Within the RELAZA2 trial, AML and high-risk MDS patients in CR prospectively received pre-emptive azacitidine after developing MRD-positive disease defined as either decline of CD34-chimerism <80% or >1% burden of RUNX1/RUNX1T1 or NPM1 mutation levels. The gene discussed is NPM1; the disease is acute myeloid leukemia.