FDA REVISING TOPICAL CORTICOSTEROID BIOEQUIVALENCE REQUIREMENTS

FDA REVISING TOPICAL CORTICOSTEROID BIOEQUIVALENCE REQUIREMENTS via an interim study guidance that will be released "shortly," according to the agency. The current guideline, issued in July 1987, will be revised to include more well-defined controls for measuring the comparative vasoconstrictor activity of topical corticosteroids. One change under consideration by the agency is requiring use of a placebo arm or a placebo arm plus another active drug arm in addition to the test drug and innovator drug arms. The agency said that its protocol will continue to use the vasoconstrictor assay, but that it will change the suggested methods for using the assay. FDA's intent, in changing the protocol, is to ensure consistency among companies or labs when they test generic corticosteroids. The agency decided to modify its protocol after looking over studies submitted in support of generic corticosteroid applications. An FDAer noted that it has not provided a "firm guidance as to the specifics of the test," such as how much material should be rubbed on arms and when readings should be taken. The agency believes that "there ought to be one uniform way that everybody ought to do it." FDA said that results of two studies involving use of the vasoconstrictor assay, conducted by the assay's developer Richard Stoughton, MD, also influenced the agency's decision to strengthen its protocol. Stoughton's studies found differences between the potencies of brand-name and generic corticosteroids. The agency noted that FDA adopted the assay, which was designed to show differences in potencies, to determine bioequivalence between corticosteroids. FDA said it will be inviting comments on the interim guidance and anticipates issuing the final guidance "in a year."