The amino acid sequences for a variable region and a constant region in TOCILIZUMAB, which is a humanized anti-IL-6 receptor IgGl antibody, are modified so as to improve the pharmacokinetics of TOCILIZUMAB while enhancing the antigen-neutralizing ability of TOCILIZUMAB. In this manner, it becomes possible to produce a second-generation molecule which can be administered at reduced frequency, can exhibit its therapeutic effect sustainably, has improved immunogenicity, safeness and physical properties (stability and uniformity), and is therefore superior to TOCILIZUMAB. Thus, disclosed is a pharmaceutical composition comprising the molecule. Also disclosed is a method for producing the pharmaceutical composition.
