An immediate-release (IR) tablet formulation containing afuresertib, an inhibitor of the serine/threonine protein kinase Akt (protein kinase B) with potential antineoplastic activity. Upon oral administration of the IR formulation, afuresertib binds to and inhibits the activity of Akt, which may result in the inhibition of PI3K/Akt signaling pathway, decreased tumor cell proliferation and the induction of tumor cell apoptosis in Akt-expressing tumor cells. Activation of the PI3K/Akt signaling pathway is frequently associated with tumorigenesis and dysregulated PI3K/Akt signaling may contribute to tumor resistance to a variety of antineoplastic agents.