Asciminib

Asciminib is a tyrosine kinase inhibitor (TKI) used in the treatment of chronic-phase Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML). More specifically, it is an inhibitor of the ABL1 kinase activity of the BCR-ABL1 fusion protein which serves as a driver of CML proliferation in most patients with the disease. It has also shown benefit in Ph+ CML with the T315I mutation, which produces a mutant BCR-ABL1 which is typically treatment-resistant as compared to wild-type BCR-ABL1. Existing inhibitors of ABL compete at the ATP binding sites of these proteins and can be classified into those that target the active conformation of the kinase domain (dasatinib, bosutinib) and those that target the inactive kinase domain (imatinib, nilotinib, ponatinib). Asciminib is unique in that it acts as an allosteric inhibitor, binding at the myristoyl pocket of the BCR-ABL1 protein and locking it into an inactive conformation. Asciminib received FDA approval on October 29, 2021 (Scemblix, Novartis AG).