The invention relates to novel solvates of methyl {4,6-diamino-2-[1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]pyrimidin-5-yl}carbamate, in particular the semi-ethanol solvate of the formula (Ia), to processes for their preparation, to medicaments comprising them and to their use for controlling diseases