HOUSTON – Midostaurin maintenance therapy along with standard-of-care treatment after allogeneic stem cell transplant (alloSCT) in patients with acute myeloid leukemia (AML) appears to reduce the risk of relapse, according to findings from the randomized, phase 2 RADIUS trial.
Sharon Worcester/MDedge News
Dr. Richard T. Maziarz
Notably, the effect of midostaurin in this open-label, exploratory trial was most pronounced in patients with high levels of phosphorylated FLT3 (pFLT3) inhibition as assessed by plasma inhibitor activity assay, Richard T. Maziarz, MD, reported at the Transplantation & Cellular Therapy Meetings.
“The median [pFLT3 reduction] was less than 70% ... those patients who had the deepest level inhibition maintained the highest likelihood of staying free of disease,” Dr. Maziarz, a professor of medicine at Oregon Health & Science University, Portland, said at the meeting held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research. At its meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy (ASTCT).
Midostaurin is a multitargeted tyrosine kinase inhibitor (TKI) that was shown in the pivotal RATIFY trial to significantly improve event-free and overall survival versus placebo when interspersed with induction and consolidation chemotherapy and also when used for maintenance in adults with newly diagnosed FLT3-mutated AML, Dr. Maziarz explained. He noted that patients in the RATIFY study who underwent alloSCT did not receive midostaurin maintenance (N Engl J Med. 2017; 377:454-64).
Although alloSCT provides the greatest likelihood of sustained remission in AML, relapse rates remain high at 30%-59%, he said, adding that, “in the setting of transplantation, FLT3 expression, or FLT3-ITD [internal tandem duplication] ... is a poor risk feature.”