Cetuximab Plus Irinotecan in Pretreated Metastatic Colorectal Cancer Progressing on Irinotecan: The LABEL Study

BackgroundThe aim of this multicenter phase II study was to demonstrate the activity of the epidermal growth factor receptor (EGFR)–targeting monoclonal antibody cetuximab combined with irinotecan in the treatment of Latin American patients with EGFR-expressing metastatic colorectal cancer (mCRC) in whom previous treatment with an irinotecan-containing regimen had failed.Patients and MethodsPatients received cetuximab, as a 400 mg/m2 initial infusion followed by 250 mg/m2 weekly, plus the same irinotecan regimen that had previously failed, until the occurrence of disease progression or unacceptable toxicity. The primary endpoint was response. Secondary endpoints included progression-free survival (PFS), duration of response, overall survival (OS), and safety.ResultsSeventy-nine patients received treatment. One patient had a complete response, 20 had partial responses, and disease was stabilized in 23 patients, giving an overall response rate of 27% and a disease control rate of 56%. The median duration of response was 23.9 weeks. Median PFS was 17.4 weeks, median OS was 9.2 months, and the 12-month OS rate was 38%. The most common adverse events according to System Organ Class were skin and subcutaneous tissue disorders (91% of the patients). Grade 3/4 adverse events occurred in 45 patients (57%), with the most common being diarrhea (20%), neutropenia (11%), and rash (6%). Seven patients (9%) had grade 3/4 acne-like skin rash. No grade 3/4 infusion-related reactions were reported.ConclusionCetuximab in combination with irinotecan is active and tolerable in Latin American patients with mCRC progressing on irinotecan, with a safety profile similar to that described in European studies.