French Social Affairs and Health minister Marisol Touraine
French Social Affairs and Health minister Marisol Touraine (L) and professor Gilles Edan (R), head of the neuroscience unit at Rennes Hospital speak after six people were hospitalised following an experimental drug trial. One man has since died Getty

A man who was left brain dead following an experimental drug trial in France has now been formally declared dead, local media has reported. The victim was one of six people taken for hospital treatment on Friday after being given an oral drug at a private laboratory in the city of Rennes the previous week.

Four of the remaining five people remain in a stable condition suffering from "neurological problems", while the fifth is believed to have suffered no symptoms. In total 90 volunteers took the experimental medication, which was manufactured by the Portuguese pharmaceutical company Bial.

Initial reports suggested that the drug in question was a cannabis-based painkiller but this has since been denied by the French health ministry. An investigation into exactly what went wrong has now been opened by the Paris prosecutor.

biotral
The drug trial was carried out by the French company Biotrial, which is internationally respected having conducted thousands of similar experiments since being established in 1989Getty Images

In the hours after the volunteers fell ill, the chief neuroscientist at Rennes Hospital, Gilles Edan, said there was no known antidote to the medication, the BBC reported. The hospital has since said that it has tested 10 of the 84 volunteers who were not hospitalised and found they were not suffering from any of the neurological "anomalies" that caused the victim's death at midday on Sunday.

The drug trial was carried out by the French company Biotrial, which is internationally respected having conducted thousands of similar experiments since being established in 1989. The trial has been ongoing since last July, with the only people falling sick having taken the drug on Thursday, 7 January, before beginning to show signs of serious side-effects the following week.

Every year tens of thousands of volunteers take part in experimental drug trials around the world, with the vast majority suffering no ill effects whatsoever. The process, which is never risk-free, is vital to the production of new medication as drugs – including those to treat serious diseases such as cancer – must undergo detailed testing on humans before being released to the wide public.