Nine-Weeks Treatment With 683699 In Subjects With Moderately-To-Severely Active Crohn's Disease

Inclusion criteria: * Diagnosed with CD and reconfirmed in previous 2 years by a radiologic or endoscopic assessment including histology. * CDAI (Crohn's Disease Activity Index) score of 220-450 after 1 week of screening. * CRP (C-Reactive Protein) level of \>4mg at screening. Exclusion criteria: * Significantly abnormal laboratory tests or ECG (electrocardiogram) results. * Current use of an elemental diet or parenteral nutrition. * Clinically significant positive stool culture. * Ongoing neoplastic disease of the bowel. * Bowel perforation other than fistulae. * Has an ileostomy or colostomy. * Fixed symptomatic gastrointestinal (GI) stricture within 6 months or obstructive symptoms within 3 months of screening. * Any bowel resection within 12 months of screening or bowel resection without subsequent demonstration of recurrence of active CD. * More than 100cm of bowel resected. * Non-curative bowel surgery with 2 months of screening. * Symptoms attributed to short bowel syndrome. * Uncontrolled bacterial, viral, or fungal infection or congenital or acquired immunodeficiency. * Women who are pregnant, breast feeding, or planning to become pregnant during the study. Permitted medications: * Less than or equal to 20mg/day oral corticosteroids for at least 4 weeks prior to screening and on stable doses for 2 weeks prior to screening. * Azathioprine and 6-MP (6-Mercaptopurine) stable dose for 3 months prior to screening. * 5-ASA (5-Aminosalicylic acid) stable dose for 1 month prior to screening. Prohibited medications: * Greater than 20mg/day oral corticosteroids, or systemic intravenous corticosteroids, or antibiotics as a treatment for CD within 4 weeks prior to screening. * Cyclosporine or methotrexate during the 2 months prior to screening. * Infliximab or other biological treatments within 3 months prior to screening.