A Next-generation Sequencing-based Assay for Minimal Residual Disease Assessment in AML Patients with -ITD Mutations

Internal tandem duplications in (ITDs) are common in acute myeloid leukemia (AML) and confer a poor prognosis. A sensitive and specific assay for the detection of minimal residual disease (MRD) in ITD mutated AML could guide therapy decisions. Existing assays for MRD in ITD AML have not been particularly useful because of limited sensitivity. We developed a sensitive and specific MRD assay for ITD mutations using next-generation sequencing. The initial validation of this assay was performed by spiking fixed amounts of mutant DNA into wild-type DNA to establish a sensitivity of detection equivalent to ≥1 ITD-containing cell in 10 000, with a minimum input of 100 000 cell equivalents of DNA. We subsequently validated the assay in bone marrow samples from patients with ITD AML in remission. Finally, we analyzed bone marrow samples from 80 patients with ITD relapsed/refractory AML participating in a trial of a novel FLT3 inhibitor, gilteritinib, and demonstrated a relationship between the mutation burden, as detected by the assay, and overall survival. This novel MRD assay is specific and 2 orders of magnitude more sensitive than currently available polymerase chain reaction- or next-generation sequencing-based ITD assays. The assay is being prospectively validated in ongoing randomized clinical trials.