Intermittent two-drug antiretroviral therapies maintain long-term viral suppression in real life in highly experienced HIV-infected patients.

Objectives: To assess in real life whether two-drug regimens (2-DRs) given 4-5 days a week in virally suppressed patients can maintain viral suppression over 48 and 96 weeks.

Methods: This observational single-centre study enrolled all patients who initiated an intermittent 2-DR between 01/01/2016 and 30/06/2019. The primary outcome was the rate of virological failure (VF), defined as confirmed plasma viral load (pVL) ≥50 copies/mL or single pVL ≥50 copies/mL followed by ART change at week 48 (W48) and W96. Secondary outcomes were the 2-DR intermittent strategy success rate (pVL <50 copies/mL with no ART change), change in CD4 count, CD4/CD8 ratio and rate of residual viraemia.

Results: Eighty-five patients were included; 67/85 (79%) were men, median age = 57 years (IQR = 50-63), CD4 nadir = 233 cells/mm3 (110-327), ART duration = 21 years (13-24), duration of virological suppression = 6.5 years (3.7-10.8) and CD4 count = 658 cells/mm3 (519-867). Intermittent 2-DRs consisted of integrase strand transfer inhibitor (INSTI)/NNRTI (58%), INSTI/NRTI (13%), two NRTIs (11%), PI/NRTI (7%) and other combinations (11%). The median follow-up was 90 weeks (IQR = 64-111). Overall, four VFs occurred, leading to a virological success rate of 98.8% (95% CI = 93.6-100) at W48 and 95.3% (95% CI = 88.4-98.7) at W96. Resuming the same 2-DR 7 days a week led to viral resuppression in three patients, whereas the M184V mutation emerged in one patient, leading to ART modification. There was no significant change in the CD4 count or residual viraemia rate, but a small increase in the CD4/CD8 ratio (P = 0.009) occurred over the study period.

Conclusions: This observational study shows the potential for intermittent 2-DRs to maintain a high virological success rate, which should be assessed in larger prospective randomized studies.