Background: Alkaline phosphatase (ALP) is a strong prognostic factor in patients with metastatic colorectal cancer (MCRC). Patients with ALP more than three times the upper limit of normal (ULN) were excluded from our previous studies evaluating chemotherapy. An exploratory cohort of patients with ALP >3 ULN was included in the OPTIMOX1 study.
Patients and methods: Previously untreated patients with MCRC were randomized to FOLFOX4 until progression (arm A) or FOLFOX7 for six cycles, maintenance without oxaliplatin for 12 cycles and reintroduction of FOLFOX7 (arm B). Patients were stratified according to ALP level <or=3 ULN versus 3-5 ULN.
Results: Among the 620 patients in OPTIMOX1 study, 63 had ALP 3-5 ULN; 33 in arm A and 30 in arm B. The response rate in these patients was 56% versus 59% in patients with ALP <or=3 ULN. Median progression-free survival and overall survival were, respectively, 6.4 and 11.5 months in patients with ALP 3-5 ULN and 9.0 and 21.1 months in patients with ALP <or=3 ULN. Thirty-three percent of the patients in the cohort experienced grade 3/4 toxicity.
Conclusion: Both FOLFOX regimens achieved high tumor response rates and offer good palliation in MCRC patients with a poor prognosis.