The USA offers protection of inventions through the intellectual property rights associated with patents or trade secrets. Patents provide broad, time-limited rights to the patentee in exchange for public disclosure of the invention. In contrast, trade secrets are not publicly known, and have narrower rights and, in principle, an indefinite duration.

Patents arise from federal law. Congress created the US patent system based on its authority in the US Constitution, which grants Congress power “to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries”. Title 35 of the US Code contains the federal laws related to patents.

Trade secret law is primarily based on state law. Specific definitions vary but, generally, a trade secret must not be known to the public and must confer economic benefit on its holder because it is not publicly known, and the trade secret-holder must take reasonable measures to keep such information secret. Most states have adopted the Uniform Trade Secrets Act (1979) as amended, or a variation of it, so there is a measure of uniformity among the state laws. In addition to state law causes of action, the Defend Trade Secrets Act of 2016 provides a federal cause of action for trade secret misappropriation.

The statutory language creates a foundation for patents and trade secrets, but the law continues to evolve through case law as courts interpret legal terms and concepts.

The US Patent and Trademark Office (USPTO) conducts the patent approval process and grants any resulting patents. Applicants file either a provisional or non-provisional patent application with the USPTO.

Provisional applications provide a quick and inexpensive way for inventors to establish a US filing date for their invention, which can be claimed in a non-provisional application that is filed later. A provisional application must contain a description of the invention and may include drawings necessary to understand the invention. A provisional application has fewer requirements than a non-provisional application but cannot develop into a patent without a corresponding non-provisional application filed within 12 months.

A non-provisional patent application must include both a description of the invention and claims describing the scope of the protections sought in the patent. A non-provisional application may be filed without a prior provisional application. However, a non-provisional application may gain the benefit of the earlier filing date of a corresponding provisional application if filed within 12 months of the provisional application.

Non-provisional applications undergo substantive examination by the USPTO to ensure compliance with the legal requirements for a patent. As a preliminary matter, a patent must claim patent-eligible subject matter. At a minimum, the US Supreme Court has stated that laws of nature, natural phenomena and abstract ideas are not patentable. Patents must also describe an invention that is novel and non-obvious with sufficient detail and clarity that a person of ordinary skill in the art of the invention can make and use it without undue experimentation.

Patent Prosecution

The interaction between patent applicants (or their representatives) and the USPTO is called patent prosecution. During patent prosecution, an examiner at the USPTO will review the patent application and information already available to the public to determine whether the application meets the requirements for patenting based on the laws found in Title 35 of the US Code, the regulations listed in Title 37 of the Code of Federal Regulations and the guidance provided in the USPTO Manual of Patent Examining Procedure. If the examiner finds evidence that the invention has already been publicly disclosed or discovers another reason why the application does not comply with the patent requirements, the examiner may issue a rejection describing the deficiencies of the patent application. The applicant has an opportunity to respond to the rejection, which may include amending the claims in the application, having a phone conference with the examiner and presenting arguments that the rejection was improper. This process may be repeated until the examiner issues a final rejection or allows the application. If the patent application is allowed, the USPTO issues a patent creating enforceable rights for the patentee.

Trade Secrets

By their nature, trade secrets are not disclosed publicly or registered with any agency. Information becomes a trade secret when the holder takes affirmative action to keep the information secret. This can include physical protection of the information, use of non-disclosure agreements or lawsuits to recover for misappropriation of the trade secrets.

The time required to obtain a patent can vary greatly depending on many factors, including the subject matter of the patent, the number of rejections and appeals during patent prosecution and the type of USPTO examination programme. The USPTO has several patent application initiatives that can expedite patent applications meeting the programme requirements. For example, applications qualifying for Track One prioritised examination reach a final disposition an average of five months from petition grant. According to statistics provided by the USPTO, the average time for a final decision on a patent application is about two years, but some take several years.

Patent applicants are not obliged to be represented by a lawyer. However, the USPTO cautions that the patent application process is an undertaking requiring knowledge of patent law and rules, USPTO practices and procedures, and the scientific or technical matters involved in the particular invention. Because of the complexities involved, most inventors employ the services of registered patent lawyers or patent agents.

The cost associated with obtaining a patent varies based on many factors. Administrative fees imposed by the USPTO depend on the type of entity (large, small or micro), the number of claims in the application, the amount of time taken to respond to USPTO rejections, the use of patent application initiative programmes and other procedural details. Lawyers’ fees in connection to the application may also vary depending on the complexity of the application and patent prosecution.

Generally, a patent expires 20 years after its filing date, but this term can vary depending on the timing of the patent application and patent prosecution. Patents issued and applications filed before 8 June 1995 expire either 20 years from filing or 17 years from issue, whichever is later. 

Patent applications filed after 8 June 1995 expire 20 years after the earliest effective US filing date. This may be earlier than the filing date of the patent application if it claims priority to an earlier non-provisional or international application.

Under limited circumstances, a patent term may be extended to account for administrative delays when acquiring the patent. For example, if the USPTO does not issue a patent within three years after its filing date, the patent holder may obtain an extension of the patent term equal to the period in excess of three years. For certain drug products and medical devices, a patent may be extended for up to five years to account for the regulatory review conducted by the US Food and Drug Administration (FDA).

