This is a Phase 2, open-label, single-arm study evaluating the combination of tucatinib with Doxil in participants with HER2+ breast cancer who have received at least one prior line of anti-HER2 therapy for locally advanced/metastatic disease or relapsed within 6 months of completion of anti-HER2 adjuvant therapy.~This study will start with a lead-in phase wherein the first 6 patients will be evaluated weekly for one treatment cycle (28 days) to ensure the regimen is safe and tolerable. If no severe and/or unexpected toxicities are observed in these initial patients, the study will continue to enroll a total of 36 patients.
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