Biweekly cetuximab and irinotecan as third-line therapy in patients with advanced colorectal cancer after failure to irinotecan, oxaliplatin and 5-fluorouracil

Background: Standard weekly cetuximab and irinotecan (CetIri) is an effective regimen in heavily pretreated patients with advanced colorectal cancer (ACRC). Inspired by a pharmacokinetic study demonstrating no differences between weekly and biweekly cetuximab, we present the results of 74 consecutive patients treated with biweekly CetIri. Methods: Biweekly CetIri schedule: cetuximab 500 mg/m(2), first course was given as a 120-min infusion followed 1 h later by irinotecan 180 mg/m(2) as a 30-min infusion. Subsequent courses of cetuximab were given in 60 min, immediately followed by irinotecan-resulting in an overall treatment time of 90 min. Results: All patients had ACRC resistant to 5-fluorouracil and irinotecan and 95% to oxaliplatin. Median age was 63 years, median performance status was 0. Median duration of therapy was 4.3 months. Response rate was 25%. Median progression-free survival and overall survival were 5.4 months and 8.9 months, respectively, comparable to own historical controls receiving weekly CetIri. Grade 3-4 toxicity was rare (skin 7%, nail 3%, diarrhoea 10%, fatigue 3%, neutropenia 9%). One patient experienced severe allergic reaction. Conclusion: Salvage therapy with simplified biweekly CetIri is a convenient, effective and well-tolerated regimen in heavily pretreated patients with ACRC. A confirmatory phase II study is ongoing.