Randomized phase II study of nimotuzumab, an anti-EGFR antibody, plus irinotecan in patients with 5-fluorouracil–based regimen-refractory advanced or recurrent gastric cancer in Korea and Japan: Preliminary results.

Abstract

87 Background: Nimotuzumab is a humanized IgG1 anti-EGFR monoclonal antibody. In previous studies, nimotuzumab has demonstrated efficacy associated with an absence of severe skin toxicity, commonly caused by other EGFR-targeting therapies. Methods: This is a Korea and Japan collaborative, multi-center, randomized, open-label study of nimotuzumab (400 mg, IV q1 week) plus irinotecan (150 mg/m2 IV q2 weeks) (N+I) versus irinotecan (I) in patients with advanced or metastatic gastric cancer refractory to 5-fluorouracil-based regimen. The primary endpoint was PFS with an external review and the secondary endpoints included safety, ORR, OS, PK, and a biomarker. Results: Eighty-two eligible patients (ECOG PS 0-1, one prior regimen) were treated with N+I (n = 40) or I (n = 42). Baseline characteristics were balanced between both arms. Archival tumor tissues collected from 48 patients (N+I arm: 26, I arm: 22) were analyzed for EGFR and K-ras. EGFR status, 0/1+/2+/3+, examined by immunohistochemistry was 44%/25%/13%/17%, respectively. Two patients in N+I arm had a K-ras mutation in codon 12 or 13. The efficacy analysis was conducted 6 months after completion of randomization with median follow-up period of 197 days. Median PFS was 73.0 days in N+I arm compared with 85.0 days in I arm (HR 0.860; 95% CI, 0.516, 1.435). MST was 293.0 days in N+I arm compared with 227.0 days in I arm (HR 0.717; 95% CI, 0.420, 1.224). In the sub-analysis, the hazard ratio in PFS for patients with EGFR +1/2+/3+ was 0.463 (95%CI, 0.177, 1.212) and that of EGFR 2+/3+ was 0.341 (95% CI, 0.080, 1.457) and the hazard ratio in OS was 0.584 (95% CI, 0.242, 1.409) and 0.295 (95% CI, 0.077, 1.129), respectively. The incidence of adverse events was similar between both arms. No adverse events of grade 3 skin rash or grade 3 infusion-related reaction were reported. Conclusions: These results didn't demonstrate clear benefit at this sample size. However, EGFR-positive patients treated nimotuzumab showed a potential improvement of PFS and OS. This study supports the selection of gastric cancer patients by molecular status for future study of nimotuzumab. [Table: see text]