The Immunological and Blood Effects of STA-5326 Mesylate on Patients With Crohn's Disease

The purpose of this study is to measure the mucosal immunological effects and peripheral blood effects of the oral IL-12/23 inhibitor, STA-5326 mesylate, in subjects with active Crohn's disease (CD). Crohn's disease is a chronic, relapsing inflammatory condition of the small and large bowel associated with excessive Th1 cytokine production. Since IL-12 is a key cytokine driving the Th1 response, novel therapies targeting IL-12 have been successful in treating CD in animal models and in humans. Data from humans and from animal models further suggest that both IL-12 and IL-23 may have a role in this active gut inflammation. STA-5326 mesylate is an oral drug that suppresses IL-12p40 production (a subunit shared by IL-12 and IL-23) in vitro and has apparent safety and clinical activity in a recent open-label trial of treatment for CD. This protocol will enroll and randomize 12 subjects with moderate to severe active CD (CD Activity Index \[CDAI\] 220 to 450, inclusive) for 4 weeks of daily study drug treatment (9 subjects will receive 100 mg STA-5326 mesylate and 3 will receive placebo). Subjects will be evaluated for safety that will include monitoring of adverse events and concomitant medications, clinical laboratory testing, electrocardiogram (ECG) tracings, and physical examinations including vital signs. Efficacy assessments will include the CDAI, the Simple Endoscopic Score for CD (SES-CD), results from the Inflammatory Bowel Disease Questionnaire (IBDQ), and changes from Baseline for plasma C reactive protein (CRP) (measured by high sensitivity assay). In addition, immunologic effects (lymphocyte phenotyping cytokine secretion from peripheral blood and lamina propria mononuclear cells \[LPMCs\]) will be assessed. Descriptive statistics (n, mean, median, standard deviation, minimum and maximum range) will be used to summarize data for each treatment group.