Allergan owns patents, including the ’356 patent, that cover the drug eluxadoline. The ’356 patent was awarded significant patent term adjustment (PTA) because of PTO delays during prosecution. Allegan filed continuation applications claiming the benefit of the ’356 patent’s priority date. These applications matured into patents that did not receive PTA and therefore were set to expire before the ’356 patent. After Allergan asserted the ’356 patent in litigation, the defendants argued that Allergan’s later-filed, later-issued, earlier-expiring patents were obviousness-type double patenting (ODP) references that rendered the ’356 patent invalid. Allergan never disputed that the subject matter of the claims were obvious variants. The district court agreed with defendants and invalidated the claims under ODP, and Allergan appealed.
The Federal Circuit reversed and determined that the later-filed, later-issued, earlier-expiring patents were not proper ODP references. The court held that a “first-filed, first-issued, later-expiring claim cannot be invalidated by a later-filed, later-issued, earlier-expiring reference claim having a common priority date.” The Federal Circuit distinguished its holding in Cellect by stating that “Cellect does not address, let alone resolve, any variation of the question presented here—namely, under what circumstances can a claim properly serve as an ODP reference—and therefore has little to say on the precise issue before us.”
The court held that a “later-filed, later-issued” patent cannot be an ODP reference to “the first-filed, first-issued patent in its family” because “[t]hat is the only conclusion consistent with the purpose of the ODP doctrine, which is to prevent patentees from obtaining a second patent on a patentably indistinct invention to effectively extend the life of a first patent to that subject matter.” The court further held that “the first-filed, first-issued patent in its family…is the patent that sets the maximum period of exclusivity for the claimed subject matter and any patentably indistinct variants.”
The court further noted that “it is not atypical for a patent applicant to first seek to protect the most valuable inventive asset (e.g., a pharmaceutical genus claim) before filing continuing applications on enhancements or modifications” to that invention. Moreover, the court noted that it is “unsurprising that prosecution of a first-of-its-kind invention can be protracted” such that an eventual patent on that invention “is awarded some amount of PTA.” But following the first application, it is generally expected that “a subsequently filed continuing application claiming the same priority date and covering a modification of that [first] invention proceeds much more efficiently through prosecution” such that PTA is not awarded on the later-filed patent. This pattern results in the later-filed, later issued continuation patent expiring first.
But, the court held, in such circumstances there is no unjust extension of patent term of the invention claimed in the child patent when the claims in the child patent did not even exist until after the parent patent issued.
The court further reasoned that “To hold otherwise—that a first-filed, first-issued parent patent having duly received PTA can be invalidated by a later-filed, later-issued child patent with less, if any, PTA—would not only run afoul of the fundamental purposes of ODP, but effectively abrogate the benefit Congress intended to bestow on patentees when codifying PTA.” Otherwise patent owners would be required to file a terminal disclaimer disclaiming any term of the parent that extends beyond that of the child, which, in effect would disclaim the PTA. That result would effectively gut the intent of Congress when it enacted the statute granting PTA.
This article appeared in the 2024 Federal Circuit IP Appeals: Summaries of Key 2024 Decisions report.
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