We profiled two IDH1 mutant glioma models, grown as intracranial xenografts, treated with an IDH1 inhbitor. One model, BT424, was responsive to IDH1 inhibition by compound treatement and also displayed more transcriptional changes in response to treatment. The other model, GB10, was not responsive to IDH1 inhibition and was transcriptionally quiet after treatment with compound. Overall design: BT142 or GB10 xenograft bearing animals were treated with 30 mpk MRK-A or vehicle for 4 weeks