The European Commission announced new surprise inspections in the pharmaceutical sector yesterday amid suspicions companies are colluding to block the development of cheaper generic drugs.

A spokeswoman for AstraZeneca, Britain’s second biggest drugmaker by sales after market leader GlaxoSmithKline, said that it had been inspected in checks relating to heartburn drugs.

“Commission officials carried out unannounced inspections at the premises of a limited number of companies active in the pharma-ceutical sector in several member states,” the commission said of the spot checks held on Tuesday.

“The Commission has reason to believe that the companies concerned may have acted individually or jointly, notably to delay generic entry for a particular medicine.

“If confirmed, this could be a potential violation of EU antitrust rules that prohibit restrictive business practices and/or the abuse of a dominant market position.”

The AstraZeneca spokeswoman said visits “relate to alleged practices regarding esomeprazole (Nexium) in Europe and we’re cooperating with the authorities”.

European citizens spend hundreds of euros on medicine each year, with the market worth hundreds of billions of euros at retail prices, according to commission data.

The relationship between companies that patent their products as brand-named medicine, as well as their ties with generic drug prod-ucers, has been a focus for commission inspectors over recent years.

Generic drugs are cheaper and save patients and insurance firms money without compromising on effectiveness. But some companies have in the past been accused of using patent filings to stop generic medicines hitting the market, or tying up potential competitors for years in legal disputes.

In the worst example uncovered, 1,300 separate patent filings were made for a single medicine across the 27-nation EU.