The U.S. District Court for the Eastern District of Texas recently ruled against generic drug manufacturers, granting an injunction barring U.S. Food and Drug Administration (FDA) approval of three abbreviated new drug applications.   Pozen Inc. v. Par Pharmaceutical et al., No. 6:08-cv-437 (E.D. Tex., Aug. 5, 2011) (Davis, J.).  The ruling, which is the first Hatch-Waxman Act patent case to go to trial in E.D. Texas adjudicated Pozen’s contentions that certain generic drug companies infringed various patents covering the migraine pharmaceutical sold as Treximet®.  In a detailed decision, the district court weighed multiple non-infringement positions as well as invalidity defenses based on double patenting, obviousness, anticipation, and lack of written description and engaged in a Therasense analysis before dismissing allegations of inequitable conduct.

The migraine tablet combining therapeutic agents sumatriptan and naproxen sodium was brought to market by Pozen’s exclusive licensee GlaxoSmithKline (GSK), which was obligated to pay Pozen a royalty that would decrease by 70 percent once a generic version of the drug entered the market.  After the defendants sought approval for generic versions of Treximet® under the Hatch-Waxman Act and certified that the three contested patents were invalid and/or would not be infringed, Pozen sued.

Judge Davis rejected the defendants’ non-infringement arguments based on impermissibly narrow claim construction that was not supported by the claim language, especially since the generic products were admittedly bioequivalent to Treximet®.  In connection with one of the asserted patents, the court delved into a function-way-result equivalence analysis that compared the architecture of the branded and generic tablets.  In applying a claim construction that required identified percentages in formulating sumatriptan and naproxen into distinct tablet layers, the court accepted plaintiff’s equivalence theory to broaden the specific numerical range provided in an earlier order.  The court concluded that the function of achieving separate, distinct layers of each agent was achieved in substantially the same way in the generic product as in the claimed invention.  Further, evaluating alleged disclaimers made by the patent owner during the course of the prosecution, Judge Davis concluded that the generic products could not avoid infringement through a characterization as “admixtures” that would obviate Pozen’s infringement allegations.

Regarding validity, Judge Davis separately discussed each alleged invalidating prior art reference and, in doing so, considered the related expert testimony, declarations from the prior art author where in evidence and clinical records.  The court ultimately concluded that there was insufficient evidence to overcome the presumption of validity.  The defendant’s written description arguments were also rejected, as the court concluded that the disclosure was adequate to inform one of skill in the art how to make and use the claimed invention.

The court found little merit in the defendants’ contention that two pilot studies submitted to the U.S. Patent and Trademark Office (USPTO) skewed results for the sake of presenting advantageous, yet misleading data.  Following Pozen’s explanation at trial, Judge Davis was satisfied that the testing data and representations made to the USPTO were accurate and, furthermore, that there was no evidence indicating deceptive intent as required by the Federal Circuit’s Therasense decision.  (See IP Update Vol. 14, No.6.)

In light of the licensing agreement between Pozen and its exclusive distributor GSK, Judge Davis found that the launch of a generic product would “devastate Pozen” and could even force the patentee out of business.  He found that the reduction of revenue combined with decreased resources satisfied the eBay requirement for irreparable harm.  Balancing the equities and finding that monetary damages could not compensate for the effects of the defendants’ infringement, the court issued an injunction that blocked the generics from entering the market until the expiration of the asserted patents.

Practice Note:  Generic drug cases are most typically filed in the district courts in Delaware, New Jersey and New York.  This action was closely watched by commentators familiar with Hatch-Waxman litigation, especially after the Eastern District of Texas amended its local Rules in April 2011 to adopt provisions modeled after local Rules in New Jersey that facilitate early disclosures.  So-called Hatch-Waxman.  These disclosure requirements mandate that the defendants provide the entirety of the disputed Abbreviated New Drug Application, as well as invalidity and non-infringement contentions early in the case.  Similarly, a name-brand drug company is required to disclose all infringement positions in chart form.  As with all patent cases in the Eastern District of Texas, these disclosures include the expectation that all accompanying documents and things will be produced without formal requests for production.