MONROVIA, Calif.--(BUSINESS WIRE)--Dec. 7, 2005--Xencor, Inc., a biotherapeutics company developing protein and antibody therapeutics, today announced that it has licensed rights to its XmAb(TM) proprietary engineered Fc domains to MedImmune, Inc. (Nasdaq:MEDI) for use in the creation of monoclonal antibodies against select targets of interest. The agreement is Xencor’s fifth for its XmAb technology in the last year.