In the MONET Trial, 256 patients with virologic suppression were randomised, in an open-label design, to either darunavir/ritonavir 800/100 mg monotherapy once daily (n = 127) or darunavir/ritonavir 800/100 mg once daily + 2 nucleoside reverse transcriptase inhibitors (n = 129) for 144 weks. Although monotherapy showed noninferior efficacy to triple therapy when switches were not considered as failures, it was associated with a higher risk of low level plasma HIV-1 RNA elevations, between 50 and 400 copies/ml. A substudy was conducted in 146 patients to assess HIV DNA in stored PBMC. Level of HIV-1 DNA/106 PBMC was similar in both groups at baseline, with no significant changes within or between groups through 144 weeks. In both treatment groups, baseline HIV-1 DNA correlated with plasma HIV-1 RNA (< 5 ; 5-49 or > 50 copies/ml), and was significantly higher in patients with nadir CD4 counts < 200/mm3 (p < 0.05) and in patients who experienced during follow-up at least 1 HIV-1 measurement above 50 copies/ml (p < 0.05).