) on antiretroviral therapy (ART) for 12 (±3) months in Tianjin, China. From Jan 2018 to Dec 2020, PLWH with HIV-1 RNA greater than 1000 copies/mL visiting the ART clinic in the Tianjin Second People's Hospital were enrolled. Viral RNA isolated from blood samples were taken for genotypic resistance testing using an in-house method. Major drug resistance mutations were analyzed for reverse transcriptase and protease Sanger sequences using the Stanford University HIV Drug Resistance Database. Multivariable Poisson regressions were used to evaluate the factors associated with drug resistance mutations. HIV drug resistance testing was successfully performed on 584 ART-naive and 71 ART-experienced participants. Pre-treatment drug resistance mutation prevalence was 13.5% (79/584) to any antiretroviral drug, 12.5% (73/584) to non-nucleoside reverse transcriptase inhibitors (NNRTIs), 1.5% (9/584) to nucleoside reverse-transcriptase inhibitors (NRTIs), and 0.3% (2/584) to protease inhibitors (PIs). Acquired drug resistance to any antiretroviral drug among PLWH on ART with viral load >1000 copies/mL was 88.7% (63/71). The prevalence of mutation for NNRTIs, NRTIs, and PIs were 93.7% (59/63), 82.5% (52/63), and 3.2% (2/63), respectively. Pre-treatment and acquired drug resistance mutations were highly prevalent among PLWH in Tianjin; therefore, routine baseline genotypic resistance testing and adequate intervals of viral load surveillance are urgently needed for the long-term treatment success. Our findings provide important evidence for first- and second-line regimen drugs for PLWH, especially in China.

HIV-1 drug resistance mutations among individuals with low-level viraemia while taking combination ART in Botswana.

To assess whether a single instance of low-level viraemia (LLV) is associated with the presence of drug resistance mutations (DRMs) and predicts subsequent virological failure (VF) in adults receiving ART in 30 communities participating in the Botswana Combination Prevention Project. A total of 6078 HIV-1 C pol sequences were generated and analysed using the Stanford HIV drug resistance database. LLV was defined as plasma VL = 51-999 copies/mL and VF was defined as plasma VL ≥ 1000 copies/mL. Among 6078 people with HIV (PWH), 4443 (73%) were on ART for at least 6 months. Of the 332 persons on ART with VL > 50 copies/mL, 175 (4%) had VL ≥ 1000 copies/mL and 157 (4%) had LLV at baseline. The prevalence of any DRM was 57 (36%) and 78 (45%) in persons with LLV and VL ≥ 1000 copies/mL, respectively. Major DRMs were found in 31 (20%) with LLV and 53 (30%) with VL ≥ 1000 copies/mL (P = 0.04). Among the 135 PWH with at least one DRM, 17% had NRTI-, 35% NNRTI-, 6% PI- and 3% INSTI-associated mutations. Among the 3596 participants who were followed up, 1709 (48%) were on ART for ≥6 months at entry and had at least one subsequent VL measurement (median 29 months), 43 (3%) of whom had LLV. The OR of experiencing VF in persons with LLV at entry was 36-fold higher than in the virally suppressed group. A single LLV measurement while on ART strongly predicted the risk of future VF, suggesting the use of VL > 50 copies/mL as an indication for more intensive adherence support with more frequent VL monitoring.

Pretreatment drug resistance in people living with HIV: A large retrospective cohort study in Chongqing, China.

ObjectivesThe emergence of pretreatment drug resistance (PDR) caused by increased usage of antiretroviral therapy (ART) represents a significant challenge to HIV management. In this study, we evaluated the prevalence of PDR in people living with HIV (PLWH) in Chongqing, China.MethodsWe retrospectively collected the data of 1110 ART‐naïve PLWH in Chongqing from January 1, 2018 to June 30, 2021. HIV‐1 genotypes and drug resistance were analyzed using the HIV‐1 pol sequence. Risk factors associated with PDR were evaluated via the logistic regression model.ResultsNine genotypes were detected among 1110 participants, with CRF07_BC (55.68%) being the dominant genotype, followed by CRF01_AE (21.44%), CRF08_BC (14.14%), and other genotypes (8.74%). Of all the participants, 24.14% exhibited drug resistance mutations (DRMs). The predominant DRMs for non‐nucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTIs) were V179D/E/A/DIN (13.60%) and M184V/I (1.44%), respectively, whereas only two major DRMs (M46L and I54L) were identified for protease inhibitors (PIs). The total prevalence of PDR was 10.54%, with 2.43%, 7.66%, and 1.71% participants exhibiting PDR to NRTIs, NNRTIs, and PIs, respectively. Furthermore, female PLWH, delays in ART initiation, and the CRF08_BC genotype were associated with a higher risk of PDR.ConclusionsOur study provides the first large cohort data on the prevalence of PDR in Chongqing, China. HIV‐1 genotypes are diverse and complex, with a moderate level of PDR, which does not reach the threshold for the initiation of a public health response. Nevertheless, continuous surveillance of PDR is both useful and advisable.

