Dolutegravir in the long term in children and adolescents: frequent virological failure but rare acquired genotypic resistance

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.

Bictegravir/emtricitabine/tenofovir alafenamide in paediatrics: Real-life experience from a French cohort (2019-2023)

OBJECTIVES

Although widely recommended, data on bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) efficacy in HIV-1-infected children/adolescents are mainly extrapolated from studies in adults and one paediatric trial in which subjects have good treatment adherence. This study aimed to provide data about the risk of virological failure (VF) and acquired genotypic resistance in children and adolescents receiving BIC/FTC/TAF in a real-world setting.

METHODS

This retrospective monocentric study included 74 paediatric patients who received BIC/FTC/TAF during ≥6 months in 2019-2023. VF was defined as not achieving a plasma viral load <50 copies/mL within 6 months of BIC/FTC/TAF initiation or as experiencing virological rebound ≥50 copies/mL.

RESULTS

Most patients were antiretroviral therapy (ART)-experienced (93.2%), previously exposed to integrase inhibitors (85.1%) and displayed viral suppression at baseline (67.6%). Their median age was 11.2 years [interquartile range (IQR): 8.8-15.2]. BIC/FTC/TAF introduction reduced treatment burden in most ART-experienced subjects. Genotypic susceptibility score of BIC/FTC/TAF was ≥2 in all cases. Median follow-up was 40 months (IQR: 21-46). VF occurred in 28 people (37.8%), more frequently in the case of VF versus viral suppression at baseline (68% vs. 26%, P = 0.02). BIC/FTC/TAF was interrupted for suspected intolerance in only one case (1.4%). Nucleoside reverse transcriptase inhibitor (NRTI) mutation (T69D/N) emerged in one patient (3.6% of VF) after 47 months of continuous detectable viraemia while on ART. No acquisition of mutations in the integrase gene was observed.

CONCLUSION

Because of its high genetic barrier to resistance, BIC/FTC/TAF could be especially useful in the paediatric population, in which the risk of poor treatment adherence and VF is high.

Efficacy, Safety, and Tolerability of Doravirine/Lamivudine/Tenofovir Disoproxil Fumarate Fixed-Dose Combination Tablets in Adolescents Living With HIV: Results Through Week 96 from IMPAACT 2014

BACKGROUND

IMPAACT 2014 study is a phase I/II, multicenter, open-label, nonrandomized study of doravirine (DOR) co-formulated with lamivudine (3TC) and tenofovir disoproxil fumarate (TDF) as fixed-dose combination (DOR FDC) in adolescents with HIV-1. We report the efficacy, safety, and tolerability of DOR FDC through 96 weeks.

METHODS

Participants were adolescents aged 12 to <18 years who weighed at least 45 kg and who were either antiretroviral (ARV)-naïve or virologically suppressed without documented resistance mutations to DOR/3TC/TDF. The efficacy endpoint was the proportion of participants with HIV-1 RNA <40 copies/mL assessed at weeks 48 and 96 using the observed failure approach. Safety and tolerability outcomes were incidence of adverse events (AEs) and treatment discontinuations.

RESULTS

A total of 45 adolescents, median age 15 (range, 12-17) years, 58% females, were enrolled and 2 (4.4%) participants were ARV naïve. Of the 45 participants, 42 (93.3%) completed the study and 41 (91.1%) completed the study treatment. At week 48, 41/42 (97.6%; 95% confidence interval [CI], 87.4-99.9) and week 96, 37/40 (92.5%; 95% CI, 79.6-98.4) participants had achieved or maintained HIV-1 RNA <40 copies/mL. There were no treatment-related discontinuations due to AEs and no drug-related AEs ≥grade 3 or deaths.

CONCLUSIONS

We found once-daily dosing of DOR FDC to be safe and well tolerated for maintaining viral suppression through 96 weeks in adolescents living with HIV-1.

