Inclusion Criteria:

- Subjects with histologically confirmed hepatic metastases from primary colorectal
carcinoma.

- Not amenable to complete surgical resection for attempted cure as determined by the
Principal Investigator (PI).

- Tumor progression after prior therapy for colorectal carcinoma, including
fluoropyrimidine (5 FU or capecitabine), irinotecan, oxaliplatin, or cetuximab.

- One or more metastatic hepatic tumors that is measurable on CT scan. In addition,
subjects may have nonhepatic metastatic tumors.

- ECOG performance status of ≤ 1.

- Age ≥ 18 years.

- Signed, written IRB-approved informed consent.

- Men and women of reproductive potential must be willing to follow accepted birth
control methods during treatment and for 3 months after completion of treatment.

- Acceptable liver function:

- Bilirubin ≤ 1.5 x upper limit of normal;

- AST, ALT ≤ 2.0 x upper limit of normal;

- Albumin ≤ 3.0 g/dL.

- Acceptable hematologic status:

- Granulocyte ≥ 1000 cells/mm3;

- Platelet count ≥ 150,000 plts/mm3;

- Hemoglobin > 9 g/dL.

- Acceptable coagulation status: INR within normal limits.

- Acceptable kidney function: Serum creatinine within normal limits.

Exclusion Criteria:

- New York Heart Association Class III or IV cardiac disease, myocardial infarction
within the past 6 months prior to Day 1, unstable arrhythmia, or evidence of ischemia
on ECG within 14 days prior to Day 1.

- Seizure disorders requiring anticonvulsant therapy.

- Severe chronic obstructive pulmonary disease with hypoxemia.

- Major surgery, other than diagnostic surgery, within 4 weeks prior to Day 1.

- Active uncontrolled bacterial, viral, or fungal infections, requiring systemic
therapy.

- Pregnant or nursing women.

- Treatment with radiation therapy, surgery, chemotherapy, or investigational therapy
within 1 month prior to study entry.

- Unwillingness or inability to comply with procedures required in this protocol.

- Known infection with HIV, hepatitis B, or hepatitis C.

- Serious nonmalignant disease (e.g., hydronephrosis, liver failure, or other
conditions) that could compromise protocol objectives in the opinion of the
investigator and/or the sponsor.

- Clinically significant bleeding event within the last 3 months, unrelated to trauma.

- More than 50% of liver replaced by tumor (estimated by the PI from CT scan within 14
days of Day 1).

- Previous treatment with Ad.hIFN-β.

- Any prior treatment with a gene delivery vector or an adenovirus therapeutic agent.