High pathologic complete response (pCR) in HER2-positive breast cancer to novel nonanthracycline neoadjuvant chemotherapy.

Abstract

625 Background: The addition of trastuzumab to preoperative chemotherapy for HER2-positive breast cancers has been shown to increase pCR rates. The purpose of this study was to evaluate the efficacy of trastuzumab in combination with dose-dense nab-paclitaxel followed by weekly vinorelbine. Methods: Patients with stage I (> 1.0 cm), II, or IIIA HER2-positive (by standard definitions) breast cancer received nab-paclitaxel 260 mg/m2 iv every 2 weeks for 4 cycles followed by vinorelbine 25 mg/m2 iv weekly with trastuzumab given weekly throughout chemotherapy (4 mg/kg loading dose then 2 mg/kg weekly) for 20 weeks. Tissue was collected at baseline, at optional midway biopsy, and post-therapy. Primary endpoint was pCR rate; secondary endpoints included response rate and toxicity. Cardiac evaluation was performed at baseline, after 4 cycles of nab-paclitaxel, after 12 weeks of vinorelbine and every 3 months thereafter. Results: To date, 21 of 50 planned patients have been accrued (3/2008 to 12/2009). 11 patient...