Green Tea Helps Leukemia Patients in Clinical Trial
Mayo Clinic researchers have found that a green tea extract seems to reduce the number of leukemia cells in patients who have chronic lymphocytic leukemia (CLL). The findings point to a natural substance called epigallocatechin gallate (EGCG), the major component of green tea, as the beneficial factor.
Scientists will present these latest clinical trial results on Monday, June 7, at the American Society of Clinical Oncology meeting. This new study, a phase II clinical trial, is the latest in a series of clinical work showing that EGCG is effective in reducing the life of CLL leukemic cells.
Chronic lymphocytic leukemia is one of four main types of leukemia. According to the Leukemia and Lymphoma Society, approximately 15,490 new cases of CLL were diagnosed in 2009, and there are about 85,710 people in the United States who are living with or who are in remission from the disease.
Chronic lymphocytic leukemia begins when there is a mutation in the DNA of a lymphocyte. In 95 percent of people who have the disease, the mutation occurs in a B lymphocyte, while the other 5 percent occurs in T lymphocytes or NK cells, another type of lymphocyte.
CLL occurs most often in people who are 60 years or older. The number of people who develop the disease begins to rise after age 50, and children do not get this form of leukemia. Signs and symptoms include tiring easily, shortness of breath, swollen lymph nodes or spleen, increased susceptibility to infections, weight loss, aches, fever, and night sweats.
In this phase II trial, the Mayo Clinic researchers evaluated data from 41 patients with CLL who were given EGCG for six months. A 20 percent or greater reduction in the number of leukemia cells was seen in 31 percent of patients, and 69 percent of patients who had enlarged lymph nodes experienced a 50 percent or greater reduction in node size.
Tait Shanafelt, MD, a hematologist at Mayo Clinic and the study’s lead author, noted that while a phase III trial was necessary to determine whether EGCG can delay progression of the disease, “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.” He also pointed out that EGCG is not a substitute for chemotherapy.
All of the patients in the trials have been in the early stage of CLL and asymptomatic, thus typically they would not receive treatment until their disease had progressed. Therefore the researchers were aggressive about studying side effects from use of EGCG and reported even transient grade 1 and 2 reactions. Generally, grade 1 are mild side effects; grade 2, moderate; 3, severe; 4, life threatening or disabling; and 5, fatal. Only three patients experienced a grade 3 side effect during the six-month treatment period.
Thus far, the green tea extract EGCG has demonstrated benefits for people who have chronic lymphocytic leukemia. Neil Kay, MD, a hematology research who was involved in early testing of the green tea extract in leukemic blood cells, noted that “Without a phase III clinical trial, we cannot make a recommendation that EGCG be used by CLL patients, but those who want to take supplements should consult with their oncologists and need to receive appropriate monitoring using laboratory tests.”
The Leukemia and Lymphoma Society