Disclosed is a use of a peptide immunogen in the preparation of a medicament for treating a patient, wherein the patient is being treated with a specific antibody containing composition, wherein antibody is susceptible to cleavage by one or more proteases associated with the specific disease being treated, and wherein the peptide is a peptide fragment or analogue representative of a proteolytic cleavage site on IgG produced by the one or more proteases associated with the specific disease being treated by antibody therapy.
