Study of Tucatinib and Doxil in Participants With Human Epidermal Growth Factor Receptor 2 Positive (HER2+) Metastatic Breast Cancer

Study Summary

This clinical trial is evaluating tucatinib in combination with Doxil in participants with human epidermal growth factor 2 positive (HER2+) locally advanced or metastatic breast cancer. The main goals of this study are to: * Learn how well the combination of tucatinib and Doxil works * Learn more about the side effects of the combination of tucatinib and Doxil