Quizartinib for Newly Diagnosed FLT3-Internal Tandem Duplication-Negative AML: The Randomized, Double-Blind, Placebo-Controlled, Phase II QUIWI Study

Abstract

Purpose: Quizartinib, an oral, selective, second-generation, type-II FMS-like tyrosine kinase 3 (FLT3) inhibitor with high binding affinity to internal tandem duplication (ITD) and wild-type (WT) FLT3, has shown early clinical activity as monotherapy in patients with relapsed/refractory FLT3-ITD-negative AML. The phase III QuANTUM-First trial showed that quizartinib significantly prolonged survival versus placebo when added to standard chemotherapy, followed by single-agent maintenance, in patients with newly diagnosed (ND) FLT3-ITD-positive AML. We investigated the safety and efficacy of quizartinib in patients with ND FLT3-ITD-negative AML.

Methods: The phase II, randomized, double-blind, placebo-controlled QUIWI trial enrolled patients age 18-70 years with ND FLT3-ITD-negative (mutant-to-WT allelic ratio <0.03) AML. Patients were randomly assigned 2:1 to receive standard induction and consolidation chemotherapy combined with either quizartinib 60 mg once daily or placebo, followed by single-agent maintenance with quizartinib or placebo. The primary end point was event-free survival (EFS). Secondary end points included overall survival (OS) and safety.

Results: Overall, 273 patients were randomly assigned to quizartinib (n = 180) or placebo (n = 93). At data cutoff, median EFS was 20.4 months and 9.9 months in the quizartinib and placebo arms, respectively (P = .046). Median OS was not reached and 29.3 months in the quizartinib and placebo arms, respectively (P = .012); 3-year OS rates were 60.8% and 45.7%. The most frequently reported adverse events (any grade) were fever, rash, diarrhea, and mucositis.

Conclusion: The addition of quizartinib to standard chemotherapy was associated with significantly longer EFS and OS than placebo in patients with ND FLT3-ITD-negative AML.