Phase I Study of Ixabepilone Plus Lapatinib With or Without Capecitabine in the Treatment of Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer

Lapatinib, 1000 mg, administered orally, once a day, every day, for 7 to 14 consecutive days as a lead-in period prior to the first administration of ixabepilone (Day 1). Following the lapatinib lead-in phase of Cycle 1, and on Day 1 of subsequent cycles, ixabepilone, 32 mg/m\^2, administered as a 3-hour IV infusion. Lapatinib, 1000 mg, administered orally, once a day, every day, for a 21-day cycle.

Initiated a minimum of 14 days following Day 1 of previous cohort (ixabepilone, 32 mg/m\^2 + lapatinib, 1000 mg). Lapatinib, 1250 mg, administered orally once a day, every day, for 7 to 14 consecutive days as a lead-in period prior to the first administration of ixabepilone. Following the lapatinib lead-in phase of Cycle 1, and on Day 1 of subsequent cycles, ixabepilone, 32 mg/m\^2, administered as a 3-hour IV infusion. Lapatinib administered, 1250 mg, orally, once a day, every day, for a 21-day cycle.

Initiated a minimum of 14 days following Day 1 of previous cohort (ixabepilone, 32 mg/m\^2 + lapatinib, 1250 mg). Lapatinib, 1250 mg, administered orally once a day, every day, for 7 to 14 consecutive days as a lead-in period prior to the first administration of ixabepilone. Following the lapatinib lead-in phase of Cycle 1, and on Day 1 of subsequent cycles, ixabepilone, 40 mg/m\^2, administered as a 3-hour IV infusion. Lapatinib, 1250 mg, administered orally, once a day, every day, for a 21-day cycle.

Planned escalating doses of the triplet combination of ixabepilone, lapatinib, and capecitabine. No participants were enrolled in this arm due to premature termination of the study.