Marisol Touraine, France's Health Minister
French health minister Marisol Touraine said a 'very serious accident' happened at a private lab in Rennes.iStock, Getty Images

Six people are fighting for their lives in France after a trial for a cannabis-based painkiller went horribly wrong. One person is brain-dead and five are in a critical condition after volunteers had a bad reaction to the drug, which was being tested at a private clinic in Rennes.

Marisol Touraine, the country's health minister, said there was a "very serious accident" and is planning an emergency visit to the city in north-west France as soon as possible. The trial was a Phase I clinical trial - the stage at which potential medicines are first tested - has been suspended and the volunteers recalled.

The patient who is now in coma was hospitalised Monday at the Rennes University Hospital and the other five were admitted there Wednesday and Thursday.

Reports claim the laboratory the test was led by the Biotrial centre, which is approved by the Ministry of Health. A description on the company's website says: "Biotrial's mission is to provide our sponsors with high-quality pharmacology services, adding value to their projects by working together and meeting all needs throughout the development process.

The French ministry of health said in a bleak assessment: "One of them is in intensive care, and is brain-dead." The trial is reported to have been based on a analgesic, described as "a drug taken orally (and) developed by a European laboratory", AFP reported and iTELE TV has claimed the drug was cannabis-based. Eight people were taking part in the test, of which two had taken a placebo.

The lab behind the test is reported to be approved by the Ministry of Health and an investigation has been launched. It is not yet known if the test was for sick people or not.


French health minister Marisol Touraine confirmed:

  • 6th patient hospitalised as a precaution
  • 8 candidates, all men, aged 28 to 49
  • All volunteers have now pulled out of test
  • Product not based on cannabis or any cannabis derivative
  • The test was authorised in June 2015 by National Agency for Medicines
  • "To date, 90 people were administered with this molecule with varying doses" according to the minister
  • The tests began on 7 January with volunteers first showing symptoms on 10 January. Tests were discontinued the next day

Phase one trials

Phase one trials aim to test the safety of a new medicine. A small number of people, who may be healthy volunteers, are given the medicine. Researchers test for side effects and calculate what the right dose might be to use in treatment (known as dose-ranging studies).

This will usually be the first time the medicine has been tried on humans, so there's an unavoidable element of risk. To minimise the risk, researchers start with small doses and only increase the dose if the volunteers don't experience any side effects, or if they only experience minor side effects.

Source: NHS