The judicially-created doctrine of obviousness-type double patenting prohibits a party from obtaining an extension of exclusive rights through claims in a later patent that are not patently distinct from claims in an earlier patent.1 Typically, an applicant can void an obviousness-type double patenting rejection by filing a terminal disclaimer.2 However, as illustrated in In re Hubbell,3 a patent examiner may reject an applicant’s pending patent claims based on obviousness-type double patenting, even where there is no common ownership with the conflicting patent.4 In this scenario, the lack of common ownership precludes the applicant from filing a terminal disclaimer to overcome the rejection.5

In In re Hubbell, California Institute of Technology (“CalTech”) inventors filed U.S. Patent Application 10/650,509 (“the ‘509 application”) claiming proteins for tissue repair and regeneration.6 Before filing the ‘509 application, two of the named inventors moved from CalTech to Eidgenössische Technische Hochschule Zürich (“ETHZ”).7 The inventors, along with an additional researcher, further developed the technology claimed in the ‘509 application and filed an application directed to a species of the ‘509 application’s claimed invention.8 The application resulted in U.S. Patent No. 7,601,685 (“the ‘685 patent”) and was jointly assigned to ETHZ and Universität Zürich.9

During prosecution of the ‘509 application, the Examiner rejected the claims for obviousness-type double patenting over the ‘685 patent.10 While not having the same set of inventors or a common assignee, the Examiner relied on the ‘509 application and the ‘685 patent sharing two common inventors.11 The applicants appealed the Examiner’s decision, arguing that common ownership is a requirement for obviousness-type double patenting.12 On appeal, the Board of Patent Appeals and Interferences (“the Board”) affirmed the Examiner’s obviousness-type double patenting rejection, noting that the Manual of Patent Examining Procedure specifically contemplates application of obviousness-type double patenting where there is no co-ownership.13 The applicants appealed the Board’s decision to the Federal Circuit.14

The Federal Circuit affirmed the Board’s decision that an examiner may reject an applicant’s claims for double patenting, even where there was no common ownership with the conflicting patent.15 The court considered the rationale behind the obviousness-type double patenting rejection and emphasized the concern that a potential infringer could be subject to multiple infringement suits from a patentee asserting essentially the same patented invention.16 The court noted that this harassment justification is “particularly pertinent” where the patents are not commonly owned.17 Therefore, despite the lack of common ownership, the obviousness-type double patenting rejection prevents the potential harassment of an infringer by multiple patentees asserting patentably-indistinct claims.18

The Federal Circuit also refused to create a new equitable right to file a terminal disclaimer to overcome this type of double patenting rejection.19 The court recognized that a terminal disclaimer is effective only where there is common ownership between the conflicting claims.20 Thus, the court adhered to the statutory requirement that a terminal disclaimer requires common ownership between the conflicting claims that formed the double patenting rejection basis.21

Judge Newman, dissenting, argued that the majority ruling finding double patenting without common ownership or inventorship of the conflicting claims runs contrary to statute and precedent.22 Discussing the legal development of double patenting, Judge Newman reasoned that the requirement of either common ownership or inventorship is and should remain a requirement for double patenting.23 In her view, rather than creating a new protocol for double patenting, the standard examination process is sufficient to determine patentability of these patent claims.24 Alternatively, Judge Newman asserted that if the court can find obviousness-type double patenting without common ownership or inventorship, then it should also be possible to file a terminal disclaimer without common ownership or inventorship.25

The In re Hubbell decision illustrates a double-patenting snare: a common inventor creates the window for a double patenting rejection, but lack of common ownership precludes a filing of a terminal disclaimer to overcome this rejection. To avoid this trap, patent practioners must be aware of each inventor’s invention before, during, and after the inventor’s employment with the company, with an eye towards maintaining patentably distinct claim scope.