Test Now Available to Detect Resistance to Gleevec® in Chronic Myeloid Leukemia

Genzyme Corporation has announced that they have just made a test available to the public that can detect whether a patient with chronic myeloid leukemia (CML) is resistant to treatment with Gleevec® (imatinib mesylate).

 

Chronic myeloid leukemia (CML), also called chronic granulocytic leukemia, is a cancer that originates in the immune cells. It affects approximately 4,600 people annually in the U.S. In CML large numbers of young immune cells do not mature, resulting in an excess accumulation of these cells. The leukemia cells then crowd the bone marrow and blood, suppressing formation and function of other blood cells normally present in these areas. In addition, the leukemia cells cannot perform their function properly, leaving patients susceptible to infection.

 

Chronic myeloid leukemia begins with a chronic phase, during which few clinical problems, if any, occur. However, when left untreated, the chronic phase progresses into acute phases; these phases, called the accelerated and blastic phases, are characterized by fast-growing and aggressive cancer. Patients reaching these acute phases have a poor prognosis for long-term survival.

 

Historically, the only curative option for patients with CML was an allogeneic stem cell transplant. However, treatment-related mortality and side effects can both be substantial in patients undergoing an allogeneic stem cell transplant; researchers have thus focused efforts on curative treatment options that are more easily tolerated. Philadelphia chromosome-positive CML refers to the majority of cases of CML in which a genetic abnormality, referred to as the Philadelphia chromosome, results in the constantly activated growth of cancer cells. Roughly 30% of adult patients with ALL also have this genetic abnormality.

 

Gleevec is a biological agent that binds to and slows or stops the uncontrolled growth of cancer cells with this genetic mutation. Unfortunately, a small number of patients who are treated with Gleevec do not achieve anticancer responses; researchers are evaluating novel agents for these patients.

 

The new BCR-ABL Mutation Analysis test can help determine whether a patient will be resistant to the anticancer effects of Gleevec. It tests for specific mutations that are present when a patient does not respond to Gleevec. These results can help physicians individualize treatment for patients with CML.

 

Patients diagnosed with CML who are not responsive to Gleevec or who have stopped responding to Gleevec may wish to speak with their physician regarding the new BCR-ABL Mutation Analysis test. Clinical trials continue to evaluate novel drugs with anticancer effects in patients with CML that does not respond to Gleevec.