Patent Post-Issuance Correction Toolkit: Reissue, Reexamination, Disclaimers, and Certificates

By Casey Scott McKay · 2023-09-25

A patent that issues with a defect is not necessarily lost, and the mechanism for fixing it depends on what the defect is. This toolkit maps the post-issuance options - reissue for errors that make a patent wholly or partly inoperative, certificates of correction for clerical and minor mistakes, statutory disclaimers for claims that cannot survive, terminal disclaimers for double patenting, and correction of inventorship - and explains when each is available and what each costs. It works the constraints that catch practitioners: the two-year limit on broadening reissue, the recapture rule, the original patent requirement, and intervening rights that can immunise an accused infringer. It then covers reexamination and supplemental examination, and closes with a portfolio remediation approach.

IP and Technology > Patent Counseling Transactions | Toolkit | Published 25 September 2023 - Updated 25 December 2024 | Casey Scott McKay - marksy.us

Summary. A patent that issues with a defect is not necessarily lost, and the mechanism for fixing it depends on what the defect is. This toolkit maps the post-issuance options — reissue for errors that make a patent wholly or partly inoperative, certificates of correction for clerical and minor mistakes, statutory disclaimers for claims that cannot survive, terminal disclaimers for double patenting, and correction of inventorship — and explains when each is available and what each costs. It works the constraints that catch practitioners: the two-year limit on broadening reissue, the recapture rule, the original patent requirement, and intervening rights that can immunise an accused infringer. It then covers reexamination and supplemental examination, and closes with a portfolio remediation approach.

Keywords: reissue · broadening reissue two year rule · recapture rule · original patent requirement · intervening rights · certificate of correction · statutory disclaimer · terminal disclaimer · correction of inventorship · ex parte reexamination · supplemental examination · inter partes review · post grant review · obviousness type double patenting · In re Cellect · Allergan v MSN · error requirement · claim narrowing · portfolio remediation

Start Here

A patent issues. Eighteen months later, preparing to assert it, counsel reads it properly for the first time and finds three problems.

The independent claim contains a limitation that was added during prosecution and that the accused product does not have — so the claim is narrower than it needed to be.

An inventor who contributed to two of the claims was never named.

And a dependent claim refers to "the housing" where the parent claim says "the enclosure," which is an antecedent basis problem that a defendant will argue renders it indefinite.

Three problems, three different mechanisms, three different sets of constraints, and one of them has a deadline that has probably already passed.

This toolkit answers three questions.

Which mechanism fits which defect? They are not interchangeable, and using the wrong one wastes months.
What are the deadlines and bars? The two-year broadening limit, the recapture rule, and the original patent requirement each foreclose options that look available.
What does correction cost in enforcement terms? Intervening rights can immunise an accused infringer entirely, which sometimes makes correction the wrong choice.

If you read only one thing, read The Clock You Did Not Know You Were Running. Terminal disclaimers are the correction mechanism most often used without understanding what it costs, and the article explains the term arithmetic behind the decision.

Reissue

The statutory basis. 35 U.S.C. § 251 permits reissue where a patent is, through error, deemed wholly or partly inoperative or invalid by reason of a defective specification or drawing, or by reason of the patentee claiming more or less than it had a right to claim.

Error is required. Deceptive intent is no longer a bar following the America Invents Act amendments, but there must still be an error — a deliberate choice made with full knowledge is not one.

Surrender of the original. The original patent is surrendered and the reissue patent takes its place for the unexpired term.

Broadening reissue: two years. A reissue enlarging the scope of the claims must be applied for within two years of the original grant. This is the deadline that has usually passed by the time anyone looks, and it cannot be extended.

What counts as broadening. A claim that is broader in any respect, even if narrower in others. The test is whether the reissue claim would be infringed by anything that would not have infringed the original.

Narrowing reissue has no time limit, and is available throughout the patent's term.

