Tangible Results from Research

Chronic tiredness, lack of energy, unexplained weight loss, night sweats and fever are possible indicators of a type of cancer called Chronic Myelogenous Leukemia (CML). Leukemia is a cancer of the blood and bone marrow in which certain blood cells become abnormal and these abnormal cells continue to proliferate. The “chronic” of CML refers to the fact that it is a slowly growing phase of the cancer and “myelogenous” refers to the specific cancerous cell being produced…a myeloid white blood cell.

The diagnosis of CML is made easily because in more than 95% of patients there is a distinctive chromosomal rearrangement, the Philadelphia chromosome. The Philadelphia chromosome results from the exchange or translocation of genetic material between chromosomes 9 and 22. This translocation and subsequent fusion produces an abnormal protein called tyrosine kinase that stimulates the bone marrow to continue to produce immature white cells or blasts. There are three phases of the disease: chronic, acute and blast. The phases differentiate according to the number of blast cells present in the blood and bone marrow and the severity of the symptoms. CML usually occurs during or after middle age, rarely affecting children.

Standard treatment for CML has been a bone marrow transplant, drug therapy or some combination of the two. There are significant risks with transplants and only a small percentage of patients are candidates for the procedure. Standard drug therapies include interferon and hydroxyurea/busulfan but the difficulty with many drug therapies is tolerance by the patient.

An exciting new product resulting from research and our increased understanding of the genetics of disease is a drug called Gleevec. Gleevec is an oral drug therapy with very few side effects that has proven tremendously successful in treating CML. Gleevec functions by inhibiting the abnormal protein, tyrosine kinase, which is produced by the Philadelphia chromosome. It acts to block or inhibit the abnormal production of immature white blood cells that is responsible for the disease.

I recently attended a lecture at which a hematologic oncologist proclaimed Gleevec as “truly a miracle drug.” This physician was genuinely excited and enthusiastic about the good news and results for his patients. It is truly an exciting time in healthcare because as we come to understand more about the role of our genes in disease, perhaps there will be more “miracle” treatments available.