Restriction Requirement

A restriction requirement is a USPTO examiner's formal determination that a patent application contains claims to two or more independent and distinct inventions — and that the applicant must therefore elect one of those inventions for examination. The legal basis is 35 U.S.C. § 121 and MPEP § 800 et seq. The core principle: the USPTO is only obligated to examine one invention per application (and pays one examiner to do so). If an application contains multiple distinct inventions, the applicant must choose one for examination in the current application and file separate divisional applications for the others. Restriction is proper when the claimed inventions satisfy a two-way test: (1) they are claimed separately (separate claim groups); AND (2) they are independent or distinct — meaning that if each were filed in a separate application, they would not be subject to double patenting between them (neither would anticipate or render obvious the other). The key types of restriction are: product/process, combination/subcombination, and multiple independent products or processes. Restriction requirements are very common — particularly in certain art units (biotech, chemistry, electrical) and applications with broad disclosure. In ANDA/pharmaceutical art units, nearly all new chemical entity applications receive restriction requirements because the application typically discloses both the compound and methods of treating various diseases.

Election of species is a requirement distinct from (though related to) a restriction requirement. A restriction requirement separates independent inventions; election of species separates specific embodiments within a single broad invention. When an application claims a genus (broad category) and multiple specific species (individual embodiments) within that genus, the examiner may require the applicant to elect one species for examination when: (1) the species are materially distinct in structure or character; and (2) the number of species is large enough that examining all would create an undue search burden. The applicant elects one specific species (e.g., a specific compound, antibody sequence, or device configuration). The examiner then examines the elected species and any generic claim that 'reads on' the elected species — that is, claims that would be satisfied by the elected species. If the elected species is found allowable and the examiner has enough information, other species may be examined in the same application. Species not examined in the parent can be pursued in divisional applications. Key difference from restriction: restriction separates independent inventions that have independent utility. Election of species selects among embodiments of the same invention (members of a genus) for examination purposes. In practice, the two are often combined — an examiner may restrict between multiple independent inventions AND require election of species within one or more of those inventions in the same Office action.

Whether to traverse a restriction requirement requires strategic analysis — traversal is not always worth the effort, but sometimes it is. Reasons to traverse: (1) The restriction appears improper — e.g., the examiner restricted a process from its product when the process is uniquely applicable to making that specific product and no other products, or the subcombination lacks genuine separate utility. A well-founded traverse may persuade the examiner to withdraw the restriction, allowing prosecution of all claims in one application. (2) Preserving the right to challenge — only by traversing on the record can you challenge the restriction in an appeal or court proceeding. Electing without traverse is a waiver of the right to challenge. (3) The groupings are commercially important — if the examiner's groupings do not align with your most commercially important claims, traversal can sometimes lead to regrouping. Reasons not to traverse: (1) The restriction is proper — traversing an obviously proper restriction wastes response time and antagonizes the examiner. (2) The cost of drafting a substantive traverse is not justified by the strategic benefit. (3) Divisional applications will be filed anyway — if you planned to file divisionals regardless, the traverse may not provide material benefit. Practical approach: consult with patent counsel on each restriction. Routine restrictions on clearly distinct inventions often don't warrant traverse. Non-obvious restrictions — especially where allowance of one invention would clearly not lead to allowance of the other — are worth a focused, concise traverse. Even where traversal is unlikely to succeed, preserving the argument in the record costs relatively little and preserves options.

A divisional application is a type of patent application filed as a result of a restriction requirement, claiming subject matter that was non-elected in the parent application. Divisionals share the parent's priority date and receive special protection under 35 U.S.C. § 121. Key features: (1) Same priority date: the divisional application claims the benefit of the parent's filing date under 35 U.S.C. § 120. Prior art against the divisional's claims is evaluated from the parent's filing date, not the divisional's filing date. (2) No deadline (relative to restriction): divisionals can be filed at any time before the elected application issues. However, once the parent issues, no new divisionals can be filed from the parent (though divisionals from prior divisionals may be possible). (3) § 121 safe harbor: if the restriction requirement was made by the examiner (not voluntary by the applicant), a patent issuing on a divisional cannot be held invalid for double patenting by a patent issuing on the parent or other divisionals from the same parent. This prevents the USPTO from restricting inventions into separate applications and then using those separate patents against each other. (4) No terminal disclaimer required: unlike continuation patents claiming overlapping subject matter, properly restricted divisionals that qualify for the § 121 safe harbor do not require terminal disclaimers to overcome double-patenting rejections. (5) Multiple divisionals: multiple divisionals can be filed from a single restriction, one for each non-elected invention group. The restriction requirement itself is the roadmap — each group the examiner identified as a separate invention can be the basis for a separate divisional. Practical note: divisional applications must still be written to claim the non-elected subject matter with new independent claims, and must satisfy all patent-application requirements including proper drawings and specification support for the claimed subject matter.

Restriction requirements (U.S.) and unity of invention objections (PCT/international) serve similar purposes — limiting examination to related inventions — but have different standards and consequences. U.S. restriction (35 U.S.C. § 121): standard is 'independent and distinct inventions.' Two inventions are distinct if there is no need to search the other to examine one (separate utility test). Restriction results in: applicant must elect one invention; others are pursued in divisional applications with same priority date and § 121 safe harbor. Restriction is common even among related inventions — examiners restrict liberally. PCT unity of invention (PCT Rule 13; MPEP § 1850 for national phase): standard is 'unity of invention' — claims that relate to a 'single general inventive concept.' Inventions have unity if they share the same or corresponding special technical feature — a technical feature that contributes to the prior art in the relevant field, that makes the invention novel and inventive. PCT unity is more permissive than U.S. restriction: a genus and its species have unity if the genus shares a single general inventive concept. An invention covering a product and its method of production and use has unity if the product is the heart of the claimed technology. If the PCT International Searching Authority (ISA) or International Preliminary Examining Authority (IPEA) finds lack of unity, it may limit its search and examination to the 'first invention' and invite the applicant to pay additional search fees. Unlike U.S. restriction, national phase entry is still possible for all inventions regardless of unity — the applicant can enter national phase in any country for any claims, and each national office independently decides whether to require restriction. In national phase in the U.S., the examiner applies U.S. restriction practice regardless of PCT unity findings. Practical note: a PCT application with an ISA unity objection does not automatically generate a U.S. restriction — but the same application in U.S. national phase often gets a similar restriction requirement from the U.S. examiner.