The draft guidance published by FDA in June 2013 suggests that the bioequivalence requirements for generic cyclosporines may be fulfilled by an in vitro study and that clinical trials in humans may not be necessary in all cases.

Allergan argues, however, that there is currently no available scientifically valid method for measuring bioavailability in vivo for a drug like Restasis that is applied topically to, and acts locally in, the eye. This they say contravenes the law, which states that bioavailability must be ‘demonstrated by scientifically valid measurements intended to reflect the rate and extent to which the active ingredient or therapeutic ingredient becomes available at the site of drug action’.

Allergan adds that in fact the company has manufactured and tested several experimental products that are close variations of Restasis and conform to the Q1/Q2 and physicochemical criteria set forth in the draft guidance but that are not bioequivalent to Restasis.

Allergan states that ‘taking scientifically unjustified shortcuts around this critical requirement short-changes patients and physicians who depend on Restasis’ proven safety and effectiveness, and it risks undermining public confidence in generic drugs more broadly.’

Allergan therefore believes that FDA needs to revise its guidance to explain that ‘comparative clinical trials are required to demonstrate equivalent safety and effectiveness for a proposed generic referring to Restasis’. The company says that this is necessary both to protect patients and to comply with the law. They reiterate that the draft guidance violates the Federal Food, Drug, and Cosmetic Act [21 U.S.C. § 355(j)(8)(A)].

If the FDA guidance is accepted, it could mean that generics of Restasis could enter the market years earlier than anticipated due to the lack of need for time-consuming clinical trials in humans.

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