The recapture rule. A patentee may not recapture through reissue subject matter that was surrendered during prosecution to obtain allowance. In re Clement sets out the three-step analysis: whether the reissue claims are broader than the original in some aspect, whether the broader aspect relates to surrendered subject matter, and whether the surrendered subject matter has crept into the claim. North American Container v. Plastipak Packaging applies it.

The original patent requirement. 35 U.S.C. § 251 requires the reissue to be for the invention disclosed in the original patent. Antares Pharma v. Medac Pharma holds this is more demanding than written description: the specification must clearly and unequivocally disclose the newly claimed invention as a separate invention. Reissue claims directed to an embodiment merely mentioned in passing can fail.

Regulations. 37 C.F.R. § 1.171 and following govern the application, including the reissue oath identifying the error relied upon.

Continuations of reissue applications are available and are how a patentee pursues multiple claim sets, subject to the same constraints.

Intervening Rights

The reason reissue is sometimes the wrong answer.

The statutory basis. 35 U.S.C. § 252 provides for intervening rights where reissue claims are not substantially identical to the original claims.

Absolute intervening rights. A person who made, purchased, or used a specific thing before the reissue may continue to use or sell that specific thing, free of liability. This is a complete defence as to those articles.

Equitable intervening rights. A court may permit continued manufacture, use, or sale where substantial preparation was made before the reissue, to the extent and on terms the court deems equitable to protect investments made.

"Substantially identical" is the trigger. Where the reissue claim is substantially identical to the original, the original claim continues in effect and there are no intervening rights. Where it is not, intervening rights attach and pre-reissue damages for those claims are lost.

Marine Polymer Technologies v. HemCon addresses the analogous analysis in reexamination, holding that intervening rights do not arise where claims were not amended, notwithstanding arguments made during the proceeding.

The strategic consequence. Correcting a claim that reads on an accused product may extinguish the very damages the correction was meant to enable. Model this before filing.

The same analysis applies to reexamination and post-grant proceedings, where amended claims trigger the same intervening rights framework.

Certificates of Correction

The cheap option, available for a narrow class of defects.

Office mistakes. 35 U.S.C. § 254 permits a certificate correcting a mistake incurred through the fault of the Patent Office, at no cost to the patentee.

Applicant mistakes. 35 U.S.C. § 255 permits correction of a mistake of a clerical or typographical nature, or of minor character, made in good faith, where the correction does not involve changes that would constitute new matter or require reexamination.

The limit that matters. A certificate of correction cannot broaden the claims. Superior Fireplace Products v. Majestic Products holds that where a correction would broaden a claim, it is invalid unless it is clear from the specification, prosecution history, and claims that a broadening error occurred and how it should be corrected — a demanding standard.

Effect. A certificate of correction has the same effect as if the correction had been in the original patent, but only for causes of action arising after issue of the certificate where the correction is substantive.

Common uses. Typographical errors in claims, incorrect priority or cross-reference data, misspelled names, incorrect assignee, and drawing errors.

Regulations. 37 C.F.R. § 1.322 for Office mistakes and 37 C.F.R. § 1.323 for applicant mistakes.

What it will not fix. A claim limitation that should not be there. An antecedent basis problem that changes scope. A missing inventor. Those need reissue, or 35 U.S.C. § 256 respectively.

Timing. Available throughout the term, and worth doing promptly because the corrective effect for substantive corrections is prospective.

Disclaimers

Two entirely different instruments that share a name.

Statutory disclaimer. 35 U.S.C. § 253 permits a patentee to disclaim any complete claim. The disclaimed claim is treated as never having existed.

Why do it. To remove a claim that is clearly invalid, narrowing the issues, avoiding a fee award argument, or mooting a challenge. In litigation, disclaiming the weakest claims can materially improve the posture.

Effect on pending proceedings. A disclaimed claim generally cannot be the subject of a validity challenge, which is why disclaimer is used defensively in inter partes review.

Terminal disclaimer. The same section permits a patentee to disclaim the terminal part of the term. Its principal use is overcoming obviousness-type double patenting, which requires common ownership and a disclaimer of term beyond the reference patent.

