Patients with suspected AML harboring IDH2 R140/R172 mutations were screened under the Beat AML Master Trial and consented for this study (n = 64). Eligible patients started on ENA monotherapy with up to 5 cycles to achieve a CR or CRi (n = 60). Patients who achieved a CR/CRi by 5 cycles continued on ENA monotherapy until relapse (n = 29). Patients who did not achieve a CR/CRi started ENA plus AZA combination therapy (n = 17). Patients who experienced treatment failure, death, withdrew, or an adverse event warranting discontinuation during the first 5 cycles of ENA monotherapy went off study (n = 14). Patients were accrued in 2 stages, n = 24 and n = 36, respectively.