The present invention pertains to the use of 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-(4-pyridin-3-yl)pyrimidin-2-ylamino)phenyl]-benzamide or a pharmaceutically acceptable salt thereof or a pyrimidylaminobenzamide of formula I wherein the radicals and symbols are as defined herein, or a pharmaceutically acceptable salt thereof, for the manufacture of medicament for treating pulmonary arterial hypertension (PAH), especially in patients who failed prior PAH therapy.
