A Phase IIA Open Label, Adaptive, Randomized Clinical Trial of Dalotuzumab (MK-0646) Treatment in Combination With Irinotecan Versus Cetuximab and Irinotecan for Patients With Metastatic Rectal Cancers (mRC) Expressing High IGF-1/Low IGF-2 Levels

Inclusion Criteria:

- Metastatic colorectal cancer with primary tumor originating from the rectum

- Available archival (recent or remote) tumor, or newly obtained formalin-fixed tissue
available for analysis for biomarker studies

- At least one measurable lesion greater than or equal to 10 mm

- Disease has progressed after treatment with both irinotecan and oxaliplatin
containing regimens and should have progressed on or within 3 months of completing
their last line of therapy

- Performance status 0-1 on the Eastern Cooperative Oncology Group (ECOG) Performance
Scale

Exclusion Criteria:

- Known diabetic who is poorly controlled

- Chemotherapy or biological therapy within 2 weeks prior to initial dosing on this
study, or whose toxicities from agents administered 2 weeks earlier have not resolved
to at least grade 1 or baseline, or who is within 3 weeks from a prior surgery

- Radiotherapy within 2 weeks prior to initial dosing on this study, unless the
radiotherapy was for management of pain

- Currently participating or has participated in a study with an investigational
compound or device within 30 days or 5 half-lives of the investigational agent,
whichever is longer, of initial dosing on this study

- Could not complete previous course of irinotecan due to intolerable toxicity, other
than discontinuation due to fatigue following prolonged administration (>4 months
exposure)

- Prior exposure to insulin-like growth factor 1 receptor (IGF-1R) inhibitors or
epidermal growth factor receptor (EGFR) inhibitors

- Known Central Nervous System (CNS) metastases and/or carcinomatous meningitis

- Primary CNS tumor

- History of a prior malignancy with the exception of cervical intraepithelial
neoplasia; basal cell carcinoma of the skin; adequately treated localized prostate
carcinoma; potentially curative therapy with no evidence of that disease for 5 years,
deemed low risk for recurrence by treating physician.

- Human Immunodeficiency Virus (HIV)-positive

- Active Hepatitis B or C receiving antiviral treatment regimens

- Symptomatic ascites or pleural effusion

- Concurrently using growth hormone (GH), or growth hormone inhibitors