The condition. A terminal disclaimer filed to overcome double patenting requires that the patents be commonly owned and enforceable only for so long as they remain commonly owned.

In re Cellect holds that obviousness-type double patenting is assessed against the expiration date including patent term adjustment, which means PTA-extended patents can be cut back by a terminal disclaimer to a family member's date.

Allergan v. MSN Laboratories holds that a first-filed, first-issued patent in a family is not invalidated by a later-issued family member on double patenting grounds, which meaningfully narrows the exposure created by Cellect.

Regulations. 37 C.F.R. § 1.321 governs both.

The cost. A terminal disclaimer surrenders term and ties enforceability to common ownership. Consider whether the double patenting rejection can be traversed instead. See Managing Patent Term Across a Family.

Correction of Inventorship

The mechanism. 35 U.S.C. § 256 permits correction where a person is named who is not an inventor, or an inventor is omitted, through error and without deceptive intention.

Two routes. A petition to the Office where all parties agree, or a district court order where they do not, with the court directing the Office to issue a certificate.

No deceptive intent requirement remains after the America Invents Act amendments, which materially widened the availability of correction.

Why it matters beyond formality. Inventorship determines ownership in the first instance. An omitted inventor who never assigned holds an undivided interest, may license the accused infringer non-exclusively without accounting to the co-owners, and can defeat standing for an infringement suit.

The patent-specific rule. Unlike copyright, a patent co-owner may make, use, sell, and license without the consent of the others and without any duty to account. That makes a missing inventor an existential problem for an assertion programme.

Standing. All co-owners must generally join an infringement action, and a co-owner who refuses can prevent the suit.

Determination is claim by claim. Inventorship attaches to conception of the subject matter of the claims, and a person who contributed to one claim is an inventor of the patent.

Correct before assertion. Discovering an inventorship problem during litigation, from a defendant's motion, is materially worse than correcting it beforehand.

Collect the assignment at the same time. Correcting inventorship without obtaining the newly named inventor's assignment converts a formal defect into an ownership problem. See Determining and Correcting Inventorship.

Reexamination and Supplemental Examination

Ex parte reexamination. 35 U.S.C. § 302 permits any person, including the patent owner, to request reexamination on the basis of patents or printed publications. 35 U.S.C. § 303 requires a substantial new question of patentability. 37 C.F.R. § 1.510 governs the request.

Owner-initiated reexamination. A patentee anticipating a validity challenge may request reexamination over the art it expects to face, obtaining a certificate that strengthens the presumption under 35 U.S.C. § 282.

The risk. Claims can be narrowed or cancelled, and amended claims trigger intervening rights under 35 U.S.C. § 307 on the same framework as reissue.

No amendment enlarging scope. 35 U.S.C. § 305 prohibits broadening claims in reexamination, which distinguishes it from reissue.

Supplemental examination. 35 U.S.C. § 257 permits a patent owner to request that the Office consider, reconsider, or correct information believed relevant to the patent. Where the Office concludes the information does not raise a substantial new question, or where reexamination is ordered and concluded, the information generally cannot be the basis for holding the patent unenforceable for inequitable conduct.

Why it exists. To provide a route to cure prosecution conduct that might otherwise support an inequitable conduct defence under Therasense v. Becton, Dickinson.

Its limits. The protection does not apply to allegations already pleaded with particularity in a pending action, or where the patentee has already been notified in a defined way. Timing is therefore critical: it must be used before the allegation is made.

Inter partes review and post-grant review. 35 U.S.C. § 311 and 35 U.S.C. § 321 provide adversarial proceedings, principally used by challengers rather than owners, though a patentee may amend claims within them subject to substantial constraints. See The Second Look.

Choosing between them. Owner-initiated reexamination is quieter and cheaper than reissue and cannot broaden. Reissue is the only route to broaden, and only within two years. Supplemental examination addresses conduct rather than claims.

Choosing the Mechanism

A triage sequence that resolves most cases in ten minutes.

