Does the Sequence of Anthracycline and Taxane Matter? The NeoSAMBA Trial

Abstract

BACKGROUND Taxanes usually follow anthracyclines in breast cancer neo/adjuvant treatment, likely because of their later introduction into clinical practice. However, there is no biological rationale that justifies this current standard of care. We compared a taxane followed by an anthracycline-based regimen with the reverse sequence in the neoadjuvant setting. PATIENTS AND METHODS In a randomized, open-label, single-center phase II trial, women with inoperable, locally advanced, HER2-negative breast cancer were stratified by hormone receptor status and randomized to three cycles of docetaxel (T) followed by three cycles of fluorouracil, doxorubicin, and cyclophosphamide (FAC) versus three cycles of FAC followed by three cycles of docetaxel. Surgery, radiotherapy, and adjuvant hormonal therapy were administered as per local guidelines. The primary endpoint was pathological complete response (pCR), and secondary endpoints included toxicity, event-free survival (EFS), and overall survival (OS). RESULTS Treatment sequence did not improve pCR, which was 7% with T-FAC and 3% with FAC-T. However, after a median follow-up of 79 months, the 5-year EFS rate was 75.7% (95% confidence interval [CI], 65.4%-87.7%) with T-FAC and 48.2% (95% CI, 37.0%-62.7%) with FAC-T (hazard ratio [HR], 0.46; 95% CI, 0.26-0.81; log-rank p = .0054), and the 5-year OS rate was 89.7% (95% CI, 82.2%-97.8%) with T-FAC and 64.7% (95% CI, 53.6%-78.1%) with FAC-T (HR, 0.41; 95% CI, 0.22-0.78; p = .0052). There were no unexpected toxicities. CONCLUSION We showed for the first time an improvement in EFS and OS with taxane-first compared with anthracycline-first sequencing chemotherapy in HER2-negative, locally advanced breast cancer. Confirmation of these results may have implications for clinical practice. This trial was registered with Clinicatrials.gov identifier NCT01270373. IMPLICATIONS FOR PRACTICE The NeoSAMBA trial showed a benefit for taxane-first sequencing chemotherapy consistent with the systematic review of the literature as well as the larger Neo-tAnGo study. Many recent and current ongoing clinical trials have already followed this treatment strategy. As a taxane-before-anthracycline sequence carries neither an incremental cost nor an increased toxicity, and given the available literature on this issue, reinforced taxane-first regimen can be easily incorporated into daily clinical practice while we wait for confirmation of these findings from larger trials.