The USPTO website provides general information about all US patents. Furthermore, the FDA maintains publications identifying patents applicable to certain approved pharmaceutical products. For drug products, the FDA publication is Approved Drug Products with Therapeutic Equivalence Evaluations (more commonly known as the “Orange Book”). Similarly, the FDA maintains the List of Licensed Biological Products with Reference Product Exclusivity and Biosimilarity or Interchangeability Evaluations (known as the “Purple Book”), which contains information about approved biological products. The FDA also maintains electronic databases on its website holding the information contained in both the Orange Book and the Purple Book. 

A patent gives its owner the right to exclude others from making, using, selling and importing the patented invention. To maintain the enforceability of a utility patent, the USPTO must receive maintenance fees for the patent, due 3.5, 7.5 and 11.5 years after the date of issue. Design and plant patents do not require maintenance fees.

The remedies available to the patent holder vary depending on the chosen forum of enforcement. In a district court, a patent holder may seek equitable remedies in the form of a preliminary or permanent injunction and may seek monetary damages for both past and future infringement. 

At the US International Trade Commission (ITC), a patent holder may seek cease-and-desist orders and exclusion orders to prevent the importation of patent-infringing goods. The exclusion orders direct US Customs and Border Protection to exclude articles from entry into the USA. A limited exclusion order prevents specified entities from importing the articles, and a general exclusion order prevents any entity from importing the articles. The ITC cease-and-desist orders can direct infringers to stop importing infringing articles and to stop sales of infringing articles in US inventory. The ITC cannot award monetary damages.

Innovator drug companies with Orange Book-listed patents may have additional protections based on the Hatch-Waxman Act, which ties drug marketing approval to the resolution of patent disputes. Under the Hatch-Waxman Act, generic drug manufacturers who file an abbreviated new drug application (ANDA) for a generic version of an FDA-approved drug must submit a certification for each Orange Book-listed patent for the innovator drug product:

• a Paragraph I certification that no patent information has been submitted to the FDA;
• a Paragraph II certification that the patent has expired;
• a Paragraph III certification that the patent will expire before the generic drug product enters the market; or
• a Paragraph IV certification that the patent is invalid, unenforceable or will not be infringed by the generic drug product.

The ANDA filer is required to provide notice to the patent holder upon submission of a Paragraph iv certification. The patent holder then has the option to file a lawsuit for patent infringement within 45 days. Such a filing triggers a regulatory stay of final approval for the ANDA of up to 30 months. Importantly, the first generic manufacturer to file an ANDA with a Paragraph IV certification is entitled to a 180-day period of marketing exclusivity, providing an incentive for generic manufacturers to challenge these patents early.

While the Biologics Price Competition and Innovation Act (BPCIA) provides a framework for innovator biologic companies to assert Purple Book-listed patents against biosimilar manufacturers in a precursor to patent litigation (referred to as the “patent dance”), FDA approval of a Biologics License Application (BLA) for a biosimilar is not dependent on the resolution of disputes over Purple Book-listed patents.

The USA allows certain extensions of patent terms for administrative delays. Delays by the USPTO in the issue of patents can lead to patent term compensation for the time of the delay (commonly referred to as “patent term adjustment” or PTA). This extension does not apply to delays resulting from the patent applicant’s actions, including requests for continued examination or appeals. The possible extension for USPTO delays is unlimited.

Certain drug products and medical devices can receive annual patent term extensions (PTEs) if the product is undergoing administrative review by the FDA. These extensions are renewable for up to five years.

Any third party may submit patents, published patent applications or other printed publications as part of a third-party preissuance submission. The submission must include a concise description of the asserted relevance of each submitted document. These submissions may be made online at the USPTO website. Submissions must be made before the later of six months after publication of the patent application or the date of a USPTO communication rejecting any claims in the application. However, a notice of allowance for the patent application immediately terminates the timeframe for third-party submissions.

During patent prosecution, the USPTO may issue a final rejection of the patent claims. If the applicant wishes to challenge the final rejection, they may request continued examination or may file an appeal to the Patent Trial and Appeal Board (PTAB). The applicant may appeal PTAB decisions to the US Court of Appeals for the Federal Circuit. Further review may be sought from the US Supreme Court through a petition for a writ of certiorari.

Patent holders must pay maintenance fees to keep patents in force. The payments are due 3.5, 7.5 and 11.5 years after the date of issue. The USPTO allows payment of each fee six months before the due date but does not allow any other pre-payment of the maintenance fees. Payments that are less than six months past the due date have a surcharge of USD108–540 in addition to the normal fee.

Under some circumstances, a patent can be reinstated after not paying the maintenance fee in a timely manner. The USPTO requires a statement that the delay in payment was unintentional and submission of a petition fee of USD452–2,260 for delays of up to two years, or USD600–3,000 for delays of greater than two years, in addition to the required maintenance fees.

