There will be two cohorts with a total of 24 patients in this study. Cohort A will enroll 6 naïve postmenopausal female patients who have never received irinotecan treatment before. Patients in this group will have 4 rounds of studies following different protocol to determine (1) the impact of XCHT on raloxifene PK (Round 0, co-administration of XCHT and raloxifene); (2) the impact of XCHT on irinotecan PK (Round 1, co-administration of XCHT and standard FOLFIRI); (3) the safety of co- administration of XCHT, raloxifene, and FOLFIRI and evaluation of raloxifene as a probe for XCHT treatment to prevent irinotecan-induced severe delayed-onset diarrhea (Round 2 and 3, co-administration of XCHT, raloxifene, and standard FOLFIRI). The reason to recruit postmenopausal women is that these patients usually take raloxifene to prevent osteoporosis and the risk of raloxifene is expected to be limited.~Cohort B will recruit 18 patients who were treated with irinotecan previously and have at least one diarrhea episode with a severity of ≥grade 2. The reason we propose to recruit patients who had diarrhea induced by irinotecan is that these patients are supposed to be sensitive to irinotecan so that we can determine the PK changes and safety. Patients in this group will have 3 rounds of FOLFIRI chemotherapy to determine (1) the impact of FOLFIRI on raloxifene PK (Round 1, co-administration of FOLFIRI with raloxifene); (2) the complete PK profile of SN-38, SN-38G, raloxifene, raloxifene-glucuronide, and XCHT components (Round 2, co- administration of FOLFIRI with XCHT and raloxifene); and (3) the safety of co-administration of XCHT, raloxifene, and FOLFIRI in sensitive patients and evaluation of raloxifene as a probe for XCHT treatment to prevent irinotecan-induced diarrhea (Round 3, co-administration of XCHT, raloxifene and standard FOLFIRI).
Run-in safety study, to determine the safety of co-administration of irinotecan, raloxifene, and Xiao Chai Hu Tang (XCHT), and to optimize the blood collection time points for pharmacokinetic (PK) study for another randomized control trial.