A Study of ASP2215 (Gilteritinib) by Itself, ASP2215 Combined With Azacitidine or Azacitidine by Itself to Treat Adult Patients Who Have Recently Been Diagnosed With Acute Myeloid Leukemia With a FLT3 Gene Mutation and Who Cannot Receive Standard Chemotherapy

This was a clinical study for adult participants who were recently diagnosed with acute myeloid leukemia or AML. AML is a type of cancer. It is when bone marrow makes white blood cells that are not normal. These are called leukemia cells. Some participants with AML have a mutation, or change, in the FLT3 gene. This gene helps leukemia cells make a protein called FLT3. This protein causes the leukemia cells to grow faster. For participants with AML who could not receive standard chemotherapy, azacitidine (also known as Vidaza®) was a current standard of care treatment option in the United States. This clinical study tested an experimental medicine called ASP2215, also known as gilteritinib. Gilteritinib worked by stopping the leukemia cells from making the FLT3 protein. This helped stop the leukemia cells from growing faster. This study compared two different treatments. Participants were assigned to one of these two groups by chance: a medicine called azacitidine, also known as Vidaza®, or an experimental medicine gilteritinib in combination with azacitidine. There was a twice as much chance to receive both medicines combined than azacitidine alone. The clinical study may help show which treatment helps patients live longer.

Participants considered an adult according to local regulation at the time of obtaining informed consent participated in the study. Safety Cohort Prior to initiation of the randomized trial, 15 participants were enrolled to evaluate the safety and tolerability of ASP2215 given with azacitidine therapy in the study population. Randomized Trial Approximately 250 participants were randomized in a 2:1 ratio to receive ASP2215 plus azacitidine (Arm AC) or azacitidine only (Arm C). Participants entered the screening period up to 14 days prior to the start of treatment. Participants administered treatment over 28-day cycles. Earlier protocol versions included a 1:1:1 randomization ratio to receive Arm A: ASP2215, Arm AC: ASP2215 + azacitidine or Arm C: azacitidine. Participants previously randomized to Arm A continued following treatment and assessments as outlined in the protocol.