An oral formulation of the phosphate salt of fludarabine, a synthetic purine nucleoside analogue antimetabolite with antineoplastic activity. Fudarabine is preferentially transported into malignant cells and metabolized by deoxycytidine kinase to its active form, 2-fluoro-ara-ATP; 2-fluoro-ara-ATP competes directly with deoxyadenosine triphosphate (dATP) and inhibits alpha DNA polymerase, RNA reductase, and DNA primase, which may result in inhibition of DNA synthesis and cell death.