Study of Labetuzumab Govitecan in Participants With Metastatic Colorectal Cancer

Inclusion Criteria: * Histologically or cytologically confirmed colorectal adenocarcinoma. * Stage IV (metastatic) disease. * Previously treated with at least one prior irinotecan-containing regimen for colorectal cancer. * Adequate performance status (Eastern Cooperative Oncology Group (ECOG) 0 or 1). * Expected survival \> 6 months. * Carcinoembryonic antigen (CEA) plasma levels \> 5 ng/mL. * Measurable disease by computed tomography (CT) or Magnetic resonance imaging (MRI). * At least 4 weeks beyond treatment (chemotherapy, immunotherapy and/or radiation therapy) or major surgery and recovered from all acute toxicities. * At least 2 weeks beyond corticosteroids. * Adequate hematology without ongoing transfusional support (hemoglobin \> 9 g/dL, absolute neutrophil count (ANC) \> 1,500 per mm\^3, platelets \> 100,000 per mm\^3). * Adequate renal and hepatic function (creatinine ≤ 1.5 x IULN, bilirubin ≤ institutional upper limit of normal (IULN), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3.0 x IULN or 5 x IULN if know liver metastases). * Otherwise, all toxicity at study entry ≤ Grade 1 by National cancer institute common terminology criteria for adverse events (NCI CTC) v4.0. Exclusion Criteria: * Women who are pregnant or lactating. * Women of childbearing potential and fertile men unwilling to use effective contraception during study until conclusion of 12-week post-treatment evaluation period. * Individuals with Gilbert's disease or known central nervous system (CNS) metastatic disease. * Individuals with CEA plasma levels \> 1000 ng/mL must be approved in advance by the Sponsor. * Presence of bulky disease (defined as any single mass \> 10 cm in its greatest dimension). * Individuals with active ≥ grade 2 anorexia, nausea or vomiting, and/or signs of intestinal obstruction. * Individuals with non-melanoma skin cancer or carcinoma in situ of the cervix are eligible, while individuals with other prior malignancies must have had at least a 3-year disease-free interval. * Individuals known to be human immunodeficiency virus (HIV) positive, hepatitis B positive, or hepatitis C positive. * Known history of unstable angina, myocardial infarction, or congestive heart failure present within 6 months or clinically significant cardiac arrhythmia (other than stable atrial fibrillation) requiring anti-arrhythmia therapy. * Known history of clinically significant active chronic obstructive pulmonary disease (COPD), or other moderate-to-severe chronic respiratory illness present within 6 months. * Infection requiring intravenous antibiotic use within 1 week. * Other concurrent medical or psychiatric conditions that, in the Investigator's opinion, may be likely to confound study interpretation or prevent completion of study procedures and follow-up examinations.