Molecular Mechanisms of Quizartinib Response in FLT3-ITD Negative AML: An Updated Analysis from the Pethema Quiwi Trial

Introduction

FLT3 ITD negative acute myeloid leukemia (AML) remains challenging to treat due to limited targeted therapeutic options. The QUIWI trial showed promising outcomes with quizartinib (Quiza) combined with standard chemotherapy in this setting. This analysis aims to compare transcriptional profiles of long-term survivors to hypothesize molecular mechanisms underlying differential responses to Quiza versus placebo.

Methods

RNA sequencing (RNAseq) was performed on an expanded cohort of 243 patients from the QUIWI trial, with RNA extracted, assessed for integrity (TapeStation), and quantified (Qubit). PolyA RNAseq using TruSeq technology was conducted, followed by sequence alignment to the GRCh37 reference genome using Hisat and differential expression analysis with DESeq2. P-values were adjusted using the FDR method. Gene ontology and pathway analyses were performed using the WebGestalt portal.

Results

At the time of analysis, the median follow-up was 3.25 years, and the median overall survival (OS) was not reached for the Quiza subgroup. The analysis focused on patients who survived a minimum of 24 months in both placebo and Quiza arms, identifying 267 differentially expressed genes (DEGs) with a false discovery rate (FDR) of 10% between both groups. Among the DEGs, 211 genes were overexpressed in the Quiza group, whereas 56 genes were overexpressed in the placebo group. A significant enrichment of significantly underexpressed heat shock protein genes (HSPA1A, HSPA2, DNAJA3, AHSA1, DNAJB1, FDR < 5%) was observed among longer responders to Quiza. This results aligned with previous evidence indicating mechanistic relationships between FLT3 inhibitors and heat shock proteins reported by Katayama et al. (2018) and Fleischmann et al. (2021). Additionally, genes involved in nucleic acid metabolism, DNA replication, transcription, and splicing (DNTT, FTSJ3, METTL13, TWNK, SF3B3) were significantly underexpressed among longer Quiza responders compared to the placebo group. Conversely, the Quiza group exhibited a notable and significant enrichment in genes associated with the enzyme-linked receptor protein signaling pathway (FDR < 5%). This included several transmembrane receptor proteins with tyrosine kinase function (FGFR3, EPHB2, AXL, ROR2), 2 protein phosphatases (PTPRU and PPM1L), and the MAPK pathway inhibitor SPRY4.

Conclusion

This analysis provides new insights into the molecular mechanisms of Quiza action in FLT3-ITD negative AML. The significant underexpression of heat shock protein genes among longer responders to Quiza suggests a potential role of these proteins as drivers of resistance. Additionally, the broader activation of tyrosine kinase genes indicates possible off-target effects contributing to the efficacy of Quiza in this subset of AML patients. These hypotheses warrant further mechanistic exploration in future studies to enhance therapeutic strategies and clinical outcomes for this challenging AML population.

Mosquera Orgueira:Takeda: Speakers Bureau; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy; Biodigital THX: Current equity holder in private company; Pfizer: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Other; Novartis: Other; GSK: Consultancy. Bernal:Jazz Pharmceutical: Consultancy; Abbvie: Consultancy; Astellas: Honoraria. Salamero:Astellas, Jazz, BMS: Consultancy; Jazz, Abbvie: Honoraria. Vidriales Vicente:F. Hoffmann-La Roche: Other: All authors received support for third-party writing assistance, furnished by Bena Lim, PhD, CMPP, of Nucleus Global, an Inizio company, and funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland.. Ayala:Altum Sequencing: Current equity holder in private company; Astellas: Speakers Bureau; BMS: Speakers Bureau; Incyte: Consultancy; Novartis: Consultancy, Speakers Bureau. Montesinos:Janssen: Membership on an entity's Board of Directors or advisory committees, Other: research support, Speakers Bureau; Daiichi Sankyo, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: research support, Research Funding, Speakers Bureau; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: research support, Speakers Bureau; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: research support, Research Funding, Speakers Bureau; Servier: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: research support, Research Funding, Speakers Bureau; Jazzpharma: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau; Kura Oncology: Consultancy; Syndax: Consultancy; Glycomimetics: Consultancy.