- Determine if primary prophylaxis comprising filgrastim (G-CSF) makes it possible to obtain neutropenia lower than grade 4 or a 30% decrease in fever in patients with metastatic colorectal cancer receiving first-line FOLFIRI and bevacizumab and who are homozygous for allele UGT1A1*28 (genotype 7/7), a promoter of the gene coding for enzyme UGT1A1.