Synthetic Biologics, Inc. announced the appointment of senior biotech executive John Monahan, PhD, to the Company's Board of Directors, effective immediately. Dr. Monahan replaces Scott L. Tarriff who has stepped down after serving on the board since 2012. Dr. Monahan has more than 45 years of executive leadership experience in the pharmaceutical and biotechnology industries. Dr. Monahan Co-Founded Avigen Inc. in 1992, a company which has become a leader in its sector for the development of novel pharmaceutical products for the treatment of serious human diseases.