1. Capecitabine for metastatic disease at any time, for patients assigned to cohorts using capecitabine plus ONT-380 (Combination 1) or capecitabine plus trastuzumab plus ONT-380 (Combination 3). However, patients who have previous treatment with capecitabine for metastatic disease are eligible for enrollment into cohorts using trastuzumab plus ONT-380 (Combination 2). Patients who have received capecitabine for adjuvant or neoadjuvant treatment at least 12 months prior to starting study treatment are eligible to enroll into all cohorts (Combination 1, 2, or 3).