美国明尼苏达州梅奥诊所的一项研究表明，绿茶中的一种活性成分儿茶素酸酯(EGCG)可有效控制慢性淋巴细胞性白血病(CLL)病情，这为攻克该病带来了新希望。该研究结果刊登在近日的《临床肿瘤学杂志》（Journal of Clinical Oncology）网络版上。
在临床试验中，梅奥诊所的研究人员每天两次给33名慢性淋巴细胞性白血病患者服用8种不同剂量的olyphenonE囊剂(该药的主要活性成分是EGCG)，剂量介于400毫克到2000毫克之间。结果发现，病人的淋巴细胞数量降低了三分之一。此外研究人员还发现，病人对该囊剂具有很强的耐受性，即使是每次高达2000毫克，还是没有达到病人的最大耐受剂量。
研究人员发现，病人不仅能够忍受这种高剂量绿茶提取物，而且许多人的慢性淋巴细胞白血病呈现某种程度的好转，在患有淋巴结增大症状的病人中，大部分人的淋巴结会缩小一半甚至更多。
该项临床研究是梅奥诊所多年来就绿茶提取物对癌细胞作用研究项目的最新举措，之前已在实验室研究中证明了EGCG具有杀死白血病癌细胞的功能。目前此项研究已进入第二阶段，后续参与临床试验的病人数与第一阶段人数大致相同。所有人都将服用与原来试验中同样的最高剂量。
在美国，慢性淋巴细胞性白血病是一种常见的白血病。虽然在很多情况下可以通过血液测试进行早期诊断，然而却没有有效的治疗方法。统计显示，大约一半的该病患者会过早死亡。研究人员希望，EGCG能够稳定早期慢性淋巴细胞性白血病患者的病情，或者与其他治疗手段结合，提高对该疾病的治疗效果。（生物谷Bioon.com）
生物谷推荐原始出处：
Journal of Clinical Oncology, 10.1200/JCO.2008.21.1284
Phase I Trial of Daily Oral Polyphenon E in Patients With Asymptomatic Rai Stage 0 to II Chronic Lymphocytic Leukemia
Tait D. Shanafelt,* Tim G. Call, Clive S. Zent, Betsy LaPlant, Deborah A. Bowen, Michelle Roos, Charla R. Secreto, Asish K. Ghosh, Brian F. Kabat, Mao-Jung Lee, Chung S. Yang, Diane F. Jelinek, Charles Erlichman, and Neil E. Kay
From the Department of Internal Medicine, Division of Hematology; Division of Biostatistics, and Departments of Immunology and Oncology, Mayo Clinical, Rochester, MN; and the Department of Chemical Biology, and the Ernest Mario School of Pharmacy Rutgers, the State University of New Jersey, Piscataway, NJ.
Purpose: To define the optimal dose of Polyphenon E for chronic daily administration and tolerability in patients with chronic lymphocytic leukemia (CLL).
Patients and Methods: Previously untreated patients with asymptomatic Rai stage 0 to II CLL were eligible for participation. Polyphenon E with a standardized dose of epigallocatechin-3-gallate (EGCG) was administered using the standard phase I design with three to six patients per dose level (range, 400 to 2,000 mg by mouth twice a day). Trough plasma EGCG levels were measured 1 month after initiation of therapy. Response was classified using the National Cancer Institute (NCI) Working Group (WG) Criteria.
Results: Thirty-three eligible patients were accrued to dose levels 1 to 8. The maximum-tolerated dose was not reached. The most common adverse effects included transaminitis (33%, all grade 1), abdominal pain (30% grade 1, 0% grade 2, and 3% grade 3), and nausea (39% grade 1 and 9% grade 2). One patient experienced an NCI WG partial remission. Other signs of clinical activity were also observed, with 11 patients (33%) having a sustained 20% reduction in absolute lymphocyte count (ALC) and 11 (92%) of 12 patients with palpable adenopathy experiencing at least a 50% reduction in the sum of the products of all nodal areas during treatment. Trough plasma EGCG levels after 1 month of treatment ranged from 2.9 to 3,974 ng/mL (median, 40.4 ng/mL).
Conclusion: Daily oral EGCG in the Polyphenon E preparation was well tolerated by CLL patients in this phase I trial. Declines in ALC and/or lymphadenopathy were observed in the majority of patients. A phase II trial to evaluate efficacy using 2,000 mg twice a day began in November 2007.
