The severe complications experienced by participants in a French clinical trial are due to an unknown toxic effect from the drug being tested, according to the doctors on duty.
The Rennes University Hospital clinicians on duty at the time of the January trial, which led to one death, published a case study of the incident in The New England Journal of Medicine on 3 November.
Their paper includes medical data from Guillaume Molinet, the man who died during the trial, along with data for three other men who were hospitalised.