Direct tumor extension into the stomach, duodenum, small bowel or large bowel Participants may not have current signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within months prior to starting study drugs Patients may not have current signs and/or symptoms of bowel obstruction within month prior to starting study drugs, except if it was a temporary incident (improved within < hours [hr] with medical management) Tumor is causing symptomatic bowel obstruction (patients who have had a temporary diverting ostomy are eligible) OVCA pts excluded with any of the following: non-epithelial, including malignant mixed mullerian tumors, unresolved bowel obstruction Symptomatic bowel obstruction within months prior to screening visit Lesions suspected to be at higher-risk for bleeding such as bowel involvement with tumor that invades into the bowel wall or involves the intraluminal component of bowel by imaging or direct visualization or central pulmonary lesions Hospitalization for bowel obstruction within months prior to enrollment No condition that could affect the absorption of study drug, including any of the following:\r\n* Malabsorption syndrome\r\n* Disease significantly affecting gastrointestinal function\r\n* Bowel obstruction or sub-obstruction a radiographically confirmed bowel obstruction within months prior to the first dose of study drug Any gastrointestinal condition causing malabsorption or obstruction (e.g. celiac sprue, gastric bypass surgery, strictures, adhesions, history of small bowel resection, blind loop syndrome) Ongoing bowel perforation or presence of bowel fistula or abscess or history of small or large bowel obstruction within months of registration, including subjects with palliative gastric drainage catheters. Subjects with palliative diverting ileostomy or colostomy are allowed if they have been symptom-free for more than months. Malignant bowel obstruction Active bowel obstruction, ileus, or active or remote pancreatitis History of bowel obstruction within days from proposed start of treatment Morbidities or concurrent major illness (for example, bowel obstruction or a second active malignancy) that, in the opinion of the treating healthcare provider, would make participation in the trial problematic History of bowel obstruction within month prior to starting study drugs No recent (=< months) of partial or complete bowel obstruction unless surgically corrected Evidence of complete or partial bowel obstruction Severe constipation or condition where exacerbation of constipation is not advisable (e.g. small bowel obstruction history) Subjects with bowel obstruction Hydronephrosis or biliary obstruction Any signs or symptoms of bowel obstruction within days prior to study entry For individual baskets: Appendiceal adenocarcinoma: Must not have clinically symptomatic malignant bowel obstruction; Cutaneous squamous cell carcinoma: none; Small bowel adenocarcinoma: must not have clinically symptomatic malignant small bowel obstruction Patients with known urinary outflow obstruction Urinary tract obstruction or marked hydronephrosis Clearance of mTc mercaptoacetyltriglycine (MAG) within . x ULN and no evidence of obstruction on the scan Unresolved partial or complete small or large bowel obstruction. Subject with extensive pelvic mass at risk of fistulization, or history of bowel obstruction within months prior to the proposed first dose of study treatment History of bowel obstruction within month prior to starting study drugs Direct tumor extension into the stomach, duodenum, small bowel or large bowel Clinical evidence of bowel obstruction at the time of study entry Patients with risk factors for bowel obstruction or bowel perforation (e.g., acute diverticulitis) will be excluded Patients who have a history of a small or large bowel obstruction within weeks of screening or who have and active partial small bowel obstruction or percutaneous endoscopic gastrostomy (PEG)-tube Small bowel obstruction Patients with complete bowel obstruction or who are at high risk for gastrointestinal (GI) perforation or severe hemorrhage and patients with inflammatory bowel disease Any gastrointestinal condition causing malabsorption or obstruction (eg, celiac sprue, gastric bypass surgery, strictures, adhesions, history of small bowel resection, blind loop syndrome) Clinically significant ulcerative colitis, inflammatory bowel disease, or partial or complete small bowel obstruction are to be excluded PHASE I STUDY ELIGIBILITY CRITERIA:\r\nCurrent signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within days before study enrollment PHASE II COLORECTAL CANCER COHORT (MEDI+C ONLY):\r\nCurrent signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within days before study enrollment Current signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within months prior to starting study drugs Tumor-induced symptomatic bowel obstruction Any gastrointestinal condition causing malabsorption or obstruction (eg, celiac sprue, gastric bypass surgery, strictures, adhesions, history of small bowel resection, blind loop syndrome) Patients with tumor-caused symptomatic bowel obstruction The presence of complete or partial bowel obstruction based upon clinical assessment Poor bowel preparation No evidence of biliary duct obstruction, unless obstruction is controlled by local treatment or, in whom the biliary tree can be decompressed by endoscopic or percutaneous stenting with subsequent reduction in bilirubin to below . x upper level of normal (ULN) Patients