Background:
- About 80% of patients with hairy cell leukemia (HCL) have tumor cells that have a
protein on their surface called cluster of differentiation 25 (CD25).
- The experimental drug LMB-2 is a recombinant immunotoxin that has been shown to kill
leukemia and lymphoma cells with the CD25 protein. (A recombinant immunotoxin is a
genetically engineered drug that has two parts - a protein that binds or targets a
cancer cell, and a toxin that kills the cancer cell to which it binds.)
Objectives:
- To evaluate the safety and effectiveness of LMB-2 in patients with HCL whose cancer
cells contain the CD25 protein.
- To evaluate the effects of LMB-2 on the immune system, determine how the drug is
metabolized by the body and examine its side effects.
Eligibility:
-Adults with hairy cell leukemia whose tumor cells have CD25 on their surface
Design:
- Up to 27 patients may be included in the study.
- Patients receive an infusion of LMB-2 through a vein every other day for three doses
(days 1, 3, 5), constituting one treatment cycle.
- Patients may receive up to six treatment cycles every 4 weeks unless their cancer
worsens or they develop unacceptable side effects.
- Blood is drawn weekly for various tests.
- Before each cycle and in follow-up visits, disease status is evaluated with a physical
examination, blood tests, chest x-ray and electrocardiogram.
- Before the first cycle, patients may have a computed tomography (CT) scan,
echocardiogram (heart ultrasound test) and bone marrow biopsy. With the patient's
permission, these tests may be repeated before other cycles also.