Chapter §12.05 Twenty-Year Patent Term Did Not Eliminate Double Patenting Concerns

• Jurisdiction: United States

§12.05 Twenty-Year Patent Term Did Not Eliminate Double Patenting Concerns

It was commonly thought that double patenting problems were minimized, if not eliminated, by the URAA-implemented change in computing the term of a U.S. patent.⁵¹ For patents issuing from applications that are filed on or after June 8, 1995, the patent term expires 20 years after the application's earliest effective U.S. filing date.⁵² Moreover, any patent issuing from a continuing application that claims the benefit of the filing date of an earlier-filed co-pending application in accordance with 35 U.S.C. §120/§121 will expire 20 years from the earlier-filed application's filing date.⁵³ Thus, a series of patents that are owned by the same entity, issuing from a chain of continuing applications, will all expire on the same date. This would seem to eliminate the "extension of monopoly" concern on which the double patenting prohibition is traditionally based.⁵⁴

For example, suppose Inventor files a first (parent) patent application in 2012. While the parent application is still pending, Inventor files a continuation application in 2014, claiming the benefit of the 2012 filing date of the parent application.⁵⁵ If a first patent thereafter issues from the parent application, and a second patent issues from the continuation application, both patents will expire on the same date.⁵⁶ Thus it can be said that the second patent does not "extend the monopoly" of the first patent.

Despite the URAA's change in patent term computation, double patenting problems may still arise in a variety of situations.

First, the same entity cannot obtain two patents on the identical invention, even if the two patents expire on the same day. This would violate the same invention-type double patenting prohibition, which is based on the language of 35 U.S.C. §101.⁵⁷

Second, assuming the claimed inventions of the two patents are not identical but merely obvious variants, obviousness-type double patenting remains a concern even though the two patents expire on the same day (as in the example of multiple patents issuing from a chain of continuing applications). Assume that initially the two patents are owned by the same entity (person or firm). That common ownership may end in time, such that different entities own each patent. The policy concern in such a situation is that an accused infringer could face infringement lawsuits brought by multiple patent owners, each owning a patent on an obvious variant of the same invention.⁵⁸

Third, double patenting concerns may arise due to patent term adjustment or patent term extension.⁵⁹ For example, even if two patents issue from parent and continuation applications, respectively, and would otherwise expire on the same date under the URAA-implemented 20-year term, their respective terms could be different due to patent term adjustment. Even assuming the two patents remain commonly owned by the same assignee, that assignee might obtain a first patent having expiration date Z and a second patent, claiming an obvious variant of the invention claimed...