The US Food and Drug Administration would impose a stay on Dr Reddy’s AmVaz NDA as the agency plans a re-evaluation of the data submitted by the company while obtaining approval.

AmVaz (Amlodipine Maleate) was approved for marketing by the FDA on October 31, 2003 and is indicated for the treatment of hypertension (high blood pressure) and angina.

The FDA letter, received by Dr Reddy's Laboratories (DRL) on February 5, 2004, indicated that reevaluation was prompted by questions raised about the source of the data relied on by FDA in its review and that the agency would stay the approval for AmVaz pending the expedited reevaluation

The FDA further indicated in the letter that it believes that the approval of AmVaz did not rely on any proprietary data from Pfizer's NDA, a company statement said.

Commenting on the development, GV Prasad, CEO, DRL, said, "We are confident that FDA's initial decision was correct and remain optimistic about a positive outcome from FDA's reevaluation."

AmVaz is DRL’s generic version of Pfizer’s top selling hypertension drug, Norvasc.