These observations led to the design of the INDIGO trial, a multicenter, randomized, placebo-controlled Phase III study comparing the efficacy of vorasidenib with placebo in patients with residual/recurrent mut-IDH1/2 grade 2 glioma who have not yet received previous radiation or CT and are under radiographic surveillance following surgery (NCT04164901). Here, IDH1 is linked to central nervous system cancer.