DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed colorectal cancer

  • Metastatic disease by diagnostic imaging studies

• Measurable disease

  • At least 1 unidimensionally measurable lesion with minimum lesion size at least twice the slice thickness of the imaging study used

• Refractory* to irinotecan, evidenced by clinical documentation

  • Received at least 1 prior irinotecan-containing chemotherapy regimen for metastatic disease and progressed during or within 6 weeks after completion of therapy NOTE: *Tumor marker (e.g., carcinoembryonic antigen [CEA]) elevation alone is not considered adequate evidence of treatment failure

• Must have received prior irinotecan according to 1 of the following schedules:

  • Weekly administration with a starting dose of 100-125 mg/m^2
  • Biweekly administration (every other week) with a starting dose of approximately 180 mg/m^2
  • Once every three weekly administration with a starting dose of 300-350 mg/m^2
• No known brain metastases
• No prior primary CNS tumors

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-1 OR
• Karnofsky 80-100%

Life expectancy

• More than 3 months

Hematopoietic

• WBC ≥ 3,000/mm^3
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 9 g/dL
• No bleeding diathesis or coagulopathy

Hepatic

• Bilirubin normal
• AST and ALT ≤ 2.5 times upper limit of normal (ULN) (5 times ULN in the presence of known liver metastases)
• INR < 1.5 (for patients receiving warfarin)

Renal

• Creatinine ≤ ULN OR
• Creatinine clearance ≥ 60 mL/min
• No proteinuria* NOTE: *Patients with ≥ 1+ proteinuria at baseline must have protein < 500 mg/24-hour urine collection

Cardiovascular

• No prior stroke
• No symptomatic congestive heart failure
• No unstable angina pectoris
• No uncontrolled hypertension
• No clinically significant cardiac arrhythmia

• None of the following arterial thromboembolic events within the past 6 months:

  • Myocardial infarction
  • Cerebrovascular accident
  • Transient ischemic attack
  • Unstable angina

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for at least 3 months after study participation
• No significant traumatic injury within the past 28 days
• No grade 3 or greater neurotoxicity
• No uncontrolled seizures
• No prior allergic reactions attributed to compounds of similar chemical or biological composition to study agents
• No prior irinotecan intolerance
• No ongoing or active infection requiring parenteral antibiotics
• No serious nonhealing active wound, ulcer, or bone fracture
• No psychiatric illness or social situation that would preclude study compliance
• No other concurrent uncontrolled illness that would preclude study participation
• No known hypersensitivity to Chinese hamster ovary cell products or other recombinant human antibodies

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior cetuximab
• No other prior epidermal growth factor receptor-directed therapy

• No prior anticancer murine or chimeric monoclonal antibody therapy

  • Prior humanized monoclonal antibody therapy allowed
• No prior bevacizumab
• No other prior vascular endothelial growth factor-targeted therapy

Chemotherapy

• See Disease Characteristics
• More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin)

Endocrine therapy

• Not specified

Radiotherapy

• More than 4 weeks since prior radiotherapy

Surgery

• More than 28 days since prior major surgical procedure or open biopsy

Other

• Recovered from all prior therapy
• Any number of prior standard or investigational regimens allowed
• No other concurrent investigational agents
• No other concurrent anticancer therapy
• No recent or concurrent thrombolytic agents
• No recent or concurrent full-dose warfarin except as required to maintain patency of preexisting, permanent indwelling IV catheters

• No concurrent therapeutic heparin

  • Concurrent prophylactic low-molecular weight heparin allowed
• No concurrent chronic daily aspirin (> 325 mg/day)
• No concurrent nonsteroidal anti-inflammatory medications known to inhibit platelet function
• No concurrent combination antiretroviral therapy for HIV-positive patients