A patent that issues after but expires before another patent still qualifies as a double patenting reference for that other patent. This expiration-date centric analysis is a departure from the traditional issue-date centric analysis. “[L]ooking to patent issue dates had previously served as a reliable stand-in for the date that really mattered—patent expiration.” In a post-URAA world, however, “there are now instances, like here, in which a patent that issues first does not expire first.” Therefore, “it is the comparison of [] patent expiration dates that should control, not merely the issuance dates.”
Background / Facts: There are two patents at issue here, both related to the inhibition of viruses through selective interference with certain enzymes and both at least presumed to be obvious variants of one another. While the patents list the same inventors and the written descriptions disclose similar content, they do not claim priority to a common patent application and have different expiration dates. In particular, although the first-filed application expires before the second-filed application (under the then-recently enacted URAA implementing a 20-year from filing term), the second-filed application was nevertheless issued first.
Issue(s): Whether a later-issued patent can serve as a double patenting reference for an earlier-issued patent if the later one expires first.
Holding(s): Yes. “[I]t is a bedrock principle of our patent system that when a patent expires, the public is free to use not only the same invention claimed in the expired patent but also obvious or patentably indistinct modifications of that invention. … [T]hat principle is violated when a patent expires and the public is nevertheless barred from practicing obvious modifications of the invention claimed in that patent because the inventor holds another later-expiring patent with claims for obvious modifications of the invention.” Although the court acknowledged several prior cases that describe the double patenting bar as applicable to the “second” or “later” issuing patent, it noted that “those cases dealt with patents to which the URAA did not apply and, critical to a double patenting analysis, to patents for which the expiration date was inextricably intertwined with the issuance date.” Thus, “the focus on controlling the patent term of later issued patents in those cases makes perfect sense: before the URAA, later issued patents expired later.” In a post-URAA world, however, “we see little import here in the fact that the [later-filed] patent issued first.”