Methods and analysis Study design, settings, sample size and recruitment strategy Trial CTN PT047, referred as the CIAO (‘CMV Inhibition with letermovir in ART-treated people living with HIV: an Open-label, randomized, controlled trial’) study is a multi-centre, open-label, randomised, controlled clinical trial to assess the influence of letermovir on gut translocation (LPS and BDG markers) in blood in ART-treated CMV-seropositive adult PLWH; protocol version # 2.1; 27 July 2022.