Patients receive glutaminase inhibitor CB-839 orally (PO) twice daily (BID) on days 1-28, panitumumab intravenously (IV) over 60-90 minutes on days 1 and 15, and irinotecan hydrochloride IV over 90 minutes on day 1 and 15. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity.