Efficacy and safety of cetuximab/irinotecan in chemotherapy-refractory metastatic colorectal adenocarcinomas: a clinical practice setting, multicenter experience

Abstract

Background: This study was designed to evaluate the efficacy and safety of irinotecan/cetuximab administered as third- or fourth-line therapy in a retrospective series of patients with metastatic colorectal cancer refractory to oxaliplatin and irinotecan.

Patients and methods: Most patients (90%) had been previously treated with adjuvant 5-fluorouracil/leucovorin, and all had received oxaliplatin-based regimens before receiving irinotecan-based second-line treatment. Sixty patients with irinotecan-refractory colorectal cancer received a regimen comprising weekly irinotecan 120 mg/m2 as a 1-hour intravenous infusion and cetuximab 400 mg/m2 infused over 2 hours as the initial dose and 250 mg/m2 infused over 1 hour for the subsequent administrations. A single treatment cycle comprised 4 weekly infusions followed by 2 weeks of rest.

Results: According to an intent-to-treat analysis, a partial response was exhibited in 12 of 60 enrolled patients (20%; 95% confidence interval, 11%-32%) with a median duration of 5.1 months (range, 3-7.4 months). The tumor growth control rate was 50% (95% confidence interval, 37%-63%). Objective responses did not correlate with performance status, number of sites of disease, and pretreatments or epidermal growth factor receptor status. The median progression-free survival was 3.1 months (range, 1.2-9 months), whereas median overall survival was 6 months (range, 2-13 months). Both survival parameters correlated with performance status at the beginning of treatment. The main grade 3/4 toxicities were nausea (33%), diarrhea (27%), leukopenia (18%), asthenia (13%), and acne-like reaction (13%).

Conclusion: Our data suggest that the weekly irinotecan/cetuximab regimen is feasible in an outpatient setting and tolerated by most patients. At present, combinations of chemotherapy with cetuximab are being evaluated in patients with earlier-stage disease in a number of ongoing studies.