Radiosynthesis of [F]brequinar for PET imaging of hDHODH for potential studies of acute myeloid leukemia and cancers.

Dihydroorotate dehydrogenase (DHODH), an enzyme that plays a critical role in the pyrimidine biosynthesis, has been recognized as a promising target for the treatment of diseases that involve cellular proliferation, such as autoimmune diseases and cancers. Pharmacological inhibition of human DHODH (hDHODH) that offers a potential therapeutic strategy for the treatment in adult subjects with acute myeloid leukemia (AML) has recently been supported by phase I/II clinical trials for the treatment of patients with relapsed/refractory AML. To facilitate the development of optimized hDHODH inhibitors, the presence of an imaging probe that is able to demonstrate target engagement is critical and desirable.