Virologic Outcomes and ARV Switch Profiles 2 Years After National Rollout of Dolutegravir to Children Less Than 15 Years in Southern Mozambique

BACKGROUND

Dolutegravir (DTG) was scaled up globally to optimize treatment for children living with HIV. We evaluated the rollout and virological outcomes after DTG introduction in Mozambique.

METHODS

Data from children 0-14 years with visits from September 2019 to August 2021 were extracted from records in 16 facilities in 12 districts. Among children ever on DTG, we report treatment switches, defined as changes in anchor drug, regardless of changes to nucleoside reverse transcriptase inhibitor (NRTI) backbones. Among those on DTG for ≥6 months, we described viral load suppression rates by children newly initiating and switching to DTG and by the NRTI backbone at the time of the DTG switch.

RESULTS

Overall, 3,347 children were ever on DTG-based treatment (median age 9.5 years; 52.8% female). Most children (3,202, 95.7%) switched to DTG from another antiretroviral regimen. During the 2-year follow-up, 9.9% never switched from DTG; 52.7% had 1 regimen change, of which 97.6% were switched to DTG. However, 37.2% of children experienced ≥2 anchor drug changes. Overall median time on DTG was 18.6 months; nearly all children ≥5 years (98.6%) were on DTG at the last visit. Viral suppression was 79.7% (63/79) for children newly initiating DTG and 85.8% (1,775/2,068) for those switching to DTG. Suppression rates were 84.8% and 85.7% among children who switched and maintained NRTI backbones, respectively.

CONCLUSIONS

Viral suppression rates of ≥80% with minor variations by backbone were achieved during the 2-year DTG rollout. However, there were multiple anchor drug switches for over one-third of children, which may be attributable in part to drug stockouts. Long-term pediatric HIV management will only be successful with immediate and sustainable access to optimized child-friendly drugs and formulations.

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.

Pharmacokinetics, Tolerability, and Safety of Doravirine and Doravirine/Lamivudine/Tenofovir Disoproxil Fumarate Fixed-Dose Combination Tablets in Adolescents Living With HIV: Week 24 Results From IMPAACT 2014

BACKGROUND

We studied the pharmacokinetics (PK) and safety of 100-mg doravirine and doravirine/lamivudine/tenofovir disoproxil fumarate fixed-dose combination (100/300/300 mg DOR FDC) treatment in adolescents with HIV-1.

METHODS

Adolescents ages 12 to younger than 18 years were enrolled in 2 sequential cohorts. Cohort 1 evaluated intensive PK and short-term safety of 100-mg single-dose doravirine in adolescents ≥35 kg. Cohort 2 participants either initiated treatment with DOR FDC (antiretroviral (ARV)-naïve) or switched to DOR FDC from a previous ARV regimen (virologically suppressed). The first 10 Cohort 2 participants had intensive PK evaluations, and safety, sparse PK, and HIV RNA were assessed through week 24.

RESULTS

Fifty-five adolescents, median age 15.0 years and baseline weight 51.5 kg, were enrolled. Nine participants completed Cohort 1 PK assessments (8 of the 9 participants weighed ≥45 kg) and 45 initiated study drug in Cohort 2. The doravirine geometric mean (GM) AUC 0-∞ was 34.8 μM∙hour, and the GM C 24 was 514 nM after a single dose, with a predicted steady-state GM C 24,ss,pred of 690 nM. Cohort 2 enrolled adolescents weighing ≥45 kg. Plasma concentrations of doravirine, tenofovir, and lamivudine achieved by Cohort 2 participants were similar to those reported in adults. No drug-related serious or grade 3 or 4 adverse events occurred. Forty-two of 45 participants (93.3%; 95% CI: [81.7, 98.6]) achieved or maintained HIV-1 RNA <40 copies/mL.

CONCLUSIONS

Doravirine and DOR FDC achieved target PK in adolescents with HIV-1. DOR FDC was well-tolerated and maintained excellent virologic efficacy through 24 weeks, offering a favorable option for adolescents.

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.