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Quantum-First (Q-F): Clinical Bridging Study for FMS-like Tyrosine Kinase 3-Internal Tandem Duplication ( FLT3-ITD) Companion Diagnostic Development

J. E. Rohrbach, Ken C. N. Chang, Maha Karnoub, Li Liu, Y. M. Kamel, Shirin Khambata-Ford, Shawn Rivera, J. Lameh et al.

Blood, 2023

3,468 participants · 1 citation

Abstract

Background

Q-F (NCT02668653) showed that the highly potent, selective, type 2 FLT3 inhibitor quizartinib (Q) + standard chemotherapy ± transplantation, followed by Q monotherapy for ≥36 cycles, reduced the relative risk of death by 22.4% vs placebo (P) in newly diagnosed (nd) FLT3-ITD+ AML, with HR of 0.776 and P value of 0.0324 (PMID: 37116523). In Q-F, FLT3-ITD mutation status was determined using a FLT3-ITD mutation detection clinical trial assay (CTA) validated under design control by Navigate BioPharma Services, Inc. We describe the results of the bridging study, aimed to show agreement between the CTA & the LeukoStrat CDx FLT3 Mutation Assay (CDx, by Invivoscribe) in FLT3-ITD+ pt selection and to determine if Q efficacy (overall survival [OS]) was maintained in nd FLT3-ITD+ AML pts from Q-F, if pts had been selected using the CDx.

Methods

In both CTA & CDx, DNA, extracted from bone marrow (n=884 each) or peripheral blood (n=139 each), was amplified via PCR and amplicons were detected via capillary electrophoresis. A sample was considered CTA+ if the variant allele frequency ( FLT3-ITD/total FLT3) was ≥3% and CDx+ if the signal ratio (SR; FLT3-ITD/ FLT3 WT) was ≥0.05. The agreement between CTA & CDx was based on evaluating CTA+ & CTA− samples with the CDx assay. A primary analysis included the CDx detected (CDx+ & CDx−) and the CDx invalid results. A secondary analysis used CDx+ and CDx− results only. To establish agreement between CDx & CTA, positive % agreement (PPA)…

How strong is the evidence?

Evidence Hub reads this as a randomized trial. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 3,468 participants or records.

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