with evidence of high-grade symptomatic duodenal obstruction History of prior bowel fistula, ulcerations, or perforations Unresolved partial or complete small or large bowel obstruction. Any signs, symptoms, and/or radiographic evidence of a complete or partial bowel obstruction Clinically significant gastrointestinal (GI) disorders, including history of small bowel obstruction unless the obstruction was a surgically treated remote episode Current signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within months prior to starting study drugs Lesions suspected to be at higher-risk for bleeding such as bowel involvement with tumor that invades into the bowel wall or involves the intraluminal component of bowel by imaging or direct visualization or central pulmonary lesions Any gastrointestinal condition causing malabsorption or obstruction (eg, celiac sprue, gastric bypass surgery, strictures, adhesions, history of small bowel resection, blind loop syndrome); unable or unwilling to swallow tablets BID Imaging evidence of common bile duct obstruction History of gastrointestinal disease causing malabsorption or obstruction such as, but not limited to Crohns disease, celiac sprue, tropical sprue, bacterial overgrowth/blind loop syndrome, gastric bypass surgery, strictures, adhesions, achalasia, bowel obstruction, or extensive small bowel resection Known urinary tract obstruction The participant has bowel obstruction or history of chronic diarrhea that is considered clinically significant. Patients must not have an acute or subacute intestinal obstruction; no history of bowel obstruction, gastrointestinal (GI) perforation, major abdominal surgery with bowel resection, or perirectal/perianal abscess within months prior to randomization Severe gastrointestinal conditions such as clinical or radiological evidence of bowel obstruction within weeks prior to study entry, uncontrolled diarrhea in the last weeks prior to enrollment, or history of inflammatory bowel disease. History of bowel obstruction or malabsorption syndromes (within the last months) which might limit the absorption of the study drug Active bowel obstruction, or hospitalization for bowel obstruction within months prior to screening Patients must be able to tolerate oral medication and not have evidence of active bowel obstruction\r\n* Note: patients can have a history of prior bowel obstruction, provided the patient is not having symptoms of bowel obstruction at the time of enrolment and the bowel obstruction is not anticipated to recur during the participation in the study Appendiceal adenocarcinoma basket\r\n* Complete or partial bowel obstruction History of bowel obstruction, including sub-occlusive disease, related to the underlying disease and history of abdominal fistula, gastrointestinal perforation or intra-abdominal abscess; evidence of recto-sigmoid involvement by pelvic examination or bowel involvement on CT scan or clinical symptoms of bowel obstruction Has symptoms of bowel obstruction in the past months Have an acute or subacute bowel obstruction or history of chronic diarrhea which is considered clinically significant in the opinion of the investigator. Clinically significant signs and/or symptoms of bowel obstruction within months prior to starting treatment Participants may not have evidence of a bowel obstruction, abdominal fistula, or intra-abdominal abscess within months of study entry; participants with current signs or symptoms suggestive of bowel obstruction including early or partial obstruction are ineligible; participants with a history of gastrointestinal perforation at any time point are ineligible The following are additional exclusion criteria for patients enrolling post safety run in:\r\n* Any clinical or radiographic evidence of a partial or complete bowel obstruction (small or large bowel) currently or within the past months\r\n* No current dependency on total parental nutrition (TPN) or within the past days Has other serious illness or medical condition, such as active infection, unresolved bowel obstruction, psychiatric disorders, or cerebrovascular accident within year of study start Participant has persistent diarrhea or clinically significant malabsorption syndrome or known sub-acute bowel obstruction ? Grade , despite medical management Concomitant diseases/conditions: cardiac disease, immunodeficiency, chronic active hepatitis or cirrhosis, uncontrolled infection, bowel obstruction, any other major illness Participants may not have current signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within months prior to starting study drugs History of bowel obstruction, refractory ascites, or bowel perforation due to advanced disease within the past months from start of study treatment No evidence of biliary duct obstruction, unless obstruction is controlled by local treatment or, in whom the biliary tree can be decompressed by endoscopic or percutaneous stenting with subsequent reduction in bilirubin to below . x upper level of normal (ULN) Presence of bowel fistula No prior GI perforation, or GI obstruction or involvement of the bowel on imaging History of bowel obstruction, including sub-occlusive disease, related to the underlying disease and history of abdominal fistula, gastrointestinal perforation or intra-abdominal abscess; evidence of recto sigmoid involvement by pelvic examination or bowel involvement on CT scan or clinical symptoms of bowel obstruction Anticipation of immediate need for a major surgical procedure (e.g., impending bowel