Randomized phase III study of irinotecan and 5-FU/FA with or without cetuximab in the first-line treatment of patients with metastatic colorectal cancer (mCRC): The CRYSTAL trial

Abstract

4000 Background: Cetuximab in combination with irinotecan-based regimens has proven activity in previously-treated patients (pts) with mCRC. The present trial investigated the effectiveness of cetuximab in combination with standard FOLFIRI compared with FOLFIRI alone in the first-line treatment of pts with epidermal growth factor receptor (EGFR)-expressing mCRC. Methods: Pts were randomized 1:1 to receive either cetuximab (400 mg/m2 initial dose then 250 mg/m2/week [w]) plus FOLFIRI q 2 w (irinotecan 180 mg/m2, FA 400 mg/m2, 5-FU bolus 400 mg/m2, 5-FU infusion 2,400 mg/m2 over 46 hours) (Group A) or FOLFIRI alone (Group B). The primary endpoint was progression-free survival (PFS), with secondary endpoints of overall survival (OS), response rate (RR), disease control rate and safety. 633 events were required to statistically differentiate PFS between groups with 80% power. Results: Between August 2004 and October 2005, 1,217 pts were randomized, 608 to Group A and 609 to Group B (60% male, median age 61 [19–84], ECOG performance status: 0=54%; 1=43.5%; 2=3.5%). Median PFS was significantly longer for Group A compared to Group B (8,9 months [8 - 9,5] for Group A vs. 8 months [7.6 - 9] for Group B, p=0.036). Response Rate was also significantly increased by cetuximab (46.9% vs. 38.7%, p=0.005). Treatment was generally well tolerated with neutropenia (26.7% Group A, 23.3% Group B), diarrhea (15.2% and 10.5% respectively) and skin reactions (18.7% and 0.2% respectively) being the most common grade 3/4 adverse events. Conclusions: Cetuximab in combination with FOLFIRI significantly increases response rate and significantly prolongs PFS in the first-line treatment of pts with mCRC, reducing the relative risk of progression by approximately 15%. Treatment-related side effects of cetuximab in combination with FOLFIRI were as expected, with diarrhea being moderately and skin reactions significantly more frequent as compared to FOLFIRI alone. [Table: see text]