FDA GENERIC PROPRANOLOL APPROVALS ARE DE FACTO DENIALS OF AYERST PETITION

FDA GENERIC PROPRANOLOL APPROVALS ARE DE FACTO DENIALS OF AYERST PETITION to delay ANDA clearance of Inderal solid dose form competitors. Ayerst asked the agency in two July 24 petitions to 1) revise the approval requirements for generic versions of propranolol to include additional testing, and 2) to delay ANDA propranolol approvals until FDA takes action on Ayerst's petition. However, although the agency has not formally responded to Ayerst, the approval on July 31 of two ANDAs for propranolol tablet products (see story, p. 3) effectively nullifies the Ayerst initiative. Ayerst asked that FDA: 1) revise the current FDA guidelines for conducting propranolol HCI bioequivalence studies to add the additional pharmacokinetic and pharmacodynamic testing necessary to adequately evaluate safety and effectiveness; 2) issue a labeling standard that provides adequate information for the use of different brands of propranolol HCI without infringing upon the exclusivity provided the Inderal labeling by the FD&C Act; and 3) establish adequate criteria for assuring the safety of new sources of propranolol HCI." Specifically, Ayerst said that FDA should require "single and multiple dose bioequivalence" and "pharmacodynamic studies" for all dose strengths submitted for review. To "assure the safety of new sources of propranolol HCI," Ayerst said that FDA should also require either "chemical testing that assures the propranolol HCI proposed for use in different brands of propranolol HCI products is the same as that used in Ayerst's Inderal products in regard to impurities present as well as all other relevant characteristics," or "carcinogenicity studies proving the safety of each new source of propranolol HCI." Under the patent restoration/ANDA law, Ayerst said, Inderal labeling includes some indications -- such as for reduction of mortality after heart attack -- that are protected under an exclusive marketing provision. Ayerst said in the petition that FDA should "review this matter and determine whether a labeling standard can be prepared to provide adequate information for use" of generic propranolol products that does not infringe on Ayerst's indications, which are the subject of exclusivity until Sept. 25, 1986.