(ShareCast News) - Specialist HIV company ViiV Healthcare, which is majority-owned by GlaxoSmithKline with Pfizer and Shionogi Limited as shareholders, has started two phase III studies to evaluate an investigational long-acting, injectable regimen of cabotegravir and rilpivirine for the treatment of HIV-1 infection. The studies will examine the safety and efficacy of monthly dosing with the two-drug, injectable regimen in both treatment-naïve and treatment-experienced patients.This investigational, long-acting, injectable regimen is being co-developed as part of a collaboration with Janssen Sciences Ireland UC.John C Pottage, chief scientific and medical officer at ViiV, said: "Currently the treatment of HIV involves life-long therapy with multiple antiretrovirals, so it is important that we continue to improve on the durability, safety, tolerability, and convenience of treatment regimens."This phase III programme with long-acting cabotegravir and rilpivirine as a potential HIV treatment regimen is part of ViiV Healthcare's broader development programme evaluating two-drug treatment regimens and we look forward to seeing results from the ATLAS and FLAIR studies in 2018." At 1545 GMT, Glaxo shares were flat at 1,523p.