Pozen Inc. v. Par Pharm., Inc.

Case Name: Pozen Inc. v. Par Pharm., Inc., Case Nos. 2011-1584, -1585, -1586, 2012 U.S. App. LEXIS 20360 (Fed. Cir. Sept. 28, 2012) (Circuit Judges Newman, Clevenger, and Wallach presiding; Opinion by Wallach, J.) (Appeal from E.D. Tex, Davis, J.)

Drug Product and Patent(s)-in-Suit:Treximet® (sumatriptan and naproxen); U.S. Patent Nos. 6,060,499 (“the ’499 patent”), 6,586,458 (“the ’458 patent”), and 7,332,183 (“the ’183 patent”)

Nature of the Case and Issue(s) Presented: The appeal centered on two issues: (i) whether the district court incorrectly found the patents valid over the obviousness challenge asserted by the defendants; and (ii) whether the district court incorrectly found infringement under the doctrine of equivalents.

At trial, the defendants asserted that the asserted claims were invalid because several different combinations of prior art showed that it would have been obvious to combine sumatriptan and naproxen to treat migraines. Each of those drugs was known to help treat migraines such that using them in combination would have been obvious. Pozen responded that none of the prior art combinations taught the use of those drugs simultaneously to get a long-lasting efficacy in the treatment of migraines.

As for infringement, the claim limitation at issue was directed at having “substantially all” of sumatriptan in one layer and naproxen in another layer. The district court construed this limitation to mean at least 90%, and preferably greater than 95%, of the sumatriptan in one layer and the likewise for naproxen. The accused products only had 85% of one component in one layer and 100% of the other drug in the other layer. The district court held that those products infringed under the doctrine of equivalents because 85% of a drug in one layer was an insubstantial difference than 90%. On appeal, the defendants argued that the district court erred because the accused products did not fall within the claimed range as construed by the district court. Pozen argued that there was no evidence to support that the accused products were not insubstantially different than the claimed invention. The Federal Circuit affirmed the findings of validity and infringement. 

Why Pozen Prevailed: First, the Federal Circuit agreed with the district court that none of the prior art combinations taught treating migraines with both drugs given simultaneously. The prior art taught other combinations of drugs to treat migraines, but not the claimed combination, nor the claimed dosage amount. The two patient records, relied on by defendants, were not found to render the claims obvious because they did not show that the drugs were given simultaneously and, for one patient, the treatment was discontinued almost immediately because it was ineffective. Thus, the Federal Circuit affirmed the lower court’s validity holding.

Next, the Federal Circuit rejected he defendant’s argument that the claim term “substantially all” was a “fuzzy” quantitive limitation not entitled to a range of equivalents since it was construed to encompass a range of 90% to 100% drug content.  Any equivalent would be subsumed within the court’s construction for literal infringement and therefore the range could not extend as low as 85%.  But Pozen never argued that 90% was an absolute floor, and the patent specification gave “substantially all” a quantitative definition of “at least 90%, and preferably greater than 95%.”  Thus, application of the doctrine of equivalents was appropriate to determine if 85% was an insubstantial difference from 90%.

The Federal Circuit affirmed the district court’s ruling because both ANDA’s demonstrated that the accused products perform the substantially same function, in substantially the same way, to achieve the substantially same results of the claimed invention. The accused products had two layers, each with substantially all of one drug in their respective layers. The Federal Circuit rejected the argument that the accused products do not infringe because one of the layers has both drugs as that layer was substantially indifferent to the claimed layer having at least 90% of one drug in the layer.  Thus, the Federal Circuit affirmed the finding of infringement under the doctrine of equivalents.