SAKK 24/09: safety and tolerability of bevacizumab plus paclitaxel vs. bevacizumab plus metronomic cyclophosphamide and capecitabine as first-line therapy in patients with HER2-negative advanced stage breast cancer - a multicenter, randomized phase III trial

Abstract

Background: Adding bevacizumab to chemotherapy improves response rates and progression-free survival (PFS) in metastatic breast cancer (mBC). We aimed to demonstrate decreased toxicity with metronomic chemotherapy/bevacizumab compared with paclitaxel/bevacizumab.

Methods: This multicenter, randomized phase III trial compared bevacizumab with either paclitaxel (arm A) or daily oral capecitabine-cyclophosphamide (arm B) as first-line treatment in patients with HER2-negative advanced breast cancer. The primary endpoint was the incidence of selected grade 3-5 adverse events (AE) including: febrile neutropenia, infection, sensory/motor neuropathy, and mucositis. Secondary endpoints included objective response rate, disease control rate, PFS, overall survival (OS), quality of life (QoL), and pharmacoeconomics. The study was registered prospectively with ClinicalTrials.gov, number NCT01131195 on May 25, 2010.

Results: Between September 2010 and December 2012, 147 patients were included at 22 centers. The incidence of primary endpoint-defining AEs was similar in arm A (25 % [18/71]; 95 % CI 15-35 %) and arm B (24 % [16/68]; 95 % CI 13-34 %; P = 0.96). Objective response rates were 58 % (42/73; 95 % CI 0.46-0.69) and 50 % (37/74; 95 % CI 0.39-0.61) in arms A and B, respectively (P = 0.45). Median PFS was 10.3 months (95 % CI 8.7-11.3) in arm A and 8.5 months (95 % CI 6.5-11.9) in arm B (P = 0.90). Other secondary efficacy endpoints were not significantly different between study arms. The only statistically significant differences in QoL were less hair loss and less numbness in arm B. Treatment costs between the two arms were equivalent.

Conclusion: This trial failed to meet its primary endpoint of a reduced rate of prespecified grade 3-5 AEs with metronomic bevacizumab, cyclophosphamide and capecitabine.

Keywords: Bevacizumab; Breast cancer; Metronomic chemotherapy; Toxicity.

Fig. 1

CONSORT diagram. The flow diagram shows the intention-to-treat population of 147 patients included in the primary analysis of bevacizumab plus paclitaxel (arm A) compared with bevacizumab plus metronomic chemotherapy (arm B). Bev=bevacizumab; PD=progressive disease

Fig. 2

Progression free survival according to treatment arm. The continuous line indicates the standard arm (a), the dashed line the experimental arm (b)

Fig. 3

Physical well-being, hair loss, numbness, treatment burden, mood and coping effort. Data are means with 95 % CIs from baseline over 12 treatment cycles with the number of patients for each cycle. Higher scores indicate better condition. The continuous lines indicate the standard arm (a), the dashed lines the experimental arm (b)