Therapeutic proteins (biologics and biosimilars) may be recognised by the human immune system as antigens and could provoke an immune response, a process known as immunogenicity. Protein drug immunogenicity can lead to safety issues and impact drug efficacy and potency. Immunogenicity is defined as the propensity of antigenic motifs within therapeutic biologics to stimulate an immune response to itself and to related proteins or to induce immunologically related non-clinical effects or adverse events.
An immunogenic response to a biopharmaceutical is not necessarily undesirable; however, immunogenicity may in some cases lead to lack of efficacy and other unwanted effects. In this chapter, immunogenicity will refer to an adverse immune response to biologic drugs.
In this chapter, we discuss immune responses, factors affecting immunogenicity of therapeutic proteins, and the clinical practice guidance surrounding this.