Randomized, open-label, phase II study comparing the efficacy and the safety of cabazitaxel versus weekly paclitaxel given as neoadjuvant treatment in patients with operable triple-negative or luminal b/HER2 normal breast cancer (GENEVIEVE).

Abstract

TPS1138 Background: Cabazitaxel is a new taxoid promoting the tubulin assembly in vitro and stabilizing microtubules against cold-induced depolymerization as efficiently as docetaxel. It has shown superior survival against mitoxantrone plus prednisone in docetaxel pre-treated hormone refractory metastatic prostate cancer pts leading to its registration. It showed a favorable toxicity profile with a low rate of alopecia. In the GENEVIEVE study it will be compared to weekly paclitaxel, which is currently most widely used in breast cancer (BC) pts. Methods: This is a prospective multicenter, randomized, open label study investigating efficacy and safety of cabazitaxel. Pts with uni- or bilateral primary BC (stage cT3/T2/T1c and cN+/T1c and pNSLN+), tumor lesion ≥ 2cm (palpation) or ≥ 1cm (sonography) and centrally confirmed TNBC or luminal B/HER2- can be included. Pts will be randomized to four q3w cabazitaxel (25mg/m² i.v.) vs. 12 q1w paclitaxel (80mg/m² i.v.). Randomization will be stratified by nodal status and subtype. Treatment will be given until surgery, disease progression, unacceptable toxicity or withdrawal of consent. The primary objective is pathologic complete response (pCR) (ypT0/is ypN0/+). Secondary objectives are pCR in stratified subgroups and by other definitions, objective response rate, pCR and local recurrence free survival in pts with clinical complete response and neg. core biopsy before surgery, breast conservation rate, toxicity, compliance, survival rates, biomarkers predicting response. Assuming 15% pCR in controls and targeting a smallest clinical improvement of 10% (i.e. pCR = 25% in experimental arm), a total of 326 pts (163/arm) are required for the one-sided proportion comparison test (α=0.1) with 80% power. The trial is registered under NCT01779479. Results: Recruitment is planned for 12 mths in 45 (+10 back-up) sites in Germany. 1st pt in is planned for Feb 2013. Conclusion: GENEVIEVE will rapidly and precisely compare efficacy and tolerability of cabacitaxel vs. paclitaxel to decide if further development in BC is reasonable. Clinical trial information: NCT01779479.