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

Abstract

3504 Background: The OPTIMOX1 study (JCO 2006) has shown that the strategy of 6 cycles of FOLFOX7 followed by maintenance therapy and FOLFOX reintroduction was as active and better tolerated than FOLFOX4 until progression. The aim of the OPTIMOX2 study was to evaluate a complete stop of chemotherapy after 6 bimonthly cycles of FOLFOX. Methods: Initially planned as a phase III study, OPTIMOX2 was downgraded to a large phase II study since the availability of bevacizumab. Patients (pts) were randomized between an OPTIMOX1 arm: 6 cycles of FOLFOX7 followed by LV5FU until progression and 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: 187/200 planned pts were included between Feb 2004 and Nov 2005. Response rates were (OPTIMOX1 arm/OPTIMOX2 arm): CR 2%/2%, PR 54%/51%, stable 24%/33%, progression 11%/7%, non assessable 9%/7%. Median PFS were (OPTIMOX1 arm/OPTIMOX2 arm) 36/28 weeks (p=.01), PFS in responders 41/30 weeks (p=.001), PFS in stable patients 34/26 weeks (p=.23). 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 41 weeks in the OPTIMOX1 arm and 36 in the OPTIMOX2 arm, p=.17. Median duration of chemotherapy-free interval in the OPTIMOX2 arm was 25 weeks (5.7 months). Conclusions: Maintenance LV5FU therapy prolongs PFS. The quality of life of almost 6 months CFI can balance a small advantage in DDC for maintenance therapy. Our next goal is to evaluate maintenance therapy with targeted agents alone. [Table: see text]