The French government has started an investigation after a clinical trial of an experimental medicine left one man dead and five other patients desperately ill in hospital.
Exposure to the drug in the first-in-man (FIM) trial - conducted by clinical research organisation Biotrial on a compound in development at Portuguese pharma company Bial-Portela - seems to have caused serious neurological adverse reactions.
Since news of the fatality emerged, it has been revealed that the drug has been administered to around 90 test subjects, with approximately another 30 receiving a placebo, since the trial started in early January.
The other five hospitalised patients have neurological problems of "varying gravity", according to doctors at the University Hospital of Rennes.
The orally-active drug - BIA 10-2474 - was intended to treat mood and motor disorders associated with neurodegenerative disorders and anxiety and is a fatty acid amide hydrolase (FAAH) inhibitor. It has previously been tested in non-human primates.
Speaking to reporters, France's Health Minister Marisol Touraine said "an incident of exceptional gravity happened during a phase 1 clinical trial in Rennes … involving men aged between 28 and 49".
He stressed that contrary to preliminary news reports the drug was not based on cannabis but interacts with the endocannabinoid system.
"The families are devastated [and] we will make sure they are given all the answers, particularly as at the moment I am not aware of any comparable events," continued Touraine.
France's National Agency for the Safety of Medicines and Health Products (MSNA) and Inspectorate-General of Social Affairs (IGAS) are spearheading the investigation.
In a statement Biotrial said: "The trial has been conducted in full compliance with the international regulations. Procedures were followed at every stage throughout the trial, in particular the emergency procedures for the transfer of subjects to the hospital."
Incidents of this type are thankfully very rare, but there is at least one precedent outside France.
Several years ago, an FIM trial of TeGenero's immunomodulatory drug TGN-1412 left six men fighting for their lives with multiple organ failure, and while there were no deaths some patients were left maimed.
The trial was conducted by CRO Parexel at a site in the UK, and an investigation by the Medicines and Healthcare products Regulatory Agency (MHRA) eventually concluded that it had been conducted in accordance with agreed protocols.