Provided herein are solid forms, salts, and formulations of 3-((1R,3R)-1-(2,6-difluoro-4-((1-(3-fluoropropyl)azetidin-3-yl)amino)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol, processes and synthesis thereof, and methods of their use in the treatment of cancer.本文提供3-((1R,3R)-1-(2,6-二氟-4-((1-(3-氟丙基)氮雜環丁-3-基)胺基)苯基)-3-甲基-1,3,4,9-四氫-2H-吡啶并[3,4-b]吲哚-2-基)-2,2-二氟丙-1-醇之固體形式、鹽及調配物、其製程及合成以及其在治療癌症中之使用方法。