Phase II Study of Irinotecan Plus Panitumumab as Second-Line Therapy for Patients with Advanced Esophageal Adenocarcinoma

Lesson Learned: Panitumumab plus irinotecan is not active for the treatment of esophageal adenocarcinoma. Background: Esophageal adenocarcinoma (EAC) is a lethal cancer with increasing incidence. Panitumumab (Pa) is a fully humanized IgG2 monoclonal antibody against human EGFR. Cetuximab (Cx) combined with irinotecan (Ir) is active for second-line treatment of colorectal cancer. This phase II study was designed to evaluate Pa plus Ir as second-line therapy for advanced EAC. Methods: The primary endpoint was response rate (RR). Patients with one prior treatment were given Pa 9 mg/m² on day 1 and Ir 125 mg/m² on days 1 and 8 of each 21-day cycle. Inclusion criteria were confirmed EAC, measurable disease, no prior Ir or Pa, performance status <2, and normal organ function. Results: Twenty-four patients were enrolled; 18 were eligible and evaluable. These patients were all white, with a median age of 62.5 years (range, 33–79 years), and included 15 men and 3 women. The median number of cycles was 3.5. The most common grade 1–2 adverse events were fatigue, diarrhea, anemia, leukopenia, and hypoalbuminemia. Grade 3–4 adverse events included hematologic, gastrointestinal, electrolyte, rash, fatigue, and weight loss. The median follow-up was 7.2 months (range, 2.3–14 months). There were no complete remissions. The partial response rate was 6% (1/18; 95% confidence interval [CI], 0.01–0.26). The clinical benefit (partial response [PR] plus stable disease [SD]) rate was 50%. The median overall survival was 7.2 months (95% CI, 4.1–8.9) with an 11.1% 1-year survival rate. The median progression-free survival was 2.9 months (95% CI, 1.6–5.3). Conclusion: Irinotecan and panitumumab as second-line treatment for advanced EAC are not active.