Monoclonal antibodies (biologicals) are increasingly emerging as targeted therapies that block specific molecular pathways in severe asthma. Monoclonal antibodies work by binding to and blocking the function of a specific target molecule (e.g. anti-IgE or anti-interleukin-5). Monoclonal antibody treatments are also expensive. As such, patient phenotyping and targeted use of biologicals in severe asthma is critical. An individual will only respond to a particular treatment, if that specific molecule / pathway underlies their disease. For more information, see Diagnosis & Assessment – Phenotyping.