ACORN: An observational study of bevacizumab in combination with first-line chemotherapy for treatment of metastatic colorectal cancer in the UK

ABSTRACT Introduction Survival in metastatic colorectal cancer (mCRC) is worse than expected in the UK. 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 multicentre, prospective, UK-based, observational, phase 4 study (ClinicalTrials.gov: NCT01506167) that recruited patients with mCRC scheduled to receive bevacizumabin combination with first-line chemotherapy as part of routine clinical practice. Primary endpoints included progression-free survival (PFS), overall survival (OS), serious adverse events (AEs), and grade 3–5 bevacizumab-related AEs. Results 714 patients were recruited between 30 August 2012 and 4 February 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 geographical location in the UK. Median PFS (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(13.9%) patients received post-progression bevacizumab. The safety profile of bevacizumabwas consistent with previous studies. Conclusions ACORNprovided evidence that there were no clear differences observed in outcomes between bevacizumabwith capecitabine-based chemotherapy and fluorouracil-based regimens and confirmed the safety profile of bevacizumabin a real-world, UK-based population. The lower than expected OS is likely due to the short total chemotherapy duration, less frequent use of bevacizumabbeyond disease progression, and higher rates of in situ primary tumours.