The present invention relates to novel crystalline, water-soluble salts of a plk inhibitor. Such crystal salts are for example L-tartrate, succinate, phosphate, mesylate, maleate, L-malate, hydrochloride, fumarate (half mole of counterion), fumarate, citrate (half mole of counterion), benzenesulfonate and L-aspartate (half mole of counterion). New crystal forms of the base as well as solvates and hydrates of such new salt forms, a process for their preparation, their utility in therapy and to the pharmaceutical compositions containing them are also claimed and described in the present application.