Is the defect typographical or clerical, with no scope effect? Certificate of correction under 35 U.S.C. § 254 or 35 U.S.C. § 255. Cheapest and fastest.

Is a named inventor wrong or missing? 35 U.S.C. § 256 correction, with the assignment obtained at the same time.

Is a claim invalid and worth abandoning? Statutory disclaimer under 35 U.S.C. § 253.

Is there a double patenting problem? Terminal disclaimer under 35 U.S.C. § 253 and 37 C.F.R. § 1.321, after considering whether the rejection can be traversed and what term is surrendered.

Are the claims narrower than they should be? Reissue under 35 U.S.C. § 251 — but only within two years of grant, only if the recapture rule permits, and only if the original patent requirement is satisfied.

Are the claims broader than the prior art supports? Narrowing reissue, available at any time, or owner-initiated reexamination.

Is there prosecution conduct that could support an inequitable conduct defence? Supplemental examination under 35 U.S.C. § 257, before any allegation is pleaded.

Is the specification defective? Reissue, subject to the no-new-matter rule.

Before any of it: model intervening rights. If the correction changes claim scope in a way that is not substantially identical, 35 U.S.C. § 252 may immunise the very defendant the correction was meant to reach.

The Recapture Rule, Worked

The rule that defeats more reissue applications than any other, and the one most frequently misunderstood.

The principle. A patentee cannot use reissue to recapture subject matter deliberately surrendered during prosecution to obtain allowance. Reissue corrects error; it does not undo strategy.

Step one — is the reissue claim broader than the original in any aspect? If not, recapture does not apply. A claim broader in one respect and narrower in others is still broader for this purpose.

Step two — does the broader aspect relate to surrendered subject matter? Examine the prosecution history for amendments and arguments made to overcome prior art rejections. What was given up to get allowance is what was surrendered.

Step three — has the surrendered subject matter crept into the reissue claim? In re Clement frames this as whether the reissue claim is materially narrowed in other respects such that the surrendered subject matter is not entirely recaptured.

Arguments count as well as amendments. A limitation not added by amendment but argued to distinguish prior art can constitute surrender.

North American Container v. Plastipak Packaging applies the analysis and illustrates that a claim omitting a limitation added during prosecution to overcome art will generally be barred.

What is not surrender. A limitation added for reasons unrelated to patentability — clarity, examiner suggestion, or an amendment to a different rejection — is not surrender of the subject matter it excludes.

Practical approach. Before drafting reissue claims, produce a surrender map: every amendment and every argument made to overcome art, with the subject matter each gave up. Draft around it.

The original patent requirement runs alongside. Antares Pharma v. Medac Pharma requires the specification to clearly and unequivocally disclose the newly claimed invention as a separate invention — a higher bar than written description under 35 U.S.C. § 112. Reissue claims covering an embodiment merely mentioned, or an aspect not presented as an invention, can fail even where written description would be satisfied.

Which means the specification you have determines what reissue can do. A specification that describes one embodiment in detail supports reissue claims to that embodiment; it may not support claims to a variant disclosed in a sentence.

Intervening Rights, Worked

The question. Are the corrected claims substantially identical to the original claims?

If yes. The original claims continue in effect under 35 U.S.C. § 252, pre-correction damages are preserved, and no intervening rights arise.

If no. Absolute intervening rights protect specific articles made, purchased, or used before the correction. Equitable intervening rights may permit continued activity where substantial preparation was made.

"Substantially identical" is about scope, not wording. A claim reworded without changing scope is substantially identical. A claim narrowed to avoid prior art is not.

Marine Polymer Technologies v. HemCon confirms that arguments made during a proceeding, without claim amendment, do not create intervening rights — the claims must actually change.

The modelling exercise. Before filing, ask: which accused products exist today; were they made, purchased, or used before the correction would issue; and would the corrected claim be substantially identical to the original as to them. If the answer is that the principal defendant is protected, the correction may destroy the case it was meant to enable.

The alternative. Assert the original claims as they are, accept the weaker position, and pursue correction only for future infringement or for other defendants.

