One person was left brain-dead and five others were in serious condition after participating in a drug trial in the northwestern French city of Rennes, Health Minister Marisol Touraine said on Friday.

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“What happened is unprecedented,” Touraine said at a press conference in Rennes, after meeting with the victims’ families.

The minister said that the drug had been manufactured by the Portugal-based pharmaceutical group Bial, and was being tested at a facility in Rennes by the research company Biotrial.

She also dismissed earlier media reports that the medication, which was meant to treat mood disorders such as anxiety, contained cannabis.

Professor Pierre-Gilles Edan, head of the neurology department at the hospital where the sick volunteers were taken, said that aside from the man who was left brain-dead, three of the other victims had suffered symptoms that could lead to a “possibly irreversible handicap.” Edan added that there was no known antidote to the drug.

All tests on the drug have since been suspended and study participants called back. Overall, 128 volunteers between the ages of 28 and 49 took part in the trial, but only 90 were actually given the drug. The remaining 38 received a placebo.

Touraine specified that the six volunteers who were hospitalised had taken the drug regularly and in high doses.

The study was a Phase I clinical trial, in which healthy volunteers take the medication to "evaluate the safety of its use, tolerance and pharmacological profile of the molecule", Touraine said in a statement earlier in the day.

Clinical trials typically have three phases to assess a new drug or device for safety and effectiveness. Human participation in such trials and scrutiny by outside watchdogs are essential for getting market authorisation.

Touraine said in the statement that she was determined to “shed light” on what happened in the trial, while the Paris prosecutor’s office said that an investigation had been opened into the incident.

Cases of early-stage clinical trials going badly wrong are rare but not unheard of. The last drug trial disaster in Europe occurred in 2006, when six healthy volunteers given an experimental drug in London ended up in intensive care.

(FRANCE 24 with AFP, AP and REUTERS)

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