Safety and Efficacy of ALX-0600 in Subjects With Active Crohn's Disease Who Completed Protocol CL0600-008

Inclusion Criteria: * Subjects must have completed participation in the Pilot Active Crohn's Disease Study. * Subjects must continue to meet all inclusion criteria for Pilot Active Crohn's Disease Study with the following exceptions: * CDAI score greater than 220 * Stool samples not required * C-reactive protein levels are not an exclusion criterion Exclusion Criteria: * Subject must continue to meet all exclusion criteria for Pilot Active Crohn's Disease Study with the following exceptions: * Participation in a clinical study of an experimental drug or device within 30 days before signing consent.