The MHRA concluded that the most likely cause of the reaction in trial subjects was an unpredicted biological action of the drug in humans. The UK Secretary of State for Health agreed to establish a group of leading international experts to consider those issues and to provide a report on the future authorization of such trials with an interim report at three months, with Gordon Duff, Professor of Molecular Medicine at Sheffield University, as Chair of the group. Until the expert group report, all further clinical trial applications involving first-in-humans trials of any monoclonal antibody or other novel molecules targeting the immune system were not to be authorised in the UK.