Effectiveness of integrase strand transfer inhibitors in HIV-infected treatment-experienced individuals across Europe.

To explore the effectiveness and durability of integrase strand transfer inhibitor (INSTI)-based regimens in pre-treated subjects. Treatment-experienced individuals starting an INSTI-based regimen during 2012-2019 were selected from the INTEGRATE collaborative study. The time to virological failure [VF: one measurement of viral load (VL) ≥1000 copies/mL or two ≥50 copies/ml or one VL measurement ≥50 copies/mL followed by treatment change] and to INSTI discontinuation were evaluated. Of 13560 treatments analysed, 4284 were from INSTI-naïve, non-viraemic (IN-NV) individuals, 1465 were from INSTI-naïve, viraemic (IN-V) individuals, 6016 were from INSTI-experienced, non-viraemic (IE-NV) individuals and 1795 were from INSTI-experienced, viraemic (IE-V) individuals. Major INSTI drug resistance mutations (DRMs) were previously detected in 4/519 (0.8%) IN-NV, 3/394 (0.8%) IN-V, 7/1510 (0.5%) IE-NV and 25/935 (2.7%) IE-V individuals. The 1-year estimated probabilities of VF were 3.1% [95% confidence interval (CI): 2.5-3.8] in IN-NV, 18.4% (95% CI: 15.8-21.2) in IN-V, 4.2% (95% CI: 3.6-4.9) in IE-NV and 23.9% (95% CI: 20.9-26.9) in IE-V subjects. The 1-year estimated probabilities of INSTI discontinuation were 12.1% (95% CI: 11.1-13.0) in IN-NV, 19.6% (95% CI: 17.5-21.6) in IN-V, 10.8% (95% CI: 10.0-11.6) in IE-NV and 21.7% (95% CI: 19.7-23.5) in IE-V subjects. Both VF and INSTI discontinuation occur at substantial rates in viraemic subjects. Detection of DRMs in a proportion of INSTI-experienced individuals makes INSTI resistance testing mandatory after failure.

Resource and infrastructure challenges on the RESIST-2 Trial: an implementation study of drug resistance genotype-based algorithmic ART switches in HIV-2-infected adults in Senegal

BackgroundSecond-line treatment of HIV-2 in resource-limited settings (RLS) is complicated by a lack of controlled trial data, limited availability of HIV-2-active antiretroviral drugs, and inadequate access to drug resistance testing. We conducted an implementation trial of a dried blood spot- (DBS) based, drug resistance genotype-informed antiretroviral therapy (ART) switching algorithm for HIV-2-infected patients in Senegal.MethodsHIV-2-infected adults initiating or receiving ART through the Senegalese national AIDS program were invited to participate in this single-arm trial. DBS from participants with virologic failure (defined as viral load (VL) > 250 copies/mL after > 6 months on the current ART regimen) were shipped to Seattle for genotypic drug resistance testing. Participants with evidence of drug resistance in protease or reverse transcriptase were switched to new regimens according to a pre-specified algorithm. Participant clinical and immuno-virologic outcomes were assessed, as were implementation challenges.ResultsWe enrolled 152 participants. Ten were initiating ART. The remainder were ART-experienced, with 91.0% virologically suppressed (< 50 copies/mL). Problems with viral load testing capability resulted in obtaining VL results for only 227 of 613 (37.0%) participant-visits. Six of 115 participants (5.2%) with VL available after > 6 months on current ART regimen experienced virologic failure, with per-protocol genotypic testing attempted. One additional test was performed for a participant with a VL of 222 copies/mL. Genotypes from three participants showed no evidence of major drug resistance mutations, two showed nucleoside reverse transcriptase inhibitor (NRTI) resistance, one showed both NRTI and protease inhibitor resistance, and one test failed. No integrase inhibitor resistance was observed. Five of six successfully-tested participants switched to the correct regimen or received additional adherence counseling according to the algorithm; the sixth was lost to follow-up. Follow-up VL testing was available for two participants; both of these were virally suppressed (< 10 copies/mL). The trial was terminated early due to the COVID-19 pandemic (which prevented further VL and genotypic testing), planned rollout of dolutegravir-based 1st-line ART, and funding.ConclusionsThe RESIST-2 trial demonstrated that a DBS-based genotypic test can be used to help inform second-line ART decisions as part of a programmatic algorithm in RLS, albeit with significant implementation challenges.Trial registrationClinicalTrials.govNCT03394196. Registered on January 9, 2018.