The US Food and Drug Administration has filed a motion in a Maryland court seeking documents from Ranbaxy Laboratories as part of an ongoing investigation looking into claims that the Indian drugmaker falsified data on treatments that were eventually approved.

The file put before the court claims prosecutors in the USA noted that a "pattern of systemic fraudulent conduct" resulted in a number of Ranbaxy's generic drugs that got onto the market in the USA without meeting the FDA’s standards. "The government has reason to believe that these violations have resulted and continue to result in the introduction of adulterated and misbranded products", the documents note.

The suit filed against Ranbaxy and its US-based consultant Parexel alleges that the company concealed and forged crucial data to get a favourable judgement on an ongoing investigation by the FDA into the sale of sub-standard drugs in the USA.

The investigation stems from an FDA inspection of Ranbaxy's facilities at Panota Sahib in June 2006, where it found discrepancies in manufacturing processes and maintenance of data. This was followed by a raid by US officials who searched the Indian drugmaker’s US headquarters in New Jersey in February 2007.

A spokesman for the Gurgaon-based firm said that a motion has indeed been filed seeking certain documents but no legal proceedings in the sense of a prosecution have been started. He noted that Ranbaxy “strongly denies the allegations contained in the motion” and while an investigation has been underway for three years, “despite this, no charge has been filed”. Ranbaxy, which says it has been cooperating fully with the US Department of Justice since the investigation began, is scheduled to file a response in court later today.

However Ranbaxy’s confidence may not be shared by investors and the company’s shares hit a seven-year low, amid fears that the case could scupper the deal signed recently with Daiichi Sankyo which would see the Japanese firm pay up to $4.6 billion to take control of the firm.