Darunavir-based dual therapy of treatment-experienced HIV-infected patients: analysis from a national multicenter database

We assessed the virological response of dual therapy with DRV/r, plus raltegravir, maraviroc or etravirine, in virological failure patients and in virologically suppressed patients collected in the Italian Antiretroviral Resistance Database (ARCA). The primary endpoint was the percentage of patients remaining free of virological failure (confirmed > 50 copies/mL or any change in the regimen). Subjects had a resistance test and at least one follow-up visit. Observation was censored at last visit under dual therapy and survival analysis and proportional hazard models were used. Sixty-seven percent of the 221 patients started DRV/r with RAL, 20.4 % with ETV, and 12.2 % with MAR; 31.2 % virological failures were observed. At survival analysis, the overall proportion of failure was 29.2 % at 1 year and 33.8 % at 2 years. The proportion of failure was lower in patients starting with undetectable vs. detectable viral load (13.3 and 25.2 % vs. 37.4 and 38.8 % at 1 and 2 years, respectively, p = 0.001 for both analyses) and in patients treated with DRV 600 BID vs. 800 QD (HR: 0.56, 95 % CI: 0.31-0.99, p < 0.05). By regimen, the adjusted proportional model showed no significant difference among the three regimens. A significant lower risk of failure was associated with higher GSS (HIV-DB HR: 0.53, 95 % CI: 0.32-0.88, p = 0.014; Rega 0.60, 0.40-0.88, p < 0.01; ANRS 0.55, 0.34-0.90, p = 0.017), while a higher risk of failure with detectable HIV-RNA (3.02, 1.70-5.72, p < 0.001). Among experienced patients, the best candidates for dual-therapy regimens including DRV/r are those with undetectable viral load and higher GSS.