One person has been left brain-dead and three others face irreversible brain damage after taking part in a drugs trial in France.
Six volunteers were hospitalised last week after taking part in the phase one trial of a new medication meant to treat mood disorders such as anxiety, developed by Portuguese pharmaceutical company Bial.
Health Minister Marisol Touraine said the men, aged between 28 and 49, were part of a group of 90 people who had taken the drug, while about 30 others had received a placebo.
All were given varying doses and the six men hospitalised were the group who were taking the drug “regularly”.
The group which fell ill started taking the drug on January 7 and the first patient began showing negative symptoms on January 10, Ms Touraine said.
Bial halted the trial a day later, she added.
The Paris prosecutor’s office said an investigation had been opened.
Pierre-Gilles Edan, head of the neurology department at the hospital in Rennes where the trial volunteers were admitted for treatment, said that aside from the man who was clinically dead, three others were suffering a “handicap that could be irreversible”.
He said another also had neurological problems while a sixth volunteer had no symptoms but was being monitored.
“A serious accident took place,” Ms Touraine said.
Ms Touraine vowed to “shed light” on who was responsible for the “unprecedented” accident.
“The shock is even greater given the fact that the people taking part in clinical trials are healthy,” she said.
In a statement, Bial said it would cooperate with an investigation to “determine in a rigorous and exhaustive manner” what had happened.
“Following the best international medical practices, [the sick patients] were immediately transferred by the company responsible for conducting the clinical trial to observation at the University Hospital of Rennes, being currently under permanent medical supervision,” the company said.
She said the drug acted on natural receptors found in the body known as endocannibinoids which regulate mood and appetite, and not the compound found in the cannabis plant.
‘Worst ever seen during a drug trial in France’
The study was a phase one clinical trial, in which a drug is tested on humans for the first time, after likely tests on animals and in the laboratory to ensure its safety.
Ms Touraine said the drug molecule had previously been tested on chimpanzees.
France’s national drug safety body (ANSM) confirmed the incident was the worst ever seen during a drug trial in the country.
“This type of incident is tragic but very rare in the world of clinical trials,” said Professor Jayne Lawrence, chief scientist with Britain’s Royal Pharmaceutical Society.
“All medicines have side-effects, but these are generally mild and severe reactions are incredibly rare.”
She said there were very strict regulatory standards in the European Union for such trials and “those in charge of the trial would have had to have shown they had done everything they could to protect patient safety before the trial was allowed to go ahead.”
Clinical trials typically have three phases to assess a new drug after preliminary tests on animals and human cells in petri dishes.
Human participation in such trials and scrutiny by outside watchdogs are essential for obtaining market authorisation.
After phase one, phase two and phase three are progressively larger trials, typically involving hundreds or thousands of volunteers, to assess the drug’s effectiveness.
The trial was being conducted by the privately-owned Biotrial company which has its French headquarters in Rennes and began in July 2015.
The research company conducts its phase one trials at a 150-bed facility in Rennes and also in New Jersey in the United States, from where it carries out “a large variety of early clinical studies”, according to its website.
The pharmaceutical company Bial says on its website its products include anti-inflammatories, antidiabetics, cardiovascular, anti-asthmatics, antibiotics, antidepressants and antianemics.
Every year thousands of volunteers, often students looking to make extra money, take part in such clinical trials which are seen as safe.