In the small case study, the researchers report on four patients who appeared to have an improvement in the clinical state of their disease after starting over-the-counter products containing epigallocatechin gallate (EGCG), an extract of green tea. Three of the four patients met the standard criteria used to define a response treatment for clinical trials. These same investigators had previously shown that EGCG kills leukemia cells from patients with CLL in the test tube by interrupting the communication signals they need to survive. That study was published in Blood in 2004.

"The experience of these individuals provides some suggestion that our previously published laboratory findings may actually translate into clinical effects for patients with this disease," says Tait Shanafelt, M.D., Mayo Clinic hematologist and lead author of the article. Despite these encouraging preliminary findings, he urges caution. "We do not know how many patients were taking similar products and failed to have any benefit. We also do not yet know the optimal dose that should be used, the frequency with which patients should take the medication, and what side effects will be observed with long-term administration."

Dr. Shanafelt and his colleagues say more studies are needed to determine these things before they would recommend widespread use by patients. Dr. Shanafelt is also the lead investigator in an ongoing clinical trial sponsored by the National Cancer Institute studying pharmacologic doses of EGCG in pill form for patients with CLL.

CLL is a blood and bone marrow cancer that affects 8,000 to 15,000 new patients each year in the United States. Its called chronic leukemia because it progress
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Contact: Elizabeth Zimmermann
newsbureau@mayo.edu
507-284-5005
Mayo Clinic
13-Dec-2005