Background: Anthracycline- and taxane-based neoadjuvant chemotherapy (NAC) results in a pCR in 30-35% of TNBC patients (pts), which is associated with improved recurrence-free and overall survival (RFS/OS). Thus, pCR rates may be useful in evaluating novel regimens in TNBC. In advanced TNBC, platinum analogues like Cb are active and addition of B to chemotherapy increases response rates and time to progression. CALGB 40603 is a 2×2 randomized phase II study designed to determine if the addition of either Cb or B to standard NAC significantly increases pCR rates in TNBC. Methods: Pts had operable clinical stage II-III TNBC, defined as hormone receptors Results: 454 pts enrolled, median age 48, stage II 68%/stage III 32%. Of 354 pts with treatment data, 59 did not complete NAC, 30 withdrew due to AEs, more often with B vs. not (11.5% vs. 3.5%). B was discontinued in 23% of assigned pts vs. 6-13% for other agents. Grade 3-4 neutropenia (56% vs. 20%) and thrombocytopenia (22% vs. 4%) were more common with Cb vs. not, while grade 3 hypertension was more common with B vs. not (11% vs. There is no evidence of an interaction between the effects of Cb and B (p = 0.64 and 0.44, for breast and breast/axilla, respectively). Conclusions: Preliminary results suggest that adding Cb or B to standard NAC significantly increases pCR rates in stage II-III TNBC. These increases are additive, with pCR (breast) in 60.6% and pCR (breast/axilla) in 50% of pts who received both. Complete and confirmed results will be reported, including pCR rates for basal-like tumors vs. not. Pts will be followed for RFS/OS to assess the impact of pCR on these endpoints. Conduct of the trial was supported by grants from the NIH (ACTNOW and CA31946/CA33601), Genentech and the BCRF. Clinical trial information: NCT00861705. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S5-01.