This invention relates to methods and compositions for treating pancreatic cancer. More specifically, this invention relates to treating pancreatic cancer with certain ATR inhibitors in combination with gemcitabine and/or radiation therapy. This invention also relates to methods and compositions for treating non- small cell lung cancer. More specifically, this invention relates to treating non-small cell lung cancer with an ATR inhibitor in combination with cisplatin or carboplatin, etoposide, and ionizing radiation.
