Patent Post-Grant Proceedings: IPR, PGR, and Reexamination at the PTAB

Summary. Since 2012, the cheapest and fastest way to kill a United States patent has not been a district court trial. It has been an inter partes review at the Patent Trial and Appeal Board, where a panel of technically trained administrative judges applies a preponderance standard, no presumption of validity attaches, and a final written decision issues within twelve months of institution. This article explains the full menu of post-grant options, inter partes review, post-grant review, ex parte reexamination, supplemental examination, and reissue, and shows how to choose among them. It covers eligibility windows, the one-year time bar of § 315(b) and how service of a complaint starts it, real-party-in-interest and privity traps, the discretionary denial doctrines built on Fintiv, General Plastic, and § 325(d), the mechanics of institution and trial, motions to amend after Aqua Products, and the estoppel that attaches under § 315(e). It also addresses the parallel district court case: when to move for a stay, how the two proceedings interact, and what the different burdens of proof mean in practice. It closes with strategy for petitioners and patent owners, a worked example, an FAQ, and related reading.

A software company receives a complaint alleging infringement of a patent it has never heard of, asserted by an entity that makes nothing. The complaint demands a royalty on every transaction the company processes. Defense counsel gives the usual estimate: three to five years, seven figures, and a jury in a district the plaintiff chose.

Then someone asks the better question. Is the patent any good?

The prior art search comes back with two references the examiner never saw, both published years before the priority date, both describing the claimed method in almost exactly the claimed terms. Eleven months later, the Patent Trial and Appeal Board issues a final written decision holding every asserted claim unpatentable. The district court case, stayed since institution, is dismissed.

That sequence is why the America Invents Act's post-grant proceedings changed patent litigation more than any other development of the last three decades. This article explains how they work.

The short answer

Three facts drive almost every strategic decision:

1. The burden and standard are different from district court. At the PTAB, unpatentability must be shown by a preponderance of the evidence, 35 U.S.C. § 316(e). In district court, invalidity requires clear and convincing evidence. Microsoft Corp. v. i4i Ltd. Partnership, 564 U.S. 91 (2011). The same art can fail in one forum and succeed in the other.
2. The clock is real. A final written decision must issue within one year of institution, extendable by six months for good cause. 35 U.S.C. § 316(a)(11).
3. Estoppel is the price. Once a final written decision issues, the petitioner is barred in district court, the ITC, and the Office from asserting any ground it raised or reasonably could have raised. § 315(e).

Part I: Inter partes review

Who, when, and what

Who. Any person who is not the patent owner and who has not previously filed a civil action challenging validity. § 311(a); § 315(a)(1). Note that a declaratory judgment counterclaim of invalidity does not trigger the § 315(a)(1) bar, § 315(a)(3), which is why accused infringers counterclaim rather than file first.

When. IPR may not be filed until the later of nine months after grant or the termination of any PGR. § 311(c). And critically:

An IPR may not be instituted if the petition is filed more than 1 year after the date on which the petitioner, real party in interest, or privy of the petitioner is served with a complaint alleging infringement of the patent. § 315(b).

What. Only §§ 102 and 103, and only on the basis of patents and printed publications. § 311(b). No § 101 eligibility. No § 112 written description or enablement. No public use, on-sale, or prior invention evidence. If your best invalidity theory is that the invention was on sale two years before filing, IPR cannot help you.

The § 315(b) time bar

This is where petitions die most often, and the traps are subtle.

• Service, not filing, starts the clock. A complaint filed and never served does not start it.
• A complaint later dismissed without prejudice generally does not count, on the theory that the parties are returned to their prior positions. But a complaint dismissed with prejudice does trigger the bar in most panels' view, and the Federal Circuit's treatment has evolved. Do not rely on a dismissal to reset the clock without checking current authority.
• Real parties in interest and privies count. If your indemnitor was served two years ago, your petition may be time barred even though you were served last month. This is the single most litigated issue in IPR practice.
• The Director's determination is largely unreviewable. Thryv, Inc. v. Click-To-Call Technologies, LP, 590 U.S. 45 (2020), held that § 314(d)'s bar on appeal of institution decisions extends to § 315(b) time-bar determinations. That cuts both ways: a wrongly instituted petition cannot be undone on appeal, and a wrongly denied one cannot either.

Practical rule: docket the one-year deadline the day the complaint is served, and work backward six months for the petition. A good petition takes months to prepare: prior art search, expert declaration, claim charts, and claim construction positions.

