) 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the regulatory agency to revise and replace the draft guidance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.
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
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,
Anacor Pharmaceuticals, Inc.
) look well positioned. While Actelion and Questcor are Zacks
Rank #1 (Strong Buy) stocks, Anacor is a Zacks Rank #2 (Buy)
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