During some post-grant proceedings before the USPTO, the patent holder can amend claims of an issued patent. During ex parte re-examination, the patent holder may amend claims to respond to the USPTO’s findings of substantial new questions of patentability. In an inter partes review (IPR) proceeding, if the challenged claims are determined to be invalid, the patent owner may seek to add substitute claims.

At any time before the expiry of the patent, a patent holder may seek reissue of the patent to correct certain errors, such as errors in the drawings or specification, or errors in the claimed scope of the invention. No new matter can be added during a reissue. If a reissue is sought within two years of the grant of the original patent, the scope of the claims can be narrowed or enlarged. Otherwise, only amendments that narrow the scope of the claims are permitted.

A patent holder has several options when seeking enforcement of patent rights. District court litigation can provide injunctions, monetary remedies for infringement and declaratory judgments. As discussed at 1.5 Rights and Obligations of Owners of Intellectual Property Rights, the ITC can issue exclusion orders and cease-and-desist orders. If an applicable contract provides for alternative dispute resolution proceedings, such as mediation or arbitration, or the parties agree to alternative dispute resolution proceedings, they may be used in lieu of litigation. Alternative dispute resolution proceedings can allow more flexible solutions, and a final resolution can often be reached faster and less expensively. Additionally, the ITC and many courts offer mediation programmes.

A third party may challenge the validity of an issued patent through district court litigation or through post-grant proceedings at the USPTO. A party with standing may seek a declaratory judgment of patent invalidity in a district court. As a defendant in a patent infringement lawsuit, a party may argue patent invalidity as a counterclaim or affirmative defence. Patent invalidity may also be raised as a defence in an ITC investigation.

Challenges to patent validity at the USPTO take the form of post-grant review (PGR), IPR and ex parte re-examination. The timing and type of patent affect which of these proceedings is available to a third party.

PGR

PGR is available during the first nine months after the issue of a patent. Any party that is not the patent holder and has not challenged the patent validity in a civil action may request PGR. PGR allows the broadest grounds for challenging patent validity.

IPR

After the nine-month window of PGR, a third party may challenge validity through an IPR proceeding. As is the case with PGR, the IPR petitioner must not be the patent holder and must not have challenged the patent in civil litigation. There is an additional requirement that the petitioner must not have been served with a complaint alleging infringement more than one year prior to the IPR petition. The IPR also has more limited grounds to challenge patent invalidity, only allowing arguments of obviousness and lack of novelty based on patents and printed publications.

There are no actions available in the USA for a compulsory licence.

Federal district courts have original jurisdiction over patent matters. Parties may appeal district court decisions to the US Court of Appeals for the Federal Circuit. Decisions of the Federal Circuit are subject to discretionary appeal to the US Supreme Court through a petition for certiorari.

In certain circumstances involving importation of patent-infringing articles, the ITC may have jurisdiction. In an ITC investigation, an administrative law judge makes an initial determination on liability. A party may petition the ITC to review the administrative law judge’s initial determination. After the ITC’s final decision, a party may appeal the decision to the Federal Circuit, with further discretionary appeal to the US Supreme Court.

Two administrative agencies provide a review of patents before administrative law judges. The USPTO has the PTAB, which provides a review of patent application rejections and several post-grant proceedings discussed in the foregoing. The ITC conducts investigations related to the importation of patent-infringing articles. Both PTAB and ITC decisions may be appealed to the US Court of Appeals for the Federal Circuit, with further review available from the US Supreme Court.

There are no prerequisites to filing a lawsuit in a district court (other than a reasonable pre-filing investigation), unless the parties’ contract provides otherwise. Lack of pre-filing notice may, however, limit recovery of monetary damages in certain instances.

While individuals are not required to be represented by a lawyer, all federal courts require corporations to have legal representation. It is generally viewed as exceedingly unwise for an individual to pursue patent litigation without experienced counsel. In proceedings before the PTAB, at least one representative of each party must be a registered practitioner of the USPTO.

A patent holder may seek a preliminary injunction to protect the rights of the parties while litigation is pending. Preliminary injunctions require demonstration:

• of a reasonable likelihood of success on the merits;
• of irreparable harm to the party if the preliminary injunction is denied;
• that the balance of the hardships favours issuing a preliminary injunction; and
• that the impact on the public interest favours the party bringing the motion.

If a court determines that a preliminary injunction is appropriate, such an order will only be issued if the party seeking it posts a bond in an amount that the court considers proper to compensate the other party should the injunction be determined to have been improperly granted.

Although rarely granted, a patent holder could seek earlier relief through a temporary restraining order. In addition to meeting the requirements for a preliminary injunction, the patent holder must demonstrate that immediate and irreparable injury will result to the movant before the adverse party can be heard in opposition, and certify in writing any efforts made to give notice and the reasons why it should not be required. An ex parte temporary restraining order may be granted only in the very limited circumstances where providing notice will itself prevent, or interfere with, the ability to obtain relief.

The potential opponent may oppose the preliminary injunction by arguing against the factors described in the foregoing for granting a preliminary injunction – most particularly that monetary relief at the end of the case will adequately compensate the plaintiff for any injury it incurs. Alternatively, a potential infringer could seek a declaratory judgment of patent invalidity or non-infringement in a federal district court. A party could also seek to challenge patent validity through one of the post-grant proceedings available through the USPTO.

