The main goal is to find out what effect, good and/or bad effects AG-120 (ivosidenib) on your tumor. A second goal of the study is to evaluate side effects that might be caused by AG-120 (ivosidenib), which could shrink your cancer but it could also cause side effects. Also to learn more about the pharmacology and pharmacodynamics (how your body handles the drug, and how the drug affects your body) of AG-120 (ivosidenib).