The U.S. Food and Drug Administration (FDA) has declared Sun Pharma's response to the import ban imposed in March to be inadequate, stating that the company has failed to take sufficient measures to correct the violations that led to the enforcement action.

In a warning letter sent to the chief executive officer of the Indian company, Subramanian Kalyanasundaram, the FDA stated that after having conducted a detailed review of Sun Pharma's initial response following the import ban, the regulator found that laboratory records did not include complete data and that workers at the Gujarat facility had been inadequately trained. The FDA added that the company carried out laboratory tests, which it referred to as unofficial, and then disregarded the results, instead reporting results from additional tests.

Sun Pharma failed to carry out a proper investigation into the common practice of deleting data at the facility and why it took place, the letter stated. The company's response did not identify what criteria were used in tests and designations of samples, or what impurity standards were used to control manufacturing processes. These violations, in combination with other sub-standard procedures detected during the inspection, suggested a "general lack of reliability and accuracy of data" provided by Sun Pharma, the FDA said.

The letter requires the drug maker to undertake extensive corrective measures and notes that, if it fails to do so, the regulator may continue to ban imports of Sun Pharma's products and may withhold approval of new applications or products submitted by the company.