Vanderbilt University Medical Center investigators are testing a device that measures leukemia patients' individual responses to different types of chemotherapy drugs - a technique that could one day help physicians devise more targeted treatment plans.
The test, known as a microculture kinetic assay, or MiCK assay, measures how light scatters off of leukemia cells to determine the effectiveness of drugs being used to attack the cells. If proven effective, the device could help physicians weed out ineffective chemotherapy drugs for their patients, thus saving them from some of the nasty side effects associated with the treatment.
"The MiCK assay was originally developed to look at a process by which cells die. This process is termed apoptosis and is also how chemotherapy effects leukemic cells," said Dr. Vladimir D. Kravtsov, assistant professor of Medicine.
"The chemotherapy drugs induce cell death by apoptosis, which causes cells to form protrusions on the cell body and eventually break up. The assay reads the changes in the optical density of the cell so that we can get a constant monitoring on what is happening."
Although the MiCK assay is still in the testing phase, this technique could revolutionize leukemia therapy by allowing physicians to more accurately identify which drugs will be most effective for their patients.
The MiCK assay can test up to 15 different drugs and each drug is tested at 6 different dosage levels. So with a very small sample of blood or bone marrow 96 different tests can be run at one time.
Between 24 and 72 hours after the testing is completed, information can be obtained about which drugs, and what dosages of those drugs, were most effective in affecting for inducing apoptosis in that patient's leukemic cells.
"This method allows us to understand when these drugs are most lethal to cells, which drugs work best, and which drugs don't work in specific patients," said Kravtsov.
In patients that are resistant to drugs normally used to treat leukemia, the MiCK assay can help physicians mae decisions about treatment with more extensive techniques like bone marrow transplantation rather than trying to find another drug that may or may not work.
The technique also could allow physicians to eliminate ineffective chemotherapy drugs from a patient's treatment regimen.
"If you are exposing the body to a drug that is not effective, then you are increasing the toxic levels in the body of that patient which is harmful. Just the simple exclusion of one ineffective drug lowers the toxicity in the patient," said Kravtsov.
"In cancer chemotherapy there is no way to avoid the side effects. Instead you have to measure the risks of therapy against its rewards. Knowing the effectivness of each drug is therefore very important," said Dr. Mark J. Koury, professor of Medicine.
Kravtsov and Koury are contemplating the use of the assay in patients that have other forms of cancer as well.
"Any tumor which has a homogeneous group of cells can be tested by the assay and we are working with others to try and test other types of cancer cells," said Koury.