Crossover Evaluation of Effect of Atorvastatin on PK of Irinotecan in CRC Patients Receiving FOLFIRI

This is a single-center, prospective, randomized, crossover study to address the pharmacokinetic effects of atorvastatin on irinotecan metabolism in patients receiving their first cycle of FOLFIRI (5-fluorouracil + leucovorin + irinotecan). Each cycle of FOLFIRI is defined as 28 days, with a dose of FOLFIRI administered on day 1 and day 15. Patients will be recruited from the UNC Lineberger Cancer Center, referred by their primary oncologist for the treatment of metastatic colorectal cancer (mCRC). After obtaining informed consent, the patient will be randomized to either ARM A or ARM B. Blood samples will be collected on day 1 and 15 of FOLFIRI prior to treatment with irinotecan (baseline), immediately following the end of the irinotecan infusion, and at 0.5, 1, 1.5, 2, 4, 6, and 24 hours following the end of the irinotecan infusion. ARM A subjects will receive atorvastatin 20 mg orally once daily given for two weeks starting on Day -14 during PERIOD ONE. ARM A will then receive no statin during PERIOD TWO. Patients will receive FOLFIRI infusion on day 1 and day 15. Blood samples will be collected at baseline and periodically through 24 hours. ARM B subjects will receive no atorvastatin during PERIOD ONE. ARM B subjects will receive atorvastatin 20 mg orally once daily for two weeks during PERIOD TWO (starting on Day 2). Patients will receive FOLFIRI infusion on day 1 and day 15. Blood samples will be collected at baseline and periodically through 24 hours. DNA extraction and genetic analysis of UGT1A1 polymorphisms will be performed in collaboration with Dr. Federico Innocenti and those patients homozygous for the UGT1A1\*28 allele will be excluded due to their altered irinotecan metabolism. Patients will be followed until Day 1 of Cycle 2 of FOLFIRI. Patients removed from study for unacceptable adverse events will be followed until resolution or stabilization of the event(s).