Obviousness type double patenting (ODP), or non-statutory double patenting, is a judicially created doctrine meant to prevent a party from extending an earlier commonly owned patent’s term by claiming patentably indistinct subject matter through claims in a later patent. An ODP rejection of the second patent application with indistinct patentable claims can be overcome by filing a terminal disclaimer as long as both patents are commonly owned or a joint research agreement exists for both patents. Absent these factors, a terminal disclaimer will not overcome an ODP rejection even if there is a common inventor. A terminal disclaimer disclaims the patent term of the later issued patent that extends beyond the term of the earlier expiring patent. Reissue proceedings cannot be used to withdraw a terminal disclaimer from an already expired issued patent. Nor can the reissue of a patent cure an improper terminal disclaimer.

Patent term adjustment extends the term of a patent to accommodate any delay caused by the USPTO during the patent’s prosecution. Filing a terminal disclaimer could cause any patent term adjustment to be lost. However, the right to a patent term extension under 35 U.S.C. § 156 based on the Hatch-Waxman Act is not lost by filing a terminal disclaimer.

Unlike the typical situation where a terminal disclaimer is filed to overcome an ODP rejection for claims which are indistinct as compared to an earlier filed and earlier expiring patent, last April the Federal Circuit took a different and surprising approach to ODP in Gilead Sciences, Inc. v. Natco Pharma Ltd. In Gilead, the Federal Circuit’s decision vacated and remanded that of the district court and held that plaintiff Gilead’s earlier issued (but later expiring) ‘483 patent could be invalidated for ODP in view of Gilead’s later issued (but earlier expiring) ‘375 patent. The Gileadcourt explained that “looking instead to the earliest expiration date of all the patents an inventor has on his invention and its obvious variants best fits and serves the doctrine of double patenting” and “preserves the public’s rights to use the invention (and its obvious variants) that are claimed in a patent when that patent expires.”

This ruling had the overall effect of shortening the original patent’s term after the second patent issued. Many in the patent community, particularly in the pharmaceutical industry, were surprised when the Federal Circuit issued this opinion. The finding that an earlier issued patent could be invalidated for ODP by a later issued patent led former Chief Judge Randall Rader to dissent strongly and conclude that the majority’s decision was an unwarranted expansion of the doctrine of ODP that would have “unforeseen consequences.”

More recently, the Federal Circuit responded to a contention in AbbVie Inc. v. Mathilda & Terence Kennedy Institute of Rheumatology Trust that the implementation of a 20-year period of patent protection that runs from a patent’s earliest claimed priority date eliminated the need for the ODP doctrine. The AbbVie Court ruled that a crucial purpose of the doctrine was to prevent an inventor from securing a second, later expiring patent for the same invention and that problem still existed. Patents claiming overlapping subject matter that were filed at the same time could still have different patent terms due to examination delays at the PTO.

Gilead most likely does not disturb the patent term extension on patents which cover products which require FDA approval. The two patents in Gilead did not have a common priority date as they belonged to separate families. Per Gilead, expiration of a patent in a family of patents which are commonly owned or have a joint research agreement may also terminate patently indistinct claims in the family. A restriction on some claims may prevent a Gilead-like outcome. If the USPTO restricts the claims in an application to a single invention under 35 U.S.C. § 121, and if a divisional application is filed to pursue the claims that were not elected in the original application, the divisional application would not be subject to an ODP rejection. However, the non-elected claims of the first application must literally be included in a divisional rather than a continuation application as the protections of Section 121 are available only to divisional and not to continuation applications.