Dataset from A Phase 1, Multicenter, Open-label, Single Sequence Crossover Study to Evaluate Drug-drug Interaction Potential of OATP1B/CYP3A Inhibitor on the Pharmacokinetics of DS-8201a in Subjects With HER2-expressing Advanced Solid Malignant Tumors

HER2-positive cancer is a cancer that tests positive for a protein called human epidermal
growth factor receptor 2 (HER2). HER2 promotes the growth of certain cancer cells. This study
will test an experimental drug called DS-8201a that has not been approved by the health
authorities yet.

DS-8201a will be tested for safety in patients with advanced solid malignant tumors that test
positive for HER2. It also will test how DS-8201a moves within the body (pharmacokinetics).