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.