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IP Alert: Narrow Species Claim Is Invalid for Double Patenting Over Prior Broader Genus Claim

August 27, 2014

The judicially created doctrine of obviousness-type double patenting is intended to prevent a patentee from obtaining multiple separate patents for inventions that are not patentably distinct. On August 21, the Court of Appeals for the Federal Circuit decided the case of AbbVie Inc. v. The Mathilda and Terence Kennedy Institute of Rheumatology Trust, a significant decision under the law of double patenting. The case demonstrates that obviousness-type double patenting can be a potent defense in patent litigation.

The AbbVie case concerned two patents, both owned by the Kennedy Institute. The first patent (No. 6,270,766) was filed in 1996, claiming a priority date of 1992. This patent expired in 2012. The second patent (No. 7,846,442) was filed in 2005 as a grandchild of the ’766 patent. The applicant did not claim the benefit of the 1992 priority date, but instead claimed priority only to the 1996 filing date of the ’766 patent. Because the patent claims priority only to 1996, not to 1992, the patent has a 20-year term that expires in 2016 and an actual expiration date in 2018 after adding patent term adjustment. 

Both the ’766 and the ’442 patents claim a method of treating rheumatoid arthritis by administering two components together. The ’766 patent claims were directed to the treatment of “all individuals in need” of rheumatoid arthritis treatment. The ’442 patent claims were more narrowly directed to treat the more specific group of individuals with “active disease,” defined as a more limited subset of “individuals in need.”

Plaintiff AbbVie sells the drug Humira under a license for the ’766 patent. Throughout the life of the ’766 patent, AbbVie paid more than $100 million in royalties to the Kennedy Institute under the license. Unwilling to pay further royalties after the ’766 patent expired, AbbVie sought a declaratory judgment that the claims of the ’442 patent were invalid over the ’766 patent for obviousness-type double patenting.

The district court held the ’442 patent invalid for double patenting. The Kennedy Institute argued that successfully treating individuals with an “active disease” was an unexpected result that patentably distinguished the claims of the ’442 from those of the ’766 patent. The court rejected this argument, reasoning that a person of ordinary skill would not have considered there to be substantial differences between the two categories of patients.

On appeal, the Federal Circuit affirmed. The court acknowledged that there are circumstances when a narrow species could be non-obvious and patent eligible despite a patent on its genus, for example, when that species produced results that were unexpected as of the date of the original invention. In the case at hand, however, the court held that a person of ordinary skill would have expected the results achieved by the narrow species when the earlier-expiring patent was filed. The court noted that “where a genus is so limited that a person of ordinary skill in the art can ‘at once envisage each member of this limited class,’. . . a reference describing the genus anticipates every species within the genus.” 

Here, the court observed that the ’766 patent was based on the same study that the Kennedy Institute relied on to demonstrate that the methods claimed in the ’442 patent produced unexpected results. Prior to filing the ’766 patent, the inventors conducted a study demonstrating that rheumatoid arthritis patients responded positively to the treatment methods claimed in the ’766 patent. The ’766 patent disclosure relied on this study to demonstrate the effectiveness of the claimed treatment. But the Kennedy Institute’s definition of the term “active disease” in the ’442 patent was taken directly from this same study. Thus, it would not have been considered “unexpected” at the time the ’766 patent was filed that patients with “active disease” would also respond to the treatment. The court concluded that the ’442 patent merely claimed the known utility of the ’766 patent and did not claim a species that generated unexpected results. 

The Kennedy Institute argued that an inquiry into the ’766 patent for evidence of unexpected results was improper because it amounted to treating a reference patent’s disclosure as prior art. The court disagreed, explaining that examination of an earlier-filed patent to determine questions of obviousness is different from using that reference as prior art. It is entirely proper for the court to look at the disclosure of a parent patent (in this case, the ’766 patent) to determine whether the results produced by the claims of the continuing patent (here, the ’442 patent) could be considered “unexpected.” 

Of further note is that a terminal disclaimer apparently would not have been of commercial value to the Kennedy Institute. A terminal disclaimer filed during prosecution is effective to overcome a double patenting rejection. In this case, although a terminal disclaimer could have prevented the invalidity holding for double patenting, such terminal disclaimer would have tied the term of the ’442 patent to that of the ’766 patent and apparently would not have resulted in a longer period of patent protection. Nor would the fact that the ’442 patent had been accorded patent term adjustment have changed this outcome, because such patent term adjustment would have been subject to the terminal disclaimer.  

Importantly, the AbbVie decision does not categorically prevent the issuance of later-expiring patents claiming a species where the earlier-expiring patent claims a broader genus. To the contrary, the AbbVie decision makes clear that the double patenting analysis must be made on a case-by-case basis. AbbVie also demonstrates that patent litigators and other interested parties in contested patent matters should be on the lookout for double patenting questions in issued patents.

For more information, please contact Fitch Even partner Michael J. Krautner, the author of this alert.

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