The maleate salt form of glasdegib, an orally bioavailable small-molecule, smoothened (SMO) receptor inhibitor, with potential antineoplastic activity. Upon oral administration, glasdegib targets, binds to and inhibits the activity of SMO. This inhibits the activity of the Hedgehog (Hh) signaling pathway and inhibits the growth of tumor cells in which this pathway is aberrantly activated. SMO, a transmembrane protein, is involved in Hh signal transduction. The Hh signaling pathway plays an important role in cellular growth, differentiation, repair, and cancer stem cell (CSC) survival. Constitutive activation of Hh pathway signaling has been observed in various types of malignancies and is associated with uncontrolled cellular proliferation in a variety of cancers.