* At least 500 deaths thought to be caused by Mediator
* Drug pulled in France years after other countries
* Case put health authorities and industry under scrutiny
By Thierry Lévêque
NANTERRE, France, May 14 (Reuters) - French drugmaker Servier and its founder went on trial on Monday accused of misleading patients and authorities about a diabetes drug often prescribed for weight loss that officials blame for at least 500 deaths.
The case, one of France's worst health scandals, has put authorities under scrutiny for allowing the sale of Mediator long after the medicine had been pulled in other European countries.
Although licensed as a diabetes treatment, the drug was widely prescribed, with a state subsidy, as an appetite suppressant to help people lose weight.
It is now suspected of causing heart valve disorders and was withdrawn in France in November 2009, around a decade after being pulled in Spain, Italy and the United States.
Several hundred civil plaintiffs who have joined the criminal case argue that Servier intentionally misled doctors about the drug, even though the dangers had been known since the 1990s.
State health inspectors also say the drug should have been withdrawn in France a decade earlier, and the plaintiffs are seeking damages and interest of 100,000 euros ($129,000) each.
"Servier let people use a toxic product for years. There is no debate about it," said Charles Joseph Oudin, one of the presumed victims' lawyers.
The focus of the Nanterre trial is on whether Servier made misleading claims, while a second, broader trial in Paris is due much later after an investigation that will examine allegations of manslaughter and corruption.
The defendants in Nanterre deny the allegations against them and are seeking to stop the trial on grounds that they should not be tried in two separate cases.
Servier's founder and president, 90-year-old Jacques Servier, and four other executives risk custodial sentences of up to four years plus fines. The privately-owned Servier and its subsidiary Biopharma also face fines and the possibility of being banned from some activities.
Mediator - designed as an add-on treatment for diabetes patients who were overweight - was sold to as many as 5 million people in France between 1976 and November 2009.
However, many of those were not diabetics but simply seeking help to lose weight.
The offices of the Afssaps healthcare regulator were searched by investigators in February in connection with the case.
Concerns about the agency - whose head resigned over the case - have grown following a scandal over defective breast implants manufactured by the now-bankrupt French company PIP.
The Mediator case has also drawn attention to pharmaceutical companies' influence in France's public health system as well as their sway over politicians.
It has also triggered a push at European Union level to step up monitoring of drug safety.
According to the health ministry, at least 500 people died of heart valve trouble in France because of exposure to Mediator's active ingredient, benfluorex. Other estimates based on extrapolations put the death toll closer to 2,000.
Less than a year before the drug was pulled, Servier was awarded France's national merit medal, the Legion d'Honneur, by President Nicolas Sarkozy, who had previously served as his lawyer. ($1 = 0.7726 euros) (Writing by Leigh Thomas; Editing by Kevin Liffey)