Measurable residual mutated IDH1before allogeneic transplant for acute myeloid leukemia

Measurable residual disease (MRD) in adults with acute myeloid leukemia (AML) in complete remission is an important prognostic marker, but detection methodology requires optimization. Persistence of mutated NPM1or FLT3-ITD in the blood of adult patients with AML in first complete remission (CR1) prior to allogeneic hematopoietic cell transplant (alloHCT) associates with increased relapse and death after transplant. The prognostic implications of persistence of other common AML-associated mutations, such as IDH1, at this treatment landmark however remain incompletely defined. We performed testing for residual IDH1variants (IDH1m) in pre-transplant CR1 blood of 148 adult patients undergoing alloHCT for IDH1-mutated AML at a CIBMTR reporting site between 2013 and 2019. No statistically significant post-transplant differences were observed between those testing IDH1m positive (n= 53, 36%) and negative pre-transplant (overall survival (OS): p= 0.4; relapse: p= 0.5). For patients with IDH1mutated AML co-mutated with NPM1and/or FLT3-ITD, only detection of persistent mutated NPM1and/or FLT3-ITD was associated with significantly higher rates of relapse (p= 0.01). These data, from the largest study to date, do not support the detection of IDH1mutation in CR1 blood prior to alloHCT as evidence of AML MRD for increased post-transplant relapse risk.