The logo of French drugmaker Sanofi is seen in front of the company's headquarters in Paris, France, March 8, 2016. REUTERS/Philippe Wojazer/File Photo

NEW YORK (Reuters) - Three of the biggest makers of diabetes treatments, Sanofi SA, Novo Nordisk and Eli Lilly and Co, were named in a class action lawsuit about price fixing filed by a group of patients.

The suit, filed on Monday in a federal court in Massachusetts, said the companies have simultaneously hiked the price of insulin by over 150 percent during the past five years.

Plaintiffs claim that Sanofi, Novo Nordisk and Eli Lilly raised their public benchmark price for insulin products while maintaining a lower “true” price they charged large pharmacy benefit managers like Express Scripts, CVS Health and OptumRX.

The PBMs act as intermediaries with health insurers and keep a percentage of the price difference, according to the lawsuit.

The lawsuit, which seeks class action status, alleged violations of the federal racketeering statute, which allows for triple damages, as well as consumer protection laws in virtually every state.