Multicenter Phase II Study of Second-line Cetuximab plus Folinic Acid/5-Fluorouracil/Irinotecan (FOLFIRI) in KRAS Wild-type Metastatic Colorectal Cancer: The FLIER Study

Background: This study was the first multicenter phase II study of cetuximab plus folinic acid/5-fluorouracil/irinotecan (FOLFIRI) in KRAS wild-type mCRC as a second-line treatment in Japan including BRAF and PIK3CA genotyping. Patients and Methods: Tumors of 112 pre-registered patients were genotyped for KRAS, BRAF, and PIK3CA. The primary study end-point was response rate, and secondary end-points were progression-free survival (PFS), overall survival (OS), and safety. Results: Sixty-seven patients (59.8%) were EGFR-positive and KRAS wild-type. The mean age of the enrolled patients (n=60) was 62.6 years (range=37-82 years). The response rate was 31.7% and stable disease was observed in 53.3%. No objective response was observed in patients with BRAF or PIK3CA mutations. The median PFS and OS were 7.4 and 18.2 months, respectively. Grade-3/4 adverse events were leucopenia (26.7%), neutropenia (43.3%), paronychia (10.0%), fissure (10.0%) and acne-like rash (5.0%). Conclusion: Second-line cetuximab plus FOLFIRI was effective and well-tolerated.