US law limits patent infringement damages to six years prior to the filing of the complaint or counterclaim for infringement. Additionally, the patent holder cannot recover damages for infringement prior to the point the infringer had notice thereof. Filing the lawsuit is notice of infringement, but the infringer could have earlier notice based on communications from the patent holder detailing the infringement, or from constructive notice by marking the patented articles with their patent numbers. Injunctive relief is available for any period the court finds appropriate up to the expiry of the patent rights.

In general, a party cannot obtain relevant information and evidence from another party or any third parties before commencing a proceeding in a district court. However, once a lawsuit has commenced, the Federal Rules of Civil Procedure require the parties to exchange initial disclosures of information, including: 

• the identity of each individual likely to have discoverable information; 
• copies of all documents a party may use to support its case;
• a computation of claimed damages; and 
• any insurance agreement that may satisfy all or part of a judgment.

Parties may then obtain non-privileged information that is relevant to any party’s claim or defence and is proportional to the needs of the case, considering: 

• the importance of the issues at stake in the action; 
• the amount in controversy; 
• the parties’ relative access to relevant information; 
• the parties’ resources; 
• the importance of the discovery in resolving the issues; and 
• whether the burden or expense of the proposed discovery outweighs its likely benefit. 

Parties may obtain discoverable information through depositions, requests for production of documents, written interrogatories or requests for admission.

Parties may subpoena third parties to provide discoverable information in the form of depositions or the production of documents. Procedures are also available to obtain discovery from third parties located outside the USA through applicable treaties or letters rogatory (formal requests for assistance sent to foreign courts).

A party or any person from whom discoverable information is sought may seek a protective order from the court to limit the scope or use of the information.

Patent litigation follows the same pleading standards as other civil cases. A complaint filed in district court must allege facts that state a claim to relief that is plausible on its face. At a minimum, a patent infringement complaint should identify the patent holder, the relevant patent(s), the accused infringer and the requested relief sought. For claims of indirect infringement, more details are typically required. Preferably, the complaint will provide additional information about the accused infringement, including the claims and elements infringed.

The Federal Rules of Civil Procedure govern amended and supplemental pleadings. A party may amend its pleadings once as a matter of course within 21 days of serving. Other amendments require the opposing party’s written consent or the court’s permission. To account for occurrences after a pleading, a party may supplement its pleadings with the court’s permission.

There are no class actions available in intellectual property cases. However, a patent holder may join multiple accused infringers in a single federal lawsuit if the actions arise out of the same transaction, occurrence or series of transactions. It is not sufficient to have unrelated defendants infringe the same patent. 

In situations where joining all defendants in a single case is not possible, there are other options to gain the advantages of consolidated actions. Cases across several districts that share a common question of fact may be co-ordinated for pre-trial proceedings before the Judicial Panel on Multidistrict Litigation. Similarly, multiple cases in the same district may be consolidated to promote judicial efficiency when there is a common question of law or fact.

ITC investigations of patent-infringing articles often involve multiple respondents. Because the ITC only needs jurisdiction over the imported articles and not the infringers, it can be easier for a patent holder to proceed against multiple infringers simultaneously.

Some patent holder actions can limit the ability to enforce a patent against others. Under patent exhaustion – also referred to as the first-sale doctrine – the patent holder’s right to control an individual article ends after an authorised sale. If the patent was procured through improper conduct before the USPTO, it could be unenforceable under the doctrine of inequitable conduct. A patent holder that expands its rights beyond the statutory patent grant may commit patent misuse. Finally, when the patent holder uses its patent impermissibly to gain market share or engages in other anti-competitive behaviour, antitrust laws may limit the enforceability of the patent.

Generally, the party bringing an infringement action must be the patent holder, although an exclusive licensee that owns “all substantial rights” in the patent may bring an infringement action in its own name without joining the patent holder. An ITC investigation requires the party filing the petition to have an interest in the patent and an injury to a domestic industry.

Direct infringement occurs when a person makes, uses, offers to sell, sells or imports in the USA a patented invention without authority. Usually, the patent holder demonstrates this by showing every claim element, or its equivalent, is present in the accused article. When more than one party infringes the patent, there can still be direct infringement if one party directs or controls the actions of another.

A party induces infringement when it actively and knowingly aids and abets another’s direct infringement. The inducer must have knowledge of the patent and actively encourage the acts that result in direct infringement. Induced infringement can result in both parties being jointly and severally liable for the infringement.

Contributory infringement involves supplying a component of a patented invention to another party that performs the direct infringement. The component must not be a staple article or commodity of commerce suitable for non-infringing use, nor can it have substantial non-infringing uses. 

There are also rules primarily directed towards the pharmaceutical industry. A party may engage in activities (such as testing) to support an ANDA for a generic version of an FDA-approved drug or a BLA for a biosimilar of an FDA-approved biologic – even if that drug or biologic is patented – without incurring patent infringement liability. However, filing an ANDA or BLA is considered an act of “artificial” infringement if the ANDA or BLA applicant seeks approval to engage in commercial manufacture, use or sale before patent expiry.

