In its precedential decision in August, the Federal Circuit reversed the district court’s ruling which found certain claims of patents covering Allergan’s Viberzi drug invalid for obviousness-type double patenting (“ODP”). Allergan USA, Inc. v. MSN Laboratories Private Ltd., No. 2024-1061 (Fed. Cir. Aug. 13, 2024). Framing the issue as whether “a first-filed, first-issued, later-expiring claim be invalidated by a later-filed, later-issued, earlier-expiring reference claim having a common priority date,” the Federal Circuit held that “it cannot.” Slip. Op. at 11.
The parent-patent at issue, U.S. Patent No. 7,741,356 (“the ’356 patent”) was issued on June 22, 2010 from the first-ever patent application to cover eluxadoline filed on March 14, 2005. The ’356 patent ultimately received a patent term adjustment of 467 days and is to expire on June 24, 2026.
A number of continuing applications that each claim priority from the March 14, 2005 filing date of the ’356 patent were filed. In particular, the application resulting in U.S. Patent No. 8,344,011 (“the ’011 patent”) was filed on July 19, 2010. The ’011 patent issued without any delay in prosecution on January 1, 2013 and is to expire on March 14, 2025. The application resulting in U.S. Patent No. 8,607,709 (“the ’709 patent”) was filed on November 30, 2012. The ’709 patent issued without any delay in prosecution on December 17, 2013 and is to expire March 14, 2025.
All three patents would have expired on the same day as they share a priority date but for the PTA awarded to the ’356 patent. The district court, noting that when analyzing ODP, a court compares patent expiration dates, rather than filing or issuance dates, held that claim 40 of the ’356 patent was invalid because it was undisputed that claim 40 and the reference claims of the ’110 and ’709 patents are not patentably distinct, and because claim 40, having been awarded additional PTA days, expires after the reference claims. In so holding, the district court relied on In re Cellect, LLC, 81 F. 4th 1216, 1208 (Fed. Cir. 2023), which held that patents covering the same invention but with different expiration dates can be invalidated for ODP, even if the original patent still has an ongoing PTA. (See more on In re Cellect here).
The Federal Circuit explained that Cellect answered a different question and established that when evaluating ODP on a patent that has received PTA, the relevant expiration date is the expiration date including PTA, not the original expiration date measured twenty years from the priority date. But the case does not mandate that the ’356 patent must be invalidated by the ’011 and ’709 reference patents simply because it expires later. Considering 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 Federal Circuit held that the ’011 and ’709 patents cannot be proper ODP references to be used to invalidate the ’356 patent. The Federal Circuit noted that the ’356 patent is “undoubtedly the ‘first’ patent to cover eluxadoline, whether we measure by filing date or by issuance date” and that the ’011 and ’709 patents are “unquestionably ‘second’ to that patent” as “neither of the applications leading to those patents were even filed after the ’356 patent issued.” Thus, “the claims of the ’356 patent do not ‘extend or prolong the monopoly [on eluxadoline] beyond the period allowed by law” and “therefore are not subject to ODP over the ’011 and ’709 patents.” In other words, “that the ’356 patent expires later is of no consequence because it is not a ‘second, later expiring patent for the same invention.”
This decision is, as characterized by the Federal Circuit, “‘a prime example’ of when ODP does not apply.” At least where the patent is the very first patent in a family, if it’s first-filed and first-issued, it probably has a good chance against being invalidated for ODP by later-filed and issued patents even if it is later-expiring due to PTA it received.