FDA Hearing To Determine Generic Premarin Fate

As the Marketletter goes to press, an advisory committee to the US Food and Drug Administration has been hearing two sides of an argument that will determine whether or not generic competition will threaten Wyeth-Ayerst's $850 million hormone replacement therapy product Premarin (conjugated estrogens) in the near future.

The public hearing, held on July 27-28, will consider a Citizen's Petition brought by Wyeth which aims to reclassify a component of Premarin, called delta 8,9 dehydroestrone sulfate (DHES), from an impurity to a concomitant and active component of the product. Wyeth filed the petition with the FDA in June, allegedly, say generics firms, in an attempt to prevent the approval of generic versions of the product (Marketletters passim).

At least three generics firms have filed Abbreviated New Drug Applications for generic Premarin in the USA. The latest, Barr Laboratories, has just made an initial application which covers two strengths (0.625mg and 1.25mg), but will eventually support the introduction of all five strengths of the branded product. Duramed and Zenith Laboratories are also seeking approval for generic versions, and will give evidence at the hearing.