Abstract: An antitumor composition comprising a pharmacologically effective quantity of an ester of 1-.beta.-D-arabinofuranosylcytosine-5'-phosphate represented by the general formula ##STR1## where R is a monovalent aliphatic hydrocarbon group having 14 to 23 carbon atoms, and A designates a hydrogen atom or a pharmaceutically-acceptable alkali cation, and a vehicle is effective when administered by a non-injection method, particularly orally.
Abstract: A new composition of matter, 1-.beta.-D-arabinofuranosylcytosine-5'-oleyl phosphate, represented by the structural formula ##STR1## and its pharmaceutically-acceptable salts exhibit antitumor properties and are especially useful for oral administration thereof.