In a bid to advance the development of an all-oral, interferon-free treatment regimen for hepatitis C virus (HCV) infection, Vertex Pharmaceuticals has formed non-exclusive agreements with GlaxoSmithKline (GSK) and Janssen Pharmaceuticals to conduct separate Phase II proof-of-concept studies of its nucleotide analogue HCV polymerase inhibitor VX-135 in combination with GSK’s NS5A inhibitor GSK2336805 and with Janssen’s protease inhibitor simeprevir (TMC435), which is being developed with Medivir. Vertex licensed VX-135 from Alios BioPharma in June 2011.