Disclosed are tablets comprising hydrolytically stable formulations of (6-(5-fluoro-2-(3,4,5-trimethoxyphenylamino)pyrimidin-4-ylamino)-2,2-dimethyl-3-oxo-2H-pyrido[3,2-b][1,4]oxazin-4(3H)-yl)methyl phosphate disodium salt (Compound 1) prepared by a wet granulation process.