RATIONALE: Monoclonal antibodies can locate cancer cells and either kill them or deliver
cancer-killing substances to them without harming normal cells.
PURPOSE: Phase I trial to study the effectiveness of radiolabeled monoclonal antibody in
treating patients with myelodysplastic syndrome or relapsed or refractory acute myeloid
leukemia or chronic myelogenous leukemia.
OBJECTIVES: I. Determine the safety and toxicity of yttrium-90-labeled humanized monoclonal
antibody M195 (90Y-MOAB HuM195) in patients with relapsed or refractory myeloid
malignancies. II. Determine the pharmacology and dosimetry of 90Y-MOAB HuM195. III. Study
the biological effects of 90Y-MOAB HuM195, including the ability to elicit human anti-human
antibody responses and antileukemic responses.
OUTLINE: This study seeks to estimate the maximum tolerated dose (MTD) of yttrium-90-labeled
humanized monoclonal antibody M195 (90Y-MOAB HuM195). All patients receive a single
intravenous dose of 90Y-MOAB HuM195. Groups of 3 to 6 patients are treated at escalated
doses of yttrium-90 until the MTD is determined. Patients with active leukemia who exhibit
at least a 50% clearing of marrow blasts after the first dose may receive a second dose
after 4-8 weeks provided remaining blasts are CD33-positive, there is no evidence of human
anti-human antibody response, and any toxicity has resolved. All patients are followed
monthly for 4 months after treatment.
PROJECTED ACCRUAL: Up to 24 patients will be treated. The study is expected to require 12-18
months to complete.
DISEASE CHARACTERISTICS: Pathologically confirmed myeloid malignancies as follows: Acute
myelogenous leukemia that is relapsed or refractory after at least 2 courses of standard
induction chemotherapy Accelerated or myeloblastic chronic myelogenous leukemia Refractory
anemia with excess blasts (RAEB) RAEB in transformation Chronic myelomonocytic leukemia
More than 25% of bone marrow blasts positive for the CD33 antigen Clear signs of active
leukemia following recovery from prior therapy required No rapidly accelerating blast
count No clinically unstable disease No active CNS leukemia
PATIENT CHARACTERISTICS: Age: Over 16 Performance status: Karnofsky 60%-100% Life
expectancy: At least 6 weeks Hematopoietic: Not specified Hepatic: Bilirubin less than 2.5
mg/dL AST less than 3 times normal Alkaline phosphatase less than 3 times normal Renal:
Creatinine less than 2.0 mg/dL Cardiovascular: No NYHA class III/IV status Pulmonary: No
clinically significant pulmonary disease Other: No serious infection uncontrolled by
antibiotics No pregnant or nursing women Negative pregnancy test required of fertile women
PRIOR CONCURRENT THERAPY: Recovered from prior therapy Biologic therapy: No detectable
antibodies to M195 from prior monoclonal antibody M195 or HuM195 Chemotherapy: At least 2
days since hydroxyurea At least 3 weeks since other chemotherapy Endocrine therapy: Not
specified Radiotherapy: At least 3 weeks since radiotherapy Surgery: Not specified