Real party in interest and privity

Section 312(a)(2) requires the petition to identify "all real parties in interest." Failure to do so can result in the petition being denied or, worse, a final decision being vacated. The inquiry is practical: who is funding, directing, or controlling the petition, and who would benefit?

Common danger zones:

• Indemnification relationships. A supplier funding a customer's petition is usually an RPI.
• Joint defense groups. Coordinated funding and strategy create both RPI and privity exposure.
• Membership organizations filing on behalf of members.
• Corporate affiliates, particularly where the parent controls litigation strategy.

Disclose broadly. The cost of over-disclosure is nearly zero; the cost of under-disclosure can be the entire proceeding.

Institution

The Board institutes if "there is a reasonable likelihood that the petitioner would prevail with respect to at least 1 of the claims challenged." § 314(a).

SAS Institute Inc. v. Iancu, 584 U.S. 357 (2018), held that the Board must institute on all challenged claims and all grounds or not at all. Partial institution is gone. That has two consequences: petitioners should not pad petitions with weak grounds that could drag down the whole petition, and patent owners should attack the weakest ground because it is now attached to the strongest.

Cuozzo Speed Technologies, LLC v. Lee, 579 U.S. 261 (2016), held that institution decisions are generally not appealable under § 314(d), and upheld the Office's then-applicable broadest-reasonable-interpretation standard. The claim construction standard has since changed by rule: since November 2018, the Board applies the same Phillips standard used in district court, which reduced forum-shopping on construction and increased the persuasive weight of prior district court constructions.

Discretionary denial

Even where the merits threshold is met, the Director has discretion not to institute. Three doctrines matter.

Parallel litigation (the Fintiv factors). Apple Inc. v. Fintiv, Inc., IPR2020-00019 (PTAB Mar. 20, 2020) (precedential), set out six factors: (1) whether a stay exists or is likely; (2) proximity of the district court trial date to the Board's projected statutory deadline; (3) investment in the parallel proceeding; (4) overlap of issues; (5) whether the petitioner and defendant are the same party; and (6) other circumstances, including merits strength.

Fintiv practice has been unusually volatile. Office guidance has swung between narrowing discretionary denial (through memoranda that limited Fintiv where the petition presented compelling merits or where the petitioner stipulated not to raise the same grounds in district court) and restoring broader discretion. As of this writing the Office has moved back toward more robust discretionary denial, including a separate briefing track in which discretionary considerations are addressed before the merits. Check current Office guidance before relying on any particular formulation, and build the record for whichever framework applies: an early petition, a Sotera-style stipulation, and a stay motion filed promptly.

Serial petitions (General Plastic). General Plastic Industrial Co. v. Canon Kabushiki Kaisha, IPR2016-01357 (PTAB Sept. 6, 2017) (precedential), sets out seven factors targeting follow-on petitions against the same patent, focused on whether the petitioner knew of the art earlier, whether it received the patent owner's preliminary response before filing again, and the finite resources of the Board. The practical lesson: file your best petition first, and file it once.

Previously presented art (§ 325(d)). Section 325(d) permits denial where "the same or substantially the same prior art or arguments previously were presented to the Office." The two-part framework in Advanced Bionics, LLC v. MED-EL Elektromedizinische Geräte GmbH, IPR2019-01469 (PTAB Feb. 13, 2020) (precedential), asks whether the same or substantially the same art or arguments were previously presented, and if so whether the petitioner has shown the Office materially erred. The Becton, Dickinson factors supply the detail.

Petitioner's response: distinguish your art from what the examiner saw, explain specifically why the examiner erred if the art overlaps, file early, stipulate away overlapping district court grounds, and move for a stay immediately.

Trial mechanics

The proceeding is fast and front-loaded. A typical schedule:

1. Petition filed, with all evidence and expert declaration. There is no meaningful opportunity to supplement later.
2. Patent owner preliminary response within three months. Optional but nearly always filed. New testimonial evidence is permitted, with factual disputes resolved in the petitioner's favor at institution.
3. Institution decision within three months of the preliminary response (so within six months of filing).
4. Patent owner response and any motion to amend.
5. Petitioner reply and opposition to amendment.
6. Patent owner sur-reply.
7. Depositions of declarants throughout; discovery is limited to routine discovery plus additional discovery on a showing of "necessary in the interest of justice." § 316(a)(5).
8. Oral hearing.
9. Final written decision within one year of institution. § 318(a).