Or correct and accept the timing. Where the infringement is ongoing and the products are continuously made, absolute intervening rights protect only the specific articles already made — which may be a small part of the exposure.

Equitable intervening rights are discretionary, and a defendant that invested heavily in reliance on the original claim scope presents a sympathetic case for them.

Reexamination triggers the same analysis under 35 U.S.C. § 307, which is a reason for a patentee to think carefully before requesting owner-initiated reexamination on an asserted patent.

Terminal Disclaimers After Cellect and Allergan

The correction mechanism most often used reflexively, with the largest hidden cost.

What it does. 35 U.S.C. § 253 with 37 C.F.R. § 1.321 permits disclaiming the terminal portion of the term, and conditions enforceability on continued common ownership with the reference patent.

Why it is filed. Almost always to overcome an obviousness-type double patenting rejection, a judicially created doctrine preventing extension of the monopoly through patentably indistinct claims.

In re Cellect holds that obviousness-type double patenting is assessed against the expiration date as adjusted by patent term adjustment under 35 U.S.C. § 154. A patent that earned substantial PTA can therefore be cut back by a terminal disclaimer to a family member's earlier expiry — surrendering exactly the term the PTA awarded.

Allergan v. MSN Laboratories holds that a first-filed, first-issued patent in a family cannot be invalidated for obviousness-type double patenting by a later-issued family member claiming a patentably indistinct invention. That materially narrows the exposure and changes the calculus for families where the parent carries the PTA.

Two costs, both frequently overlooked. Term surrendered, which can be years on a PTA-heavy patent. And the common ownership condition, which makes disclaimed patents unenforceable if the family is later split — a real risk in divestitures and in patent sales.

Alternatives to consider first. Traverse the rejection by arguing the claims are patentably distinct. Amend to create distinctness. Or, where the family structure permits, rely on the safe harbour at 35 U.S.C. § 121 for divisionals filed in response to a restriction requirement.

The safe harbour is narrow. It protects divisionals filed as a result of a restriction requirement, and consequential amendments can lose it. Check whether the family qualifies before assuming it does.

Portfolio consequence. A family with terminal disclaimers across it must move as a unit in any transaction. Diligence should identify every disclaimed patent and its reference patent, and any transaction structure that would separate them is a defect. See Managing Patent Term Across a Family.

Before filing one, ask three questions. How much term is being surrendered on the current expiry arithmetic. Whether the rejection could be traversed. And whether the family will remain commonly owned for the full term.

Portfolio Remediation

Correction is most valuable run as a portfolio exercise before it is needed.

Build the register. One row per patent: grant date, two-year broadening reissue deadline, known defects, mechanism selected, status.

The two-year column is the point. Broadening reissue under 35 U.S.C. § 251 is available only within two years of grant, and it is the option that is silently lost. A quarterly review of patents approaching the deadline is the single highest-return habit in this area.

Review claims against products at grant. The right time to discover that a claim is narrower than it needed to be is within the two-year window, not on the eve of assertion.

Audit inventorship at grant. Compare the named inventors against the conception records for each claim. Correct under 35 U.S.C. § 256 and collect assignments while everyone is still employed.

Audit assignments. 35 U.S.C. § 261 requires a writing, and recordation provides constructive notice and priority. Gaps are cheap to fix early.

Audit terminal disclaimers. Which patents carry them, against which reference patents, and whether the common ownership condition constrains any planned transaction.

Audit certificates needed. Typographical errors, priority claim errors, and assignee errors accumulate and are cheap to correct under 35 U.S.C. § 254 and 35 U.S.C. § 255.

Audit prosecution conduct on key patents. Where an inequitable conduct exposure exists, supplemental examination under 35 U.S.C. § 257 is available only before the allegation is pleaded.

Prioritise by value. A portfolio of four hundred patents does not need four hundred reviews. The twenty that will be asserted or sold need all of it; the rest need the two-year deadline tracked and nothing else.

