Astellas' Phase III trial of gilteritinib disappoints

The US subsidiary of Japanese drug major Astellas Pharma (TYO: 4503) today announced disappointing top-line results from the Phase III MORPHO clinical trial evaluating gilteritinib as a maintenance therapy following allogeneic hematopoietic stem cell transplantation (HSCT) for patients with FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD) mutated acute myeloid leukemia (AML).

The data showed that the study did not meet its pre-defined primary endpoint of relapse-free survival (RFS) for patients treated with gilteritinib compared to placebo. The study was conducted in collaboration with the Blood and Marrow Transplant Clinical Trials Network BMT CTN.

The Phase III MORPHO trial is a randomized, double-blind, placebo-controlled, multicenter trial that compares gilteritinib to placebo as maintenance therapy over a period of two years following HSCT in 356 patients with FLT3-ITD mutated AML and in remission after induction therapy. The most frequent treatment-emergent adverse events (TEAEs) were decrease in neutrophil count, diarrhea and nausea, which were generally consistent with previous studies of gilteritinib. Detailed results will be submitted for publication and for consideration at upcoming medical meetings. Since RFS was not statistically significant at the primary analysis, the study, including follow-up, will be stopped as per the study protocol.