Five years with dolutegravir plus lamivudine as a switch strategy : much more than a positive finding

Background: Results from clinical trials and observational studies suggest that dolutegravir plus lamivudine could be an effective and well-tolerated option for simplification in HIV-1 positive patients. We aimed to assess long-time efficacy and safety in our multicenter cohort. Methods: This was a retrospective study enrolling HIV-1-infected, virologically suppressed patients switching to dolutegravir+lamivudine. We performed survival analysis to evaluate time to virological failure (VF, defined by a single HIV-RNA ≥1,000 copies/mL or by two consecutive HIV-RNA ≥ 50 copies/mL) and treatment discontinuation (TD, defined as the interruption of either 3TC or DTG), assessing predictors via Cox regression analyses. Results: Seven-hundred eighty-five patients were considered for the analysis: 554 were males (70.6%), with a median age of 52 years (IQR 45-58). Estimated probabilities of maintaining virological suppression at weeks 96, 144 and 240 were 97.7% (SD ±0.6), 96.9% (SD ±0.8) and 96.4% (SD ±0.9). A non-B HIV subtype (p=0.014) and a previous VF (p=0.037), resulted predictors of VF. We did not observe differences in probability of VF in PLWHIV with a M184V resistance mutation (p=0.689); however, in a deeper analysis, M184V mutation was a predictor of VF (p=0.038) in patients with time of virological suppression < 88 months. Estimated probabilities of remaining on study regimen at 96, 144 and 240 weeks were 82.9% (SD±1.4), 79.7% (SD±1.6) and 74.3% (SD±2.2), respectively. Conclusions: Our findings show the long-term efficacy and tolerability of dolutegravir plus lamivudine in virologically suppressed patients.