Irinotecan, a prodrug of SN-38, is used to treat many types of metastatic and drug-resistant cancers, and often represents the therapy of the last resort. Unfortunately, a large percentage (up to 40%) of these patients will experience serious (Grade 2) and severe (Grade 3-4) delayed-onset diarrhea (SDOD), which really downgrade patient?s quality of life. SDOD may lead to prolonged hospitalization and even death in some instances. The long-term goal of our research is to develop experimental therapeutics and/or nutritional supplemental approach to reduce SDOD, so patients can sustain their chemotherapy. Our recent studies have shown that inactivation of intestinal UDP-glucuronosyltransferases (UGTs) by SN-38 is a new mechanism by which SN-38 causes SDOD, and that a Traditional Chinese Medicine, Xiao-Chai-Hu-Tang (XCHT), could attenuate the inactivation of intestinal UGTs in mice. Therefore, the central hypothesis of this current proposal is Therefore, we hypothesize that XCHT will prevent or reduce irinotecan-induced SDOD by attenuating the decline in UGT activities, reducing gut SN-38 exposure, and promoting the recovery of gut UGT activities. We plan to test this hypothesis using four Specific Aims: (1) perform phytochemical, biopharmaceutical and pharmacokinetic characterization of XCHT to enable quality control, systemic and intestinal drug exposure determinations, and to provide bioanalytical methods and pharmacokinetic parameters needed for a clinical study and PK/PD modeling; (2) validate plasma raloxifene-4?-glucuronide levels as a probe to changes in intestinal Ugt/UGT activity; (3) Perform mouse ?co- trial? studies to support human mechanistic trials and to determine the mechanisms of action of XCHT against irinotecan-induced SDOD using both in vitro and in vivo models; and (4) Conduct a mechanistic clinical trial using a randomized double-blind design with a safety ?Run-In? to determine if XCHT can attenuate human intestinal UGT decrease and reduce incidence of Grade 3 or higher diarrhea caused by irinotecan chemotherapy. Aside from these primary outcomes, we will also determine if levels of Ral-4?-G, a probe of intestinal UGT activities is (negatively) correlated with systemic levels of inflammatory cytokines. Success gained through this research will provide a new mechanism by which we can target to treat SDOD caused by irinotecan chemotherapy.
. Irinotecan is an effective chemotherapeutic agent that is widely used for the treatment of cancers that are not sensitive to other drugs. Its clinical use is severely limited by the severe diarrhea that results in poor quality of life, hospitalization and even death. The purpose of this research is to develop and test a classical Chinese Medicine formula called Xiao-Chai-Hu-Tang (with hundreds of years of recorded human use) to reduce severe diarrhea so patients will have less side effects and perhaps even better therapeutic efficacy. Both animal studies and human clinical trials are proposed to determine the mechanism(s) by which XCHT act an effective agent to alleviate irinotecan-related severe diarrhea.
