Impact of resistance mutations on efficacy of dolutegravir plus rilpivirine or plus lamivudine as maintenance regimens: a cohort study

Efficacy of Lamivudine Plus Dolutegravir vs Dolutegravir-Based 3-Drug Regimens in People With HIV Who Are Virologically Suppressed

Background

Lamivudine + dolutegravir maintenance dual therapy (DT) could be less effective than 3-drug therapy (TT) in the context of resistance-associated mutations to nucleoside reverse transcriptase inhibitors (NRTIs). The ARCA database was queried to test this hypothesis with a trial emulation strategy.

Methods

People with HIV taking 2 NRTIs plus a protease inhibitor or a non-NRTI who switched to DT or dolutegravir-based TT were followed up from the first HIV RNA <50 copies/mL (baseline) to virologic failure (VF; ie, 2 consecutive HIV RNA ≥50 copies/mL or 1 HIV RNA ≥200 copies/mL). Those switching to DT within 6 months were assigned to the treatment arm and all other patients to the control arm. Each participant was also cloned, assigned to the opposite strategy, and censored at the time of deviation from that strategy. Using inverse probability of censoring weight Cox regression models, we calculated hazard ratios of VF for DT vs TT stratified for the presence of resistance-associated mutations.

Results

Overall 626 people were analyzed: 204 with DT and 422 with TT (73% men; mean age, 44 years). Ten and 31 VFs occurred with DT and TT, respectively, over a median 5.8 years. When compared with a fully active TT, the DT had similar efficacy (adjusted hazard ratio, 0.88; 95% CI, .29-2.61; P = .812) when full susceptibility was confirmed at historical genotype. When previous M184V/I was present in both groups, the risk of VF was higher for DT vs TT but was not statistically significant (adjusted hazard ratio, 3.06; 95% CI, .45-20.84; P = .252).

Conclusions

DT was not associated with a significantly higher risk of VF than dolutegravir-based TT.

Dolutegravir/Lamivudine Is Noninferior to Continuing Dolutegravir- and Non-Dolutegravir-Based Triple-Drug Antiretroviral Therapy in Virologically Suppressed People With Human Immunodeficiency Virus: DUALING Prospective Nationwide Matched Cohort Study

Background

Confirming the efficacy of dolutegravir/lamivudine in clinical practice solidifies recommendations on its use.

Methods

Prospective cohort study (DUALING) in 24 human immunodeficiency virus (HIV) treatment centers in the Netherlands. HIV RNA-suppressed cases were on triple-drug antiretroviral regimens without prior virological failure or resistance and started dolutegravir/lamivudine. Cases were 1:2 matched to controls on triple-drug antiretroviral regimens by the use of dolutegravir-based regimens, age, sex, transmission route, CD4+ T-cell nadir, and HIV RNA zenith. The primary endpoint was the treatment failure rate in cases versus controls at 1 year by intention-to-treat and on-treatment analyses with 5% noninferiority margin.

Results

The 2040 participants were 680 cases and 1380 controls. Treatment failure in the 390 dolutegravir-based cases versus controls occurred in 8.72% and 12.50% (difference: -3.78% [95% confidence interval {CI}, -7.49% to .08%]) by intention-to-treat and 1.39% and 0.80% (difference: 0.59% [95% CI, -.80% to 1.98%]) by on-treatment analyses. The treatment failure risk in 290 non-dolutegravir-based cases was also noninferior to controls. Antiretroviral regimen modifications unrelated to virological failure explained the higher treatment failure rate by intention-to-treat. A shorter time on triple-drug antiretroviral therapy and being of non-Western origin was associated with treatment failure. Treatment failure, defined as 2 consecutive HIV RNA >50 copies/mL, occurred in 4 cases and 5 controls but without genotypic resistance detected. Viral blips occured comparable in cases and controls but cases gained more weight, especially when tenofovir-based regimens were discontinued.

