The present invention relates to novel interferon gamma polypeptide variants having interferon gamma (IFNG) activity, methods for their preparation, pharmaceutical compositions comprising the polypeptide variants and their use in the treatment of diseases, in particular for the treatment of interstitial pulmonary diseases, such as idiopathic pulmonary fibrosis.These novel polypeptide variants all comprise the substitution S99T as compared to the amino acid sequence of huIFNG or fragments thereof. By performing this mutation the naturally occurring N-glycosylation site present at position 97 is significantly better utilized.Preferably, the variants comprise further modifications, e.g. in order to increase the AUC of such variants when administered subcutaneously.