I created a cohort definition to explore the question you posed, and put it out onto the public ATLAS instance: http://www.ohdsi.org/web/atlas/#/cohortdefinition/1769438
Briefly, I looked for persons with a condition occurrence of 'intrahepatic cholangiocarcinoma' (and our standard concepts cover the ICD9/10 codes you mention), a drug exposure of 'enasidenib' (which has a standard concept in the vocab at ingredient level and various clinical drug concepts), and a IDH observation (which could include procedure to perform genetic panel or observation of a mutation).
I ran this cohort across my databases to assess feasibility for you. I do see a fair number of 'intrahepatic cholangiocarcinoma' cases (ranging from the hundreds to thousands across various databases), but I don't see any of these patients with exposure to enasidenib.
I created a separate cohort to look at new users of enasidenib: http://www.ohdsi.org/web/atlas/#/cohortdefinition/1769439
there I saw that there are very few number of exposures to this drug in general: <30 persons in all databases that I have access to.
I see this drug was only approved in Aug2017, for the indication of AML. Given the recency of the drug and the off-label use you are looking for, I suppose it makes sense why I don't see cases. But perhaps others in the community could run these same cohorts to see if they have been lucky in helping than I do.