The available remedies for patent infringement are discussed in 6. Remedies.

An additional potential form of infringement applies to process patents. If a person makes, uses, offers to sell, sells or imports in the USA a product made by a process patented in the USA during the term of the patent, the person commits infringement under 35 U.S.C. § 271(g). This includes instances where the patented process occurs outside of the USA.

The scope of protection of a patent is determined by its claims, which describe the extent of the protection sought in a patent application. Often, significant dispute arises when determining the precise meaning of terms or phrases in the patent claims. 

In 2018, the standard for claim interpretation became more uniform, whether in a district court, the ITC or in a post-grant proceeding at the USPTO. The Phillips standard seeks to interpret the claims from the perspective of a person having skill in the relevant art of the invention based on intrinsic and extrinsic evidence. Intrinsic evidence includes the patent’s description of the invention, including the claims themselves, and the patent prosecution history. This means arguments and statements made to the USPTO during patent prosecution may limit how claims are interpreted later. Extrinsic evidence includes dictionaries, treatises and expert testimony. Extrinsic evidence can aid the decision-maker’s understanding of how a skilled person would have understood the claims at the time of the invention.

During patent prosecution, the USPTO uses a slightly different standard for analysing patent application claims. Generally, the USPTO uses the same types of information described in the foregoing, but seeks to determine the “broadest reasonable interpretation” of the claims for the purposes of issuing patents.

An accused patent infringer may seek to avoid liability by proving that no infringement occurred, or that the patent is invalid or unenforceable.

Several defences to patent infringement do not require challenging the patent itself, either by showing the accused article does not infringe or the use of the patent was lawful. For example, direct infringement requires all the elements of the patent claim be present, so demonstrating missing elements in the article can avoid liability by direct infringement. Showing an implied or express licence can negate the infringement requirement of unauthorised use of a patented invention. In the medical field, gathering data to support an ANDA for a generic version of a patented and FDA-approved drug does not create patent infringement liability – although the filing of the ANDA may. The courts also recognise a more general experimental use exception to liability, but it is a very narrow exception, requiring no business motive in the experimental use. Under certain circumstances, prior commercial use of an invention occurring more than a year before the patent application can avoid infringement liability. Finally, infringement damages are limited by law to the six years prior to the filing of the complaint, so infringement before this period would not incur liability.

The accused infringer may also challenge the validity of the patent because there will be no liability for an invalid patent. The grounds for challenging the patent may include lack of patent-eligible subject matter, lack of novelty, lack of enablement or written disclosure, obviousness of the invention, public knowledge or prior offers to sell.

The patent holder’s actions can also be the basis of a defence against infringement. Inequitable conduct can result from improper conduct before the USPTO. Relying on a patent holder’s conduct and representations may create equitable estoppel if the patent holder later acts inconsistently with the reliance. A patent holder that impermissibly expands its rights beyond the statutory patent grant may commit patent misuse. Under patent exhaustion – also referred to as the first sale doctrine – the patent holder’s right to control an individual article ends after an authorised sale. In some circumstances, a patent holder’s failure to keep patents together that are subject to a terminal disclaimer may be used as a defence to patent infringement.

That an accused infringer has its own patent does not, by itself, provide a defence to an infringement claim.

Standard-Essential Patents

Some patent holders may have standard-essential patents (SEPs). An SEP is a patent that covers technology that is considered essential to an industry standard. These SEP holders generally have an obligation to license these patents on fair, reasonable and non-discriminatory (FRAND) terms. If the SEP holder fails to offer a potential infringer FRAND terms, the accused infringer can assert the breach of FRAND obligations as an affirmative defence in a subsequent infringement action.

Parties may submit expert reports in connection with the claim construction process to assist the court in construing disputed terms. Parties almost always rely on expert reports and expert testimony in connection with infringement, invalidity and damages issues. Experts are especially effective when a case involves a jury because a good expert can explain complicated information in a clear and understandable fashion.

Under the Federal Rules of Evidence, the court has authority to appoint an expert witness. However, this rule is rarely invoked. Generally, a party relying on expert testimony chooses and retains its own expert. In rare cases, a district court judge faced with a technology with which they are unfamiliar may appoint their own expert (the cost of which is typically split between the parties) to assist the court in understanding the technology. When this happens, it is often in the context of claim construction proceedings.

Courts use specialised claim construction hearings called Markman hearings to examine evidence from the parties on the appropriate meaning of the relevant terms in a patent claim. In a district court, patent claim interpretation is performed by the judge, even if there is a jury trial.

Amicus briefs are very rarely submitted at the trial court (district court) level. District court judges rarely solicit amicus participation in a patent case, but some judges will, in a technically complex case, ask the parties to pay for a technical expert who will advise the court on technical issues. Amicus briefs are often filed in cases of industry-wide importance when the case is at the Federal Circuit level. In such instances, it is not unusual for the parties to reach out to a potential amici (typically academics, public interest groups or industry associations who have an interest in the issues) and solicit supporting briefs. A third party may seek permission from the court to submit an amicus brief, and such permission is typically granted. For example, in Amarin Pharma, Inc. v Hikma Pharms USA Inc., No 2023-1169 (Fed. Cir. 2024), which addressed whether generic drug products with “skinny labels” carving out patented uses could create induced infringement patent liability, a number of amicus briefs were filed.

