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,
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