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Continuation Drafter
Continuation practice · Tier A

The cure is permanent, and it was nearly made more expensive

Terminal disclaimer mechanics

File it while the patents are alive and before issuance, because after issuance it will not be nullified. Price in the common-ownership tie, not just the lost term.

How to read the ledger below. Each numbered point carries the kind of evidence behind it. ESTABLISHED is stated in the authority's own text, with a locator. IMPLEMENTED is the rule as the authority actually applied it. OBSERVED is carried by a source outside this one. ASSUMED is the drafter's inference, flagged as such and not the authority speaking. Quotations are checked against a cached copy of the primary source by script.

In one paragraph

A terminal disclaimer filed to overcome nonstatutory double patenting gives up term and also ties enforceability to continued common ownership with the reference patent under 37 CFR 1.321, and MPEP 1490 states that once a patent issues a recorded terminal disclaimer will not be nullified, so the window to reconsider closes at issuance. The USPTO proposed in May 2024 to require a further agreement that the patent go unenforced if any claim of the reference patent were invalidated over prior art, drew more than 300 comments, and withdrew that proposal on 4 December 2024, so it is not law.

Reader summary

A terminal disclaimer is the standard way to overcome a nonstatutory double patenting rejection, and the Office's own guidance describes it as the other side of the same coin as the rejection. What practitioners sometimes underprice is that the instrument does two things at once. It gives up term, which is the visible cost. It also binds enforceability to continued common ownership with the reference patent, which is the cost that surfaces years later during a sale, a spin-out, or a bankruptcy.

The timing is unforgiving in one direction and forgiving in the other. Before the patent issues, an unnecessary disclaimer can generally be undone; MPEP 1490 says there is no statutory prohibition on nullifying one and quotes the CCPA calling the situation an unhappy circumstance. After issuance, it will not be nullified. That asymmetry, read together with the rule that a disclaimer cannot be filed once the reference patent has expired, defines a window that opens during prosecution and closes permanently.

In May 2024 the Office proposed making the instrument considerably more expensive: a disclaimer would have had to carry an additional agreement that the patent would go unenforced if any claim of the reference patent were later invalidated over prior art. That would have converted a term-and-ownership concession into a validity-linkage concession. It drew more than 300 comments and was withdrawn on December 4, 2024, in light of resource constraints. It is not law, was never law, and advising on it as though it were is the posture error this corpus exists to prevent.

Why this matters when you are drafting

Two costs, and the second one is easy to miss. Claim 3 is the ownership tie. A disclaimer filed today constrains who may own and enforce the patent for the rest of its life. If a client's plans include divesting part of a portfolio, spinning out a business unit, or licensing to an entity that may later acquire the reference patent, the disclaimer is a live constraint on those transactions, not merely a shortened term.

The window closes at issuance, and separately at expiration. Claim 4 is absolute after issuance. in-re-cellect in this corpus supplies the other edge, that a disclaimer cannot be filed once the patent has expired. Between them, the safe move is to decide during prosecution, and MPEP practice allows filing without waiting for a rejection.

A provisional rejection between co-pending applications resolves on patent term filing date. Claim 8 is the mechanic to know when two of your own applications are cited against each other. Which one the Office lets through is not a matter of argument; it follows from the dates, and it determines which application ends up carrying the disclaimer.

Consonance is a drafting constraint on divisional branches. Claim 7 means the safe harbor can be lost by amending claims away from the shape the restriction requirement created. That is a decision made at the drafting desk, often long after the restriction, and often without anyone re-reading the requirement.

Do not advise on the 2024 rule. Claims 9 through 11. It would have been a significant change, it was withdrawn, and the withdrawal says the decision was taken in light of resource constraints rather than on the merits, which means the idea is not obviously dead as a policy matter. Track it; do not apply it.

