About Us

Stephen A Harrison, MD

Gastroenterologist Hepatologist
Specializing in Liver Disease

Led by our Medical Director, Dr. Stephen Harrison, Pinnacle has five board-certified investigators involved with the daily oversight of clinical trials. Our coordinating team consists of eight Clinical Research Coordinators and Research Assistants with extensive experience in conducting all phases of clinical trials. Our quality control, and regulatory team work with sponsors to ensure the highest quality of data collection and documentation, according the good clinical practices and the FDA regulations for every trial.


Dr. Harrison earned his medical degree from the University of Mississippi School of Medicine. He completed his internal medicine residency and gastroenterology fellowship at Brooke Army Medical Center and  a 4th year advanced liver disease fellowship at Saint Louis University. He is board certified in both internal Medicine and Gastroenterology. Dr. Harrison served as a Professor of Medicine at the Uniformed Services University of the Health Sciences and is currently a Visiting Professor of Hepatology at Radcliffe Department of Medicine, University of Oxford. He is a past Associate Editor for Hepatology and is currently an Associate Editor for Alimentary Pharmacology and Therapeutics. He is a peer-reviewer for over 20 medical journals and is internationally known for studies in hepatitis C and non- alcoholic fatty liver disease with over 150 peer reviewed publications in these fields. Dr. Harrison most recently served as a Colonel in the United States Army. Retiring in 2016, he concluded 20 years of dedicated service to his country. During his army tenure, he served as the Director of Graduate Medical Education at Brooke Army Medical Center, Associate Dean for the san Antonio Uniformed Services Health Education Consortium and Gastroenterology Consortium and Gastroenterology Consultant to the Army Surgeon General.

cutting-edge research