RecruitingPhase 3Drug trialA Study to Compare the Efficacy, Safety and Tolerability of FF/UMEC/VI With FF/VI in 12-17-year-olds With AsthmaThe primary purpose of this study is to evaluate the effects of Fluticasone Furoate (FF)/ Umeclidinium (UMEC)/ Vilanterol (VI) on lung function compared with FF/VI after 24 weeks of treatment.