A Federal Circuit Prescription to Take Away the Pain for Generics

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The Federal Circuit recently reversed a lower court’s ruling of validity under the § 112 written description requirement effectively opening the door for a number of generic drug manufacturers to enter the market with a generic form of the pain relieving drug  ®. In its precedential opinion, the court ruled that the claims of U.S. Patent Nos. 6,926,907 and 8,557,285, which are directed to a single drug form that includes both an enteric-coated non-steroidal anti-inflammatory drug (NSAID) and an acid inhibitor to raise the gastric pH, were not adequately supported by the disclosure in the patents and thus invalid. 


Nuvo Pharmaceuticals sells Vimovo®, which is a commercial embodiment of the ’907 and ’285 patents. Prior to the invention claimed in the ʼ907 patent and ʼ285 patents, it was accepted that non-steroidal anti-inflammatories (NSAIDs) cause gastrointestinal (GI) complications, and it was also known that acid inhibitors could be used to treat such undesirable side effects by raising the pH in the GI tract. However, the dual therapy was not effective for several reasons. First, the stomach acid degrades the acid inhibitor before it is able to reach the small intestine and have any effect on the acidity in the GI tract. Second, even when the acid inhibitor is coated to protect it from degradation, the NSAID may be released before the acid inhibitor can raise the pH level in the GI tract, thus leaving patients susceptible to GI complications. In an attempt to solve this problem, the named inventor of Vimovo®, Dr. John Plachetka, conceived of a single drug form where an uncoated acid inhibitor would control the acidity in the GI tract before the NSAID is released.


After Dr. Reddy’s Laboratories, Mylan Pharmaceuticals, and Lupin Pharmaceuticals submitted Abbreviated New Drug Applications (ANDAs) to the FDA in an effort to bring to market a generic version of Vimovo®, Nuvo and Horizon Medicine sued the generic drug manufacturers in the District of New Jersey attempting to prevent the sale of the generic versions prior to the expiration of the ʼ907 and ʼ285 patents. While the generic drug manufacturers stipulated to infringement (with the exception of a second drug form applied for by Dr. Reddy’s in a separate ANDA), they launched an aggressive defense of invalidity based on obviousness under 35 U.S.C. § 103, lack of enablement under 35 U.S.C. § 112, and lack of written description under § 112. 


Before trial, the district court agreed with Dr. Reddy’s on summary judgment that its second ANDA drug did not infringe the ʼ907 patent because the asserted claims prevent the release of “essentially any NSAID” until the pH reaches at least 3.5, whereas Dr. Reddy’s second ANDA product contains some amount of uncoated NSAID that is released immediately (regardless of pH). At trial, the court considered the generic drug manufacturers’ arguments of invalidity, but ultimately held that the asserted claims of the ʼ907 and ʼ285 patents were not obvious over the prior art. More specifically, the court found that a person of ordinary skill in the art would not have reasonably expected that an uncoated acid inhibitor, such as esomeprazole, would prevent the gastrointestinal injury brought about by the NSAIDs. With regard to enablement, the court held that specifications of both patents teach how to make and use the invention. The written description arguments from the generic drug manufacturers were also rejected by the court, including the generic drug manufacturers’ position that (1) the use of “comprising” in the claims allows for the claimed drug to include some uncoated naproxen that is released regardless of the pH, which is not supported by the specification, and (2) the specification provides no data or support demonstrating that the uncoated acid inhibitor was “effective to raise the gastric pH” as required in the patents. Finally, Dr. Reddy’s second ANDA product was found to infringe the claims of the ʼ285 patent.


On appeal, the generic drug manufacturers partially appealed the written description ruling from the lower court, i.e., the two points discussed above. They took the position that adequate written description under § 112 requires supporting experimental data or some rationale as to why the claimed invention is effective given the teaching away of effectiveness in the prior art. In addition, the generic drug manufacturers contended that the lower court erred in finding that the specifications of the ʼ907 and ʼ285 patents sufficiently describes uncoated naproxen. The Federal Circuit did not consider the “comprising” argument, on appeal, but instead focused on the “efficacy” written description issue. With respect to Nuvo’s counterargument on appeal that the claims of the ʼ907 and ʼ285 patents do not require the uncoated acid inhibitor to be effective to raise the gastric pH—only that the drug needs to contain an effective amount of uncoated acid inhibitor—the court explained that it is “nonsensical to read the claims to require effective amounts . . . without specifying the result effectively achieved.” As an aside, the court found this argument and the majority of Nuvo’s other counterarguments raised in the appeal to be forfeited because they were not previously made in the lower court. 


After clarifying that, based on the record below, the claims are read to require a therapeutically effective amount of uncoated acid inhibitor that can raise the gastric pH to at least 3.5, the court “scour[ed] the record created below for evidence supporting the district court’s written description finding.” In doing so, the court also reminded us that (1) the written description requirement is not necessarily met just because the claim language appears in the specification (as contended by Nuvo’s expert at trial), and (2) experimental data or rationale is not necessarily required to demonstrate effectiveness. Unfortunately for Nuvo, the Federal Circuit concluded that the evidence demonstrated that a skilled artisan would not have known or understood that an uncoated acid inhibitor is effective and that the shared specification of both patents failed to demonstrate that the inventor “possessed more than a mere wish or hope” that the uncoated acid inhibitor would work to raise the gastric pH to at least 3.5. In fact, the inventor’s testimony at trial, that he only had a “general concept of coordinated delivery with acid inhibition,” was considered to “illuminate[] the absence of critical [written] description in this case.”


Nuvo’s final argument also failed to save its patents from invalidity under § 112. In this vein, the Federal Circuit was unpersuaded that, because the specifications of both patents teach how to make and use the claimed invention, the therapeutic effectiveness of the uncoated acid inhibitor is inherent and thus needs no express disclosure in the specification. While the court noted that, under a narrow set of circumstances, the written description requirement under § 112 may be met without explicit disclosure if the claimed features are necessarily inherent in what is expressly described, it could not find any evidence in the record to demonstrate inherency of efficacy here. In concluding its opinion, the court noted that “the inventor chose to claim the therapeutic effectiveness of uncoated PPI, but he did not adequately describe the efficacy of uncoated PPI so as to demonstrate to ordinary skilled artisans that he possessed and actually invented what he claimed.” 


Nuvo cross-appealed the court’s summary judgment ruling of non-infringement of the ʼ907 patent for Dr. Reddy’s second ANDA product on the basis that the lower court erred in assigning a claim construction of the term “essentially any NSAID” to prevent even small amounts of uncoated NSAID to be present in the drug before the pH reaches at least 3.5.  However, because the court found the claims of the ʼ907 and ʼ285 patent invalid under § 112, Nuvo’s cross-appeal challenging the district court’s summary judgment non-infringement ruling with respect to Dr. Reddy’s second ANDA product was considered moot.


This opinion serves to remind patent drafters that the written description requirement under 35 U.S.C. § 112 cannot be ignored and can be the fatal flaw in an otherwise sound patent.  When a claim specifically requires a result, the result must be supported by adequate disclosure in the specification. It is not enough to repeat the claim language in the specification. Moreover, teaching how to make and use an invention does not necessarily satisfy the written description requirement. Rather, the disclosure in the specification must demonstrate that the inventor possessed the claimed invention at the time of invention. Since written description analyses are highly fact specific, patent drafters need to pay close attention to the claim language and ensure that the disclosure in the specification adequately supports any results, such as therapeutic effectiveness, featured in the claims.