Siân Ratcliffe Smethurst, Ph.D.

Dr. Siân Ratcliffe Smethurst serves as Chief Operating Officer at Premier Research, where she oversees Clinical Research and Development. In this role, she is responsible for advancing operational excellence, quality, and consistency across the organization’s clinical development functions, including study design and delivery, data management, and regulatory support—ensuring sponsors are supported by integrated, high-impact execution. 

With more than 25 years of scientific and operational leadership experience in the biopharmaceutical industry, Dr. Ratcliffe Smethurst has held senior leadership roles at Biogen and Pfizer, spanning all phases of Research, Development, and Medical. Her experience includes a broad range of therapeutic areas, including oncology, neurology, psychiatry, pain, rare disease, immunology, internal medicine, women’s health, and vaccines. 

Most recently, Dr. Ratcliffe Smethurst served as Senior Vice President and Head of Quantitative Sciences & Development Operations at Biogen, where she led a large global organization accountable for the design, strategic planning, execution, and analysis of the company’s clinical trial portfolio. Earlier in her career at Pfizer, she held senior leadership and group head roles across Clinical Operations, Medical Writing, Clinical Development, Preclinical Safety, Safety Risk Management, and Regulatory Strategy. She has also co-led multiple cross-industry initiatives focused on advancing clinical trial innovation, precision medicine, and translational sciences—strengthening collaboration across the research ecosystem. 

Dr. Ratcliffe Smethurst holds a Ph.D. in Pharmacology from the University of Cambridge, where she also completed postdoctoral research and held academic appointments. She serves on the Executive Committee of the International Society for CNS Clinical Trials Methodology.