LONDON, July 11, 2012 /PRNewswire/ -- Shionogi-ViiV Healthcare LLC today announced that initial results have been received from the Phase III SINGLE (ING114467) study of the investigational integrase inhibitor dolutegravir in treatment-naive adults with HIV-1. The study demonstrated superiority of the dolutegravir-based regimen compared to the single tablet regimen Atripla ®. At 48 weeks, 88% of study participants on the dolutegravir regimen were virologically suppressed (<50 copies/mL) vs. 81% of participants on the single tablet regimen Atripla [difference and 95% CI; 7.4% (+2.5% to +12.3%); difference in the primary endpoint was statistically significant, p=0.003]. Differences in efficacy were primarily driven by a higher rate of discontinuation due to adverse events on the Atripla arm. The SINGLE study was designed to demonstrate non-inferiority of the dolutegravir-based regimen versus Atripla, and the primary analysis met this criterion. Statistical superiority was concluded as part of a subsequent, pre-specified testing procedure. SINGLE is an ongoing double blind, double dummy study designed to compare the efficacy and safety of two antiretroviral regimens: dolutegravir 50mg plus abacavir/lamivudine (Kivexa®/Epzicom®) versus Atripla® (tenofovir/emtricitabine/efavirenz). The primary endpoint was the proportion of study participants with undetectable HIV-1 RNA (<50c/mL) at 48 weeks; 414 treatment-naive study participants were randomised and exposed to the dolutegravir-based regimen and 419 to the Atripla arm. Overall, 2% of subjects on the dolutegravir-based regimen discontinued due to adverse events vs. 10% of those receiving the Atripla regimen. The most common drug related adverse events on Atripla were in the nervous system System Organ Class (reported by 41% of Atripla recipients, vs. 15% of participants receiving the dolutegravir-based regimen), while the most common drug related adverse events on the dolutegravir-based regimen were in the gastrointestinal system organ class (reported by 22% of subjects receiving the dolutegravir-based regimen and 22% of subjects receiving Atripla).