the triple therapy arms in their primary efficacy analyses at week 48 [5, 7]. However, longer term analyses showed a slightly higher

risk of low-level viraemia for patients taking DRV/r monotherapy [6, 8]; so far, the patients with low-level viraemia have not developed phenotypic resistance to PIs. More detailed analyses of these trials may help to identify patients find more at the lowest risk of viraemia during monotherapy treatment, who could be most suitable for treatment with DRV/r monotherapy. In the MONOI trial, patients with low-level viraemia at baseline, problems with adherence or higher HIV DNA levels at baseline were more likely to show elevations in HIV RNA up to week 96 [9]. In a similar analysis of the Only-Kaletra-04 (OK-04) trial of lopinavir/ritonavir monotherapy, patients with poor adherence, lower nadir CD4 cell counts and lower baseline haemoglobin levels were

most likely to lose virological suppression over selleck kinase inhibitor 96 weeks of randomized treatment [10]. In other studies of standard triple combinations of antiretroviral treatment, coinfection with hepatitis C virus (HCV) has been a consistent predictor of lower HIV RNA suppression rates [11-15]. This trend has been seen across trials of PIs [12, 13, 15] and nonnucleoside reverse transcriptase inhibitors [11, 14]. Coinfection with HCV may be associated with prior or current injecting drug use, which could affect adherence to study medication. In addition, the efficacy endpoint used in these HIV clinical trials – the time to loss of virological response (TLOVR) – can be difficult to interpret. This endpoint classifies virological failure as any confirmed elevation above

50 copies/mL, occurring at any time during the trial. However, these elevations in HIV RNA may be low level, may not be associated with drug resistance and may occur for short time periods, with subsequent resuppression of HIV RNA by the Verteporfin manufacturer end of the trial. The results of the MONET trial were analysed at the final week 144 time-point, to assess whether there were baseline factors affecting the efficacy in the two treatment arms. In addition, the efficacy data were analysed by a strict intent-to-treat (ITT) (switches not considered failures) endpoint, which classified patients as success or failure depending on their HIV RNA levels at the end of the trial, regardless of transient elevations in HIV RNA at earlier time-points. The MONET trial recruited patients who had HIV RNA levels below 50 copies/mL at screening, while on a stable triple antiretroviral regimen, for at least 24 weeks, and no history of virological failure since first starting antiretrovirals. The trial methodology has been described previously [5]. Briefly, patients were randomized to receive DRV/r 800/100 mg once daily, either as monotherapy (monotherapy arm) or with two investigator-selected NRTIs (triple therapy arm).