Leukemia Society of America (LSA) scientist Dr. Brian Druker has described a drug that may be useful for combatting chronic myelogenous leukemia (CML). The new drug may be able to target leukemia cells, a much sought-after approach to cancer treatment.
In CML, chromosomes 9 and 22 exchange segments and form a faulty gene called BCR-ABL that produces an abnormal protein. The protein, an elongated tyrosine kinase, is thought to cause leukemia. Dr. Druker and his collaborators designed a drug that inhibits the activity of the protein product of the abnormal gene. The drug, a tyrosine kinase inhibitor, suppresses the activity of the abnormal protein in leukemia cells in laboratory cultures and in mice with leukemia. The drug kills the leukemia cells, but not normal cells. These findings appear in Nature Medicine [2(5):561-566, 1996].
The LSA scientist plans to treat CML patients with this compound through injections in the blood. He believes that the compound will seek out the leukemic cells with the faulty protein and destroy them. Clinical trials of the new therapy should begin this fall at the Oregon Health Sciences University.
According to Dr. Druker, "Previous treatments for CML relied on chemotherapy and marrow transplantation. A drawback of standard chemotherapy treatment is that it damages healthy blood cells. Only a minority of patients can currently be helped by marrow transplantation because patients either do not have a suitable donor or are too old for the procedure, so new therapies are crucial."
Dr. Druker and his team are also investigating use of the drug to purge the marrow of leukemia cells in selected patients. Physicians first remove marrow from CML patients and treat the marrow cells with the compound. They then reinfuse the treated marrow cells into patients and the cells reconstitute themselves, restoring blood cell production.
Chronic myelogenous leukemia affects about 6,000 Americans annually, according to National Cancer Institute estimates. Development of the new drug may have far-reaching implications for patients with other cancers linked to genetic abnormalities, such as breast and colon cancer, said Dr. Druker.
Adapted from Newsline, Summer 1996