An orally bioavailable cyclin dependent kinase (CDK) inhibitor with potential antineoplastic activity. Roniciclib selectively binds to and inhibits the activity of CDK1/Cyclin B, CDK2/Cyclin E, CDK4/Cyclin D1, and CDK9/Cyclin T1, serine/threonine kinases that play key roles in the regulation of the cell cycle progression and cellular proliferation. Inhibition of these kinases leads to cell cycle arrest during the G1/S transition, thereby leading to an induction of apoptosis, and inhibition of tumor cell proliferation. CDKs are often dysregulated in cancerous cells.