A Phase I/II Study of Radioimmunotherapy With 90Y-Humanized MN-14 IgG Administered as a Single Dose to Patients With Refractory Metastatic/Recurrent Colorectal Carcinomas

Disease Characteristics:

- Patients with a documented histologic or cytologic diagnosis of a colonic or rectal
malignancy.

- Patients with recurrent, advanced and/or metastatic disease, who have either failed
standard therapy or are not eligible for any alternate therapies of higher
therapeutic priority.

- Patients with at least one identified (confirmed) and measurable tumor site* with no
tumor site > 5 cm in the greatest dimension.

Prior/Concurrent Therapy:

- Surgery: Patients are excluded if they have had major surgery either during or within
four weeks prior to study entry.

- Chemotherapy: Patients must have failed standard therapy or are not eligible for any
alternate therapies of higher therapeutic priority. Patients must have completed
chemotherapeutic agents four weeks prior to study entry.

- Biologic Therapy: Patients who have received a chimeric, CDR-grafted (humanized), or
human IgG will be eligible provided pre-study evaluations demonstrate no significant
reactivity with hMN-14 IgG (i.e., HAHA).

- Radiotherapy: No prior radiotherapy within four weeks of study entry. No prior
external beam irradiation to a field that includes more than 30% of the red marrow.
No prior radiation to maximal tolerable levels for any critical organ (e.g., 3,000
cGy for the liver, and 2,000 cGy for the lungs and kidneys). Patients who have had
standard pelvic field radiation as adjuvant therapy for rectal carcinoma will be
eligible only after the MTD is established.

- Other: Any experimental therapy (i.e., drugs, biologicals, procedures) for the
primary malignancy, either during or within four weeks prior to study entry.

Patient Characteristics/

Inclusion Criteria:

- Age Range: Male or Female at least 18 years of age

- Performance Status: Patients with a Karnofsky performance status > 70% (or
equivalent, ECOG 0-1) and expected survival of at least 3 months.

- Hematopoietic: Hemoglobin > 10 g/dL; WBC > 3000 per mm3; Granulocyte count > 1,500
per mm3; Platelet count > 100,000 per mm3

- Hepatic: Total bilirubin < 1.5 times the institutional upper limit of normal
(IULN)AST or ALT < 2 x IULN

- Renal: Creatinine < IULN

- Cardiovascular: Patients with LVEF >/= 50% by required MUGA/2D-ECHO study.

- Pulmonary: Patients with DFCO and FEV1 >/= 60% by required Pulmonary Function Tests.

- Other: Patients who have had a prior imaging study with a murine monoclonal antibody
may be included. Patients agreeing to use a medically effective method of
contraception during and for a period of three months after the treatment period. A
pregnancy test will be performed on each premenopausal female of childbearing
potential immediately prior to entry into the study. Patients able to understand and
give written informed consent.