Because the petition carries the entire case, petition drafting is where the proceeding is won or lost. Every claim limitation must be mapped, every combination must have an articulated motivation with evidentiary support, and the expert declaration must say more than "it would have been obvious." See Overcoming Obviousness Rejections for the substantive § 103 framework the Board applies.

Motions to amend

A patent owner may file one motion to amend, proposing a reasonable number of substitute claims that do not enlarge scope or introduce new matter. § 316(d).

Historically, motions to amend almost never succeeded. Two developments changed that:

• Aqua Products, Inc. v. Matal, 872 F.3d 1290 (Fed. Cir. 2017) (en banc), held that the burden of persuasion on unpatentability of substitute claims rests with the petitioner, not the patent owner. The opinion is fractured, but the Office adopted that allocation.
• The Motion to Amend Pilot Program allows the patent owner to request preliminary guidance from the Board on the proposed substitute claims and to file a revised motion. This is genuinely useful, and patent owners underuse it.

Grant rates remain modest, but the pilot has made amendment a real option rather than a formality.

Director review

United States v. Arthrex, Inc., 594 U.S. 1 (2021), held that the unreviewable authority of administrative patent judges to issue final decisions violated the Appointments Clause, and remedied it by making PTAB final written decisions reviewable by the Director. The Office implemented an interim Director review process, later formalized by rule, permitting requests for rehearing by the Director of institution decisions and final written decisions. Director review is discretionary and is granted sparingly, but it has become a meaningful avenue for issues of Office policy, and the Director has used it to designate guidance.

Appeal

A party dissatisfied with a final written decision may appeal to the Federal Circuit. § 319; 28 U.S.C. § 1295(a)(4)(A). The Board's factual findings are reviewed for substantial evidence, and its legal conclusions de novo. Obviousness is a legal conclusion based on underlying facts, which means the substantial evidence standard does much of the work and reversal rates are correspondingly modest. Standing on appeal requires Article III injury, which is why a petitioner with no ongoing infringement exposure may win at the Board and be unable to appeal a loss.

Part II: Post-grant review

PGR is broader and rarer.

Window. Nine months from issuance. § 321(c). Miss it and the option is gone forever.

Eligibility. Only patents with an effective filing date on or after March 16, 2013 (the AIA first-inventor-to-file transition). Older patents are never PGR-eligible.

Grounds. Any ground of invalidity that could be raised under § 282(b)(2) or (3): §§ 101, 102, 103, and 112, except best mode. § 321(b). This is the only post-grant vehicle for a § 101 eligibility challenge, which makes it valuable against software and diagnostic patents. See Patent Eligibility After Alice.

Threshold. "More likely than not that at least 1 of the claims challenged is unpatentable," or a showing that the petition raises "a novel or unsettled legal question that is important to other patents or patent applications." § 324(a), (b).

Estoppel. Broader than IPR, because the available grounds are broader. § 325(e). A PGR petitioner who loses is barred from raising §§ 101 and 112 defenses it could have raised. This is the principal reason PGR is used sparingly: the estoppel is expensive.

Practical use. Monitor competitor issuances and calendar the nine-month window for patents that threaten your product. Most companies discover the patent long after the window closes.

Part III: Ex parte reexamination

The oldest of the tools, created in 1980 and still useful.

Who and when. Anyone, at any time during enforceability, including anonymously through counsel. 35 U.S.C. § 302. The patent owner may also request it.

Standard. A substantial new question of patentability affecting any claim, based on patents or printed publications. § 303(a). The AIA clarified that the existence of a substantial new question is determined without regard to whether the art was previously considered, so long as it is presented in a new light.

Procedure. After the request is granted, the requester drops out (unlike the old inter partes reexamination, repealed by the AIA). The patent owner and the examiner proceed through ordinary prosecution, with the patent owner able to amend claims and add claims that do not broaden scope. § 305.

Why use it:

• No estoppel attaches to the requester.
• No standing or time bar. The § 315(b) clock does not apply, so it remains available after the IPR window closes.
• Anonymity is possible.
• Low cost relative to IPR.
• It can be filed after an IPR estoppel has attached, though the Office may exercise discretion under § 325(d), and courts may view a serial challenge unfavorably.

Why not:

• No adversarial participation. You file and then watch.
• The patent owner can amend with the examiner's cooperation, and may emerge with claims that read on your product more clearly than before, plus intervening rights complications.
• Slower than IPR in many cases, though the Office gives reexams "special dispatch" by statute.
• Weaker record for a later stay motion.

