Durability of rilpivirine-based versus integrase inhibitor-based regimens in a large cohort of naïve HIV-infected patients starting antiretroviral therapy

Objectives: Comparisons between rilpivirine (RPV) and integrase strand transfer inhibitors (INSTIs) in antiretroviral therapy (ART)-naïve HIV-infected individuals are currently lacking. This study aimed to compare, in an observational cohort setting, the durability of treatment with RPV-based and INSTI-based first-line regimens. Methods: Patients who started first-line ARTs based on RPV or INSTIs, with HIV­RNA < 100 000 copies/mL and CD4 cell count > 200 cells/μL were included. The primary endpoint was the cumulative probability of treatment failure (TF = virological failure [confirmed HIV-RNA > 50 copies/mL] or discontinuation of the anchor drug in the regimen), as assessed by the Kaplan-Meier method. A multivariable Cox regression was used to control for potential confounding. Results: Of the 1991 included patients, 986 started ART with an RPV-based regimen and 1005 with an INSTIs-based regimen. The median (IQR) follow-up was 20 (10, 35) months. The cumulative 2-year probability of TF with RPV (9.1% [95% 7.2, 11.1]) was lower than that observed in the INSTIs group (16.6% [13.8, 19.4], P = 0.0002) but not when compared with dolutegravir (DTG) alone. Starting ART with an INSTIs-based regimen vs. RPV was associated with a higher risk of TF after controlling for potential confounding factors (adjusted hazard ratio, AHR [95% CI]: 1.64 [1.28, 2.10]; P < 0.001). The results were similar when restricting the analysis to single-tablet regimens, although the probability of virological success was higher for INSTIs and DTG. Conclusions: In ART-naïve patients with low viral loads and high CD4 counts, the risk of treatment failure was lower in those who started RPV-based vs. INSTIs-based regimens other than DTG-based ones.