Bevacizumab (BEV) plus capecitabine as maintenance therapy after initial treatment with BEV plus XELOX in previously untreated patients (pts) with metastatic colorectal cancer (mCRC): Mature data from STOP and GO, a phase III, randomized, multicenter study.

Abstract

3565 Background: Colorectal cancer is one of the most frequent malignancies, second after breast cancer in women and third after lung cancer and prostate cancer in men. The aim of this study was to evaluate and compare the progression-free survival (PFS) between two arms: Arm A is a combination of BEV + XELOX; Arm B is a combination of BEV + XELOX for 6 cycles followed by maintenance BEV + capecitabine as first-line therapy in mCRC. Methods: BEV (7.5 mg/kg) + XELOX (capecitabine 1000 mg/m2 bid d1–14 + oxaliplatin 130 mg/m2 d1 q3w) were administered until progression (Arm A) or 6 cycles of BEV + XELOX followed by BEV + capecitabine were administered until progression (Arm B). PFS was the primary endpoint; secondary endpoints included overall survival (OS), objective response rate (ORR), and safety. A sample size of 118 pts was required to detect with 80% power an increase of 1.5 months in median PFS between two arms with a standard deviation of 3.9 months and significance level of 0.05 (10% drop-out rate). Results: A total of 123 pts were randomized. Demographic characteristics were balanced between the arms. Median treatment period was 7.5 (range 0.5–13.9) and 8.1 (range 0.1–20.7) months in Arms A and B, respectively. There was a statistically significant difference in median PFS between arms, although there was no significant difference in ORR and OS (see table). Tolerability was acceptable in both arms with the following grade 3/4 adverse events (AEs): Arm A 48.4%; Arm B 34.4% (p=0.116). Grade 3/4 diarrhoea occurred in 9.7% vs. 3.3%, weakness in 8.1% vs. 8.2%, hand-foot syndrome in 3.2% vs. 1.6%, and neuropathy in 4.8% vs. 3.3% of pts in Arms A and B, respectively. Conclusions: These findings suggest that maintenance therapy with BEV + capecitabine following induction with 6 cycles of BEV + XELOX may be superior to continuous BEV + XELOX until progression inpts with previously untreated mCRC. [Table: see text]