A Study of Niclosamide Enemas in Subjects With Active Ulcerative Proctitis or Ulcerative Proctosigmoiditis

Inclusion Criteria: 1. Male or female subjects aged ≥ 18 years at the time of signing the informed consent; 2. Must understand and voluntarily sign an informed consent from (ICF) prior to any study-related assessments/procedures being conducted. 3. Must be able to adhere to the study visit schedule and other protocol requirements; 4. Diagnosis of UP or UPS with a duration of at least 3 months prior to the Screening Visit 5. MMS score ≥4 to \< 8 (range: 0-9) prior to enrolment in the study. 6. Availability to perform an endoscopy (colonoscopy or flexible rectosigmoidoscopy); Exclusion Criteria: 1. Diagnosis of Crohn's disease, indeterminate colitis, ischemic colitis, microscopic colitis, radiation colitis, or diverticular disease-associated colitis; 2. UC extended more than 40 cm from the anal verge; 3. Subjects who have had surgery as a treatment for UC or who, in the opinion of the Investigator, are likely to require surgery for UC during the study; 4. History of any clinically significant neurological, renal, hepatic, gastrointestinal, pulmonary, metabolic, psychiatric, endocrine, hematological disorder or disease or any other medical condition that, in the Investigator's opinion, would preclude participation in the study; 5. Any condition, including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she was to participate in the study or confounds the ability to interpret data from the study; 6. Pregnant or breast feeding females; 7. Known active current or history of recurrent bacterial, viral, fungal, mycobacterial, or other infections (including but not limited to tuberculosis, atypical mycobacterial disease, and herpes zoster), human immunodeficiency virus (HIV), or any major episode of infection requiring hospitalization or treatment with intravenous (IV) or oral antibiotics within 4 weeks of screening; 8. Subjects who have received any investigational drug or device in the last 3 months; 9. History of alcohol, drug, or chemical abuse within the last 6 months; 10. Known hypersensitivity to niclosamide or any excipients in the formulation.