For patients with <i>IDH1</i> mutated AML co-mutated with <i>NPM1</i> and/or <i>FLT3</i>-ITD, only detection of persistent mutated <i>NPM1</i> and/or <i>FLT3</i>-ITD was associated with significantly higher rates of relapse (p = 0.01). The gene discussed is IDH1; the disease is acute myeloid leukemia.