This specification generally relates to compounds of Formula (I). And pharmaceutically acceptable salts thereof, where R1, R2 and R3 have any of the meanings defined herein. The specification also relates to the use of such compounds and salts thereof to treat or prevent ATM kinase mediated disease, including cancer. The specification further relates to crystalline forms of compounds of Formula (I) and pharmaceutically acceptable salts thereof； pharmaceutical compositions comprising such compounds and salts thereof； kits comprising such compounds and salts thereof； methods of manufacture of such compounds and salts thereof； intermediates useful in the manufacture of such compounds and salts thereof； and to methods of treating ATM kinase mediated disease, including cancer, using compounds of Formula (I) and salts thereof alone or in combination with other therapies.
