Monrovia, California-based Xencor, which develops protein and antibody therapeutics, said Wednesday that it has appointed David R. King as the Chairman of its board of directors. Xencor develops biotherapeutics are used to improve antibody effectiveness for treating cancer, inflammation, and autoimmune diseases. King joins the firm from BioRexis Pharmacueticals, where he was co-founder and CEO; King has also served at Morgan, Lewis & Bockies LLP, Principia Pharmaceutical corporation, Delsys Pharmaceutical Corp. and BioRexis.