Quizartinib

Quizartinib (AC220) is a small molecule receptor tyrosine kinase inhibitor that is currently under development for the treatment of acute myeloid leukaemia. Its molecular target is FLT3, also known as CD135 which is a proto-oncogene. Flt3 mutations are among the most common mutations in acute myeloid leukaemia due to internal tandem duplication of Flt3. The presence of this mutation is a marker of adverse outcome.

Mechanism
Specifically, Quizartinib selectively inhibits class III receptor tyrosine kinases, including FMS-related tyrosine kinase 3 (FLT3/STK1), colony-stimulating factor 1 receptor (CSF1R/FMS), stem cell factor receptor (SCFR/KIT), and platelet derived growth factor receptors (PDGFRs).

Mutations cause constitutive action of Flt3 leading to resulting in inhibition of ligand-independent leukemic cell proliferation and apoptosis.

Clinical trials
It had good results in a phase II clinical trial for refractory AML - particularly in patients who went on to have a stem cell transplant.