Safety and efficacy of first-line XELIRI with or without bevacizumab in patients with metastatic colorectal cancer: Analysis of two phase II studies.

560 Background: The safety and efficacy of first-line XELIRI (capecitabine in combination with irinotecan) and XELIRI plus bevacizumab (BEV) have been evaluated in patients with metastatic colorectal cancer (mCRC). To date, however, no randomized studies comparing these regimens have been performed. This retrospective analysis compared efficacy and safety data for the two regimens from separate phase II studies performed at a single institution. Methods: Patients with histologically documented metastatic or recurrent CRC and no prior treatment for advanced disease received irinotecan 175 mg/m 2 on day 1 and oral capecitabine 1,000 mg/m 2 twice daily on days 2-8 every 2 weeks (XELIRI study). For patients age ≥65 years, the starting doses of irinotecan and capecitabine were reduced to 140 mg/m 2 and 750 mg/m 2 , respectively. In the second study, patients received the same regimen plus BEV 5 mg/kg on day 1 (XELIRI + BEV study). Results: A total of 53 and 46 patients were entered into the XELIRI and XELIRI + BEV studies, respectively. Patient characteristics were generally similar in both groups. Efficacy results for the ITT populations are summarized in the Table. Patients treated with XELIRI + BEV had a significantly higher ORR and longer median TTP vs. XELIRI alone and a numerically longer median OS was observed (p=NS). The overall incidence of adverse events (all grades or grade 3/4) was similar in the two groups, although alopecia, mucositis, hand–foot syndrome, and haemorrhage were more common with XELIRI + BEV vs. XELIRI alone (all p<0.05). Conclusions: In this retrospective comparison of two studies, the addition of BEV to XELIRI appeared to improve outcome relative to XELIRI alone in the first-line treatment of patients with mCRC. The overall incidence of adverse events was similar in the two groups. [Table: see text] No significant financial relationships to disclose.