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

BACKGROUND: 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). MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSIONS: Among experienced patients, the best candidates for dual-therapy regimens including DRV/r are those with undetectable viral load and higher GSS.