AML - FLT3 ITD MRD Assay
Measurable Residual Disease
Detection of FLT3 ITD Mutations
Indications for Testing
Post-treatment monitoring
Stratify risk for disease recurrence

Clinical Information
Measurable residual disease (MRD) detection in patients with leukemia has
proven to be useful in the clinical management of disease and can facilitate thedevelopment of new therapies. Mutations in the fms-like tyrosine kinase 3 (FLT3)
gene are the most prevalent mutations found in acute myeloid leukemia (AML)1and are characterized by an aggressive phenotype with a high prevalence ofrelapse. Internal tandem duplication (ITD) mutations within the juxtamembrane
domain are the most common mutations of FLT3.2 The development of a sensitiveand specific assay for FLT3 ITD mutations represents a significant advancementin guiding treatment decisions.
LabPMM’s FLT3 ITD MRD test is an NGS-based, targeted, deep-sequencing
assay that detects ITDs ranging from 9 bp to 252 bp in size. Once a specific ITD(length and sequence) has been identified in a primary sample, it can easily
be tracked in subsequent samples at a sensitivity of 5x10-5, provided sufficient
DNA quantity is tested.

Identify tumor-specific markers
for post-treatment for monitoring

Interpretation
An interpretive report will beissued indicating whether FLT3
ITD MRD was detected.

Specimen Requirements
1-3 mL of peripheral blood in EDTA
0.25-1 mL of bone marrow in EDTA
1 µg of previously isolated DNA

The treatment of AML has become a paradigm for precision medicine. This MRD
assay is at least two orders of magnitude more sensitive than other commerciallyavailable FLT3 assays. It detects the persistence of a driver mutation, FLT3 ITD,
in patients with no overt evidence of disease, allowing clinicians to identify thosepatients that can benefit from continuation or modification of treatment.3

Turnaround Time

MRD detection by Next-Generation Sequencing has demonstrated utility
in predicting clinical outcomes and in generating clinically actionable results,
allowing early intervention, confirmation of disease status prior to transplant,
and increased confidence in remission status.

Shipping Conditions

7 to 10 business days

Ambient or Cool; do not freeze(peripheral blood or bone marrow)

Ambient or frozen on dry ice

Workflow Overview
Sample Receipt Peripheral blood, bone marrow aspirate, or DNA
NGS Testing, CLIA-Validated Assay Sensitivity 5x10-5(isolated DNA)Specimen Stability
2-8 °C up to 7 days prior to testing

Turnaround Time 7 to 10 Business Days
Results Report with Scientific Interpretation

CPT Codes
PLA Code: 0049U

FLT3 ITD MRD Assayas Predictor of MolecularResponse
FLT3 ITD mutated patients enrolled in theCHRYSALIS study, who were treated withFLT3-inhibitory oral doses of 120mg/day or 200mg/day gilteritinib, had their molecular responseassessed from bone marrow aspirates obtained
at baseline and at ≥1 additional time point.
FLT3 ITD and total FLT3 alleles were quantified
using the Invivoscribe FLT3 ITD MRD assay andused to determine molecular response3.
A Cox regression model of overall survival(OS) by Kaplan-Meier estimation was used
to evaluate the impact of ITD variant allele
frequency (VAF) on overall survival.
Molecular response was defined as follows: Molecular response = ITD VAF (FLT3 mutantreads: FLT3 total reads) of ≤10−2 point.
Major molecular response = ITD VAF of ≤10−3
FIGURE 1: SUBJECTS, OVERALL SURVIVAL STRATIFIED BY MOLECULAR RESPONSE, USING THE
INTERNATIONALLY-HARMONIZED FLT3 ITD MRD ASSAY (10-2)

Negative MRD status = ITD VAF of ≤10−4

As shown in Table 1 and Figure 1, patients withmolecular response had longer overall survival
than those without a molecular response. This is
the first demonstration of molecular response
to a FLT3 inhibitor in AML3.

TABLE 1: SUBJECTS, OVERALL SURVIVAL
Comparison between patients achieving a molecular response (FLT3 ITD VAF ≤10−2, ≤10−3, or negative
as defined by ITD VAF ≤10−4) by the MRD assay and those not achieving a molecular response by theMRD assay. The P values were determined by the log-rank test.

References
1. Ley, T. J. et al. (2013) N Engl J Med. 368: 2059–2074.
2. Konig, H. et al. (2015) Expert Opin Ther Targets 19:37-54.
3. Levis, M. J. et al. (2018) Blood Advances, 2: 825-831.

invivoscribe.com/clinical-services
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M-0150 Rev 01 March 2024