FDA Declines to Approve Quizartinib for FLT3-Mutated Acute Myeloid Leukemia

On June 18, the U.S. Food and Drug Administration (FDA) issued its Complete Response Letter to a new drug application for Daiichi Sankyo’s quizartinib, declining to approve the drug for use in patients with relapsed or refractory FLT3-mutated acute myeloid leukemia (AML). The decision follows the recommendation of the FDA’s Oncologic Drug Advisory Committee, which voted 8-3 against approval in May. The committee cited the inconsistency of the results across the stratification subgroups and the effects of subsequent therapies on the primary endpoint.

In May 2018, data showing that quizartinib lengthened patient’s lives more than chemotherapy encouraged Daiichi to pursue the FDA filing for the drug as a second-line treatment and it was granted priority review status in November. After reviewing the clinical trials data, FDA members expressed concerns about the lack of improvement in event-free survival and the incidence of cardiac-related adverse events. The agency also noted issues with the credibility and generalizability of the trials’ data.

Arnaud Lesegretain, Daiichi Sankyo’s vice president of oncology research and development and head of the company’s AML franchise, said that the company is undeterred: “We remain confident in the data supporting our NDA submission and are committed to bringing quizartinib forward as a potential treatment for relapsed or refractory FLT3-ITD AML,” he said. Daiichi Sankyo is evaluating the next steps for quizartinib in the U.S.

Currently, the drug is only approved for use in Japan.

Sources: Fierce Biotech, June 21, 2019; Reuters, June 21, 2019.