Background: Bevacizumab significantly improves survival when added to chemotherapy for metastatic colorectal cancer (mCRC). The Bevacizumab Expanded Access Trial (BEAT) evaluated the safety and efficacy of bevacizumab plus first-line chemotherapy in a general cohort of patients with mCRC. Patients and methods: Patients with unresectable mCRC received chemotherapy (physician's choice) plus bevacizumab [5 mg/kg every 2 weeks (5-fluorouracil regimens) or 7.5 mg/kg every 3 weeks (capecitabine regimens)]. The primary end point was safety, including prospective data collection in patients receiving unanticipated surgery during the study. Secondary objectives were progression-free survival (PFS) and overall survival (OS). Results: The final analysis comprised 1914 assessable patients (male 58%; median age 59 years). Chemotherapy included 5-fluorouracil/leucovorin (5-FU/LV) + oxaliplatin (29%), irinotecan plus 5-FU/LV (26%), capecitabine plus oxaliplatin (18%) and monotherapy (16%). Serious/grade 3–5 adverse events of interest for bevacizumab included bleeding (3%), gastrointestinal perforation (2%), arterial thromboembolism (1%), hypertension (5.3%), proteinuria (1%) and wound-healing complications (1%). Sixty-day mortality was 3%. Median PFS was 10.8 months [95% confidence interval (CI) 10.4–11.3 months] and median OS reached 22.7 months (95% CI 21.7–23.8 months). Conclusions: The BEAT study shows that the efficacy and safety profile of bevacizumab in routine clinical practice is consistent with results observed in prospective randomised clinical trials and another large observational study in the United States (BRiTE study).

Background: It has been reported that KRAS mutations (and to a lesser extent KRAS mutations with the BRAF V600E mutation) negatively affect response to anti-epidermal growth factor receptor (EGFR) mAbs in metastatic colorectal cancer (mCRC) patients, while the biological impact of the EGFR pathway represented by PI3K/PTEN/AKT on anti-EGFR treatment is still not clear. Patients and methods: We analysed formalin-fixed samples from a cohort of 32 mCRC patients treated with cetuximab by means of EGFR immunohistochemistry, EGFR and PTEN FISH analysis, and KRAS, BRAF, PI3KCA, and PTEN genomic sequencing. Results: Ten (31%) of 32 patients showed a partial response to cetuximab and 22 (69%) did not [nonresponder (NR)]. EGFR immunophenotype and FISH-based gene status did not predict an anti-EGFR mAb response, whereas KRAS mutations (24%) and PI3K pathway activation, by means of PI3KCA mutations (13%) or PTEN mutation (10%)/loss (13%), were significantly restricted to, respectively, 41% and 37% of NRs. Conclusion: These findings suggested that KRAS mutations and PI3KCA/PTEN deregulation significantly correlate with resistance to cetuximab. In line with this, patients carrying KRAS mutations or with activated PI3K profiles can benefit from targeted treatments only by switching off molecules belonging to the downstream signalling of activated EGFR, such as mammalian target of rapamycin.