The present invention relates to stabilized IgG4 antibodies, to methods of producing such antibodies and to uses of such antibodies as a medicament. In a main aspect, the invention relates to a stabilized IgG4 antibody, comprising a heavy chain and a light chain, wherein said heavy chain comprises a human IgG4 constant region having a substitution of the Arg residue at position 409, the Phe residue at position 405 or the Lys residue at position 370.
