Does the sequence of anthracycline and taxane matter? The NeoSAMBA trial.

Abstract

575 Background: Taxanes usually follow anthracyclines in breast cancer neo/adjuvant treatment, likely due to its later introduction in clinical practice. However, there is no biological rationale that justifies this current standard-of-care. We compared an anthracycline-based regimen followed by a taxane (FAC-T) neoadjuvant chemotherapy with the reverse sequence (T-FAC) (NCT01270373). Methods: In this randomized, open-label, single center phase 2 trial, women with locally advanced (LABC) HER2 negative breast cancer, stratified by hormone receptor, were randomized to 3 cycles of fluorouracil, doxorubicin and cyclophosphamide followed by 3 cycles of docetaxel vs. docetaxel followed by fluorouracil, doxorubicin and cyclophosphamide. Surgery, radiotherapy and adjuvant hormonal therapy were given as per local guidelines. The primary endpoint was pathological complete response (pCR) and secondary endpoints included disease-free (DFS) and overall survival (OS). The expected baseline pCR was 15%. With 53 patients per arm, we had a 90% probability of selecting a schedule that had a true benefit of 25%. A 10% drop-out was anticipated. Results: Between September 2010 and November 2012, we randomly allocated 118 patients: 60 received FAC-T and 58 T-FAC. The median follow-up was 53.8 months (95% CI 51.9- 55.7). The median age was 50 years. Ninety-four patients (70.7%) had stage III tumors and 31 (26.3%) had triple negative disease. pCR was higher in triple negative patients: 21.4% vs 1.2%. Treatment sequence did not improve pCR of all patients operated (114): 3 (5.2%) and 4 (7.3%) in the FAC-T and T-FAC arms, respectively. Taxane-first when compared to anthracycline-first sequencing showed a 5y DFS of 78% and 45% (HR 0.31, 95% CI 0.16–0.59) and a 5y OS of 88% and 65% (HR 0.28, 95% CI 0.12–0.66), respectively. The relative dose intensity was similar between both arms. No unexpected toxicity was reported. Conclusions: We showed for the first time an improvement in DFS and OS with taxane-first when compared to anthracycline-first sequencing chemotherapy in HER2 negative LABC. Tumor and blood samples were collected for translational analyses at three time points. Clinical trial information: NCT01270373.