Final results of OPTIMOX2, a large randomized phase II study of maintenance therapy or chemotherapy-free intervals (CFI) after FOLFOX in patients with metastatic colorectal cancer (MRC): A GERCOR study
4013 Background: The OPTIMOX2 study was designed to evaluate a complete stop of chemotherapy after 6 bimonthly cycles of FOLFOX. Methods: OPTIMOX2 is a large phase II study performed before the availability of bevacizumab. Patients (pts) were randomized between an OPTIMOX1 arm: 6 cycles of FOLFOX7 followed by LV5FU2 until progression then reintroduction of FOLFOX7, and the OPTIMOX2 arm: 6 cycles of FOLFOX7, complete stop of chemotherapy and reintroduction of FOLFOX7 before the tumor progression reached the baseline measures. Results: 202 pts were included between Feb 2004 and Apr 2006. Response rates were (OPTIMOX1/OPTIMOX2): CR+PR 63%/61%. Median PFS were OPTIMOX1/OPTIMOX2) 8.3/6.7 months (p=.04). Median duration of disease control (DDC), addition of PFS of first FOLFOX7 administration plus PFS of FOLFOX reintroduction if no progression at first evaluation, was 10.8m in the OPTIMOX1 arm and 9.0m in the OPTIMOX2 arm, p=.32. Median duration of chemotherapy-free interval (CFI) in the OPTIMOX2 arm was 4.6 months. Patients with poor prognostic factors had a shorter CFI, p=.01. Median overall survival was 24.6m in the OPTIMOX1 arm and 18.9m in the OPTIMOX2 arm, p=.05. Median survivals (OPTIMOX1/OPTIMOX2) were not reached/28.7m in patients with good prognostic and 20.9/14.5m in patients with poor prognostic. Conclusions: Maintenance LV5FU therapy prolongs PFS and OS, especially in patients with poor prognosis. CFI can be recommended only in selected patients without adverse prognostic factors. Our next study, DREAM, is evaluating maintenance therapy with targeted agents alone. No significant financial relationships to disclose.