ACORN: Observational Study of Bevacizumab in Combination With First-Line Chemotherapy for Treatment of Metastatic Colorectal Cancer in the UK.

INTRODUCTION

Survival in metastatic colorectal cancer is worse than expected in the United Kingdom. Real-world data are needed to better understand UK-specific treatment practices that may explain this.

PATIENTS AND METHODS

The Avastin ColORectal Non-interventional (ACORN) study is a multicenter, prospective, UK-based, observational, phase 4 study (ClinicalTrials.gov, NCT01506167) that recruited patients with metastatic colorectal cancer scheduled to receive bevacizumab in combination with first-line chemotherapy as part of routine clinical practice. Primary end points included progression-free survival, overall survival (OS), serious adverse events (AEs), and grade 3 to 5 bevacizumab-related AEs.

RESULTS

A total of 714 patients were recruited between August 30, 2012, and February 4, 2014. Median follow-up was 16.4 months. Median first-line chemotherapy duration was 5.6 months, with capecitabine/oxaliplatin (265 [37.1%]) being the most common regimen. Median total chemotherapy duration was 8.1 months and did not vary by geographic location in the UK. Median progression-free survival (95% confidence interval) was 8.7 (8.2-9.1) months, and median OS was 17.8 (16.1-19.3) months. There was no significant difference in efficacy by chemotherapy regimen administered. Ninety-nine patients (13.9%) received bevacizumab after disease progression. The safety profile of bevacizumab was consistent with previous studies.

CONCLUSION

ACORN provided evidence that there were no clear differences observed in outcomes between bevacizumab with capecitabine-based chemotherapy and fluorouracil-based regimens, and confirmed the safety profile of bevacizumab in a real-world UK-based population. The lower-than-expected OS is likely due to the short total chemotherapy duration, less frequent use of bevacizumab after disease progression, and higher rates of in-situ primary tumors.