Combination of Weekly Paclitaxel With Neratinib and Trastuzumab in Women With Metastatic HER2-positive Breast Cancer

Patients will receive concurrent therapy with paclitaxel (80 mg/m2 IV on days 1, 8, and 15 of a 28-day cycle), trastuzumab (4 mg/kg IV loading dose, then 2 mg/kg IV weekly), and neratinib. The neratinib dose-escalation will include 4 dose levels (120 mg, 160 mg, 200 mg, and 240 mg) as a daily oral dose. The neratinib dose-escalation for the study will proceed on the basis of dose-limiting toxicity (DLT) during cycle 1. DLT will be defined as the occurrence of 1 or more of the following events during cycle 1: any grade diarrhea that is associated with fever or dehydration; grade 3 diarrhea lasting more than 2 days on optimal medical therapy; grade 4 diarrhea of any duration; grade 3 or 4 neutropenia associated with fever; grade 4 neutropenia lasting more than 7 days; grade 4 thrombocytopenia; grade 3 or 4 non-hematological toxicity; or any toxicity-related delay of more than 2 weeks to initiate cycle 2. Patients will be enrolled at the next dose level when all evaluable patients at the same dose level have completed the first treatment cycle. Enrolled patients will remain on the assigned dose level treatment until toxicity or disease progression.