Continued Quizartinib May Show Benefit in Select FLT3-ITD+ AML Population

A pronounced survival benefit occurred with maintenance quizartinib (Vanflyta) compared with placebo in patients with newly diagnosed FLT3-ITD–positive acute myeloid leukemia (AML) who did not undergo allogeneic hematopoietic stem cell transplant (allo-HSCT), according to Harry P. Erba, MD, PhD.

In a conversation with CancerNetwork^® at the 2024 European Hematology Association (EHA) Congress, Erba, a professor of Medicine in the Division of Hematologic Malignancies and Cellular Therapy and the director of the Leukemia Program and Phase I Development in Hematologic Malignancies at Duke Cancer Institute, spoke about findings from the phase 3 QuANTUM-First study (NCT02668653) evaluating the impact of quizartinib continuation on outcomes such as overall survival.

Erba noted that there did not appear to be a significant difference in survival among patients who received allo-HSCT based on whether they received continuation therapy with quizartinib or placebo. Additionally, he emphasized caution in interpreting these data due to potential differences in the continuation of quizartinib and placebo groups. He also highlighted ongoing analyses from the trial related to patient-reported outcomes and measurable residual disease (MRD) status.

Transcript:

An interesting observation was the benefit of the continuation [therapy] was most pronounced in patients who did not go to allogeneic transplant in the first remission. In my mind, as I’m thinking about these patients, [they include] those are patients who are older and are not getting an allogeneic transplant. There, the benefit of the quizartinib maintenance was quite dramatically seen over the placebo.

On the other hand, in the patients who did undergo allogeneic transplants, there was no statistically significant difference in the survival outcomes with either placebo or quizartinib as maintenance. In fact, some have commented that, later, there seemed to be more deaths with quizartinib.

We have to be very careful about analyzing these data; there’s no benefit from that analysis. One thing to keep in mind is that the population of patients who continued continuation [therapy] after transplant was slightly different because there were more relapses in the placebo group after the transplant before continuation than there were in the patients who were on quizartinib, got to the transplant, and then were eligible for quizartinib [continuation]. It’s not an exact comparison of 2 similar groups. Biologically, they may have been different. Therein lies the reason why you need to re-randomize at that time to see the independent impact of the continuation therapy.

Having said that, the QuANTUM-First study might still be ongoing if that was our primary end point of the study; we would need so many patients to show that benefit from that re-randomization. It is a limitation of the analysis. Those are the 2 biggest updates from QuANTUM-First. We are also looking at patient-reported outcomes. There’s more data coming out on measurable residual disease [MRD] in the continuation phase. I’m looking forward to seeing the impact of MRD and the benefit of quizartinib or placebo during the continuation phase. But those data are still being analyzed.

Reference

Sekeres MA, Erba H, Montesinos P, et al. QuANTUM-First: efficacy in newly diagnosed patients with FMS-like tyrosine kinase 3-internal tandem duplication–positive (FLT3-ITD+) acute myeloid leukemia (AML) who received continuation therapy. Presented at the 2024 European Hematology Association (EHA) Hybrid Congress; June 13-16, 2024; Madrid, Spain. Abstract S142.