Neurontin® (Gabapentin) Patent Trials - Pfizer Victory Remains Possible

Implications: The at-risk product launch by [NasdaqGS:TEVA] Teva of generic equivalents to [NYSE:PFE] Pfizer's Neurontin® (gabapentin) might - and the emphasis is clearly on might - yet prove to be an expensive mistake by Teva. The recent Opinion by the United States Court of Appeals for the Federal Circuit [also known as Federal Circuit, Fed Cir, or CAFC] essentially provides Pfizer a new opportunity to proceed with an actual on-the-merits trial. Upon remand, Plaintiff Pfizer will seek to establish patent infringement by multiple Defendants, including Teva. Pfizer previously enjoyed blockbuster Neurontin® sales of at least $2 Billion/year. As reviewed in-depth later, the CAFC Opinion - (a) reverses-in-part; (b) affirms-in-part; and (c) remands for further proceedings - the prior trial court judgment which had granted summary judgment of no patent infringement in favor of multiple Defendants.

Analysis: As always in Life Sciences Patent Battles, the details are critical. In this particular case, Pfizer appealed from the judgment of the United States District Court for the District of New Jersey [USDC/DNJ]. That prior trial court decision had granted summary judgment of no patent infringement of claims 7-11 of US Patent 6054482 in favor of Defendants [Teva, IVAX, and Eon Labs].

Of the asserted Claims 7-11, only Claim 7 is independent while the remaining Claims 8-11 are dependent. In fact, each of Claims 8-11 directly depends upon Claim 7. In its entirety, Claim 7 reads. "7. A stable and pure pharmaceutical composition in unit dry medicinal dosage form consisting essentially of: (i) an active ingredient which is gabapentin in the free amino acid, crystalline anhydrous form containing less than 0.5% by weight of its corresponding lactam and less than 20 ppm of an anion of a mineral acid and (ii) one or more pharmaceutically acceptable adjuvants that do not promote conversion of more than 0.2% by weight of the gabapentin to its corresponding lactam form when stored at 25.degree. C. and an atmospheric humidity of 50% for one year." The 2 key claim phrases are " less than 20 ppm of an anion of a mineral acid" (see clause (i)) and "adjuvants" (see clause (ii)).

With respect to the trial court's legal conclusions of the meaning of each of these 2 key claim phrases, the Federal Circuits affirms the interpretation set forth by the trial court. However, with respect to the trial court's factual findings relating to the 20 ppm limitation, the Federal Circuit disagrees with the prior analysis. More specifically, the CAFC concludes that there exist genuine issues of material fact regarding whether or not Teva's samples contained less than 20 ppm of acidic chloride ions. In other words, a full on-the-merits trial will be necessary and is now required in order to answer this factual question over the 20 ppm limitation. Thus, the Federal Circuit reverses the USDC/DNJ's grant of summary judgment of no patent infringement in favor of the Defendants and remands back down to the lower court for further proceedings (i.e., a full on-the-merits trial).

At least for now, Pfizer might still achieve victory in this long-running patent battle to enforce its umbrella of patent protection which covers the Neurontin® (gabapentin) products. Any such victory will, of course, be inherently limited and not total. There are numerous generic variants of Neurontin® (gabapentin) which are currently on the market. Tremendous amounts of lost sales continue to occur on a daily basis. If Pfizer ultimately prevails over the generic infringers, the potential money damages that Pfizer might be awarded from the Defendants are simply staggering. With that ultimate goal now clearly being - at a minimum - at least a possibility, Pfizer will surely spare no effort in its renewed patent infringement litigation proceedings at the District of New Jersey.