Abstract Abstract #5118 Background: The role of trastuzumab either concurrent or sequential with adjuvant chemotherapy have clearly demonstrated significant benefits in early stage HER-2 positive breast cancer. There is now an accumulation of phase II and III trials also demonstrating improved pathological complete responses (pCR) in HER-2 positive breast cancer with neoadjuvant trastuzumab concurrent with chemotherapy. The number of patients on these trials are significantly fewer, and many of these trials are a mixture of primary operable and LABC. We have completed a multi-centre phase II trial of neoadjuvant chemotherapy and trastuzumab in HER-2 positive LABC.
 Methods: Women with HER-2 positive (IHC 3+ or FISH+) stage IIB-IIIC breast cancer were enrolled. Treatment consisted of 4 cycles of FEC100 (5-FU 500 mg/m2, epirubicin 100 mg/m2, cyclophosphamide 500 mg/m2) followed by 4 cycles of TCH (Docetaxel 75 mg/m2, carboplatin AUC 6, trastuzumab 8 mg/kg loading then 6 mg/kg q3 weekly). Trastuzumab was also continued adjuvantly for 9 months following chemotherapy and surgery. Cardiac monitoring every 3 months was mandated. A correlative translational component with baseline and interval biopsies and serum collection was also performed.
 Results: A total of 30 patients (3 stage IIB; 14 IIIA; 10 IIIB and 3 IIIC) over a 3 year time period in 4 centres were accrued. Median age was 49 years (26-77 years). 60% of tumours were ER negative. There was one clinical CHF and 2 asymptomatic falls in LVEF requiring early discontinuation of trastuzumab. There were 3 episodes (10%) of febrile neutropenia. Seven patients underwent adjuvant radiotherapy prior to surgery. The pCR rate (breast and axilla) for the entire study population was 60% (18/30). There have been 3 recurrences so far (all biopsy proven) – of which 2 were brain metastases only. Further details on toxicity and changes in LVEF will be presented.
 Conclusions: This multi-centre phase II trial clearly demonstrates significant activity (pCR 60%) for neoadjuvant anthracyclines followed by concurrent taxane, platinum and trastuzumab in a HER-2 positive LABC population. Overall the treatment regimen was well tolerated. Brain metastases however appear to be a common site of relapse in this high risk patient population and further treatment strategies directed at this site should be investigated. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5118.