Method for improving the benefit to a subject of a therapy or therapeutic agent

A method for improving the benefit to a subject of a therapy or therapeutic agent, the method comprising (a) administering to the subject an agent which reduces Fc receptor binding of serum IgG molecules in the subject;

• and (b) subsequently administering said therapy or said therapeutic agent to the subject;
• wherein:
• the amount of said agent administered is sufficient to eliminate Fc receptor binding by IgG molecules present in the serum of the subject;
• and
• steps (a) and (b) are separated by a time interval which is sufficient for Fc receptor binding by IgG molecules present in the serum of the subject to be eliminated;
• wherein the agent is a protein having IgG cysteine protease activity from Streptococcus pyogenes which is IgG-degrading enzyme of Streptococcus pyogenes (IdeS), which agent comprises of the amino acid sequence of SEQ ID NO:
• 1, or a variant thereof comprising of an amino acid sequence having at least 90% sequence identity with SEQ ID NO:
• 1, which variant does not comprise deletions and any amino acid substitutions in the variant are conservative substitutions which conserve amino acid charge.