Regnum Corp. is dedicated to advancing and marketing therapeutic agents... Regnum Corp. is dedicated to advancing and marketing therapeutic agents designed to combat both rare and infectious diseases. Its flagship product is Leronlimab (PRO 140), a monoclonal antibody functioning as a C-C chemokine receptor type 5 (CCR5) antagonist. This drug is specifically formulated to inhibit the human immunodeficiency virus (HIV) from gaining entry into human cells. Headquartered in New York, New York, Regnum Corp. operates as a subsidiary of Phoenixus AG.