Kythera Biopharmaceuticals Inc. has submitted an Investigational New Drug Application to the U.S. Food and Drug Administration for a new treatment for male pattern hair loss. The Westlake biotech plans to conduct human studies on an experimental drug called KYTH-105, or setipiprant. It is an oral drug that blocks the receptors for the substance prostaglandin D2. Research has found that men with male pattern baldness have elevated levels of PGD2. “KYTH-105 represents a unique scientific approach to the treatment of hair loss that has the potential to help millions of men achieve a positive self-image,” Dr. Frederick Beddingfield, Kythera’s chief medical officer, said in a statement. In June, Kythera announced plans to be acquired by Allergan plc in Ireland. Shares closed up 1 cent or a fraction of a percent to $74.87 on the Nasdaq.