Urea,N-[4-[1-[(2,6-difluorophenyl)methyl]-5-[[(2-ethoxyethyl)methylamino]methyl]-1,2,3,4-tetrahydro-2,4-dioxo-3-(3-pyridazinyl)thieno[2,3-d]pyrimidin-6-yl]phenyl]-N'-ethyl-