Irinotecan plus fluorouracil/leucovorin (IFL) versus fluorouracil/leucovorin alone (FL) in stage III colon cancer (intergroup trial CALGB C89803)

Abstract

3500 Background: Irinotecan prolongs survival in second line 5FU-refractory metastatic colorectal cancer (MCRC). First line irinotecan, weekly bolus 5FU, and leucovorin (IFL) was superior to daily x 5 bolus 5FU and leucovorin alone (FL) in a phase III trial in MCRC in terms of response rate, progression free survival and overall survival (OS). We conducted a phase III randomized study to evaluate whether IFL was also superior to weekly bolus FL after curative resection for stage III colon cancer. Methods: Eligible patients had TxN1–2M0 disease, Zubrod 0–2, and no prior chemotherapy. Patients (pts) received either IFL (irinotecan 125mg/m2 over 90 minutes followed by leucovorin 20 mg/m2 IV bolus and then 5FU 500mg/m2 IV bolus, given 4 weeks on, 2 weeks off, x 5 cycles (30 weeks total)) or the Roswell Park schedule of FL (leucovorin 500mg/m2 IV over 2 hours plus 5FU 500 mg/m2 at 1 hour after start of leucovorin, given 6 weeks on, two weeks off, x 4 cycles (32 weeks total)). Pts were stratified for N1 vs. N2 disease, high vs. low grade histology, and preoperative CEA of < 5 ng/ml, ≥ 5ng/ml, or unknown. Results: 1264 pts were randomized between April, 1999 and April, 2001. Median follow up is 2.6 years, and 67% of total expected deaths and 85% of total expected failures have occurred. Median OS and failure-free survival (FFS) have not yet been reached. IFL shows no improvement over FL in terms of either OS (p=0.88) or FFS (p=0.84) Futility boundaries for both of these endpoints have been exceeded. Toxicities are shown in the table. 18 deaths occurred on the IFL arm during treatment vs. 6 deaths on the FL arm (p=0.008). Conclusions: In stage III colon cancer, IFL, as compared to FL, is associated with a greater degree of neutropenia, neutropenic fever, and death on treatment, with no associated clinical benefit. Weekly bolus IFL should not be used in the management of stage III colon cancer. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Roche Pfizer Pfizer; Roche