This invention relates to crystalline solvates of (10R)-7-amino-12-fluoro-2,10,16-trimethyl-15-oxo-10,15,16,17-tetrahydro-2H-8,4-(metheno)pyrazolo[4,3-h][2,5,11]benz- oxadiazacyclotetradecine-3-carbonitrile, useful in the treatment of abnormal cell growth, such as cancer, in mammals. This invention also relates to pharmaceutical compositions comprising such crystalline solvates, and to methods of using such solvates and compositions in the treatment of abnormal cell growth in mammals, especially humans.