In a interview to 'CBS News', he said: "The data is important because the FDA or other agencies globally look at that information to give you marketing authorisation to sell the drug."
An ex-employee of the company, Thakur, who was tasked with investigations of alleged malpractices in the Ranbaxy, further said: "We started getting the files, and, lo and behold, we find that none of that exists in the first place....It means that we've gotten approvals from the FDA to sell drugs that were based on no data, or data that was fraudulent."
Comments from Ranbaxy Laboratories could not be obtained as spokespersons could not be reached.
Elaborating how the company's drug failed to provide relief, he said: "The expectations is the drug is supposed to work as intended...What we saw in this particular case is that trust was broken."
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Recounting an incident where his son was prescribed a Ranbaxy antibiotic for a fever, Thakur said: "He (son) kept getting worse, so we got another company's formulation and the fever went away."
It included USD 150 million in payments for a criminal fine and forfeiture and USD 350 million in payments for civil claims.
Thakur was awarded USD 48.6 million by a US court for the role he played in exposing malpractices in the company.
The USFDA had banned Ranbaxy in 2008 from shipping 30 generic drugs to the US from its two units in India -- Paonta Sahib in Himachal Pradesh and Dewas in Madhya Pradesh.