Once a patent case reaches the US Supreme Court, amicus participation is the rule rather than the exception. In addition, the Supreme Court will often ask the Office of the Solicitor General (which represents the interests of the US government before the Supreme Court) to file a brief with its views as to whether the Supreme Court should hear the appeal at all or, if the Supreme Court has already accepted the case for appeal, on the merits. For example, following the Federal Circuit’s decision in the aforementioned case, Hikma Pharmaceuticals filed a petition for a writ of certiorari to the Supreme Court (No 24-889). During the petition’s pendency, amicus briefs were filed by the Association for Accessible Medicines, “30 Scholars of Law, Economics, and Medicine”, and the Solicitor General.

In the federal court system, a final judgment of invalidity effectively revokes the invalidated claims of the patent. A decision that the patent holder committed some other actions that prevent liability for patent infringement, such as equitable estoppel or antitrust violations, may make a patent unenforceable. 

The ITC makes similar decisions about patents, but its decisions are not binding on district courts. For example, an ITC decision of patent invalidity does not require a district court to treat the patent as invalid, but the district court may reach the same decision based on the persuasive influence of the ITC decision.

In post-grant proceedings, the USPTO may cancel some or all of the claims of a patent. A party challenging a patent in a post-grant proceeding does not need to have the necessary standing in a federal court. However, the ability to appeal the USPTO’s decision to the Federal Circuit may be limited by a lack of standing.

Patent invalidity is examined on a claim-by-claim basis. The remaining claims of a patent remain valid, even if some claims are found invalid.

During some post-grant proceedings before the USPTO, the patent holder can amend claims but may not enlarge their scope. During ex parte re-examination, the patent holder may amend claims to respond to the USPTO’s findings of substantial new questions of patentability. In adversarial proceedings – IPR and PGR – the patent owner may file a motion to amend claims.

In district court actions, patent infringement claims and defences may be heard together. Courts have broad discretion to control proceedings to promote judicial efficiency and avoid prejudice to the parties, so some issues may be “stayed”. Typically, a judge rather than a jury will determine equitable defences such as inequitable conduct or laches.

ITC investigations hear all infringement and defences together. The ITC has a shorter timeline than district courts and no juries to consider.

Proceedings challenging patent validity must be heard separately from infringement claims at the USPTO because the USPTO does not determine infringement. Often, there is a related district court case claiming infringement during post-grant proceedings at the USPTO. The district court may stay its proceeding to await the patent invalidity decision of the USPTO.

In district court proceedings, patent litigation is subject to the same rules as other civil litigation: the Federal Rules of Civil Procedure and the Federal Rules of Evidence. Most district courts (and some individual judges) that hear a large number of patent cases, such as the District of Delaware or the Northern District of California, have their own supplemental procedures that apply in patent cases. 

The time to resolve patent litigation in district court varies widely and may take several years. Courts that are unusually efficient in getting cases to trial are often referred to as having “rocket dockets”. Examples of such courts are the Eastern and Western Districts of Texas, the Eastern District of Virginia and the Western District of Wisconsin. Courts have broad discretion to control proceedings to promote judicial efficiency and avoid prejudice to the parties, and a case may be presented as a single trial or be bifurcated or staged to have successive trials on issues such as infringement, wilfulness or damages. However, it is extremely rare for a patent case in front of a jury (almost always a patent case involving claims for money damages) to be bifurcated. Witnesses (fact and expert) presenting testimony in a hearing (eg, on claim construction or preliminary injunction motions) are subject to questioning by the judge and cross-examination by the opposing party. 

Unless the issue of damages has been bifurcated by the court (which is rare), infringement, validity and damages are typically decided at the end of a single trial by the jury or by the judge (in a bench trial). Injunctive relief is typically determined later, and that issue is always decided by the judge.

ITC

ITC investigations have their own procedures, but many of the rules are similar to those in district courts. One notable exception is the right to a jury. Unlike district court proceedings, there is no jury at the ITC or the USPTO. ITC investigations are almost always faster than district court proceedings, with trial-like evidentiary hearings taking place within nine to twelve months from the filing of a complaint. Witnesses at an ITC trial are subject to cross-examination by the opposing party, and by the judge.

IPR

IPR proceedings are quicker than district court litigation and follow a more regimented schedule. The process begins with the filing of a petition that includes the patent claims challenged and the supporting evidence. Once the petition receives a filing date, the patent owner may optionally file:

• a brief requesting discretionary denial of institution within two months; and/or
• a preliminary response addressing the merits of the petition within three months.

The petitioner may file an opposition within one month of the filing of a discretionary denial brief. While previously decided by a panel of PTAB judges, as of 20 October 2025, the USPTO Director makes the decision on whether to institute the IPR, taking into account discretionary considerations, the merits of the petition and non-discretionary considerations. Instead of a decision, the Director issues a summary notice either granting or denying institution.

