Cetuximab plus cisplatin, irinotecan, and thoracic radiotherapy as definitive treatment for locally advanced, unresectable esophageal cancer: A phase-II study of the SWOG (S0414)

Introduction: The specific aims of the study were to evaluate the 2-year overall survival (OS) and progression-free survival (PFS), toxicity profile, and best objective response rate in patients with locally advanced, clinically unresectable esophageal cancer receiving cetuximab, cisplatin, irinotecan, and thoracic radiotherapy (TRT) within a multi-institutional cooperative-group setting. Methods: Eligible patients (cT4 M0 or medically unresectable, biopsy proven, and noncervical esophageal cancer) were to receive four 21-day cycles of cetuximab 400 mg/m² (day 1, cycle 1), cetuximab 250 mg/m² (day 8, 15, cycle 1; then days 1, 8, and 15 for subsequent cycles), cisplatin 30 mg/m² (days 1 and 8, all cycles), and irinotecan 65 mg/m ² (days 1 and 8, all cycles). TRT was administered at 1.8 Gy in 28 daily fractions to a total dose of 50.4 Gy, to begin with on day 1 of cycle 3. The primary endpoint was 2-year OS, with an accrual goal of 75 patients with adenocarcinoma. Results: The study was closed because of slow accrual, with 21 eligible patients (11 squamous, 10 adenocarcinoma) enrolled from May 2005 to September 2007. Two-year OS and PFS (95% confidence interval [CI]) were 33.3% (14.6-57.0%) and 23.8% (8.2-47.2%), respectively. Kaplan-Meier estimates of median (95% CI) OS and PFS were 11.2 (6.4-43.6) and 6.4 (3.7-12.0) months, respectively. The overall response rate (95% CI) among 17 evaluable patients was 17.6% (3.8-43.4%), including 6% confirmed complete responders and 12% unconfirmed partial responders. Two deaths resulted from protocol treatment (sudden death and gastrointestinal necrosis). Ten (47.6%) and 6 (28.6%) patients had grade-3 or -4 toxicity, respectively: 52.4% were hematologic, 23.8% had fatigue, 19.0% had nausea, 19.0% had dehydration, and 19.0% had anorexia. Conclusions: Concomitant cetuximab, cisplatin, irinotecan, and TRT were poorly tolerated in the first North American cooperative group trial testing this regimen for locally advanced esophageal cancer as treatment-related mortality approached 10%. Single-institution phase-II cetuximab-based combined modality trials have yielded encouraging results in preliminary analyses. The SWOG GI Committee endorses enrollment to open clinical trials to clarify the therapeutic ratio of cetuximab- based combined modality approaches for esophageal cancer.