Safety and efficacy of first-line bevacizumab (B) plus chemotherapy (CT) for locally recurrent or metastatic breast cancer (LR/mBC): Analysis of MO19391 according to CT

1033 Background: Combination of B with first-line paclitaxel (TP) or docetaxel (TD) significantly improves PFS vs taxane alone in pts with LR/mBC. The open-label, multicenter MO19391 trial further assessed safety and efficacy of first-line B plus a taxane in >2,000 pts in routine clinical practice. Methods: Eligible pts had HER2- negative LR/mBC (or HER2-positive LR/mBC progressing after trastuzumab-containing therapy), ECOG PS 0–2, no prior CT for LR/mBC and no evidence of CNS metastases. Pts received B 10mg/kg q2w or 15mg/kg q3w plus the physician's choice of taxane (TP or TD alone or with another CT) or other non-anthracycline CT according to physician's standard of care. Treatment was continued until disease progression, unacceptable toxicity, or refusal. The primary endpoint was safety (NCI CTCAE v3.0); secondary endpoints included TTP, OS, and safety in pts developing CNS metastases. Results: From Sept 2006 to June 2008, 2,027 pts from 37 countries were enrolled. Median follow-up is 7.4 months. CT included a taxane (alone or with CT) in ∼75% of pts. Non-taxane agents included capecitabine (X) and vinorelbine (V). In the overall population, median age was 54 years (range 21–93), 70% were ER and/or PgR positive, and 32% had disease-free interval (DFI) ≤24 months. Baseline characteristics were broadly similar across subgroups. However, the X monotherapy subgroup included fewer pts with >3 metastatic lesions and more with a DFI ≤24 months and/or triple-negative disease compared with other subgroups. Safety and efficacy results grouped by CT are shown below. OS data are still immature (85% of pts alive at this analysis). Conclusions: In this large phase IV study, safety and efficacy of B plus TP or TD was similar to results of E2100 and AVADO. Variations in toxicities were consistent with the known profiles of each CT and no new safety signals for B were observed. The lowest incidences of serious Aes were seen with B plus TP or X. TTP was shorter with X and non-taxane combinations. Such findings are potentially attributable to small pt numbers and differences in baseline characteristics. These results show that B can be safely and effectively combined with a wide range of commonly used CT regimens as first-line therapy for mBC. [Table: see text] [Table: see text]