Part IV: Supplemental examination and reissue

Supplemental examination, 35 U.S.C. § 257, lets a patent owner ask the Office to consider, reconsider, or correct information believed relevant to the patent. Its principal value is prophylactic: information considered during supplemental examination cannot later be the basis for holding the patent unenforceable for inequitable conduct, subject to exceptions where the conduct was pleaded with particularity in a prior civil action or where material fraud is found. This is a powerful cure for a prosecution problem discovered during diligence. See Inequitable Conduct in Patent Prosecution and Maintaining the Duty of Candor to Avoid Inequitable Conduct.

Reissue, 35 U.S.C. § 251, lets a patent owner correct an error that renders the patent wholly or partly inoperative or invalid. Broadening reissue must be applied for within two years of grant. Reissue triggers intervening rights under § 252 for parties who relied on the original claims, and the recapture rule bars reclaiming subject matter surrendered during prosecution.

Part V: Estoppel

The statutory text

Section 315(e) provides that after a final written decision in an IPR, the petitioner, its real party in interest, and its privies may not assert, in a proceeding before the Office, in a district court civil action, or in an ITC proceeding, that a claim is invalid "on any ground that the petitioner raised or reasonably could have raised during that inter partes review."

Section 325(e) does the same for PGR.

What "reasonably could have raised" means

For several years, Shaw Industries Group, Inc. v. Automated Creel Systems, Inc., 817 F.3d 1293 (Fed. Cir. 2016), was read by many district courts to limit estoppel to grounds actually instituted, on the theory that a non-instituted ground was never "raised during" the review. That reading became untenable after SAS eliminated partial institution.

The Federal Circuit resolved it in California Institute of Technology v. Broadcom Ltd., 25 F.4th 976 (Fed. Cir. 2022), holding that estoppel applies to all grounds the petitioner reasonably could have included in its petition, not merely those instituted, and expressly overruling Shaw to the extent it held otherwise.

The practical scope

Estopped: patents and printed publications a skilled searcher conducting a diligent search reasonably could have been expected to discover.

Not estopped:

• System and product prior art (a physical device, a public use, an on-sale bar) that could not have been raised in an IPR, which is limited to patents and printed publications. Courts have divided on whether estoppel reaches a system ground where the system is described in a printed publication that was available; the careful approach is to develop system art with evidence that does not merely duplicate the publication.
• Sections 101 and 112 defenses after an IPR (though not after a PGR).
• Grounds that a diligent search would not have found, though the burden of proving that is on the party resisting estoppel and it is a hard showing.

The strategic consequence

Estoppel is the reason a defendant should never file an IPR casually. Before filing, run the full invalidity analysis and ask which defenses will survive a loss. A defendant with strong on-sale-bar evidence and mediocre publication art may prefer to keep its powder dry in district court, where it faces a higher burden but retains every defense.

Conversely, a defendant with strong publication art often should file early and aggressively, because a win terminates the case and a loss costs mostly the printed-publication grounds it was going to lose anyway.

Part VI: The parallel district court case

Stays

District courts consider three factors on a motion to stay pending PTAB review: (1) whether a stay will simplify the issues and streamline trial; (2) whether discovery is complete and a trial date set; and (3) whether a stay would unduly prejudice or present a clear tactical disadvantage to the non-moving party. Some courts add a fourth: whether a stay will reduce the burden of litigation on the parties and the court.

Timing dominates. A stay motion filed the week the petition is filed, in a case where discovery has not begun, has a much better chance than one filed after claim construction. File early, and be prepared to file the stay motion before institution (many courts will defer ruling until institution, which is fine).

Stipulations help. Offering not to pursue in district court any ground raised or that reasonably could have been raised in the IPR (a Sotera-style stipulation) strengthens both the stay motion and the position against discretionary denial.

Different forums, different odds

Numbers move year to year, but the structural asymmetries are stable:

• The PTAB applies preponderance; district courts require clear and convincing evidence.
• The PTAB has technically trained judges; district court juries do not.
• The PTAB decides on a paper record with limited discovery; district courts allow full discovery, including into conception, reduction to practice, and secondary considerations.
• Secondary considerations of nonobviousness (commercial success, long-felt need, industry praise, copying) are available in both forums but tend to land better with a jury.

