 On the basis of these considerations, a first-line doublet plus bev followed by a second-line switched doublet from oxaliplatin to irinotecan and viceversa plus bev should be considered a standard option for mCRC patients. Only retrospectively collected data are currently available about the efficacy of first-line FOLFOXIRI plus bev followed by second-line rechallenge with FOLFOXIRI plus bev. We therefore designed the present phase III randomized trial of first-line FOLFOXIRI plus bev followed by reintroduction of FOLFOXIRI plus bev at progression versus FOLFOX plus bev followed by FOLFIRI plus bev at progression in first- and second-line treatment of unresectable mCRC patients. 