The UK's Commission on Human Medicines (CHM) has replaced Professor Ian Weller as Vice-Chair. Weller retired from the position on 31 December 2014.
The CHM advises on matters relating to safety, quality and the efficacy of medicines, as well as the collection of data on adverse drug reactions.
Dr Angela Thomas is a consultant paediatric haematologist at the Royal Hospital for Sick Children in Edinburgh, a fellow of the Royal College of Physicians in Edinburgh, and a former President of the British Society for Haematology.
She has been on the CHM since 2005 and chairs the Clinical Trials, Biologicals & Vaccines Expert Advisory Group.
Dr Thomas has also been a member of and has chaired many scientific and medical committees in the UK and Europe.
'I am delighted to be taking up this new role. The Commission plays a vital role in the licensing of new medicines and in monitoring drug safety,' she said.