FDA’s rating of Syntex' Synarel

Executive Summary

When Synarel (transnasal nafarelin) was approved in February for treating endometriosis, FDA gave the drug a "1B" rating denoting a new chemical entity representing a modest therapeutic gain over existing therapies ("The Pink Sheet" Feb. 19, p. 3). However, as indicated in FDA's list of February approvals, the agency changed Synarel's rating to "1 C" or a new chemical entity offering little or no therapeutic gain ("The Pink Sheet" April 16, p. 11). According to FDA, the agency decided to change the rating because it was determined that Synarel has a side effect profile similar to an already approved endometriosis treatment, Sterling's danazol (Danocrine). FDA had originally thought that Synarel's side effect profile was better than danazol's.