Shionogi-ViiV Healthcare has said it will progress its once-daily, unboosted integrase inhibitor into Phase III clinical trials for HIV treatment.

The studies will further evaluate the safety, efficacy and resistance profile of S/GSK1349572, which showed positive antiviral activity and resistance results (once a day) in two Phase IIb trials.

The Phase IIb studies, Spring-1 and Viking, observed the investigational drug S/GSK1349572 in treatment-naive HIV subjects and in treatment-experienced subjects resistant to raltegravir.

The ongoing study Spring-1 compared S/GSK1349572 to efavirenz in 205 treatment-naive subjects and the 24-week Viking study assessed its antiviral activity, safety and tolerability.

The drug is jointly developed by ViiV Healthcare, a company established by GlaxoSmithKline and Pfizer to deliver advances in HOV care, and Japan-based pharmaceutical company Shionogi & Co.