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Emerging Therapies in CML New Strategies for Hard to Treat CML Monitoring Treatment in CML Understanding Chronic Myelogenous Leukemia

Monitoring and Adherence in CML

Summary & Participants

Imatinib, or Gleevec, is a targeted anti-cancer drug that can keep chronic myelogenous leukemia (CML) in check for most patients for many years. It is important for patients to take imatinib as prescribed by their doctor to fight the disease and to guard against resistance.

Medically Reviewed On: July 21, 2008

Webcast Transcript

ANNOUNCER: Cytogenetists examine 20 marrow cells to check for the phildelphia chromosome, which results from the translocation. Any decrease in the percentage of cells containing the Philadelphia chromosome is called a cytogenetic response. At one year, doctors have a specific target.

NEIL SHAH, MD: When we move out to 12 months, we’re expecting a deeper level of response, so we’re expecting the bone marrow to show no more than 35% of cells to contain the Philadelphia chromosome in metaphase analysis. And this is termed a major cytogenetic response.

ANNOUNCER: CML is still present after a cytogenetic response. Another more sensitive test is used to measure the remaining percent of cml cells. It is called fish or fluorescence in situ hybridization. It is performed on the blood or bone marrow and detects the presence of the abnormal BCR-ABL gene, which results from the translocation of chromosomes 22 and 9.

STEPHEN NIMER, MD: We take the cells and we look under the microscope, using a fluorescent probe that allows us to distinguish between a normal cell and a CML cell. And when we do this analysis, we look at 500 cells and then we can say whether half of the cells or 250 of the cells are the leukemia cell or if 10 out of the 500 are the leukemia cell or if 1 out of the 500 is a leukemia cell.

ANNOUNCER: The most sensitive techniques are molecular tests known as PCR or polymerase chain reaction.

STEPHEN NIMER, MD: What PCR allows us to do is to take 100,000 cells and, even one of them has this BCR/ABL in it, we can amplify that to the point where we can detect a positive result and then we know that there are CML cells still in the patient.

ANNOUNCER: Many doctors order PCR testing every three to six months. In many cases, results show an ever decreasing percentage of white blood cells with the Philadelphia chromosome.

JORGE CORTES, MD: The goal of therapy has become to achieve what people call a major molecular response, which has been equated to what’s been defined as a 3-log reduction in the levels of transcripts, product of the Philadelphia chromosome.

STEPHEN NIMER, MD: Whatever level the patient started out with, if that patient's disease goes down to 1/1000th of the amount that they started with, we say they've had a 3-log reduction.

JORGE CORTES, MD: The reason why achieving this major molecular response or 3-log reduction is important is because what we’ve shown is that it correlates with the best outcome.

STEPHEN NIMER, MD: 94% of the patients who have had this 3-log reduction are still doing marvelously well with no sign of the disease getting worse.

CAROLYN BLASDEL, RN, FNP, OCN: But even when we can’t find any evidence of CML with our most sensitive test, it’s still possible that because of there being something like a trillion cells in the bone marrow and our sensitivity is only 1 in a million, there could still be up to a million CML cells. We can’t tell.

JORGE CORTES, MD: What about the fact that we identify low levels of disease in many patients, most patients still? You can still find a little bit of disease. But let’s assume that 40 years go by and it never comes back. Is that a cure or not? Dr. Goldman and Dr. Talpaz coined this term of operational cure, meaning, you’re not really cured, but you’re really -- you’re looking like you’re cured. I mean, you’re functioning just as if you were cured. And, you know, I always like to quote a small part of this book, Don Quixote, where Don Quixote says, “You know, until death, all is life.”

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