ATLANTIS: An adaptive multi-arm phase II trial of maintenance targeted therapy after chemotherapy in patients with metastatic urothelial cancer

Background Metastatic urothelial cancer (UC) is the eighth most common cause of cancer death in the UK. Standard first-line treatment, for most patients, is cytotoxic chemotherapy. Although UC is initially sensitive to chemotherapy, relapse is almost inevitable after which outcomes are poor, with median overall survival 8 months. There is, therefore, an urgent need for novel therapies to improve outcomes for this patient group.Methods ATLANTIS is a randomised phase II, adaptive design trial of maintenance therapy in biomarker defined subgroups of patients with advanced UC. The primary end-point is progression-free survival (PFS) and the study involves over 30 UK cancer centres. Discussion ATLANTIS is the first study in the UK to employ a precision medicine approach to UC patients for maintenance treatment. Agents with positive efficacy signal will proceed to randomised phase III trials to confirm activity of novel biologically stratified therapies in UC.