In Reply We thank Dr Khaire and colleagues for their interest in our study,¹ and for their agreement that the study provides strong evidence that the detection of persistent FLT3-ITD or NPM1 variants in the blood samples of adults during first remission from AML prior to allogeneic transplant is associated with increased posttransplant relapse and death, compared with those testing negative.

The anchored multiplex PCR-based targeted DNA next-generation sequencing approach was specifically selected because of the advantages of this method for de novo discovery of both small and large ITDs in FLT3.¹ As described in the eMethods in Supplement 1,¹ unidirectional amplification from each single gene-specific primer is unrestricted by opposing primers, and multiple FLT3 gene–specific primers function independently giving overlapping reads of ITD-containing regions from both directions. As seen in eTable 6 in Supplement 1, we detected ITDs ranging in length from 6 to 207 base pairs (median, 48 base pairs).¹ This compares well with the FLT3-ITD length distribution recently reported for 3 to 201 base pairs (median, 48 base pairs) determined by capillary gel electrophoresis on initial diagnostic samples from 362 adult patients with AML² and in other studies.³ There was no significant difference in the variant allele fraction distribution of persistent FLT3-ITD and mutated NPM1, and both were detected to the 0.01% threshold as shown in eFigure 3 in Supplement 1.¹ As expected with this method, no association was observed between ITD length and variant allele fraction.