The present invention concerns novel crystalline forms of {5-(4-bromo-phenyl)-6 [2 (5 bromo-pyrimidin-2-yloxy)-ethoxy]-pyrimidin-4-yl}-sulfamide, processes for the preparation thereof, pharmaceutical compositions comprising said crystalline forms, pharmaceutical compositions prepared from such crystalline forms, and their use as endothelin receptor antagonists. It also relates to new uses of {5-(4-bromo-phenyl)-6-[2-(5-bromo-pyrimidin-2-yloxy)-ethoxy]-pyrimidin-4-yl}-sulfamide, either alone or in combination with other active ingredients or therapeutic agents.