If instituted, the IPR goes to a panel of PTAB judges, and the patent owner has three months to file its response and any motion to amend the patent claims. The petitioner has three months to reply to the patent owner response and oppose the claim amendments. The patent owner has an additional month to file a sur-reply. Following briefing, the PTAB schedules an oral hearing and issues a final written decision no more than 12 months after the institution decision (although the time may be extended by up to an additional six months for good cause).

In an IPR proceeding, direct witness testimony, including expert testimony, is presented in the form of an affidavit or declaration. The party presenting the witness will need to make the witness available for cross-examination by the opposing side, usually in the form of a deposition. Live testimony during the oral hearing is exceedingly rare, but the PTAB may permit it when the demeanour of the witness is critical to assessing credibility.

With respect to federal district court litigation, beyond choosing the particular forum in which to file suit, parties have little ability to influence who will be the decision-maker – unless they agree to waive their rights to a jury trial (which patentees almost never do). In a district court, unless a judge decides an issue in a pre-trial (eg, a summary judgment) or post-trial motion, issues of infringement, invalidity and damages are decided by a jury. Juries do not have technical expertise. There is no requirement that a judge have a technical background to preside over a patent case in district court, and most district court judges do not have technical backgrounds. 

In 2011, 14 district courts began a ten-year Patent Pilot Program (the “Program”) to enhance expertise in patent cases. New patent cases in those districts were assigned to a random judge. If the randomly assigned judge was not a designated judge in the Program, the judge could transfer the case to a participating judge in the district. The Program concluded in July 2021.

ITC investigations proceed before an administrative law judge. Because a large proportion of ITC investigations involve patents, many administrative law judges have developed substantial experience with patent cases, and many also have technical expertise. The ITC randomly assigns an administrative law judge to new investigations, and assignment is not based on any particular technical background of the judge.

The USPTO has administrative patent judges. These judges are typically experienced patent lawyers with technical backgrounds. If possible, the USPTO assigns cases to judges based on their technical background.

Appeals from all patent cases at the district courts, ITC or USPTO go to the US Court of Appeals for the Federal Circuit. The judges in the Federal Circuit have significant patent law experience from the many patent-related appeals, but do not necessarily have a technical background.

Settlement of patent disputes is quite common (except in certain types of pharmaceutical patent cases, where antitrust consideration can make settlement difficult or impossible). Parties may reach a settlement through a variety of possibilities, such as negotiation, alternative dispute resolution or mediation. Some courts require parties to attempt a resolution before proceeding with a trial. Settlement agreements can terminate the proceedings in a district court, usually without disclosure of the settlement details to the court.

The ITC has a non-mandatory mediation programme to aid resolution of disputes before pursuing a full investigation. After the investigation begins, parties may request termination of the investigation upon reaching a settlement, but a copy of any agreement will be submitted to the ITC in the process. Procedures are available to protect information within the settlement from public disclosure.

Post-grant proceedings before the USPTO follow similar settlement disclosure procedures as the ITC when seeking termination of a trial. The USPTO may continue a proceeding despite the parties’ settlement agreement. This is more likely if the proceeding is nearly completed when the settlement occurs.

Federal courts have inherent authority to control their dockets, including the power to stay proceedings when there are co-pending matters in another forum. The courts may consider several factors when deciding to stay, including the progress of the court proceeding, whether the stay will simplify issues before the court or whether a stay would unduly prejudice a party. When there is a co-pending post-grant proceeding (such as an IPR), courts are more likely to stay proceedings if the USPTO proceeding has been instituted.

Generally, decisions reached in different fora are not binding on each other, except when a patent has been cancelled by the PTO in a post-grant proceeding or where a final, non-appealable judgment of invalidity has been entered in the district court litigation. This means a district court is not obliged to agree with a USPTO decision on patent validity, but the court may find the USPTO decision very persuasive because of its perceived expertise on patents. Similarly, the USPTO may consider the progress and findings of district court litigation or ITC investigations in its own proceedings. The law regarding the effect of a foreign anti-suit injunction is still unsettled, and the decision in a particular case is likely to turn on the particular facts (and timing) involved.

In federal district courts, the patent holder may seek damages for patent infringement and injunctions to prevent ongoing infringement. By statute, damages for infringement should be adequate to compensate for the infringement, but not less than a reasonable royalty. A jury verdict will typically include a damages award, which is then reviewed by the district court judge (if a party files a motion requesting such a review) for compliance with certain legal standards regarding damages. Patent damages are limited to no more than six years before commencement of the lawsuit. In cases of wilful infringement, the courts may award three times the damages. Generally, each party pays its own lawyers’ fees, but in “exceptional” cases, courts may impose fee shifting to the losing party. In addition to monetary damages, a party may seek an injunction to prevent continued infringement.

Primary responsibility for enforcing a district court judgment lies with the patent owner, who has at its disposal a wide array of enforcement mechanisms including seeking to execute the judgment against the debtor’s assets. If a party fails to comply with an injunction, the other party may seek sanctions from the district court originally ordering the injunction.

