OBJECTIVES:

I. Assess the efficacy and safety of 4-aminosalicylic acid in patients with active Crohn's disease of the small bowel.

PROTOCOL OUTLINE: This is a randomized, placebo controlled, multicenter study. Patients are randomized to receive either oral 4-aminosalicylic acid (4-ASA) or placebo twice a day for 12 weeks. After 12 weeks patients who improved with 4-ASA and those who received placebo are given the option of receiving 4-ASA for an additional year.

Patients who were randomized to receive 4-ASA and continue treatment after 12 weeks are followed every 3 months for 1 year. Patients who were randomized to receive placebo and begin 4-ASA therapy after 12 weeks are followed monthly for 3 months, then every 3 months for 1 year.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics--

• Active small bowel Crohn's disease established by clinical evaluation and prior radiologic study, endoscopy, surgical findings and/or histopathology
• Crohn's Disease Activity Index (CDAI) must be between 150 and 450
• No ulcerative or infectious colitis or severe perianal disease

--Prior/Concurrent Therapy--

• Biologic therapy: Not specified
• Chemotherapy: Stable dose of no greater than 20 mg per day of prednisone allowed
• Endocrine therapy: No immunosuppressive drugs within the past 3 months No concurrent immunosuppressive drugs
• Radiotherapy: Not specified
• Surgery: No impending surgery No prior ileostomy or colostomy
• Other: No 5-aminosalicylates within the past 2 weeks No concurrent 5-aminosalicylates No concurrent metronidazol or ciprofloxacin

--Patient Characteristics--

• Age: 18 to 80
• Performance status: Ambulatory
• Hematopoietic: Not specified
• Hepatic: No hepatic disease
• Renal: No renal disease
• Other: Not pregnant (negative pregnancy test required) Fertile patients must use effective contraception No documented salicylate allergy