The U.S. Federal Circuit voted en banc to vacate a holding from a panel opinion with regard to the issue of experimental use, and the panel (J. Rader) has issued a new decision regarding a previous holding that the paroxetine hydrochloride anhydrate product produced by Apotex Corp. infringes Smithkline’s U.S. Patent No. 4,721,723 covering crystalline paroxetine hydrochloride hemihydrate, a form of Paxil that has some water molecules.

There is an exhaustive review and postings of the various opinions and brief’s at Dennis Crouch’s Patently Obvious blog here and here.

This case has quite a bit of history and in 2003, Seventh Circuit Judge Posner dismissed a patent infringement case involving paroxetine on the ground that the patent was not infringed. In 2004, a panel of the Federal Circuit affirmed the judgment, on the alternate ground that the patent was invalid due to public use of the invention more than a year before the patent was applied for because Smithkline conducted clinical trials more than one year prior to filing of the patent application. However, Smithkline argued that the clinical trials were an experimental use but the panel ruled that the use was not experimental. The Federal Circuit reversed the claim construction of the district court and held that claim 1 covers any amount of crystalline paroxetine hydrochloride hemihydrate without further limitation. Based on the factual findings of the district court, the Federal Circuit affirmed the district court’s finding that Apotex’s PHC anhydrate product will infringe claim 1 under that broad construction. Notwithstanding that conclusion, the Federal Circuit held, based on the undisputed facts, that SmithKline’s clinical trials constituted a public use under § 102(b) rendering claim 1 invalid. Apotex was thus not liable for infringing claim 1 of the ’723 patent.

In its new decision, the CAFC majority simply avoided the issue of experimental public use by finding alternative grounds to invalidate the patent, holding that the asserted claims “invalid for inherent anticipation by the ’196 patent under § 102(a).” This was originally rejected because Apotex “did not prove by clear and convincing evidence that it was impossible to make pure PHC anhydrate in the United States before the critical date.” The appellate panel found that Judge Posner erred by requiring Apotex to meet this standard of proof.

Now, the Federal Circuit en banc issued an order that granted the parties’ petition for rehearing en banc “for the limited purpose of vacating the panel’s original opinion addressing the issue of experimental use” and “remanded to the panel for further proceedings,” without analysis. Additionally, the panel issued a new opinion, “pursuant to an order issued by this court en banc,” deleting its earlier public use/experimental use holding and replacing it with a new holding that the patent was invalid for a completely different reason.

There’s a good discussion of the issues on Howard Bashman’s blog, How Appealing.

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One Comment

  1. Excellent, that was really well explained and helpful

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