Boston Scientific - best known for its Taxus drug-eluting stent – has received a letter from the US Food and Drug Administration warning that a recent inspection of its Massachusetts plant had unveiled “serious regulatory problems” relating to its medical devices - the implantable Vaxcel low profile infusion ports, the Taxus stent and Symmetry balloon catheters. Shares in the company dropped slightly on the New York Stock Exchange yesterday on heavy trading of almost four times the normal volume.

Specifically, the letter says Boston Scientific shipped devices with suspected defects to hospitals, despite an earlier hold being placed on certain batches. For example, in January, defective Taxus stents were distributed to five separate hospitals – all were part of a batch that had failed a drug release test and had been placed in quarantine in October last year.

The letter, sent August 10 but just posted on the FDA’s website, follows earlier concerns and a response from Boston Scientific in June, which said it was committed to making a number of corrective actions to improve its quality system. But the agency goes on to criticise this asking how and when these remedial actions will take place: “Your response does not identify how and when you plan to implement significant, broad-based corrective actions, nor does it provide sufficient evidence to establish that you have made real changes to your current quality system to ensure control over the release and distribution of your devices.”

Should Boston Scientific fail to remedy the situation, the agency warns that it may take regulatory action “without further notice,” including the seizure of stock, obtaining a court injunction against further marketing of the products, or assessing financial penalties.