This is an open-label, interventional study where a subset of participants will be randomized to one of two treatment-optimization strategies. Participants with moderate to severe Crohn's disease (CD) will receive induction treatment comprised of 3 infusions of infliximab at Weeks 0, 2, and 6. The participants will be evaluated at Week 10. Participants who are in clinical response will enter the observational phase of the study where they will receive standard of care treatment, as per the infliximab product monograph. Participants who lose response, may qualify for entry into the interventional phase of the study, where they will be randomized to one of the following treatment-optimization arms: 1) dose increase: infliximab 7 mg/kg, every 8 weeks or 2) shortened interval: infliximab 5 mg/kg every 6 weeks.