ROCHESTER, Minn.—Drinking green tea may benefit individuals with chronic lymphocytic leukemia (CLL) patients, according to new clinical research from Mayo Clinic. The findings show promise for use of the chemical epigallocatechin gallate (EGCG)—the major component of green tea—in reducing the number of leukemia cells in patients with CLL.
"Although only a comparative phase III trial can determine whether EGCG can delay progression of CLL, the benefits we have seen in most CLL patients who use the chemical suggest that it has modest clinical activity and may be useful for stabilizing this form of leukemia, potentially slowing it down," said Tait Shanafelt, MD, a Mayo Clinic hematologist and lead author of the study.
"These studies advance the notion that a nutraceutical like EGCG can and should be studied as cancer preventives," said Neil Kay, MD, a hematology researcher whose laboratory first tested the green tea extract in leukemic blood cells from CLL patients. "Using nontoxic chemicals to push back cancer growth to delay the need for toxic therapies is a worthy goal in oncology research, particularly for forms of cancer initially managed by observation such as CLL."
Using the highest dose tested in the phase I study, the researchers launched their phase II clinical trial in an additional 36 patients. The results evaluated the effects in these 36 patients as well as the six patients from the phase I trial treated at the same dose (total 42 patients). Results from 41 patients who have completed the study show that 31 percent of patients had a 20 percent or greater sustained reduction in blood leukemia count, and 69 percent of patients with enlarged lymph nodes saw a reduction of node size of 50 percent or greater.
In all, 69 percent of CLL patients had a biological response to EGCG as evidenced by a 20 percent or greater sustained reduction in blood lymphocyte count and/or a 50 percent or greater reduction in lymph node size, the researchers said.