Double patenting
Also called obviousness-type double patenting, ODP, nonstatutory double patenting, statutory double patenting, same invention double patenting, G 4/19, prohibition of double patenting
Double patenting is the grant of a second patent that claims the same invention as an earlier patent of the same applicant or, under US law, also an obvious variant of a claim in a patent or application with a common inventor or owner1,4. In US law it results when the right to exclude granted in one patent is unjustly extended by the grant of another patent or patents1.
US law has two types: statutory double patenting, which concerns the same invention, and nonstatutory (obviousness-type) double patenting, a judicially created doctrine aimed at claims that are not patentably distinct1. The EPO applies its own prohibition, confirmed by the Enlarged Board of Appeal in G 4/19 (22 June 2021)3,4.
Statutory and nonstatutory double patenting in the US
| Statutory | Nonstatutory (obviousness-type) | |
|---|---|---|
| Basis | 35 U.S.C. 101, which states in the singular that an inventor "may obtain a patent"1,2 | A judicially created doctrine grounded in public policy1 |
| Question asked | Is the same invention being claimed twice? "Same invention" means identical subject matter1 | Is any invention claimed in the application anticipated by, or an obvious variation of, an invention claimed in the patent?1 |
| Test or method | A reliable test: could a claim in the application be literally infringed without literally infringing a corresponding claim in the patent?1 | Construe the claims, identify the differences, then apply an anticipation and/or obviousness analysis1 |
| How it is avoided | Amend the conflicting claims so they are not coextensive, or cancel them. A terminal disclaimer is not effective1 | File a Terminal disclaimer, or show the claims are patentably distinct1 |
Why the doctrine exists
The MPEP says the doctrine seeks to prevent the unjustified extension of patent exclusivity beyond the term of a patent. The public should be able to act on the assumption that, when the patent expires, it is free to use not only the claimed invention but also modifications or variants that would have been obvious1.
It also serves to prevent multiple suits against an accused infringer by different assignees of patents claiming patentably indistinct variations of the same invention1.
Some commonality of inventorship or (deemed) ownership must exist between the patents or applications before double patenting can be considered. The MPEP lists the same inventive entity, at least one common joint inventor, a common applicant or common ownership, and joint research agreements1.
How nonstatutory double patenting is assessed
- The analysis compares the claims of the application with the claims of the reference patent or application, not what the reference discloses, although its disclosure may be used to interpret its claims1. The MPEP contrasts this with a prior art rejection under 35 U.S.C. 102 or 103, which relies on everything the reference fairly discloses1.
- The obviousness analysis is similar to, but not necessarily the same as, the one under 35 U.S.C. 1031.
- Domination is not double patenting. A first patent "dominates" a second when its broad claim encompasses the narrower claim, but domination alone cannot support a double patenting rejection, although the presence of domination does not preclude one1.
- A one-way test of distinctness is normally enough. A two-way test applies only when the applicant could not have filed the claims in a single application and the Office was solely responsible for the delays1.
- For copending applications the examiner may make a provisional rejection, and the MPEP says a complete response is either a showing that the claims are patentably distinct or a terminal disclaimer1.
Section 121 can shield a divisional application: claims are protected against a double patenting challenge if consonance exists between the divided groups of claims and an earlier restriction requirement1.
Term matters here. A patent issuing on a continuing utility application filed on or after June 8, 1995 expires 20 years from the earliest filing date for which a benefit is claimed under 35 U.S.C. 120, 121, 365(c) or 386(c), subject to patent term adjustment and extension, so copending applications often have the same patent term filing date1. See Continuation application.
For a patent that has received patent term adjustment (PTA), the Federal Circuit held in In re Cellect (2023), on appeal from ex parte reexamination, that obviousness-type double patenting must be based on its expiration date after PTA is added, whether or not a terminal disclaimer is required or has been filed5. The MPEP 804 revision cited on this page (R-07.2022) predates that decision1. See Patent term adjustment.
Double patenting by jurisdiction
United States
- Two types: a statutory rejection based on 35 U.S.C. 101 and a nonstatutory rejection based on a judicially created doctrine (MPEP 804)1.
- A nonstatutory rejection can be avoided by filing a terminal disclaimer, or by showing the claims are patentably distinct (MPEP 804 and 804.02)1.
- A terminal disclaimer cannot overcome a prior art rejection under 35 U.S.C. 102 or 103 (MPEP 804)1.
Europe
- In G 4/19 (22 June 2021) the Enlarged Board of Appeal answered that a European patent application can be refused under Articles 97(2) and 125 EPC if it claims the same subject-matter as a European patent granted to the same applicant that does not form part of the state of the art under Article 54(2) and (3) EPC3.
- The Board said the application can be refused on that basis whether it was filed on the same date, is an earlier application or a divisional application in respect of the application that led to the granted patent, or claims the same priority3.
- The Guidelines call it a principle of procedural law recognized in the majority of contracting states that two patents cannot be granted to the same applicant with claims directed to the same subject-matter. Typical situations are two applications filed on the same day, parent and divisional applications, and an application and its priority application4.
- An applicant may proceed with an application having the same description as a granted patent if it does not claim the same subject-matter. If claim 1 matches a dependent claim of the granted patent, an objection is raised, and if claims only partially overlap, no objection should be raised4.
- Where applications from the same applicant designating the same states have claims with the same filing or priority date and the same invention, the applicant must amend one or more applications, withdraw overlapping designations or choose which one proceeds to grant4.
US and EPO approaches compared
| United States (USPTO) | Europe (EPO) | |
|---|---|---|
| What conflicts | Identical claimed subject matter (statutory), or claims not patentably distinct, meaning anticipated by or obvious over the reference claims (nonstatutory)1 | Claims to the same subject-matter3,4 |
| Who is concerned | Patents or applications with a common inventor, applicant or owner, or a joint research agreement1 | The same applicant3,4 |
| Usual cure | Terminal disclaimer for nonstatutory cases, or a showing of patentable distinctness1 | Amend the claims, withdraw overlapping designations or choose which application proceeds to grant4 |
Seen in the record
The Enlarged Board of Appeal answered two questions referred to it on double patenting3. The record is an example of the EPO's current rule; it says nothing about any party beyond the decision.
G 4/19 (Double patenting)
The Board decided that a European patent application can be refused under Articles 97(2) and 125 EPC if it claims the same subject-matter as a European patent granted to the same applicant, and that this applies whether the application was filed on the same date, is an earlier application or a divisional application in respect of the application that led to the granted patent, or claims the same priority3.
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What is the difference between statutory and nonstatutory double patenting?
Statutory double patenting asks whether the same invention is claimed twice, meaning identical subject matter1. Nonstatutory double patenting asks whether an application claim is anticipated by, or an obvious variation of, a claim in the reference patent or application1.
Can a terminal disclaimer overcome double patenting?
For nonstatutory double patenting, yes: the rejection can be avoided by filing a Terminal disclaimer1. It is not effective against a statutory double patenting rejection, and it cannot overcome a prior art rejection under 35 U.S.C. 102 or 1031.
Does the EPO prohibit double patenting?
Yes. In G 4/19 the Enlarged Board held that an application can be refused under Articles 97(2) and 125 EPC if it claims the same subject-matter as a European patent granted to the same applicant3. The Guidelines say partially overlapping claims do not draw an objection4.
Is a double patenting rejection the same as a prior art rejection?
No. Double patenting compares claims with claims, whereas a rejection under 35 U.S.C. 102 or 103 relies on what the reference discloses, although the reference's disclosure may be used to interpret its claims1. A double patenting reference need not qualify as prior art1.
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