Abstract S1 01: The association between event free survival and pathological complete response to neoadjuvant lapatinib, trastuzumab or their combination in HER2 positive …

Background: The NeoALTTO study demonstrated a significantly higher breast pathological complete response (pCR) rate (NSABP definition – ypT0/is) with dual HER2 blockade using lapatinib and trastuzumab compared with single HER2 blockade using either lapatinib or trastuzumab (51.3% vs. 24.7% vs. 29.5%, respectively; p< 0.01 for both) in HER2 positive primary breast cancer (BC). A similar pattern was seen for locoregional pCR (ypT0/is ypN0) (Baselga J et al. Lancet 2012).Material and Methods: From January, 2008, to December, 2009, 455 patients were randomized from 99 participating sites in 23 countries. Patients were randomized to receive either lapatinib 1500 mg/d (154 pts), or trastuzumab 4 mg/kg IV loading dose followed by 2 mg/kg IV weekly (149 pts), or lapatinib 1000 mg/d with trastuzumab for a total of 6 weeks (152 pts). After this biological window, patients continued on the same targeted …