To the Editor: In his Perspective article, Topol (July 14 issue)1discusses current clinical practice with respect to nesiritide.According to the Food, Drug, and Cosmetic Act, drug approvalcan be withdrawn when "new evidence of clinical experience,not contained in such application or not available to the Secretaryuntil after such application was approved, or tests by new methods,or tests by methods not deemed reasonably applicable when suchapplication was approved, evaluated together with the evidenceavailable to the Secretary when the application was approved,shows that such drug is not shown to be safe for use under . . . [Full Text of this Article]