Pathologic complete response (pCR) following weekly (wkly) paclitaxel (cremophor or albumin-bound) and carboplatin (TC) ± trastuzumab (H), ± bevacizumab (B) in patients (pts) with doxorubicin/cyclophosphamide-resistant (AC-Res) and AC-sensitive (AC-S) large and inflammatory breast cancer

591 Introduction: Historically, pCR is rare in AC-Res in contrast to AC-S BC except following TCH in HER2+ BC in preliminary analysis (SABCS-2004, #1110). Moreover, robust predictors of pCR are needed. Methods: 106 consecutive BC pts on neoadjuvant studies were treated with GM/G-CSF supported dose-dense AC (except 7**-Table), 2 cycles if AC-Res and 4 if AC-S. Pts then received 9–12 wkly TC (3 wks on, 1 off) ± 6–8 bi-wkly B if HER2- or +12–16 wkly H if HER2+, followed by surgery. Fisher’s exact test was performed to compare pCR percentages by various characteristics. Results: pCR in breast and lymph nodes in 38 of 84 assessable tumors in the first 82 pts were documented. 67% (56/84) tumors were reduced to ≤5 mm. Overall, no difference in pCR rates were found between AC-S and AC-Res BC, but pCR rates were 2- to 4-fold higher in HER2+, AC-S (79%) and AC-Res (65%) subsets compared to HER2-, AC-S (32%) and AC-Res (16%) subsets. Higher pCR rates were associated with HER2+/hormone receptor- (HR-) > HER2+/HR+, HE...