French police visit Merck KGaA offices in inquiry into Levothyrox complaints

French police searched the French offices of Merck KGaA as consumer complaints have piled up over a formulation change the drugmaker made to thyroid drug Euthyrox at the request of French regulators.

The search of the headquarters in Lyon was handled by a division of the national police responsible for public health. The search comes after the Marseille prosecutor started an inquiry last month into whether Merck KGaA had deceived patients with the change in the drug’s formula.

The drug is taken by about 3 million patients in France, mostly women and thousands of complaints have reportedly been made to France’s drug overseer, ANSM, since the new formulation, which was introduced as Levothyrox, hit the market in March. It is manufactured at a plant in France.

A Merck spokesperson Thursday said in an emailed statement to FiercePharma that the drugmaker is cooperating with French authorities in the investigation.

"As part of the preliminary investigation opened by the Marseille Public Prosecutor’s Office on the new formulation of Levothyrox, the investigators went... to Lyon at the premises of the Merck  headquarters in France.
"Merck will cooperate fully to support the work of the investigators of the Central Office in charge of Public Health investigations (OCLAESP) and to provide them with all requested information which may be useful for their work."

Merck reworked the drug at the request of the ANSM, replacing lactose with mannitol and also adding citric acid to improve potency and extend shelf life. The company and the ANSM have said the new he the new formulation is bioequivalent to the previous one.

Merck said today that most patients have tolerated the new formulation. 

But many of those who didn't petitioned the ANSM online to restore the old formulation, and In response to furor, the French Minister of Health asked Merck to reintroduce the previous formulation within 15 days, on a temporary basis for those "patients with persistent and undesirable side effects." 

Merck said the old formulation was back in the market this week.