showed an initial positive response to biological therapy were in remission after one year. the development of anti-drug antibodies can be reduced by limiting any times when there is no biologic present in the body and by taking other immunosuppressants (such as thiopurines or methotrexate) in combination. research new biologic therapies that target both existing cellular targets (including il-12 and il-23) and new cellular targets are being developed. brazikumab and risankizumab are both il-23 specific antagonists, opposed to ustekinumab which targets both il-12 and il-23, that have shown efficacy in phase 2 trials for crohn's disease. etrolizumab is an integrin receptor antagonist that targets beta 7 integrins. etrolizumab has shown efficacy in phase 2 trials as well. the hope is that etrolizumab can show similar efficacy to natalizumab while avoiding the specific cellular target that is believed to have caused the instances of progressive multifocal leukoencephalopathy. another area of research is focusing on the personalization of biological therapy. the idea is to use a specific patient's biochemical or genetic profile to predict how a patient will respond to a biological therapy. the information could help inform which class of biologics to use first. personalized medicine is already being used in practice in the oncology field. a lot of research is being done to develop a biologic that can be delivered orally to address the many drawbacks associated with systemic administration. the general consensus in the field is that oral delivery of biologics directly to the diseased tissue could greatly reduce side effects, the development of anti-drug antibodies, and the cost of treatment.