A phase II study of panitumumab with FOLFOX or FOLFIRI as first-line chemotherapy for KRAS-wild type metastatic colorectal cancer: The PaFF-J study.

722Background: For the patients with unresectable metastatic colorectal cancer (mCRC), response to the1st line chemotherapy has strong impact on their prognosis. Shrinkage of tumors may result in conversion to surgical resection and, concurrently, improved their survival. We conducted a multicenter phase II trial to investigate the efficacy and safety of panitumumab (Pmab) with chemotherapy as the 1st line treatment in Japanese patients with mCRC. Methods: Patients with no prior chemotherapy for unresectable, KRAS wild type mCRC, 20-80 years, and PS 0-1 were arbitrarily received either FOLFOX + Pmab or FOLFIRI + Pmab. Patients were evaluated every 8 weeks until progression. The primary endpoint was overall response rate (ORR), the secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR), R0 resection rate, and safety. Results: A total of 162 patients (140 with FOLFOX + Pmab and 22 with FOLFIRI + Pmab) were analyzed. Median follow-up was 28.2 months, media...