A Study of Niclosamide in Patients With Resectable Colon Cancer

Inclusion Criteria: * Histologically confirmed diagnosis of colon adenocarcinoma with a plan to undergo surgical resection no sooner than 7 days from the projected date of study drug initiation. Patients with rectal cancer not receiving pre-operative chemoradiotherapy are also eligible. * Karnofsky performance status greater than or equal to 70% * Age ≥ 18 years. * Adequate hematologic function, with ANC \> 1500/microliter, hemoglobin ≥ 9 g/dL (may transfuse or use erythropoietin to achieve this level), platelets ≥ 100,000/microliter; INR \<1.5, PTT \<1.5X ULN * Adequate renal and hepatic function, with serum creatinine \< 1.5 mg/dL, bilirubin \< 1.5 mg/dL (except for Gilbert's syndrome which will allow bilirubin ≤ 2.0 mg/dL), ALT and AST ≤ 2.5 x upper limit of normal. * Ability to understand and provide signed informed consent that fulfills Institutional Review Board's guidelines. * Ability to return to Duke University Medical Center for adequate follow-up, as required by this protocol. Exclusion Criteria: * Patients with concurrent cytotoxic chemotherapy or radiation therapy are excluded * Known active brain or leptomeningeal metastases (defined as symptomatic metastases) or continued requirement for glucocorticoids for brain or leptomeningeal metastases. Treated, asymptomatic metastases are permitted provided the patient has been off steroids for at least 1 month prior to day 1 of study drug. * Patients with serious intercurrent chronic or acute illness, such as cardiac disease (NYHA class III or IV), hepatic disease, or other illness considered by the Principal Investigator as unwarranted high risk for investigational drug treatment. * Patients with a medical or psychological impediment to probable compliance with the protocol should be excluded. * Concurrent (or within the last 5 years) second malignancy other than non melanoma skin cancer, cervical carcinoma in situ, controlled superficial bladder cancer, or other carcinoma in situ that has been treated. * Presence of a known active acute or chronic infection including: a urinary tract infection, HIV or viral hepatitis. * Patients with prior use of niclosamide or allergies to niclosamide will be excluded from the protocol. * Concomitant use of strong CYP3A4, CYP 1A2 , or CYP2C9 substrates (See http://medicine.iupui.edu/clinpharm/ddis/main-table). * Pregnant and nursing women should be excluded from the protocol since this research may have unknown and harmful effects on an unborn child or on young children. If the patient is sexually active, the patient must agree to use a medically acceptable form of birth control while receiving treatment and for a period of 12 months following the last dose of niclosamide. It is not known whether the treatment used in this study could affect the sperm and could potentially harm a child that may be fathered while on this study. * Patients with complete bowel obstruction or who are at high risk for GI perforation or severe hemorrhage. Patients with inflammatory bowel disease.