LAUSR

Objective: Characterize virologic and immunologic outcomes of INSTI-based antiretroviral therapy (ART) in experienced patients with and without virologic failure. Design: Prospective clinical cohort. Methods: ART-experienced, INSTI-naive participants in the University of North Carolina Center for AIDS Research HIV Clinical Cohort (UCHCC) initiating an INSTI-containing regimen 2007–2016 were followed from INSTI initiation (baseline) to the earliest of: outcome of interest, loss to follow-up (LTFU, 1 year without clinical visit), or death. Outcomes of interest were virologic failure (first of two consecutive viral loads at least 200 copies/ml more than 2 weeks apart, or one viral load ≥200 before LTFU) and immune recovery (first CD4+ ≥500 cells/&mgr;l). Patients with baseline viral load at least 50 copies/ml were given 24 weeks before meeting virologic failure criteria. Kaplan–Meier curves and Cox proportional hazards models compared INSTI regimens and patient characteristics. Results: Of 773 patients, 32% were women, 59% African-American, and 42% had a viral load at least 50 copies/ml at INSTI initiation. After 2 years, 5% of patients with baseline viral load less than 50 copies/ml experienced virologic failure, compared with 35% of patients with baseline viral load at least 50 copies/ml (P < 0.01). Among patients with baseline viral load less than 50 copies/ml, dolutegravir/NRTIs was associated with longer time to virologic failure [adjusted hazard ratio (aHR) 0.11, 95% confidence interval (CI) 0.01–0.80], whereas among patients with baseline viral load at least 50 copies/ml, raltegravir/NRTIs was associated with longer time to virologic failure (aHR 0.35, 95% CI 0.18–0.68), both compared with elvitegravir/NRTIs. After 5 years suppressed, irrespective of baseline viral load, 61% of patients experienced immune recovery. Conclusion: In this cohort, INSTI-containing regimens led to low virologic failure rates in patients switching ART while suppressed. Viremic patients initiating INSTIs were at high risk of virologic failure during follow-up.