The present disclosure relates to crystalline form of (S)—N—((S)-1-cyclohexyl-2-{(S)-2-[4-(4-fluoro-benzoyl)-thiazol-2-yl]-pyrrolidin-1-yl}-2-oxo-ethyl)-2-methylamino-propionamide, salts and hydrates thereof. This disclosure also relates to solid oral formulation of (S)—N—((S)-1-cyclohexyl-2-{(S)-2-[4-(4-fluoro-benzoyl)-thiazol-2-yl]-pyrrolidin-1-yl}-2-oxo-ethyl)-2-methylamino-propionamide, pharmaceutically acceptable salts, solvates (including hydrates) thereof, as well as methods of treatment using the same.