Three Worked Corrections

The narrow claim. A patent issues in January. In March, a competitor launches a product that would infringe but for a limitation added during prosecution to overcome a rejection that, on review, the limitation was not needed to overcome. The two-year broadening reissue window under 35 U.S.C. § 251 is open. Counsel builds the surrender map and finds the limitation was added in response to a 35 U.S.C. § 112 rejection rather than a prior art rejection — so it is not surrendered subject matter and recapture does not bar broadening. The specification clearly presents the broader embodiment as an invention, satisfying Antares Pharma v. Medac Pharma. Reissue is filed. Intervening rights are modelled: the competitor's product is continuously manufactured, so absolute intervening rights reach only units already made. The reissue issues, and the case proceeds on the broader claim.

The missing inventor. A patent is being prepared for assertion. A conception-record review shows a former engineer contributed the subject matter of two dependent claims and was never named. Under 35 U.S.C. § 256 the omission is correctable, and correction is sought by petition with the former engineer's cooperation — obtained together with an assignment, because correction without assignment would create an undivided co-ownership that permits the co-owner to license the defendant without accounting. The correction issues before filing, which removes a standing defence the defendant would otherwise have raised.

The double patenting trap. A continuation is rejected for obviousness-type double patenting over its parent. The reflexive answer is a terminal disclaimer. Counsel checks first: the parent earned four hundred days of patent term adjustment under 35 U.S.C. § 154, and after In re Cellect a disclaimer would surrender that term across the family. Allergan v. MSN Laboratories protects the first-filed, first-issued parent from invalidation by the later child, so the parent's PTA is safe. The rejection on the child is traversed on patentable distinctness, and only if that fails is a disclaimer filed — limited to the child, with the parent's term intact.

Common Mistakes

Missing the two-year broadening window. The most consequential error in this area, and it is a calendar failure rather than a legal one.

Filing reissue without a surrender map, and running straight into the recapture rule.

Assuming written description support means original patent requirement support. Antares Pharma v. Medac Pharma requires more.

Not modelling intervening rights before correcting an asserted patent, and immunising the principal defendant under 35 U.S.C. § 252.

Using a certificate of correction to broaden. Superior Fireplace Products v. Majestic Products makes that a route to invalidity rather than to correction.

Correcting inventorship without collecting the assignment, converting a formal defect into a co-ownership problem where the new co-owner may license the adversary.

Filing terminal disclaimers reflexively, surrendering PTA-earned term and creating a common-ownership constraint that binds every future transaction.

Requesting owner-initiated reexamination on an asserted patent without appreciating that amended claims trigger intervening rights under 35 U.S.C. § 307.

Using supplemental examination too late. 35 U.S.C. § 257 protection is unavailable once the allegation has been pleaded with particularity.

Treating disclaimer as free. A statutory disclaimer under 35 U.S.C. § 253 is irrevocable, and a claim disclaimed to simplify one case is gone for all others.

Discovering all of it during litigation, when every option is worse and every deadline has passed.

What This Costs, Honestly

Certificate of correction. Nominal for Office mistakes under 35 U.S.C. § 254; a small fee for applicant mistakes under 35 U.S.C. § 255. Weeks, not months. Always worth doing where it fits.

Statutory disclaimer. A small fee and a filing. Immediate, irrevocable.

Terminal disclaimer. A small fee. The real cost is the term surrendered and the common ownership condition, which are not billed and can be substantial.

Correction of inventorship. By petition where parties agree, inexpensive. By district court action where they do not, a litigation.

Reissue. Comparable to prosecuting a new application, with the added work of the surrender map and the recapture analysis. Months to years. The cost of getting it wrong — a recapture bar or an original patent requirement failure — is the whole exercise.

Ex parte reexamination. Moderate, and the patentee bears the cost where it initiates. The risk is claim narrowing and intervening rights.

Supplemental examination. A substantial fee, and a further fee if reexamination is ordered. Worth it where an inequitable conduct exposure is real, and worthless once the allegation is pleaded.

