The purpose of this research study is to investigate the effects of an investigational medication, called CCX282-B, on safety and on the some of the symptoms of Crohn's Disease in patients who are experiencing an active flare-up of moderate to severe Crohn's Disease.

CCX282-B is being developed as a treatment for inflammatory bowel diseases such as Crohn's Disease. CCX282-B is a highly potent, orally active, chemokine receptor antagonist whose single target is the G-protein coupled receptor CCR9. The CCR9 receptor is expressed by most T-cells in the thymus as well as in the intestine, and by a small population of T-cells in the peripheral blood. In humans, the CCR9 receptor is implicated in Crohn's Disease and ulcerative colitis.

Crohn's Disease is an autoimmune disease involving the entire length of the gastrointestinal tract, but with most manifestations in the terminal small intestine and colon. This condition is characterized by mucosal ulcerations that penetrate deeply into the bowel wall. Sometimes the ulcerative lesions completely penetrate the bowel wall, leading to fistula formation and infectious complications requiring surgical intervention. Patients experience considerable lifestyle disruption and disability from this disease, including diarrhea, abdominal pain, malnutrition, anemia, and repetitive surgeries to remove disease-affected gastrointestinal segments.

ChemoCentryx Protocol CL003_282 is a double-blind, placebo-controlled, parallel group, two stratum, Phase 2A pilot study of the safety, tolerability, immunologic and clinical activity, and population pharmacokinetics of a single dose level of CCX282-B administered daily for four consecutive weeks to patients with active, moderate to severe Crohn's Disease. The primary immunologic and clinical activity objective of this study is to provide pilot information regarding the immunologic and clinical activity of daily oral doses of CCX282-B in the treatment of moderate to severe Crohn's Disease, based on changes in the Crohn's Disease Activity Index (CDAI). Secondary immunologic and clinical activity objectives include evaluation of the effect of CCX282-B on the Inflammatory Bowel Disease Questionnaire (IBDQ) instrument, C-reactive protein (CRP), the endoscopic appearance and biopsy of the colon and terminal ileum, and markers of leukocyte subsets and activation status. The primary safety objective of this study is to evaluate the safety and tolerability of oral doses of CCX282-B in patients with moderate to severe Crohn's Disease. In addition, blood samples will be collected for evaluation of the population pharmacokinetics of CCX282-B.

Study acquired by Amgen and all disclosures were done by previous sponsor ChemoCentryx.

Inclusion Criteria:

• Diagnosis of moderate to severe Crohn's Disease in small intestine; disease must be active at the time of study entry
• Use of adequate and approved methods of birth control throughout the study period
• Willing and able to sign an informed consent

Exclusion Criteria:

• Pregnant or breastfeeding
• Infection with hepatitis B, hepatitis C, or human immunodeficiency virus (HIV; the virus that causes AIDS)
• Abuse of alcohol or of illegal drugs