Conclusions

In routine care, dolutegravir/lamivudine was noninferior to continuing triple-drug antiretroviral regimens after 1 year, supporting the use of dolutegravir/lamivudine in clinical practice.

Clinical Trials Registration

NCT04707326.

Evaluation of integrase resistance in individuals who failed a regimen containing dolutegravir in French and Italian clinical settings

BACKGROUND

This work aims to evaluate integrase resistance and its predictors in HIV-1 infected combined antiretroviral therapy (cART) experienced individuals failing a dolutegravir-based regimen.

METHODS

Major resistance mutations (MRM) and genotypic susceptibility score (GSS) of dolutegravir companion drugs were evaluated on plasma genotypic resistance test (GRT) performed at dolutegravir failure. Logistic regression was used to evaluate factors associated to the risk of integrase strand-transfer inhibitors (INSTI)-resistance at dolutegravir failure.

RESULTS

We retrospectively analysed 467 individuals. At failure GRT, individuals had been under dolutegravir for a median (IQR) time of 11 (5-20) months; around half of them had never been exposed to INSTI (52%) and 10.7% were at first-line regimen. Fifty-eight (12.4%) individuals showed ≥1 INSTI MRM. Among them, people INSTI-exposed showed significantly higher prevalence of INSTI resistance compared to those who were INSTI naïve [46 (21.2%) versus 9 (3.9%), P < 0.001].N155H was the most prevalent MRM (5.4%), followed by G140S (4.5%) and Q148H (4.3%). These MRM were more probably present in INSTI-experienced individuals compared to those INSTI naïve. Despite failure, 89.5% of individuals harboured viral strains fully susceptible to dolutegravir and bictegravir and 85.0% to all INSTI. No INSTI exposure before receiving dolutegravir [OR: 0.35 (0.16-0.78), P < 0.010] and a GSS for companion drugs ≥2 (OR: 0.09 [0.04-0.23], P < 0.001) were negatively associated with INSTI resistance at failure.

CONCLUSIONS

In a large set of individuals failing dolutegravir in real-life, INSTI resistance was low and mainly related to previous first-generation INSTI exposure. Surveillance of integrase resistance remains crucial to preserve efficacy of INSTI class in the future.

Virological efficacy of switch to DTG plus 3TC in a retrospective observational cohort of suppressed HIV-1 patients with or without past M184V: the LAMRES study

OBJECTIVES

The aim of this study was to assess the efficacy of dolutegravir plus lamivudine (DTG+3TC) in a large set of virologically suppressed HIV-1 infected individuals with or without past M184V mutation.

METHODS

This observational study included individuals who switched to DTG+3TC with ≥1 genotype before switch. Survival analysis was used to evaluate the role of past M184V on virological rebound (VR) or blips after DTG+3TC switch.

RESULTS

A total of 712 individuals followed in several clinical centres in France, Italy and Spain were analysed. Past M184V was present in 60 (8.4%) individuals. By 3 years after switch, the overall probability of VR and blips was 6.7% and 6.9%, respectively, without any statistical significance according to the presence/absence of past M184V. A significantly higher probability of VR was found in individuals harbouring M184V before DTG+3TC with a duration of virological suppression (Ts) ≤.3.5 years compared to others (M184V+Ts ≤.3.5 years: 22.7%; M184M+Ts ≤.3.5 years: 9.0%; M184V+Ts >3.5 years: 7.8%; M184M+Ts >3.5 years: 4.9%; P = 0.007). This finding was not confirmed in multivariable models adjusting for behavioural and demographic variables. Genotypic resistance test after VR under DTG+3TC was available for 8/39 individuals; one poorly adherent individual developed M184V. No resistance to INIs was found.

CONCLUSION

In this retrospective observational study, the probability of VR and blips in patients switching to DTG+3TC was very low after 3 years of treatment regardless M184V. The effect of a short duration of previous virological suppression in individuals with M184V remains troubling and needs ad hoc clinical trials to be confirmed.