Measurable Residual Disease Monitoring by Locked Nucleic Acid Quantitative Real-Time PCR Assay for IDH1/2 Mutation in Adult AML.

Locked nucleic acid quantitative Real-Time PCR (LNA-qPCR) for IDH1/2 mutations in AML measurable residual disease (MRD) detection is rarely reported. LNA-qPCR was applied to quantify IDH1/2 mutants MRD kinetics in bone marrow from 88 IDH1/2- mutated AML patients, and correlated with NPM1 -MRD, clinical characteristics, and outcomes. The median normalized copy number (NCN) of IDH1/2 mutants decreased significantly from 53,228 (range 87-980,686)/ ALB × 10 6 at diagnosis to 773 (range 1.5-103,600)/ ALB × 10 6 at first complete remission (CR). IDH1/2 LNA-qPCR MRD was concordant with remission status or NPM1 -MRD in 79.5% (70/88) of patients. Younger patients and patients with FLT3 mutations had higher concordance. The Spearman correlation coefficient (r s ) and concordance rate between the log reduction of IDH1/2 LNA-qPCR and NPM1 -MRD were 0.68 and 81% ( K = 0.63, 95% CI 0.50-0.74), respectively. IDH1/2 -MRD > 2 log reduction at first CR predicted significantly better relapse-free survival (3-year RFS rates 52.9% vs. 31.9%, p = 0.007) and cumulative incidence of relapse (3-year CIR rates 44.5% vs. 64.5%, p = 0.012) compared to IDH1/2- MRD ≤ 2 log reduction. IDH1/2 -MRD > 2 log reduction during consolidation is also associated with a significantly lower CIR rate than IDH1/2 -MRD ≤ 2 log reduction (3-year CIR rates 42.3% vs. 68.8%, p = 0.019). LNA-qPCR for IDH1/2 mutation is a potential MRD technique to predict relapse in IDH1/2- mutated AML patients, especially for those with IDH1/2 MRD > 2 log reduction at first CR or a concurrent FLT3 mutation.