A randomised phase 2 study of 3 weekly cabazitaxel vs weekly paclitaxel chemotherapy in the first-line treatment of HER2 negative metastatic breast cancer

TPS1122Background: Breast cancer (BC) represents 25% of all cancers in women. Whilst the majority have early stage disease approximately 30% will develop metastatic breast cancer (MBC). In HER2 negative MBC, palliative chemotherapy is one of the main treatment options. It remains to be seen whether the use of adjuvant taxane chemotherapy leads to an increase in taxane resistance at the onset of MBC, although for patients with a relatively short disease free interval this may be the case. Cabazitaxel (CBZ) is a novel taxoid selected for development from preclinical evidence in cell lines resistant to docetaxel and paclitaxel including activity in a HER-2 positive BC tumour xenograft, with innate resistance to docetaxel. Clinically CBZ is licensed for metastatic castration-resistant prostate cancer following progression during or after docetaxel chemotherapy. A phase 3 RCT in this patient group showed a 3 month overall survival benefit for patients receiving CBZ and prednisolone compared with mitoxantrone a...