What the authority establishes

  1. [ESTABLISHED, the first rationale] "A rejection based on nonstatutory double patenting is based on a judicially created doctrine grounded in public policy so as to prevent the unjustified or improper timewise extension of the right to exclude granted by a patent". (MPEP 804, II.B.)
  1. [ESTABLISHED, the second rationale, and the one that explains the ownership tie] "A double patenting rejection also serves public policy interests by preventing the possibility of multiple suits against an accused infringer by different assignees of patents claiming patentably indistinct variations of the same invention". (MPEP 804, II.B.)
  1. [ESTABLISHED, the ownership condition, quoted from the regulation] A disclaimer filed to obviate double patenting must provide that the patent "shall be enforceable only for and during such period that said patent is commonly owned with the application or patent which formed the basis for the judicially created double patenting". (MPEP 1490, reproducing 37 CFR 1.321(c)(3).) This is the operative link between claim 2's rationale and the instrument.
  1. [ESTABLISHED, the irreversibility rule, and the single most consequential sentence here] "After a patent or reexamination certificate issues, a recorded terminal disclaimer will not be nullified." (MPEP 1490.)
  1. [ESTABLISHED, and the contrast that defines the window] Before issuance the position is the opposite: "there is no statutory prohibition against nullifying" an unnecessary disclaimer, which MPEP 1490 discusses by reference to In re Jentoft, 392 F.2d 633 (CCPA 1968), where an unnecessary filing was called an unhappy circumstance. (MPEP 1490.)
  1. [ESTABLISHED, the two-way test is narrow] "The two-way exception can only apply when the applicant could not avoid separate filings", and even then only where the Office controlled the rates of prosecution such that later-filed species claims issued before genus claims in an earlier application. (MPEP 804, II.B.) A practitioner hoping for two-way treatment is asking for an exception the guidance describes as doubly conditioned.
  1. [ESTABLISHED, consonance is what preserves the divisional safe harbor] The safe harbor is lost where "the claims of the application under examination and claims of the other application/patent are not consonant with the restriction requirement made by the examiner, since the claims have been changed in material respects from the claims at the time the requirement was made". (MPEP 804, I.A.) Claim scope drift across a divisional branch is therefore a live way to forfeit protection.
  1. [IMPLEMENTED, how provisional rejections resolve between co-pending applications] Where a provisional double patenting rejection "is the only rejection remaining in an application having the earlier patent term filing date, the examiner should withdraw the rejection in the application having the earlier patent term filing date and permit that application to issue as a patent", converting the provisional rejection in the other application into an actual one on issuance. (MPEP 804, I.B.) The earlier patent term filing date, not the earlier actual filing date, is what decides which application is let through.
  1. [ESTABLISHED, what the 2024 rule proposed] "The USPTO proposes to amend the rules of practice to add a new requirement for an acceptable terminal disclaimer" (P. 40439.) The requirement was that a disclaimer would not be accepted "unless the terminal disclaimer includes an additional agreement that the patent with the terminal disclaimer will not be enforced if any claim of the second patent is invalidated by prior art". (P. 40440.)
  1. [ESTABLISHED, and this is the posture point] The proposal was withdrawn. "the USPTO has decided not to move forward with the proposed rule at this time and to withdraw the proposed rule", "In light of resource constraints". (89 Fed. Reg. 96152, Dec. 4, 2024.) It never took effect.
  1. [ESTABLISHED, the scale of the response] During the comment period "the USPTO received more than 300 comments from a variety of stakeholders", of which "256 comments were unique". (89 Fed. Reg. 96152.)
  1. [ASSUMED, drafter's inference, flagged as such] Claims 3 and 4 together mean the ownership tie is the part that cannot be unwound. Term is forfeited on a schedule that is knowable at filing; the enforceability condition is contingent on ownership arrangements that may not exist yet. Neither source frames it as the more dangerous half; that is this drafter's reading of which cost is harder to price at the time of filing.

Quotations, verified against the source

Locators are mixed. A (P. n) locator is a Federal Register page in the proposed rule, machine-computed and checkable. Everything else is a citation in prose, because its source has no pagination a mapper can anchor.

  • "A rejection based on nonstatutory double patenting is based on a judicially created doctrine grounded in public policy so as to prevent the unjustified or improper timewise extension of the right to exclude granted by a patent" (MPEP 804.)
  • "A double patenting rejection also serves public policy interests by preventing the possibility of multiple suits against an accused infringer by different assignees of patents claiming patentably indistinct variations of the same invention" (MPEP 804.)
  • "The two-way exception can only apply when the applicant could not avoid separate filings" (MPEP 804.)
  • "shall be enforceable only for and during such period that said patent is commonly owned with the application or patent which formed the basis for the judicially created double patenting" (MPEP 1490, quoting 37 CFR 1.321(c)(3).)
  • "After a patent or reexamination certificate issues, a recorded terminal disclaimer will not be nullified" (MPEP 1490.)
  • "there is no statutory prohibition against nullifying" (MPEP 1490.)
  • "The USPTO proposes to amend the rules of practice to add a new requirement for an acceptable terminal disclaimer" (P. 40439.)
  • "unless the terminal disclaimer includes an additional agreement that the patent with the terminal disclaimer will not be enforced if any claim of the second patent is invalidated by prior art" (P. 40440.)
  • "the USPTO received more than 300 comments from a variety of stakeholders" (89 Fed. Reg. 96152.)
  • "256 comments were unique" (89 Fed. Reg. 96152.)
  • "the USPTO has decided not to move forward with the proposed rule at this time and to withdraw the proposed rule" (89 Fed. Reg. 96152.)
  • "In light of resource constraints" (89 Fed. Reg. 96152.)

Tensions and open questions

MPEP guidance is not law, and this record's spine is MPEP guidance. MPEP 804 and 1490 bind examiners and describe Office practice. A court is not bound by either. Claims 1 through 8 state what the Office does, which is what governs during prosecution and is not the same as what would govern in litigation.

The withdrawal reasons are administrative, not substantive. Claim 10 quotes resource constraints. Nothing in the notice says the Office concluded the proposal was wrong, which leaves open whether a similar rule returns.

The two MPEP sections are revised on different cycles. MPEP 804 here is [R-07.2022] and MPEP 1490 is [R-01.2024]. Both were retrieved on 2026-08-14 and are living documents. A reader relying on this record after a later revision should re-retrieve rather than trust the cache.

Unresolved by this record: how the ownership condition operates in practice on a transfer. Claim 3 states the condition. Nothing read here describes what happens procedurally when common ownership lapses, or who bears the burden of establishing it had not.

What this record does and does not cover

MPEP 804 and 1490 were read for the provisions in the ledger and NOT end to end. Both are long reference sections, and this record is scoped to the disclaimer as an instrument, not to the whole of double patenting practice.

What was NOT read closely, and is therefore outside what this record can support: the whole of MPEP 804's obviousness analysis; MPEP 1490's procedural and forms detail; and the body of the May 2024 proposed rule beyond its summary and its operative requirement, including its economic analysis and its discussion of the comments it anticipated.

Currency

This record was verified against its primary source on 2026-08-15. That is a fidelity check: the quotations, locators and attribution are accurate to that source. Whether the authority has since been narrowed, distinguished, abrogated or reversed has not been checked here. Confirm it still stands before relying on it.