The present invention relates to a polypeptide inhibiting the activity of glycosylated IL-17A, wherein the polypeptide comprises or consists of an amino acid sequence selected from the group consisting of: (a) GVTLFVALYDY(X1)(X2)(X3)(X4)(X5)(X6)DLSFHKGEKFQILSTHEYEDWWEARSLTTGETGYIPSNYVAPV DSIQ (SEQ ID NO: 1), wherein amino acid positions (X1) to (X6) may be any amino acid sequence； and (b) an amino acid sequence which is at least 85% identical to the amino acid sequence of (a), wherein the identity determination excludes amino acid positions (X1) to (X6) and provided that the amino acid sequence STHEYE (SEQ ID NO: 2) in amino acid positions 31 to 36 of SEQ ID NO: 1 is conserved. The invention also relates to fusion constructs, compositions and medical uses comprising said polypeptide.