The comparison that matters. A quarterly two-year-deadline review across a portfolio costs a few hours. Discovering during assertion that the broadening window closed eighteen months ago costs the case.

Diligence Questions

Which patents are within two years of grant? That is the set where broadening reissue remains available, and a buyer should know it.

Which patents carry terminal disclaimers, and against which reference patents? Common ownership under 37 C.F.R. § 1.321 constrains how the portfolio can be divided, and a transaction that splits a disclaimed family creates unenforceable patents.

Which patents have PTA, and what is the double patenting exposure? In re Cellect and Allergan v. MSN Laboratories together determine whether the adjusted term survives.

Has inventorship been verified against conception records? An unnamed inventor is a standing problem and a licensing problem.

Are all assignments in place and recorded? 35 U.S.C. § 261 requires the writing; recordation supplies notice and priority.

Have any reissues or reexaminations narrowed claims? If so, intervening rights under 35 U.S.C. § 252 and 35 U.S.C. § 307 may have extinguished damages against existing products.

Is there prosecution conduct exposure? And has supplemental examination under 35 U.S.C. § 257 been used, or is the window still open?

Are there uncorrected clerical defects that will be argued as indefiniteness under 35 U.S.C. § 112 in litigation?

What does the file wrapper show about surrender? A seller's assertion that claims could be broadened by reissue is worth checking against the prosecution history before it is priced.

Questions Clients Ask

We found a mistake in our patent. Is it invalid? Usually not. Most defects are correctable, and the question is which mechanism and whether the deadline has passed.

Can we make the claim broader? Only by reissue under 35 U.S.C. § 251, only within two years of grant, only if the recapture rule permits, and only if the specification satisfies the original patent requirement.

What if the two years have passed? Broadening is foreclosed. Narrowing reissue remains available, as do corrections and disclaimers, and a continuation still pending in the family may be the better route.

Will correcting it hurt our case? It can. Where the corrected claims are not substantially identical, intervening rights under 35 U.S.C. § 252 protect articles already made or purchased. Model that first.

We forgot an inventor. Is the patent void? No. 35 U.S.C. § 256 permits correction where the omission was through error, and deceptive intent is no longer required to be absent. Correct it and obtain the assignment.

Should we file a terminal disclaimer? Not reflexively. Check what term is being surrendered on the current expiry arithmetic, whether the rejection can be traversed, and whether the family will stay commonly owned.

Can we strengthen a patent before asserting it? Owner-initiated ex parte reexamination over the art you expect to face produces a certificate and a stronger presumption under 35 U.S.C. § 282 — at the cost of possible narrowing and intervening rights.

We are worried about prosecution conduct. Supplemental examination under 35 U.S.C. § 257, before any allegation is pleaded. After, it does not help.

A typo in the claim changes the meaning. A certificate of correction may fix it if it is clerical or minor and does not broaden. Superior Fireplace Products v. Majestic Products sets a demanding standard where broadening would result.

How long does reissue take? Comparable to prosecuting an application, and longer where the recapture analysis is contested.

Can we do this in litigation? Reissue and reexamination proceed in parallel with litigation, and a stay may or may not be granted. Correcting before filing suit is materially better than correcting during it.

The One-Page Position

Post-issuance position — [portfolio], [date]. Patents granted: [N]; within the two-year broadening reissue window: [N], reviewed [date]. Claim-to-product review completed on [N] of [N] priority patents; [N] identified as narrower than necessary, of which [N] are within the window. Inventorship audited against conception records on [N] patents; [N] corrections filed under 35 U.S.C. § 256, [N] assignments obtained. Assignments recorded on [N] of [N]. Terminal disclaimers in force on [N] patents against [N] reference patents; term surrendered [estimate]; common ownership constraint documented for transaction planning. PTA-bearing patents: [N]; double patenting exposure assessed under In re Cellect and Allergan v. MSN Laboratories. Certificates of correction: [N] filed, [N] pending. Supplemental examination: [N] considered, [N] filed. Reissues: [N] pending, intervening rights modelled on each. Recommended actions: [file broadening reissue on X before (date) / correct inventorship on Y / traverse the double patenting rejection on Z rather than disclaiming].