Interaction effects

• A final written decision cancelling claims ends the district court case as to those claims. Claims cancelled by the Office are treated as never having existed for purposes of the pending case.
• A PTAB decision upholding claims does not bind the district court on grounds the Board did not decide, but as a practical matter it makes the defendant's remaining invalidity case harder to sell.
• Damages continue to accrue during the PTAB proceeding unless there is a stay, which is why patent owners resist stays vigorously.
• Claim amendments during reexamination or IPR create intervening rights under 35 U.S.C. § 252 if the claims are substantively changed, which can eliminate past damages entirely. This is an underappreciated defensive benefit of pushing a patent owner to amend.

For the district court side of the equation, see Comprehensive Guide to Patent Infringement Litigation.

Part VII: Strategy

For the accused infringer

1. Search early and search well. The entire value of the IPR option depends on the quality of the prior art search. Budget for a professional search, including non-patent literature, foreign patents, standards documents, product manuals, and academic publications.
2. Docket the § 315(b) deadline the day you are served, and identify every entity that might be an RPI or privy.
3. Decide the forum allocation. Publication art to the Board; system art, on-sale, § 101, and § 112 to the district court.
4. File the best petition, once. General Plastic punishes serial filing.
5. Move to stay immediately, and consider a stipulation.
6. Do not pad the petition. Post-SAS, weak grounds ride along with strong ones.
7. Invest in the expert declaration. Conclusory motivation-to-combine testimony is the most common reason strong art fails.

For the patent owner

1. Prosecute with the PTAB in mind. A well-developed record, claims of varied scope, and a thorough IDS make a later petition harder. See Patent Prosecution Toolkit.
2. Use the preliminary response aggressively, including on discretionary denial. Many petitions die here, and the cost is a fraction of trial.
3. Build the § 325(d) record. If the examiner saw this art or its substantial equivalent, say so with specificity.
4. Consider the Fintiv posture. A fast trial date in a district that keeps its schedule is a real asset. Sue early, prosecute the case diligently, and oppose the stay with evidence.
5. Take the motion to amend seriously, and use the preliminary guidance pilot. A narrower claim that survives is worth more than a broad claim that does not.
6. Preserve secondary considerations evidence. Commercial success, copying, licensing, and industry praise are the patent owner's best material, and they require documents and testimony, not assertions. There must also be a nexus between the evidence and the claimed features.
7. Watch for standing on appeal. If the petitioner has no continuing exposure, a Board loss may be unappealable by them, which changes settlement dynamics.

For everyone

Settlement is permitted and common. Section 317 allows termination on joint request before a final written decision, and the Board usually grants it, though it may proceed to decision where the record warrants. Settlement agreements must be filed with the Office and are ordinarily kept separate from the public file on request. The practical implication: the leverage window closes when the final written decision issues.

A worked example

Northwind Systems, Inc. (fictional) is sued in the Western District of Texas by Cordell IP LLC (fictional), a non-practicing entity asserting U.S. Patent No. 9,XXX,XXX, which claims a method of routing payment authorization requests through a rules engine. Northwind is served on 12 January.

Day 1. Docket the § 315(b) deadline: 12 January of the following year. Identify RPIs: Northwind's payment processor indemnifies it and was served on the same patent 18 months ago. That is a problem. If the processor is an RPI or privy, the petition is already time barred. Counsel must analyze the indemnity relationship, funding, and control before filing, and structure the petition accordingly (perhaps with the processor as a named petitioner, if its own bar has not run, or with a clear record that Northwind controls and funds the petition alone).

Month 1-3. Prior art search. Two references surface: a 2009 IEEE conference paper and an expired German patent, neither cited during prosecution. Also, Northwind's own engineers recall a competitor product sold in 2010 that did the same thing. Allocate: the paper and the German patent go to the Board; the competitor product goes to the district court as a § 102(a)/(b) system and on-sale defense, preserved from estoppel.

Month 4. Assess § 101. The claims recite a generic rules engine applied to a financial process. This looks like an Alice problem, but the patent's effective filing date is 2011, so PGR is unavailable (pre-March 2013) and § 101 cannot be raised in an IPR. The eligibility defense stays in district court, where it can be raised on a Rule 12 motion. See Motions to Dismiss Under Rule 12 and Patent Subject Matter Eligibility After Alice.

Month 6. File the IPR with a strong expert declaration explaining why a person of ordinary skill would have combined the paper with the German patent, supported by contemporaneous industry documents showing the motivation. Simultaneously file a motion to stay with a Sotera-style stipulation.

