ATR and neoplasm: To prevent these toxic effects, several strategies can be proposed: (1) a treatment schedule with ATRi ON/OFF, as already performed in preclinical and clinical studies,16 18 47 (2) using the treatment locally rather than systemically, as in the case of pressurized intraperitoneal aerosol chemotherapy treatment of peritoneal metastases, and (3) creating an antibody drug conjugate armed with ATRi, which would target a specific tumor cell antigen to deliver the ATR inhibitor locally into the tumor microenvironment.