Monotherapy treatment with CS-7017 to assess progression-free-survival (PFS) of subjects who achieved an objective response of Disease Control on first line therapy with Folinic acid (leucovorin), Fluorouracil (5-FU), Oxaliplatin (Eloxatin) known as FOLFOX; or Folinic acid (leucovorin), Fluorouracil (5-FU), irinotecan (Camptosar) known as FOLFIRI.