Anticipatory Prior Art Must Enable Practice Of The Invention

In Forest Labs v. IVAX Pharms, Inc. (No. 07-1059; September 5, 2007) a Federal Circuit panel affirms a district court’s decision that a patent is novel and nonobvious over the cited prior art. The validity analysis focuses on whether or not a disclosure of a racemic mixture of citalopram, coupled with a prediction that the (-)-enantiomer of citalopram would be of particular use, would anticipate the (+)-enantiomer of citalopram. Stereoisomers are compounds sharing the same atoms and the same bonding between those atoms, but having different spatial arrangement. Enantiomers are stereoisomers that are nonsuperimposable mirror images. A racemic mixture is a mixture of equal amounts of two enantiomers.

Although the reference pharmacology paper describes a racemic mixture of citalopram, and thus does state that there is a (+)-enantiomer of citalopram, the panel observes, the reference does not tell how to make it. Accordingly, the reference does not enable the claimed invention and cannot anticipate the invention. Rejecting IVAX’s argument that, based on the teachings of other references, one of skill in the art would have been able to resolve a substantially pure (+)-enantiomer of citalopram, the defendants are found to have failed to address why the district court made mistakes in its fact-finding. In holding the patent not invalid as obvious, the panel notably does not discuss the Supreme Court’s recent KSR decision.