Analysing the efficacy and tolerability of dolutegravir plus either rilpivirine or lamivudine in a multicentre cohort of virologically suppressed PLWHIV

Objectives We aimed to investigate and compare the efficacy and safety of two dolutegravir-based two-drug regimens: dolutegravir + lamivudine versus dolutegravir + rilpivirine. Methods We analysed a cohort of people living with HIV (PLWHIV) switching to dolutegravir + lamivudine or dolutegravir + rilpivirine. We excluded from the analysis PLWHIV with no available pre-switch genotypic test or with a known resistance mutation to one of the study drugs. We evaluated incidence of virological failure (VF) and treatment discontinuation (TD), as well as changes in immunological and metabolic parameters. Results We enrolled 592 PLWHIV: 306 in the lamivudine group and 286 in the rilpivirine group. We observed nine VFs in the lamivudine group [1.4 VF per 100 patient-years of follow-up (PYFU)] and four VFs in the rilpivirine group (0.6 VF per 100 PYFU). Subsequent genotypic analysis showed no acquired resistance-associated mutations in those experiencing VF. Estimated probability of maintaining virological suppression at 144 and 240 weeks were 96.6% and 92.7%, respectively, in the lamivudine group and 98.7% and 98.7%, respectively, in the rilpivirine group (log-rank P = 0.172). The estimated probability of maintaining study regimen at Week 240 was 82.3% in the lamivudine group and 85.9% in the rilpivirine group (log-rank P = 0.018). We observed a significant improvement in CD4+ cell count at Week 240 in the lamivudine group (P = 0.012); in the rilpivirine group we registered a significant increase in CD4/CD8 ratio (P = 0.014). Conclusions Both analysed strategies are effective and safe as switch strategies in clinical practice, with a low incidence of VF and a favourable immunological recovery, even in the long term.