The invention relates to the use of 1-{(S)-3-[6-(6-methoxy-5-trifluoromethyl-pyridin-3-yl)-5,6,7,8-tetrahydro-pyrido[4,3-d]pyrimidin-4-ylamino]-pyrrolidin-1-yl}-propan-1-one or pharmaceutically acceptable salts thereof for the treatment of primary Sjögren's Syndrome.L'invention concerne l'utilisation de 1-{(S)-3-[6-(6-méthoxy-5-trifluorométhyl-pyridin-3-yl)-5,6,7,8-tétrahydro-pyrido[4,3-d]pyrimidin-4-ylamino]-pyrrolidin-1-yl}-propan-1-one ou de sels de qualité pharmaceutique de ce composé pour le traitement du syndrome de Sjögren primaire.