Forest Labs v. IVAX (TEVA) and CIPLA (Fed. Cir. 2007).
The Court of Appeals for the Federal Circuit today upheld Forest Labs patent on its billion dollar SSRI Lexapro (escitalopram oxalate) — rejecting IVAX’s arguments that the patent is anticipated and obvious. Based on two FDA extensions, the patent is set to expire on March 14, 2012.
This case is an important stepping stone in our new understanding of obviousness. Interestingly, in its multi-page discussion of obviousness, the appellate panel did not mention the Supreme Court’s recent landmark decision of KSR v. Teleflex.
History: Forest holds an expired patent on a racemic form of citalopram. After considerable effort, Forest’s scientists doubled the strength of the drug by isolating the (+) stereoisomer (which turned out to be the only active isomer) and patented that isomer in a “substantially pure” form. A prior art pharmacologic paper had suggested that the (-) stereoisomer would be the potent isomer, but that reference did not describe the preparation of the enantiomer.
Anticipation and Obviousness: The prior art reference (Smith) suggested isolation of a stereoisomer to create a more potent drug. That reference, however, did not enalbe the process of isolation. As we know, “[a] reference that is not enabling is not anticipating.” Similarly, for obviousness, the difficulty in isolating the steroisomer without undue experimentation along with other secondary factors led the court to the conclusion of nonobviousness.
At this point, the court could have explicitly distinguished this case from KSR v. Teleflex. Under KSR, knowledge of one stereoisomer would likely make the other stereoisomer obvious. (A simple variation requiring little creativity.) Based on the Smith reference, it would be obvious to consider creating a substantially pure form of escitalopram. However, KSR requires more than an obvious variation — It also requires the ability to implement that variation.
If a person of ordinary skill in the art can implement a predictable variation, and would see the benefit of doing so, §103 likely bars its patentability.
In the case of Lexapro, the facts indicated that a person of ordinary skill in the art could not implement the variation without a large amount of uncertainty and experimentation. Nonobviousness affirmed.
Appellate Practice: Most non-patent appeals typically focus on errors made by the lower court. Most patent cases, however, involve questions of law that are reviewed de novo (such as claim construction). Appeal of those issues do not require the appellant to show that the lower court was “wrong.” Instead, the appellate panel must simply be convinced of a better way.
In this case, the majority opinion chastizes IVAX on several occasions for its implicit arguments for de novo review of the factual decisions of the lower court. Those decisions are instead reviewed for clear error – a much higher standard.
[T]heir arguments … are largely a recounting of the testimony favorable to their theory of the case without explanation as to why we should have a definite and firm conviction that mistakes were made by the district court in its fact-finding. In other words, they do not inform us why the district court was not entitled to rely on the evidence favorable to Forest or demonstrate that the evidence favorable to them heavily outweighed the evidence favorable to Forest.
Discussion of Injunction in Subsequent Post
- Hal Wegner has indicated that this case should be of interest for those following the recent Plavix appeal.