An orally available, small molecule antagonist of the tyrosine kinase transforming growth factor-beta (TGF-b) receptor type 1 (TGFBR1), with potential antineoplastic activity. Upon administration, galunisertib specifically targets and binds to the kinase domain of TGFBR1, thereby preventing the activation of TGF-b-mediated signaling pathways. This may inhibit the proliferation of TGF-b-overexpressing tumor cells. Dysregulation of the TGF-b signaling pathway is seen in a number of cancers and is associated with increased cancer cell proliferation, migration, invasion and tumor progression. Check for active clinical trialsusing this agent.