Efficacy and safety findings from a randomized phase III study of capecitabine (X) + oxaliplatin (O) (XELOX) vs. infusional 5- FU/LV + O (FOLFOX-6) for metastatic colorectal cancer (MCRC)
4029 Background: X has comparable efficacy, safety and convenience benefits over 5-FU/LV (Mayo clinic) in adjuvant colon cancer and first-line MCRC. A recent phase III trial in first line MCRC showed that XELOX is well tolerated and non inferior to FOLFOX-4 for progression-free survival (PFS) [Cassidy ESMO 2006]. Methods: We initiated a phase III trial to demonstrate non inferiority in terms of best response rates (RR, RECIST) of XELOX versus FOLFOX-6 as first-line therapy in patients (pts) with MCRC. Between 16 May 03 and 31 Aug 04, 306 patients (intention to treat), were randomized to receive either XELOX (n=156: × 1,000mg/m2 bid d1–14, O 130mg/m2 d1, q3w) or FOLFOX-6 (n=150: O 100mg/m2 d1 LV 400mg/m2 2h infusion then 5-FU 400mg/m2 i.v. bolus then 2,400–3,000mg/m2 46h infusion, q2w) for 6 months. Efficacy results are presented in the per protocol population (PP) (n=284:144 pts XELOX; 140 pts FOLFOX-6). Results: Baseline characteristics were well balanced. Pts received a median of 8 and 11 cycles of XELOX (range 0–8) and FOLFOX-6 (range 0–12), respectively. Dose intensity (median) for oxaliplatin was 99.6% and 95.4% with XELOX and FOLFOX-6, respectively. Best RR (independent review, PP) was 42% and 46% with XELOX and FOLFOX-6, respectively. Difference between groups for RR was 4.7%; upper limit of 95% unilateral CI (14.4%) was below non-inferiority margin of 15%. RR by investigators (PP) was 46% for each arm. With a median follow up of 16.5 months (range 0.4–38.3), median PFS and overall survival (PP) were 9.3/19.9 vs. 9.7/18.4 months with XELOX and FOLFOX-6, respectively. In the safety population (n=304), XELOX pts had more grade 3/4 hand-foot syndrome (3 vs. 0%, p=0.21), thrombocytopenia (12 vs. 5% p=0.052), and diarrhea (12% vs. 7% p=0.1), but less grade 3/4 febrile neutropenia (0 vs. 6% p=0.001), neuropathy (8 vs. 19% p=0.003), than those on FOLFOX-6. Treatment discontinuation for toxicity was 19% and 23% in XELOX and FOLFOX-6 arms, respectively. Conclusions: The primary endpoint has been met: XELOX is non inferior to FOLFOX-6, with a good safety profile in first-line MCRC. No significant financial relationships to disclose.