Canadian Active & Maintenance Modified Pentasa Study

Inclusion Criteria for Active phase:

• Newly diagnosed or recurrent, mild to moderate Ulcerative Colitis patients.

• Extent of colonic involvement confirmed within the past 36 months

• UCDAI score of at least 3 but not greater than 8 and a score of at least 1 forendoscopy

• Screening tests to rule out any abnormalities in stool, heart or kidney.

• Male or non-pregnant females between 18 to 75 years.

• Women of childbearing potential to use efficacious contraception as judged by theinvestigator.

• Written informed consent given. Inclusion Criteria for Maintenance phase:

• Newly recruited subjects with documented mild to moderate UC entering the Run-inPhase: in clinical remission for at least 1 month and for a maximum of 3 years, andreceiving 5-ASA 1.4 to 2.5 g/day for maintenance of quiescent disease

• Subjects from Active Phase: meeting remission criteria after the 8-week active period

• Extent of colonic involvement confirmed within the past 36 months by colonoscopy

• In complete remission at entry into the Maintenance Phase, defined as i) a score of 0or 1 for stool frequency; ii) a score of 0 for rectal bleeding; iii) a score of 0 forendoscopy findings; and iv) a Physician's Global Assessment (PGA) score of 0 or 1

• Screening tests to rule out any abnormalities in stool, heart or kidney.

Exclusion Criteria:

• Use of 5-ASA products at a dose >2.5g/day within 7 days prior to entry.

• Proctitis, short bowel syndrome, prior bowel surgery, severe UC, other forms ofInflammatory Bowel Disease

• Infectious diseases, parasites, bacterial pathogens

• Allergy to aspirin or salicylate

• Liver or kidney abnormalities

• Alcohol or drug abuse

• Pregnancy

• Cancer

• Bleeding disorders, ulcers, autoimmune diseases

• Mental disorders

• Participation in clinical trial in last 30 days

• Inability to fill in diary cards / comply with protocol requirements