A Phase II Study of Crenolanib in Relapsed/Refractory Acute Myeloid Leukemia Patients With FLT3 Activating Mutations

Inclusion Criteria: * Confirmed primary AML relapsed or refractory after prior therapy, AML secondary to antecedent chemotherapy or radiation therapy, or AML due to prior myelodysplastic syndrome (MDS)/ myeloproliferative neoplasm (MPN) as defined by WHO criteria with presence of either FLT3 ITD and/or other FLT3 activating mutations * Patients with secondary AML should have failed no more than two (2) prior regimens * Patients with antecedent MDS/MPN, defined by WHO criteria, without any prior therapy for AML, regardless of the number of therapies for MDS/ MPN * Patients with primary AML should have received no more than two (2) prior cytotoxic containing salvage regimens. Reinduction with the same regimen or stem cell transplant will not be considered a separate salvage regimen. Change of drugs will be considered a salvage regimen. Unlimited FLT3 TKI therapy (even in combination with cytotoxics/hypomethylating agents) is allowed for patients enrolled in cohort B * Patients must have tested positive for FLT3-ITD and /or other FLT3 activating mutations within 30 day screening period * Males and females age ≥18 years * ECOG PS 0-2 * Adequate liver function, defined as bilirubin ≤1.5x ULN, ALT ≤3.0x ULN, and AST ≤3.0x ULN * Adequate renal function, defined as serum creatinine ≤1.5x ULN * Recovery from non-hematological toxicities of prior therapy (including HSCT) to no more than grade 1 (except alopecia) * Subjects should have received no anti-leukemic therapy (except hydroxyu…