LONDON, April 2, 2012 /PRNewswire/ -- ViiV Healthcare and Shionogi & Co., Ltd. today announced that initial results have been received from the SPRING-2 (ING113086) Phase III study of the investigational integrase inhibitor dolutegravir in treatment-naive adults with HIV-1. The study met its primary objective, demonstrating non-inferiority of dolutegravir to raltegravir. Through 48 weeks, 88% of study participants on dolutegravir were virologically suppressed (<50 copies/mL) vs. 85% of participants on raltegravir [with a 95% confidence interval (CI) for the difference, -2.2% to + 7.1%; the lower end of the CI (-2.2%) was above the prespecified -10% non-inferiority limit]. SPRING-2 is an ongoing non-inferiority study designed to compare the efficacy and safety of dolutegravir 50mg administered once-daily versus raltegravir 400mg administered twice daily, both with two nucleoside reverse transcriptase inhibitors (NRTIs); 411 treatment-naive study participants were randomized in each arm. The primary endpoint of the study was the proportion of study participants with undetectable HIV-1 RNA (<50c/mL) through 48 weeks. The tolerability of dolutegravir was similar to that of raltegravir, with rates of adverse events leading to withdrawal at 2% in both arms. Drug-related nausea was reported by 10% of patients in each arm; no other adverse events related to study medication were reported by more than 5% of participants in either arm. "The SPRING-2 findings indicate that once daily unboosted dolutegravir may offer people living with HIV an additional treatment option in the future. These are the first large-scale safety and efficacy data in naive patients, and we look forward to seeing further data in 2012 to build a more comprehensive picture of the role of dolutegravir," said Dr John Pottage, Chief Medical Officer, ViiV Healthcare. "At ViiV Healthcare we have a total focus on the needs of people living with HIV, and as a result we see the continued need for new, effective and convenient therapies. We are committed to building connections and collaborations, like the Shionogi-ViiV Healthcare dolutegravir program, to meet these needs," said Dr. Dominique Limet, Chief Executive Officer, ViiV Healthcare. "The SPRING-2 study has met its primary endpoint for dolutegravir in treatment-naive patients. This marks an important milestone for the development of dolutegravir and the Shionogi-ViiV Healthcare joint venture. We look forward to completing further Phase III studies in a variety of clinical settings in order to fully understand the potential clinical benefit for a range of HIV patient populations," said Dr. Tsutae "Den" Nagata, Chief Medical Officer, Shionogi & Co., Ltd.