An orally available, selective inhibitor of cyclin-dependent kinase 7 (CDK7) with potential antineoplastic activity. Upon oral administration, samuraciclib selectively and competitively binds to the CDK7 ATP binding site, thereby inhibiting CDK7-mediated signaling. CDK7, a serine/threonine kinase, plays a role in controlling cell cycle progression, transcriptional regulation, and promotes the expression of key oncogenes such as c-Myc through the phosphorylation of RNA polymerase II. Inhibition of CDK7 may inhibit tumor cell proliferation in certain cancers that are dependent on CDK7-mediated transcriptional regulation and signaling.