In 1993 he moved to McMaster University in Hamilton, Canada, to work with Salim Yusuf as a Clinical Research Scholar on international trials in acute coronary syndromes including the OASIS programme, and undertook formal training in clinical trials and epidemiology. In 1996 he took up the post of Director of the new Clinical Trials and Evaluation Unit (CTEU) at the Royal Brompton and Harefield Hospitals where the Unit developed an international reputation in the design and management of randomised trials in cardiovascular and respiratory diseases.
In September 2011 he took up the post of Professor of Medicine and Clinical Trials at the University of East Anglia and Director of Research at the Norfolk and Norwich University Hospitals NHS Foundation Trust in Norwich. Marcus Flather is a Fellow of the Royal College of Physicians (UK) and holds a certificate of higher specialist training in Cardiology and General (Internal) Medicine in the UK (CCST). He has about 200 peer reviewed publications, is a recognised expert in clinical trials and has more than 20 years experience of collaborating with industry partners in drug and device development.