e11510 Background: To determine the response, tolerability, and long-term outcome of a neoadjuvant platinum-containing regimen for locally advanced breast cancer (LABC). To search for correlation between pathologic complete response (pCR) and predefined biomarkers in this cohort. Patients and Methods: Patients with LABC received eight cycles of either sequence A or B. Sequence A was doxorubicin 60 mg/m2 and paclitaxel 175 mg/m2 (AT) q3w X 4 followed by cisplatin (C) 60 mg/m2 and paclitaxel 90 mg/m2 (CT) q2w X 4. Sequence B was CT x 4 followed by AT x 4. In addition to estrogen receptor and HER2, immunohistochemistry (IHC) for MDR-1, MRP-1, topoisomerase IIα(topoIIα) and p53 was performed. Results: 88 patients were evaluable for response and toxicity. Median follow-up was 97 months. The overall pCR rate was 21.5%. For subgroups ER+/HER2-, HER2 +, and double negative (ER-/ HER2-) disease the pCR was 5.9%,23.3% and 35% respectively, p=0.006. Five year(y) overall survival for the entire cohort was 71.1%. Five y overall survival was 88.1% (CI 77.1%, 99.1%) for the ER positive HER2 negative group compared to 68.5% (CI 51.3%, 85.7%) and 49.5 (CI 27.4%, 71.6%) in the HER2 positive and “double negative” group respectively (p=0.0077). Over-expression of topo IIα was correlated with pCR (p<0.001). There were no toxic deaths. Conclusions: A platinum-containing neoadjuvant regimen was well tolerated and achieved a pCR rate which compares favorably to other recent studies of multi-agent chemotherapy. Further studies tailored for specific breast cancer subtypes are required. No significant financial relationships to disclose.