OPTIMOX1: a randomized study of FOLFOX4 or FOLFOX7 with oxaliplatin in a stop-and-Go fashion in advanced colorectal cancer--a GERCOR study.

PURPOSE: In metastatic colorectal cancer, a combination of leucovorin (LV) and fluorouracil (FU) with oxaliplatin (FOLFOX) 4 is a standard first-line regimen. The cumulative neurotoxicity of oxaliplatin often requires therapy to be stopped in patients who are still responding. This study evaluates a new strategy of intermittent oxaliplatin treatment that is based on FOLFOX7, a simplified leucovorin and fluorouracil regimen with high-dose oxaliplatin.

PATIENTS AND METHODS: Previously untreated patients were randomly assigned to either FOLFOX4 administered every 2 weeks until progression (arm A) or FOLFOX7 for six cycles, maintenance without oxaliplatin for 12 cycles, and reintroduction of FOLFOX7 (arm B).

RESULTS: Six hundred twenty patients were enrolled, including an exploratory cohort of 95 elderly or poor prognosis patients. Median progression-free survival and survival times were 9.0 and 19.3 months, respectively, in patients allocated to arm A compared with 8.7 and 21.2 months, respectively, in patients allocated to arm B (P = not significant). Response rates were 58.5% with arm A and 59.2% with arm B. National Cancer Institute Common Toxicity Criteria grade 3 or 4 toxicity was observed in 54.4% of the patients in arm A v 48.7% of patients in arm B. From cycle 7, fewer patients experienced grade 3 or 4 toxicity in arm B. Grade 3 sensory neuropathy was observed in 17.9% of the patients in arm A v 13.3% of patients in arm B (P = .12). In arm B, oxaliplatin was reintroduced in only 40.1% of the patients but achieved responses or stabilizations in 69.4% of these patients.

CONCLUSION: Oxaliplatin can be safely stopped after six cycles in a FOLFOX regimen. Further study is needed to fully evaluate oxaliplatin reintroduction.