Preliminary data from a phase II study of cetuximab with irinotecan in heavily pretreated patients with epidermal growth factor (EGFR)-expressing metastatic colorectal cancer (mCRC): LABEL

Abstract

14521 Background: Cetuximab (Erbitux) is a monoclonal antibody directed against EGFR that is active in combination with irinotecan in patients (pts) with mCRC, who have progressed during or after a prior irinotecan therapy. Methods: This open, single-arm phase II Latin American study investigated this combination in pts with EGFR-expressing mCRC progressing on or within 3 months of chemotherapy containing at least 6 weeks (w) of irinotecan-based therapy. The primary objective was to assess the best overall confirmed response rate (RR). Sample size calculations were based on an expected rate of 20% (±8%). Planned enrollment was 100 pts. Secondary objectives were to explore the duration of response (DOR), progression-free survival (PFS) time, the 12-week PFS rate, and overall survival time. Pts were treated with cetuximab (initial dose 400 mg/m2 then 250 mg/m2 weekly), plus irinotecan at the same dose and schedule (including dose reductions) as pre-study. Preliminary Results: Of 151 pts from 14 centers screened and in the database, 106 (70%, 3 pts missing) were EGFR-expressing and, of these, 79/106 (75%) were treated on-study. Forty (51%) were male; median age was 59 years [27–82]; 70 (89%) pts had a Karnofsky performance status = 90 and 9 (11%) pts = 80. Nineteen (24%) pts had received = 3 prior treatment regimens, 42 (53%) were previously treated with an oxaliplatin-based regimen for metastatic disease. The confirmed overall RR was 26.6% [17.3–37.7]. Median DOR was 23.9 w [17.1–30], median PFS time was 17.7 w [11.7–18.9], and the 12-week PFS rate was 58% [47–69]. Thirty-three (42%) pts were alive at data cut-off. Median survival was 9.7 months [7.9–13.1]. Treatment was well tolerated with the most common grade 3/4 adverse events including: diarrhea, 20%; neutropenia,10%; acne-like rash, 9%. No grade 3/4 infusion-related reactions were reported. Conclusions: The overall confirmed RRs observed in this heavily pretreated population fully met the expectations for the primary endpoint of this study. LABEL confirmed in a Latin American setting the activity and safety of cetuximab plus irinotecan seen in previous studies. No significant financial relationships to disclose.