Written description for functional limitations in view of Alcon Research Ltd. v. Barr Labs


Alcon owns US 5,631,287 (‘287), of which Claim 1 recites “[a] method of enhancing the chemical stability of an aqueous composition comprising a therapeutically-effective amount of a prostaglandin, wherein the method comprises adding a chemically-stabilizing amount of a polyethoxylated castor oil to the composition.” Claim 12, which depends from Claim 1, speci?es that “the composition is a topically administrable ophthalmic composition.”

Although ‘287 is not listed in the FDA’s Orange Book as covering Alcon’s Travatan Z®, when Barr ?led an abbreviated new drug application (“ANDA”) to manufacture a generic Travatan Z®, Alcon sued for infringement of ‘287. The trial court held that Barr’s ANDA product did not infringe ‘287, and that ‘287 Claim 12 is invalid for written description and enablement failures.

With speci?c regard to written description, the trial court concluded that the disclosure was too limited and the art of stabilizing prostaglandins too unpredictable to support the breadth of Alcon’s Claim 12, which speaks merely of a “chemically stabilizing amount” of polyethoxylated castor oil (“PECO”), without naming any particular ratios of PECO to particular prostaglandins. On appeal, Barr defended the trial court’s reasoning, arguing that Alcon’s claims “overreach” (slip op. at 15). Barr argued that Alcon’s speci?c disclosure of thirty two prostaglandin/PECO combinations is not enough to support a claim to any “chemically stabilizing” ratio of PECO in combination with any prostaglandin.

The Federal Circuit disagreed with Barr and reversed the trial court with regard to invalidity, although it af?rmed the holding of non-infringement. The Federal Circuit began by noting that U.S. law does not require any working examples (slip. op. at 16), so Barr’s argument that there were not enough working examples to support the claims cannot be correct. The Federal Circuit then listed off numerous aspects of the claimed invention that are disclosed in the patent’s written description, ultimately concluding that the patent describes enough to show that the patentee had, at the time of ?ling, invented that which was claimed. The same reasoning also moved the Federal Circuit to reverse the trial court’s holding of invalidity on enablement grounds. In summary, Barr escaped liability for infringement, but all of Alcon’s claims remain valid and enforceable.

The complete opinion is available here.

DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

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