Under the Noerr-Pennington doctrine, those who petition the government for redress are immune from antitrust liability for that petitioning activity. Protected petitioning activity includes the institution and maintenance of lawsuits. Under the "sham litigation" exception to Noerr-Pennington, however, immunity does not apply to a suit if it: (1) is objectively baseless in the sense that no reasonable litigant could realistically expect success on the merits and (2) conceals an attempt to interfere directly with the business relationships of a competitor, through the use of the litigation process itself, as opposed to the outcome of that process, as an anticompetitive weapon. In a rarity, the Eastern District of Pennsylvania, in In re Wellbutrin SR Antitrust Litg., Nos. 04-5525, 04-5898, 05-396 (E.D.Pa. March 9, 2006), found that patent infringement suits instituted by GlaxoSmithKline ("GSK") were not protected by Noerr-Pennington because they came within the scope of the sham litigation exception.

In 1993, GSK filed a patent application for a depression drug, bupropion, that used a particular sustained release agent known as hydroxypropyl methycellulose ("HPMC"). The patent examiner rejected the application, finding that it was overly broad because it covered any sustained release mechanism for bupropion. GSK amended the application to limit it to only bupropion that used HPMC. In October 1996, the Patent and Trademark Office ("PTO") approved the narrowed application and GSK began marketing the drug under the name Wellbutrin SR.

Beginning in August 1999, several generic drug companies attempted to begin marketing generic versions of Wellbutrin SR, all of which used sustained release agents other than HPMC, by filing what are known as Abbreviated New Drug Applications (ANDA’s") with the FDA containing certifications that their generic versions did not infringe GSK’s patent. GSK instituted patent infringement suits against all of these ANDA filers within 45 days of these filings. Under the provisions of the Hatch-Waxman Act, the filing of these suits stayed the FDA’s approval of the marketing of the generics for thirty months or until GSK’s patent was held invalid or not infringed. The plaintiffs in this case alleged that GSK used these infringement suits to extend its monopoly over Wellbutrin SR for the length of the stay in violation of the antitrust laws and that they constituted sham litigation not protected by Noerr-Pennington. GSK filed a motion to dismiss arguing that the plaintiffs could not show that GSK’s infringement suits were objectively baseless. The Court held that under the facts alleged by plaintiff and taken to be true for purposes of the motion, GSK’s suits were objectively baseless and not entitled to Noerr-Pennington immunity.

GSK’s first argument was that its infringement suits could not be considered objectively baseless because, although the generics’ drugs used sustained release agents other than HPMC, they may still infringe GSK’s patent under the doctrine of equivalents. Under this doctrine, a product that is similar to a patented product or process but contains unimportant and insubstantial differences from what is claimed by the patent that, though actually adding nothing, take the product outside the literal scope of the patent is still considered to infringe the patent. The plaintiffs pointed out that the doctrine of equivalents is limited by the doctrine of prosecution history estoppel. Under this doctrine, if a patentee narrows its patent in response to a rejection of the patentee’s original application, the patentee is estopped from later arguing that the subject matter covered by the original broader application is considered equivalent to the narrower patent it holds under the doctrine of equivalents. GSK responded that the law of prosecution history estoppel was unsettled at the time it commenced the suits and thus the narrowing amendments it made to its original patent application did not necessarily mean that GSK could not make a successful case under the doctrine of equivalents.

The Court acknowledged that the law of prosecution history estoppel was indeed unsettled at the time GSK brought its suits. Under the more prevalent approach, a patent holder is estopped from invoking the doctrine of equivalents only if the allegedly infringing product falls within the subject matter specifically excised by the patent holder’s narrowing amendments to its patent. Under the competing approach, a patent holder is completely barred from claiming infringement by equivalence if it narrowed its patent in response to a rejection by the PTO. The Court noted, however, that uncertainty in the law by itself did not necessarily mean that GSK had a realistic chance of prevailing on the merits of its suits. Under either of the approaches to prosecution history estoppel, GSK could not claim infringement by equivalence if the generics’ drugs fell within the subject matter GSK relinquished by narrowing its patent from its original application. GSK narrowed its claim from all sustained release mechanisms to the specific use of HPMC and thereby relinquished its ability to argue that drugs using other sustained release mechanisms infringed its patent under the doctrine of equivalents. Since this was precisely the claim GSK made in its suits, it had no realistic chance of success on the merits.

GSK further argued that the fact that one of its suits, against Eon Labs, survived summary judgment necessarily meant that its suits were not objectively baseless. The Court noted that controlling authority from the Federal Circuit held that the court hearing the claim that a suit was sham litigation for purposes of Noerr-Pennington immunity must make its own assessment of the objective merits of that suit, regardless of how the suit fared in other courts. Moreover, since the assessment of objective baselessness was based on the "expectations" of a reasonable litigant, the analysis should focus on whether success could be "expected" at the time the suit was brought, not on the results of the suit.

A finding that a suit is objectively baseless for purposes of the sham litigation exception to Noerr-Pennington immunity is rather infrequent. In re Wellbutrin SR Antitrust Litg. demonstrates, however, that Noerr-Pennington immunity for lawsuits is far from assured. More specifically, where the relevant facts indicate that, at the time the suit in question was brought, the suit would likely not conform to the available legal theories, the party instituting suit may be subject to antitrust liability for it even if the relevant law is unsettled. Further, even some level of preliminary success in the challenged suit, such as survival of a motion for summary judgment, does not guarantee that the suit will not be held objectively baseless and stripped of immunity.


Authored by:
Anik Banerjee