Ranbaxy vows to work with FDA after false data charge

India's biggest drug company promised on Thursday to work with the US Food and Drug Administration after the regulator said it had falsified data.

Ranbaxy Laboratories shares plunged after the FDA said late Wednesday the Paonta Sahib plant owned by the New Delhi-based generics giant had "falsified data and test results in approved and pending drug applications".

"Ranbaxy will continue to co-operate with the US FDA," the Indian company said following the statement.

The FDA announcement that it would take "new regulatory action" against the Indian drugmaker came five months after the regulator prohibited Paonta Sahib and another of Ranbaxy's four Indian plants from sending 30 products to the United States because of manufacturing quality problems.

The shares of Ranbaxy, a unit of Japan's Daiichi Sankyo Co, slid after the FDA announcement, closing down 18 percent, or 37.30 rupees, at 169.95 rupees.

The FDA said to "address the falsified data, the FDA has invoked its Application Integrity Policy (AIP) against the Paonta Sahib facility".

Under the policy, the regulator can seek a third-party independent audit of products linked with the plant, the FDA said.

"The FDA's investigations revealed a pattern of questionable data raising significant questions regarding the reliability of certain applications," the regulator said.

Ranbaxy said it would analyse the FDA notice and other information "fully and respond appropriately in a timely manner". It noted the FDA said it had "no evidence" Ranbaxy drugs on the market "are substandard".

The FDA announcement came as another blow for Daiichi Sankyo, Japan's third largest drugmaker, which last year bought control of Ranbaxy to enter the fast-expanding copycat drugs market.

Daiichi Sankyo announced last month it would book a loss of more than 350 billion yen ($3.8 billion) due to the sliding value of its investment in Ranbaxy.

The FDA decision means it will suspend evaluations of any new or pending drug approval applications containing data supplied by the suspect Ranbaxy plant.

"Such regulatory hindrances are going creates obstacles for Ranbaxy, in particular and Indian generic companies, in general, to strengthen their base" in the lucrative US generics market," said global consultancy Frost & Sullivan.