N-[4-(2,4-difluorophenoxy)-3-(6-methyl-7-oxo-6,7-dihydro-1H-pyrrolo[2,3-c]pyridin-4-yl)phenyl]ethanesulfonamide and crystalline forms thereof are suitable pharmaceutical ingredients for pharmaceutical compositions useful in the treatment of disease, for example, cancer.N-[4-(2,4-二氟苯氧基)-3-(6-甲基-7-側氧基-6,7-二氫-1H-吡咯并[2,3-c]吡啶-4-基)苯基]乙磺醯胺及其結晶形式係可用於治療疾病(諸如癌症)之醫藥組合物的適合醫藥成份。