Dr Toh is Senior Consultant and former Head at the Department of Medical Oncology and now Deputy Medical Director (Strategic Partnerships), National Cancer Centre, Singapore. He graduated from the University of London, UK with an intercalated Bachelor of Science in 'Infection and Immunity' from St Mary's Hospital Medical School and qualified as a medical doctor from University of Cambridge, UK. Dr Toh obtained his Fellowship of the Royal College of Physicians in 2003. He received his medical oncology fellowship training at the Singapore General Hospital, Massachusetts General Hospital, Harvard Medical School, Boston, USA and at the Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, USA. Dr Toh is also alumni at the Harvard Business School. He is currently the vice-chairman of the Oncology Academic Clinical Program (ACP) for Education.

He is a recipient of the National Clinician Scientist Award for his pioneering work in cell therapy for cancer. He conducted the first cancer vaccine and T cell therapy clinical trials in Singapore, and continues to work actively in the field of cancer immunotherapy, immunology and inflammation. He also had a strong interest in drug development for gastrointestinal cancers including colon and liver cancer. Dr Toh is an Associate Professor and College Master at the Duke-NUS Medical School. He is also an adjunct Principal Investigator at the Institute of Molecular and Cell Biology, A*STAR. He was a council member in the Singapore Medical Association and the Singapore College of Physicians.