Naloxegol in Cancer Opioid-Induced Constipation

Inclusion Criteria: * Adults greater than or equal to 18 years old. * Eastern Cooperative Oncology Group (ECOG) less than or equal to 3. * Glomerular filtration rate (GFR) greater than or equal to 30 ml/min/1.73m2 by Modification of Diet in Renal Disease (MDRD). * Corrected serum calcium level less than or equal to 10.5 mg/dL. * Estimated life expectancy greater than or equal to 6 months. * Negative pregnancy test prior to initiating study treatment for females of childbearing potential. Exclusion Criteria: * Patients receiving the following medications within 3 days of Study Day 1 and/or are planned to receive throughout the duration of the study period: opioid antagonist, mixed antagonist, a strong CYP3A4 and/or P-glycoprotein (P-gp) inhibitor, a moderate CYP3A4 and/or P-gp inhibitor, and/or a strong CYP3A4 inducer. * Concurrent total parenteral nutrition and/or use of metoclopramide. * Patients at high risk for bowel perforation. * Constipation that was not primarily caused by opioids in the investigator's medical opinion. * A condition that may have affected the permeability of the blood-brain barrier (e.g., known brain metastases, meningeal metastases, brain injury, multiple sclerosis, recent brain injury, uncontrolled epilepsy) * Patient has clinically active diverticular disease. * Past medical history of irritable bowel syndrome, signs of active gastrointestinal (GI) bleeding, acute surgical abdomen, bowel stents, indwelling peritoneal catheter, mechanical GI obstruction, fecal impaction, or fecal ostomy. * Patient has motility/neurologic disorders including autonomic failure (spinal cord lesions, tumor invasion of nerves) and/or poorly controlled endocrine/metabolic disorders (hypercalcemia, hypokalemia, diabetes, hypothyroidism), as determined by the investigator. * Uncontrolled cancer pain despite analgesic therapy