Distinguished Professor David Simmons is Chief Medical Officer for Diabetes Australia, Professor of Medicine at Western Sydney University, District Advisor on Diabetes for the South Western Sydney Local Health District and previous Director of the Macarthur Diabetes Endocrinology and Metabolism Service in Sydney, Australia. Before returning to Australia in 2014, Professor Simmons was the Clinical lead for the Diabetes service at Addenbrookes Hospital, Cambridge UK. With over 500 refereed publications, he has won several national and international awards for his work in diabetes epidemiology, diabetes in pregnancy and diabetes service development including the American Diabetes Association 2020 Norbert Freinkel Award, 2022 Diabetes in Pregnancy Study Group Pederson Award and 2025 International Diabetes Epidemiology Group Peter Bennett Award. He is the immediate past president of the Australasian Diabetes in Pregnancy Society (ADIPS). He is the Chief Investigator for APHLID, an RCT of a mental health/diabetes app in young adults with type 1 diabetes, the TOBOGM study the first large RCT of diagnosing and treating early gestational diabetes mellitus and Australian Chief Investigator for the CIRCUIT RCT of closed loop in pregnancies complicated by Type 1 diabetes and the CORDELIA RCT of CGM in GDM. He remains a practising endocrinologist holding weekly diabetes in pregnancy clinics.