QuANTUM-R phase III study of AC 220 shows benefits for overall survival in acute myeloid leukemia.- Daiichi Sankyo.

Daiichi Sankyo announced updated positive results from the pivotal QuANTUM-R phase III study of AC 220 (quizartinib) which showed that patients with relapsed/refractory acute myeloid leukemia (AML) with FLT3-ITD mutations who received quizartinib had a 24 percent reduction in the risk of death compared to patients who received salvage chemotherapy (hazard ratio [HR] = 0.76, P=0.0177, 95 percent CI 0.58-0.98). The median overall survival was 6.2 months (two-sided 95 percent CI 5.3-7.2) for patients treated with quizartinib and 4.7 months (two-sided 95 percent CI 4.0-5.5) for patients treated with salvage chemotherapy. The estimated survival probability at 1 year was 27 percent for patients who received quizartinib and 20 percent for patients who received salvage chemotherapy. Secondary and key exploratory analyses including composite complete remission (CRc) are consistent and supportive of the primary analysis. Data were presented at the 23rd Congress of the European Hematology Association.

The safety profile observed in QuANTUM-R appears consistent with that observed at similar doses in the quizartinib clinical development program. The median treatment duration with quizartinib was 4 cycles of 28 days (97 days; range: 1-1,182 days) versus 1 cycle (range: 1-2) in the salvage chemotherapy arm. The median relative dose intensity for quizartinib was 89 percent. Incidence of treatment-emergent adverse events were comparable between patients who received single agent quizartinib (n=241) and those who received salvage chemotherapy (n=94). The most common adverse events (>30 percent, any Grade) in patients treated with quizartinib versus chemotherapy, respectively, included nausea (48 vs 42 percent), thrombocytopenia (39 vs 34 percent) and fatigue (39 vs 29 percent).

Comment: these findings represent the first reported clinical data demonstrating that a single agent can significantly improve overall survival, suggesting that quizartinib could potentially help these patients live longer. Additionally, in the study, a higher proportion of patients received a stem cell transplant in the quizartinib arm compared to the chemotherapy arm.