A Note on Timing

Almost everything in this toolkit is a timing problem wearing a doctrinal costume.

Broadening reissue is available for two years and then it is not. Supplemental examination protects until an allegation is pleaded and then it does not. Inventorship correction is straightforward while the inventor is employed and cooperative, and a litigation once they are neither. Intervening rights attach at the moment corrected claims issue, which means every month of delay is a month of articles a defendant may keep selling.

The practical implication is that post-issuance correction belongs in the docketing system rather than in the litigation department. A quarterly review that asks, for each patent granted in the last two years, whether the claims match the products, would prevent most of what this toolkit exists to remedy.

A Suggested Reading Path

For the mechanisms:

For the term interactions:

For the inventorship side:

Primary Authorities

| Authority | Proposition | |---|---| | 35 U.S.C. § 251 | Reissue; error; two-year broadening limit | | 35 U.S.C. § 252 | Effect of reissue; intervening rights | | 35 U.S.C. § 253 | Statutory and terminal disclaimers | | 35 U.S.C. § 254 | Certificate of correction, Office mistake | | 35 U.S.C. § 255 | Certificate of correction, applicant mistake | | 35 U.S.C. § 256 | Correction of inventorship | | 35 U.S.C. § 257 | Supplemental examination | | 35 U.S.C. § 302 | Ex parte reexamination request | | 35 U.S.C. § 303 | Substantial new question | | 35 U.S.C. § 305 | Conduct of reexamination | | 35 U.S.C. § 307 | Reexamination certificate; intervening rights | | 35 U.S.C. § 311 | Inter partes review | | 35 U.S.C. § 321 | Post-grant review | | 35 U.S.C. § 282 | Presumption of validity | | 37 C.F.R. § 1.171 | Reissue application | | 37 C.F.R. § 1.175 | Reissue oath | | 37 C.F.R. § 1.321 | Disclaimers | | 37 C.F.R. § 1.322 | Certificate, Office mistake | | 37 C.F.R. § 1.323 | Certificate, applicant mistake | | 37 C.F.R. § 1.510 | Ex parte reexamination request | | In re Clement | Recapture analysis | | North American Container v. Plastipak | Recapture applied | | Antares Pharma v. Medac Pharma | Original patent requirement | | Marine Polymer v. HemCon | Intervening rights and unamended claims | | Superior Fireplace v. Majestic Products | Broadening by certificate | | In re Cellect | ODP against PTA-adjusted expiry | | Allergan v. MSN Laboratories | First-filed first-issued patent | | Therasense v. Becton, Dickinson | Inequitable conduct standard |

Forms and Templates

The Portfolio Inventory Template is where a correction programme lives, because remediation is a portfolio exercise rather than a per-patent one: the useful record is one row per patent showing the grant date, the two-year broadening reissue deadline, any known defects, the mechanism selected, and the status. The two-year column is the one that justifies the whole document, because it is the deadline that silently forecloses the most valuable option. The Office Action Response Template carries over directly to reissue and reexamination prosecution, where the response practice is the same and the recapture analysis is the additional layer. The Assignment Agreement Template matters for terminal disclaimers, because the common ownership condition under 37 C.F.R. § 1.321 means a family split between entities can render disclaimed patents unenforceable — a defect that assignment discipline prevents and that correction cannot easily fix.

Related Toolkits and Checklists

The Patent Term Management Toolkit covers the terminal disclaimer decision in its proper context, including the interaction between patent term adjustment and obviousness-type double patenting after In re Cellect. The Inventorship and Patent Ownership Disputes Toolkit covers correction under 35 U.S.C. § 256 and the ownership consequences that follow. The Duty of Candor and IDS Practice Toolkit covers supplemental examination as a remediation route for prosecution conduct. And the Patent Litigation Toolkit covers the litigation posture that frequently drives the correction decision, including when disclaimer of weak claims improves the case.