Gregory Sullivan

Gregory M. Sullivan, MD, is Chief Medical Officer at Tonix Pharmaceuticals, where he leads clinical development for a diverse CNS portfolio including fibromyalgia, PTSD, major depressive disorder, migraine, long COVID, and cocaine intoxication. Since joining Tonix in 2014, Dr. Sullivan has overseen the progression of multiple programs from pre-IND through NDA submission, including the NDA for TNX-102 SL in fibromyalgia which was FDA-approved 15 Aug 2025. He serves as the company’s primary medical liaison with the FDA, EMA, and PMDA, and has built and led cross-functional teams of scientists, physicians, and clinical operations professionals to support successful Phase I–III trials.

Prior to joining Tonix, Dr. Sullivan spent over a decade as Assistant Professor of Clinical Psychiatry at Columbia University and as a Research Scientist at the New York State Psychiatric Institute (NYSPI), where he was Principal or Co-Investigator on numerous NIH- and foundation-sponsored clinical studies in affective and anxiety disorders. He directed outpatient clinical research in molecular imaging and neurobiology, and was a recipient of the NIH K08 Mentored Clinical Scientist Award.

Dr. Sullivan has authored or co-authored over 50 peer-reviewed articles and book chapters on topics ranging from stress neurobiology and suicidality to serotonin receptor function in depression, panic disorder, and PTSD. He has served on institutional review and medical executive committees, contributed to graduate medical education at Columbia, and previously maintained a part-time clinical psychopharmacology practice for 17 years.

He earned his MD from Columbia University College of Physicians and Surgeons and holds a BA in Biology from UC Berkeley. He completed NIH-funded postdoctoral research fellowships in molecular immunology and in affective disorders. Dr. Sullivan is a long-standing member of the Society for Neuroscience, the Society of Biological Psychiatry, and the American Society of Clinical Psychopharmacology.