obstruction, gastrointestinal perforation) or radiation therapy during the trial Hospitalization for bowel obstruction within months prior to enrollment. Patients with symptoms of partial or complete bowel obstruction and recent (within month) history of fistula, intra-abdominal abscess or bowel perforation Subjects with evidence of recto?sigmoid involvement by pelvic examination or bowel involvement on\r\ncomputed tomography (CT) scan or clinical symptoms of bowel obstruction History of small or large bowel obstruction within months of registration, including subjects with palliative gastric drainage catheters; subjects with palliative diverting ileostomy or colostomy are allowed if they have been symptom free for more than months Current signs and/or symptoms of bowel obstruction or signs and/or symptoms of bowel obstruction within months prior to starting study drugs Patients that require urgent therapy due to tumor mass effects such as bowel obstruction or blood vessel compression No medical condition that could interfere with oral medication intake (e.g., frequent vomiting or partial bowel obstruction) Patients who have required any treatment (medical or surgical) for bowel obstruction prior to diagnosis of bladder cancer or who have required surgical treatment for bowel obstruction after the cystectomy Have other serious illness or medical condition, such as active infection, unresolved bowel obstruction, psychiatric disorders, or cerebrovascular accident within year of study start Direct tumor extension into the stomach, duodenum, small bowel or large bowel Recent history (? months) or ongoing partial or complete bowel obstruction unless due to disease under study and corrected with surgery. Patients with partial or complete bowel obstruction due to abdominal carcinomatosis Current bowel obstruction At a higher than average risk, in the Investigator's opinion, of bowel perforation (e.g., symptoms of partial or complete bowel obstruction, recent (within months) history of fistula or bowel perforation, requirement for total parenteral nutrition and continuous hydration) Recent (? months) history of partial or complete bowel obstruction. History of bowel obstruction, including sub-occlusive disease, related to the underlying disease or history of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscesses. Evidence of rectosigmoid involvement by pelvic examination or bowel involvement on computed tomography (CT) scan or clinical symptoms of bowel obstruction. Has an acute/subacute bowel obstruction or history of chronic diarrhea requiring ongoing medical intervention Unresolved diarrhea and bowel obstruction No acute gastrointestinal conditions, such as: obstruction, fecal impaction, obstipation, acute surgical abdomen, ongoing need for manual maneuvers to induce bowel movements (such as digital evacuation) Have clinical evidence of current or impending bowel obstruction Patient has a 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 Severe gastrointestinal conditions such as clinical or radiological evidence of bowel obstruction within weeks prior to study entry, uncontrolled diarrhea in the last weeks prior to enrollment, or history of inflammatory bowel disease Clinical evidence of bowel obstruction at the time of study enrollment Bowel obstruction Risk for gastric aspiration (ie; ileus, esophageal or bowel obstruction, active vomiting) Known upper gastrointestinal (UGI) tract obstruction precluding ERC. Patients with complete or partial bowel obstruction as determined by the palliative care physician Patients with a bowel ostomy No cross sectional imaging findings indicative of multi-segmental (> site) small bowel obstruction, or small bowel loops matted together, or gross disease of the small bowel mesentery characterized by distortion, thickening or loss of mesenteric vascular clarity Evidence of complete or partial bowel obstruction Patients with bile duct obstruction Patients with a history of or current bowel obstruction Opiate-induced uncontrolled constipation or bowel obstruction Have clinical evidence of lymphedema, current bowel obstruction, or symptomatic brain metastases, as determined by their treating oncologist. Diagnosis of/problems with chronic diarrhea or history of bowel obstruction or esophageal stricture Previous medical history of, or suspected hypersensitivity to, the PEG based bowel cleansing preparation and/or bowel cleansing formulations' ingredients. Irritable bowel syndrome, chronic constipation, functional bowel disorders, or colonic motility disorder Unresolved bowel obstruction No evidence of biliary duct obstruction unless obstruction controlled by local treatment or, the biliary tree can be decompressed by endoscopic or percutaneous stenting with subsequent reduction in bilirubin to ?.ULN Patient must have malignant bowel obstruction (MBO) as evidenced by all of the following:\r\n* Clinical evidence of a small bowel obstruction (via history, physical, and radiographic examination)\r\n* Bowel obstruction below (distal to) ligament of Treitz\r\n* Intra-abdominal primary cancer with incurable disease Patients must have malignant bowel obstruction due to an intra-abdominal primary cancer (i.e. gastrointestinal [GI], pancreas, ovarian, uterine, cervical, kidney, bladder, prostate, gastrointestinal stromal tumor [GIST] [all sites], and sarcoma); patients may still have primary tumor as long as it is not a primary large bowel obstruction from colorectal cancer Suspicion or known history of gastrointestinal obstruction