The ITC cannot impose monetary damages for infringement, but it can issue exclusion and cease-and-desist orders. The exclusion orders direct US Customs and Border Protection to exclude infringing articles from entry into the USA. ITC cease-and-desist orders can direct infringers to stop importing infringing articles and to stop sales of infringing articles in US inventory. The ITC retains broad authority to enforce any of its orders, and a complainant in the original investigation can request a formal enforcement proceeding.

In the US legal system, each party typically pays its own lawyers’ fees and costs. Similar to the description in 6.1 Remedies for the Patentee for successful patent holders, a prevailing defendant may request lawyers’ fees and costs if the case is determined to be “exceptional”. Under US Supreme Court precedent, “an ‘exceptional’ case is simply one that stands out from others with respect to the substantive strength of a party’s litigating position (considering both the governing law and the facts of the case) or the unreasonable manner in which the case was litigated”.

The available remedies do not vary based on the technical area of a patent.

A successful patent holder in an infringement proceeding does not automatically get an injunction against the infringing party. Similarly, if the district court issues an injunction, its effect is not automatically stayed during appeal. Ordinarily, a permanent injunction is effective upon issue, but a court has broad equitable authority to modify relief. The defendant may seek a stay of the injunction by filing a motion with the issuing court or the appellate court – the US Court of Appeals for the Federal Circuit. In the absence of a stay, the injunction is enforceable pending appeal. When deciding to stay an injunction, the courts balance the likelihood of success on the merits against the equities of the parties and the public.

The appellate procedure for patent litigation is the same as for other civil litigation, except that all appeals in patent cases from district courts, ITC investigations and USPTO proceedings go to the US Court of Appeals for the Federal Circuit. 

The Federal Circuit can review factual and legal determinations of the proceedings in a lower court, if the errors were properly preserved in its record. The level of deference given to the decision-maker in a lower court varies depending on the type of error. For purely legal issues, such as statutory interpretations and judgments as a matter of law, the Federal Circuit applies a de novo standard where the court examines the record to form its own opinion, with no deference to the previous decision-maker. Factual determinations receive more deference – “clearly erroneous” if the judge made factual determinations or “substantial evidence” if the jury was the fact-finder. Equitable determinations, such as inequitable conduct, injunctions or lawyers’ fees, are left to the discretion of the trial court judge, so a review of these decisions gets the highest deference, only being reversed for “abuse of discretion”.

Pre-litigation costs vary depending on the complexity of the issues and the amount in controversy between the parties. A patent holder may require legal and technical research for claim charts, warning letters to potential infringers and analysis of potential enforcement options. An accused infringer may accrue legal fees to weigh its options for challenging the alleged infringement through an affirmative defence in a lawsuit, a declaratory judgment of invalidity or non-infringement, or a USPTO proceeding challenging patent validity.

In district courts, the fee for filing a federal civil complaint is fixed by statute, but the Judicial Conference of the United States may prescribe additional fees. Currently, the filing fee is USD405, plus a USD55 administrative fee.

The fee to request an IPR (including up to 20 claims) at the USPTO is USD23,750, and a PGR request (including up to 20 claims) is USD25,000.

The traditional rule in the USA is that each party bears its own costs, but there are limited exceptions to this default rule. The Federal Rules of Civil Procedure allow a party to seek reasonable expenses, including lawyers’ fees, incurred when an opposing party makes improper representations to the court or commits discovery misconduct. These sanctions do not award all costs and lawyers’ fees, only the expenses associated with the violation. In patent litigation, a court may award all costs and reasonable lawyers’ fees to the prevailing party if the case is determined to be “exceptional”; that is, “one that stands out from others with respect to the substantive strength of a party’s litigating position (considering both the governing law and the facts of the case) or the unreasonable manner in which the case was litigated”.

Alternative dispute resolution is common in civil cases, and its use in intellectual property disputes is becoming increasingly common. Parties may use alternative dispute resolution as an alternative to litigation by mutual agreement, contractual agreement or court order (although a court cannot force the parties to agree to a mediator’s ruling). Some courts offer mediation or special masters for settlement purposes. Parties may prefer alternative dispute resolution to take advantage of its greater flexibility, confidentiality and cost-effectiveness. Additionally, a patent owner can avoid the risk of a court’s judgment of patent invalidity.

Assignment of all or part of the rights in a patent must be in writing. The assignee or assignor may record the assignment with the USPTO, but recordation is not required to enforce the assignment.

Generally, the procedure to assign patent rights involves the same type of negotiations as other contract rights. The parties negotiate the terms of the agreement and execute a written assignment contract. An employer’s employment contract may require its employees to assign rights to the employer for inventions developed during employment. Although not required, any assignments should be recorded with the USPTO.

Generally, the procedure to assign patent rights involves the same type of negotiations as other contract rights. The parties negotiate the terms of the agreement and execute a written assignment contract. An employer’s employment contract may require its employees to assign rights to the employer for inventions developed during employment. Although not required, any assignments should be recorded with the USPTO.

Licence agreements are contractual rights; the parties agree to the terms and execute the agreement in writing. Unlike an assignment of a patent, the rights assigned by licence revert to the licensor after the agreed time period.