Disclosed is a modified Fc-containing molecule which is resistant to proteolytic degradation as compared to an IgG1 wildtype Fc-containing molecule, comprising an antibody Fc domain with a mutated IgG1 constant region, wherein the sequence of E233-L234-L235-G236 of human IgG1 is replaced with P233-V234-A235 with G236 deleted, as defined by EU numbering, and further comprises one or more substitutions from the wild-type human IgG1 sequence selected from S239D/I332E K326A/E333A E333A/K334A H268F/S324T/I332E F243L/R292P/Y300L S239D/H268F/S324T/I332E S267E/H268F/S324T/I332E K326A/I332E/E333A S239D/K326A/E333A S267E/I332E and G237X/S239D/I332E where X is A, D, P, Q or S. Also disclosed is the use of such a Fc-containing molecule in treating diseases characterised by the unwanted proliferation or migration of cells.
