Smyrk, T. C.

363 Background: Irinotecan (CPT-11) has demonstrated antitumor activity against metastatic colorectal cancer used alone or with 5-fluorouracil (5FU)/leucovorin (LV). Two arms with CPT-11, 5FU, and LV (FOLFIRI) +/- cetuximab (Cmab) were originally included in N0147. However, after CALGB 89803 (J Clin Oncol. 25:3456, 2007), PETACC-3 (J Clin Oncol. 27:3117, 2009), and Accord02 (Ann Oncol. 20:674, 2009) showed no benefit to the three-drug combination in adjuvant therapy, the CPT-11 arms of N0147 were discontinued. We report the outcomes for patients given FOLFIRI +/- Cmab. Methods: Following a signed informed consent patients with resected stage III colon cancer were randomized to one of 6 arms including 12 biweekly cycles of CPT-11 180 mg/m2 d1 with LV 400 mg/m2, 5FU 400 mg/m2 bolus IV, then 46-hr IV 5FU 2,400 mg/m2 on d1-2 without (Arm B, FOLFIRI) or with Cmab (Arm E) 400 mg/m2 d1 cycle 1 then Cmab at 250 mg/m2 d1 and 8. Primary endpoint was 3-year disease-free survival (DFS). Secondary endpoints included overall survival (OS) and toxicity. Results: 156 patients (Arm B-111, Arm E-45) were enrolled; median follow-up on 81 patients in Arm B was 60.3 months and 58.2 months in Arm E for 41 patients. wtKRAS (vs mt) status was associated with improved DFS (HR=0.6 [95% CI 0.4-1.1], p = 0.09) and OS (HR 0.7 [95% CI 0.4-1.5], p = 0.38). The addition of Cmab improved DFS and OS in the overall group and within wtKRAS pts. Grade greater than III non-hematologic adverse effects were significantly increased in the Cmab arm (46% vs. 64%, p = 0.05). Conclusions: In this randomized phase III trial adjuvant FOLFIRI resulted in a 3-year DFS lower than that expected for FOLFOX. Trends for improved DFS and OS with the addition of Cmab were observed in patients with resected stage III colon cancer patients, regardless of KRAS status. Supported by NIH Grant CA25224, Bristol-Myers Squibb, ImClone, Sanofi-Aventis, and Pfizer. [Table: see text] [Table: see text]

CRA3507 Background: FOLFOX is standard adjuvant therapy for stage III CC. Adding Cmab to FOLFOX benefits pts with metastatic CC WT KRAS tumors. N0147 assessed the potential benefit of Cmab added to FOLFOX. Methods: 21-56 days following resection and informed consent, KRAS status was centrally determined. Pts with wtKRAS CC were randomized to 12 biweekly cycles of oxaliplatin 85 mg/m2 d1, with leucovorin 400 mg/m2, 5FU 400 mg/m2 bolus IV, then 46-hr IV 5FU 2,400 mg/m2 on d1-2 (mFOLFOX6), without (arm A) or with Cmab (arm D) 250 mg/m2 d1&8, with Cmab at 400 mg/m2, cycle 1, d1. Primary endpoint was 3-yr disease free survival (DFS). Secondary endpoints included overall survival (OS) and toxicity. Planned accrual of 2,070 wtKRAS pts provided 90% power to detect hazard ratio (HR) of 1.33 with 2-sided α=0.05; with interim analyses after 25%, 50%, and 75% of planned events. Results: 1,760 wtKRAS pts (Arm A-858, Arm D-902) were enrolled at the time of closure; median follow-up on 1,624 pts is 15.9 months. Trial closed to accrual when preplanned interim analysis after 50% of planned events demonstrated no benefit to addition of Cmab. 3-yr DFS favored FOLFOX alone (HR 1.18, 95% CI 0.92-1.52; p=0.33). No benefit of Cmab was observed in any subgroups assessed. Any grade ≥ 3 AE, diarrhea, and failure to complete 12 cycles was significantly increased in arm D. Increased toxicity and greater differences in all outcomes were observed in pts aged ≥ 70 ( Table ). Conclusions: In this randomized phase III trial the addition of Cmab to mFOLFOX6 was of no benefit for pts with resected stage III wtKRAS CC. Supported by NIH Grant CA25224, Bristol-Myers Squibb, ImClone, Sanofi-Aventis, and Pfizer. [Table: see text] [Table: see text]