Definition

The hydrochloride salt form of asciminib, an orally bioavailable, allosteric Bcr-Abl1 tyrosine kinase inhibitor, with antineoplastic activity. Upon administration, asciminib targets and binds to the myristoyl pocket of the Bcr-Abl1 fusion protein at a location that is distinct from the ATP-binding domain, thereby inhibiting the activity of both wild-type Bcr-Abl and certain mutation forms, including the T315I mutation. This binding results in the inhibition of Bcr-Abl1-mediated proliferation and enhanced apoptosis of Philadelphia chromosome-positive (Ph+) hematological malignancies. The Bcr-Abl1 fusion protein tyrosine kinase is an abnormal enzyme produced by leukemia cells that contain the Philadelphia chromosome.