Background: Cetuximab plus irinotecan/folinic acid/5-fluorouracil (5-FU) (IF) was evaluated as first-line treatment of patients with advanced gastric cancer and gastroesophageal junction tumors. Preplanned analyses of the influence of tumor biomarkers on treatment outcome were carried out.
Patients and methods: Patients received weekly cetuximab (400 mg/m(2) on day 1, subsequently 250 mg/m(2)) plus irinotecan (80 mg/m(2)) and a 24-hour continuous infusion of folinic acid (200 mg/m(2)) and 5-FU (1500 mg/m(2)) on days 1, 8, 15, 22, 29 and 36 of a 50-day cycle, until progressive disease (PD).
Results: The most common grade 3/4 toxic effects in 49 patients were diarrhea (15%) and skin toxic effects (14%). In 48 assessable patients, the overall response rate was 46% and disease control rate was 79%. Median progression-free survival (PFS) and overall survival (OS) was 9.0 months [95% confidence interval (CI) 7.1-15.6] and 16.5 months (95% CI 11.7-30.1), respectively. Tumor response was more common than nonresponse in epidermal growth factor receptor-expressing tumors (P = 0.041). Tumor PTEN expression was associated with longer PFS (P = 0.035) and OS (P = 0.0127) than no PTEN expression.
Conclusion: Cetuximab plus IF was well tolerated and efficacy data were encouraging. This treatment combination and the role of selected biomarkers are under investigation in the ongoing phase III EXPAND trial.