Dual Raltegravir–Darunavir/Ritonavir Combination in Virologically Suppressed HIV-1-Infected Patients on Antiretroviral Therapy Including a Ritonavir-Boosted Protease Inhibitor Plus Two Nucleoside/Nucleotide Reverse Transcriptase Inhibitors

Background: Nucleoside reverse transcriptase inhibitor (NRTI)-sparing antiretroviral therapies may be useful in HIV-infected patients with resistance or intolerance to this class. Methods: We performed an observational study of patients on suppressive antiretroviral therapy containing two NRTIs plus one ritonavir-boosted protease inhibitor who switched to a dual regimen containing raltegravir (400 mg twice daily) and darunavir/ritonavir (800/100 mg once daily) and were followed-up for 48 weeks. Results: As a whole, 82 patients were enrolled. Mean duration of current regimen was 4.6 years and mean duration of plasma HIV RNA < 50 copies/mL before the switch was 46.2 months. Reason for simplification was toxicity in 76 patients and resistance to NRTIs in 13. After switching, the percentage of patients with HIV RNA < 50 copies/mL at week 48 was 92.7% in the intent-to-treat-exposed analysis and 97.6% in the per-protocol analysis. The switch led to a significant reduction in the mean triglyceride value (−85.2 mg/dL), in the prevalence of tubular proteinuria (−56%) and in the mean level of interleukin-6 (−0.94 pg/mL), with a significant increase in the mean phosphoremia (+0.58 mg/dL). Mean trough concentrations of both raltegravir and darunavir were within the therapeutic range. Two patients (2.4%) had virological failure due to suboptimal adherence and 4 subjects (4.9%) discontinued treatment due to adverse events, but no patients experienced Grade 3 or 4 adverse events. Conclusion: In our study, simplification to a dual therapy containing raltegravir plus darunavir/ritonavir after 48 weeks maintained viral suppression in more than 90% of patients and showed a good tolerability with a favourable effect on proteinuria, ipophosphoremia, and lipid metabolism.