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

Inclusion Criteria: 1. Age ≥18 years of age (no upper age limit) 2. Histological or cytological documentation of adenocarcinoma of the colon or rectum, and patient scheduled to begin FOLFIRI for treatment of their metastatic disease 3. Patients taking statins at the time of enrollment are permitted. Patients taking statins (or one of the prohibited drugs, see section 4.2.27 and section 12.1) must agree to a 2 week washout prior to treatment with atorvastatin (see Schema) and section 5.2 4. Life expectancy of at least 3 months 5. Eastern Cooperative Oncology Group (ECOG) performance status ≤1 6. Adequate bone marrow, renal, and hepatic function, as evidenced by the following within 7 days of treatment initiation with atorvastatin (or nothing, if enrolled into Arm B): absolute neutrophil count (ANC) ≥1,500/mm3 platelets ≥100,000/mm3 hemoglobin ≥9.0 g/dL serum creatinine ≤1.5 x upper limit of normal (ULN) AST and ALT ≤ 3 x ULN Total bilirubin ≤ 1.5 x ULN Alkaline phosphatase ≤2.5 x ULN Amylase and lipase ≤1.5 x ULN INR/PTT ≤1.5 x ULN CPK ≤ ULN 7. Women of childbearing potential and male subjects must agree to use adequate contraception for the duration of study participation. Adequate contraception is defined as any medically recommended method (or combination of methods) as per standard of care. 8. Medical oncologist agrees that two week window is appropriate/safe prior to start of FOLFIRI for trial candidate. 9. The subject is capable of understanding and complying with parameters as outlined in the protocol 10. Signed, IRB-approved written informed consent Exclusion Criteria: 1. Any prior allergies to statin therapy or adverse events that precluded further use, including but not limited to myopathy, rhabdomyolysis, etc. Patients who had to change from atorvastatin to another statin for safety or efficacy reasons will also be excluded. 2. Prior treatment with FOLFIRI or single agent irinotecan is prohibited within six weeks of enrollment. All prior toxicity from previous irinotecan administration must be resolved prior to enrollment. No more than 2 prior therapeutic regimens for metastatic disease are allowed. 3. Patients will not be allowed to receive bevacizumab or EGFR inhibitors (cetuximab or panitumumab) for the duration of the study (1 cycle). 4. Patients with baseline LDL ≤ 100 mg/dL who are not currently treated with statins 5. Patients homozygous for the UGT1A1\*28 allele, and patients of Asian descent homozygous or heterozygous for the UGT1A1\*6 allele will be excluded due to their altered irinotecan metabolism 6. Pregnant or breastfeeding patients. Women of childbearing potential must have a pregnancy test performed a maximum of 7 days before start of atorvastatin and FOLFIRI treatment, and a negative result must be documented before start of treatment with atorvastatin or FOLFIRI (whichever is received first by patient). 7. Patients who have been treated with any hematopoietic colony-stimulating growth factors (e.g., G-CSF, GM-CSF) ≤2 weeks prior to starting study drug. Erythropoietin or darbepoetin therapy, if initiated ≥2 weeks prior to enrollment, may be continued. 8. History of Gilbert's syndrome 9. Pernicious anemia or other anemias due to Vitamin B12 deficiency (due to potential masking of deficiency by leucovorin) 10. Known Dihydropyrimidine dehydrogenase (DPD) deficiency 11. Major surgical procedure, open biopsy, or significant traumatic injury within 28 days before start of Day 1 of treatment with FOLFIRI 12. Any patients with a history of stroke or TIA within 6 months prior to study enrollment 13. Active cardiac disease including any of the following: Congestive heart failure (New York Heart Association \[NYHA\]) ≥Class 2 (see Appendix C) Unstable angina (angina symptoms at rest), new-onset angina (begun within the last 3 months). Myocardial infarction less than 6 months before start of Day 1 of FOLFIRI Cardiac arrhythmias requiring anti-arrhythmic therapy (beta blockers or digoxin are permitted) 14. Ongoing infection \> Grade 2 according to NCI Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v. 4.0) 15. Known history of human immunodeficiency virus (HIV) infection 16. Presence of acute or chronic liver disease, renal disease or pancreatitis 17. Known history of chronic hepatitis B or C 18. Symptomatic metastatic brain or meningeal tumors unless the patient is \>6 months from definitive therapy, has a negative imaging study within 4 weeks of FOLFIRI initiation, and is clinically stable with respect to the tumor at the time of study entry. Also, the patient must not be undergoing acute steroid therapy or taper (chronic steroid therapy is acceptable provided that the dose is s4.2.2table for one month prior to D1 of treatment under this study) 19. History of organ allograft 20. Non-healing wound, ulcer, or bone fracture 21. Known hypersensitivity to any of the study drugs, study drug classes, or excipients in the formulation 22. Inability to swallow oral medications 23. Evidence or history of bleeding diathesis. Any hemorrhage or bleeding event \> Grade 4 within 4 weeks of start of FOLFIRI 24. Patients with diarrhea CTCAE v4 grade ≥2 25. Any malabsorption condition 26. Unresolved toxicity higher than CTCAE v. 4.0 Grade 1 attributed to any prior therapy/procedure excluding alopecia and oxaliplatin-induced neurotoxicity (which must be ≤Grade 2) 27. Patients unable or unwilling to discontinue (and substitute if necessary) use of prohibited drugs, juices and herbal supplements for at least 2 weeks prior to atorvastatin initiation (see Appendix A for list of prohibited drugs, juices and herbal supplements) 28. Substance abuse, medical, psychological, or social conditions that may interfere with the patient's participation in the study or evaluation of the study results 29. Unwilling to provide consent for genetic studies of whole blood or plasma specimens