A drug trial conducted in France has left one person brain-dead and three others facing potentially irreversible brain damage. French authorities launched three investigations at the research laboratory in Rennes.
Judicial police carried out the first searches at the Biotrial lab which had performed the trial on behalf of Portuguese pharmaceutical company Bial.
On Saturday they were joined by representatives of France's social affairs inspectorate general (IGAS) and the national drug safety agency (ANSM).
A total of 90 volunteers - healthy men aged between 28 and 48 years - were given the experimental drug in the Phase I trial. Six of them were taken to hospital last week.
Pierre-Gilles Edan, head of the neurology department at the hospital in Rennes where the volunteers were taken, said that aside from the man who was clinically dead, three others were suffering a handicap that could be irreversible and another also had neurological problems.
The sixth volunteer had no symptoms but was being monitored.
The head of Biotrial said, "The lab was cooperating with the investigators."
"Our thoughts remain with the victims and their families but our energy this morning is entirely committed to assisting the investigators and to fully cooperating in the investigations under way. The investigators and inspectors are trying to understand what could have happened and how it could have resulted in such an a tragic situation. There is no news of any change to the condition of the hospitalized volunteers," said Francois Peaucelle.
Representatives from Bial were also on site and taking part in the probes with 'total transparency', reported Peaucelle.
The Portuguese firm had issued a statement insisting it had followed 'international best practice' in developing the drug and said that it would cooperate with the investigation to 'determine in a rigorous and exhaustive manner' what had happened.
France's national drug safety body confirmed it was the worst-ever incident to have taken place in a drugs trial in the country.
Each year thousands of volunteers participate in clinical drugs trials and experts point out that tragic results are rare.
But the incident in Rennes has raised concerns about such experiments.
A university teacher in Rennes who has participated in such trials said, "I will not do it anymore and I'm going to advice against it." He admitted to being attracted by the 'easy money' participants received and that he had taken part in about 15 trials at the Biotrial lab since 2005.