Compounds or their pharmaceutically acceptable salts can inhibit the G12D mutant of Kirsten rat sarcoma (KRAS) protein and are expected to have utility as therapeutic agents, for example, for treating cancer. The disclosure also provides pharmaceutical compositions which comprise compounds disclosed herein or pharmaceutically acceptable salts thereof. The disclosure also relates to methods for use of the compounds or their pharmaceutically acceptable salts in the therapy and prophylaxis of cancer and for preparing pharmaceuticals for this purpose.