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Allergan (AGN - Analyst Report) recently issued a response to the Food and Drug Administration’s (FDA) bioequivalence draft guidelines for the company’s eye drug, Restasis (cyclosporine). Allergan requested the regulatory agency to revise and replace the draft guidance that was published on Jun 20, 2013.

According to the FDA’s draft guidelines, companies wanting to make a generic version of Restasis have two options – an in vitro study or an in vivo study. The first option implies that no clinical trial will be needed for a generic company to get its product approved provided certain criteria are met. According to the agency, the generic must be shown to be qualitatively and quantitatively similar to Restasis.

The comparative physicochemical characterization of the generic and Restasis should also be acceptable. Moreover, the comparative study should be conducted on at least three lots of the generic as well as Restasis. Some of the parameters that need to be measured include globule size distribution, viscosity, pH, zeta potential, osmolality, and surface tension.

Population bioequivalence has to be performed separately for each peak in the globule size distribution of Restasis.

As far as the second option is concerned, only one study needs to be conducted. In fact, the agency said that conducting a bioequivalence study with clinical endpoint for Restasis may not be feasible or reliable considering the product’s modest efficacy. Moreover, the study protocol will need to be approved by the FDA.

According to Allergan, the guidance that in vitro analyses alone can be submitted to establish bioequivalence of a proposed generic drug product to Restasis is unsound on a scientific as well as legal basis. On this basis, Allergan has requested the FDA to issue revised guidance explaining the need for in vivo comparative clinical studies to be conducted to establish bioequivalence of the proposed generic product to Restasis.

Our Take

Allergan’s response to the draft guidelines was in line with expectations. Currently, we have low visibility on whether any company is seeking approval for its generic version of Restasis.

The draft guidelines, if finalized in their current form, could make it easier for generic versions of Restasis to enter the market. Restasis, which posted sales of $792 million in 2012, is slated to lose exclusivity in the U.S. next year. Allergan expects Restasis sales of $870 million - $900 million in 2013. With the drug accounting for about 13.9% of total product net sales (as of 2012), the entry of generic versions would be a major setback for Allergan.

Allergan currently carries a Zacks Rank #3 (Hold). At present, companies like Actelion Ltd. (ALIOF), Questcor Pharmaceuticals , and Anacor Pharmaceuticals, Inc. (ANAC - Snapshot Report) look well positioned. While Actelion and Questcor are Zacks Rank #1 (Strong Buy) stocks, Anacor is a Zacks Rank #2 (Buy) stock.

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