Month 6-9. Cordell files a preliminary response arguing discretionary denial: the Texas trial date precedes the Board's deadline, and Cordell has invested in claim construction. Northwind's reply emphasizes the stipulation, the early filing, the compelling merits, and the realistic (rather than nominal) trial date.

Month 12. Institution granted. The district court grants the stay.

Month 24. Final written decision cancels the independent claims. Cordell appeals; the Federal Circuit affirms under the substantial evidence standard 14 months later. The district court case is dismissed.

What made the difference: the search, the RPI analysis done before filing, the allocation of grounds between forums, and the early stay motion. Every one of those decisions was made in the first ninety days.

Frequently asked questions

Is an IPR cheaper than litigation? Substantially. A full IPR through final written decision typically costs a fraction of a district court patent case through trial. But it is not cheap in absolute terms, and the cost is front-loaded because the petition carries the case.

Can I file an IPR anonymously? No. The petition must identify all real parties in interest. Ex parte reexamination can be filed anonymously through counsel, which is one of its principal remaining advantages.

What happens to my district court invalidity defenses if I lose at the Board? You lose every ground you raised or reasonably could have raised, meaning essentially all patents-and-printed-publications grounds. You keep § 101, § 112, and system or on-sale prior art defenses that could not have been raised in an IPR.

Can the patent owner amend the claims and still sue me? Yes, if the substitute claims are patentable and still read on your product. But substantive amendment triggers intervening rights under § 252, which can eliminate liability for pre-amendment activity. Amendment is not a free move for the patent owner.

Do IPRs unfairly favor challengers? The debate is genuine and long-running. Institution and cancellation rates depend heavily on what population you measure, and the Board's discretion has moved substantially over time. The structural point is that the preponderance standard and the absence of a presumption of validity are legislative choices, and Oil States Energy Services, LLC v. Greene's Energy Group, LLC, 584 U.S. 325 (2018), held that reexamining an issued patent through an agency proceeding is constitutional because a patent is a public franchise.

Should a startup file IPRs against competitor patents? Rarely as an offensive matter, because of cost, estoppel, and the risk of provoking litigation. More often the right move is a freedom-to-operate analysis and a design-around. See Conducting Freedom to Operate Analysis for New Products and Freedom to Operate Search.

How long does the whole process take? Roughly six months from petition to institution, twelve months from institution to final written decision, and twelve to eighteen months for a Federal Circuit appeal. Budget two to three years to a final, appealed result.

What is Director review and when should I ask for it? It is discretionary rehearing by the Director of an institution decision or a final written decision, created in response to Arthrex. Requests are granted sparingly and are most likely to succeed where the issue concerns Office policy, an abuse of discretion, or an important question the Director wants to address.

Closing thought

The America Invents Act did something rare in American law: it built an administrative alternative to litigation that people actually use. Whether that is good policy depends on where you sit, and reasonable people who have spent careers in patent law disagree sharply.

What is not debatable is that post-grant practice is now a distinct discipline with its own rules, its own precedent, and its own rhythms. The critical decisions, which art, which forum, which grounds, whether to file at all, are made in the first ninety days after a complaint arrives, usually before anyone has taken a deposition. Firms that treat the PTAB as an afterthought to district court litigation lose ground they cannot recover.

For patent owners, the lesson runs the other way and starts even earlier. The patent that survives an IPR is usually the one that was prosecuted carefully: a thorough search, an honest IDS, claims at multiple scopes, and a specification that supports narrowing amendments. The quality of a patent is now tested by adversaries with technical experts and a preponderance standard. Prosecute accordingly.

Related articles

• Comprehensive Guide to Patent Infringement Litigation — the district court proceeding that runs in parallel.
• Overcoming Obviousness Rejections — the substantive standard the Board applies.
• Patent Eligibility After Alice — the ground available only in PGR and district court.
• Patent Prosecution Toolkit — building a patent that survives a challenge.
• Inequitable Conduct in Patent Prosecution — the defense supplemental examination can cure.
• Conducting Freedom to Operate Analysis for New Products — finding the patents before they find you.
• Responding to a Patent Office Action — prosecution decisions that shape later challenges.
• What Constitutes Patent Infringement — the liability question the PTAB does not decide.
• Patent Litigation Toolkit — the full litigation workflow.
• Global Patent Litigation Strategies — coordinating PTAB practice with foreign oppositions.

This article is provided for general informational purposes and does not constitute legal advice. PTAB practice, particularly discretionary denial policy, changes frequently; verify current Office guidance and rules before acting. Consult qualified patent counsel about any particular patent or dispute.