An Early Phase 2 Clinical Study of KSP-0243

Inclusion Criteria:

• Patients aged 18 to 74 years old (both inclusive)

• Patients who have been given the diagnosis of ulcerative colitis for at least 12weeks

• Patients with an endoscopic view typically seen with ulcerative colitis spreading > 15 cm from the anal verge

• Patients with mild to moderate active ulcerative colitis who meet the certainconditions

• Patients who have an inadequate response to a fixed-dose oral 5-ASA formulation (mesalazine or salazosulfapyridine) continued from at least 2 weeks prior to thestart of the screening period

Exclusion Criteria:

• Patients who underwent an enterectomy or are expected to require an enterectomyduring the study period (except appendectomy)

• Patients who have or suspected to have bacterium- or parasite-induced infectiousenteritis (e.g., infection with Clostridium difficile)

• Patients with any of the following concomitant illnesses with the severityconsidered inappropriate as a study patient by the principal investigator or thesubinvestigator or medical history thereof:

• Hepatic or renal disorders or cardiovascular, endocrine, metabolic, pulmonary,gastrointestinal, neurological, urological, genitourinary, and immune diseases,