in addition to chimeric and humanized antibodies, there are other pharmaceutical purposes for the creation of chimeric constructs. etanercept, for example, is a tnfα blocker created through the combination of a tumor necrosis factor receptor (tnfr) with the immunoglobulin g1 fc segment. tnfr provides specificity for the drug target and the antibody fc segment is believed to add stability and deliverability of the drug. additional chimeric proteins used for therapeutic applications include: