Study to Evaluate Efficacy and Safety of Two Drug Regimens in Subjects With Moderate to Severe Crohn's Disease

Inclusion Criteria:

• Diagnosis of Crohn's disease (CD) for at least 90 days, confirmed by endoscopy duringthe Screening Period.
• Active CD with a Crohn's Disease Activity Index (CDAI) despite treatment with oralcorticosteroids and/or immunosuppressants.
• Mucosal ulceration on endoscopy.

Exclusion Criteria:

• Subject with ulcerative colitis or indeterminate colitis.
• Subject who has had surgical bowel resections in the past 6 months or is planningresection.
• Subjects with an ostomy or ileoanal pouch.
• Subject with symptomatic bowel stricture or abdominal or peri-anal abcess.
• Subject who has short bowel syndrome.
• Chronic recurring infections or active Tuberculosis (TB).