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Things your patent attorney should tell you

Compliance with the duty of disclosure will help avoid patent invalidation

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A strong patent can form the basis of a successful business. Obtaining a patent can be a daunting process. There are complex rules governing every aspect of the process. Failure to satisfy these rules can result in an unenforceable patent or a patent that is invalidated in litigation.

The U.S. patent rules impose every person associated with the filing and prosecution of a patent application a "duty of candor and good faith" with the United States Patent and Trademark Office (USPTO). One aspect of this duty is a requirement to disclose all information that may be material to patentability to the USPTO. "Material" information is any that could be used to form a basis for a prima facie case of unpatentability. Compliance, the duty of disclosure, is critical to the strength of a patent.

Patent attorneys often are asked questions regarding the requisites of this duty. Who has the duty? What must be disclosed? When does the duty end? What are the consequences of a breach of the duty?


Any person substantially involved in the preparation or prosecution of a patent application is required to disclose material information in good faith to the USPTO. This includes each named inventor, the assignees or those with an obligation to assign, those associated with the inventors or assignees, licensees involved in prosecution and each patent attorney or agent who prepares or prosecutes the patent application. Consequently, it is important to identify all those involved with the patent application.


The duty of disclosure provides the USPTO with the information to determine patentability. It is the patent examiner who should make the determination after considering all the facts involved in the particular case.

Thus, material information includes any information that a reasonable patent examiner would likely consider important in deciding whether to allow an application to issue as a patent.

Many people believe that the duty of disclosure is limited to reporting prior art that a patent examiner could use to support a rejection of the claims based on novelty or obviousness. The courts have held that art relevant to enablement (how to make and use the invention) also should be disclosed. Other information that is "material" to patentability includes:

• Any prior public uses, sales or offers to sell occurring more than one year prior to the filing date of the application

• Prior invention by another

• Publications, post- or pre-filing, by inventors or the assignee that describe the same or similar subject matter, that provide further details of an earlier inventive concept, that contradict or appear to contradict an earlier inventive concept or that provide other information that may be material

• Patents and applications that are co-owned or that include one inventor in common

• Search reports from a foreign patent office

• References cited in related cases, including foreign counterparts; Web site content; advertising and marketing literature, grant applications, SEC filings, FDA filings

• Disclosures to others, including confidential information received from third parties; data that contradicts or otherwise impacts an argument for patentability

• Office actions in cases that contain related claims that set forth different grounds of rejections, related applications, co-owned applications

• Inventorship disputes, litigations and interferences in related cases, and other information

If there is any question whether particular information should be provided to the USPTO, the safer course is to disclose it. The courts have held that "close cases" of materiality should be resolved by disclosure. Where an attorney or any person involved in the preparation or prosecution of a patent application knows of information and can readily determine the materiality of that information, he or she cannot intentionally avoid learning of the art and disclosing the information to the USPTO. Failing to provide information because the USPTO may use it to reject claims is the hallmark of information that must be provided.


The duty of disclosure continues for each application during prosecution of the patent application until the application issues. The duty of disclosure is ongoing and pertains until the day of issuance of the patent. Hence, even after an application is allowed and the issue fee paid, information must be provided to the USPTO, even if the application has to be withdrawn from issue to do so. The duty of disclosure also applies if a patent is involved in additional proceedings in the USPTO, such as re-examination or reissue. A breach of the duty of disclosure generally cannot be cured by re-examination or reissue.


The consequences for breaching the duty of disclosure can be serious. A breach can lead to a finding of "inequitable conduct," if the breach is material and there is evidence (of conduct and state of mind) showing intent to deceive the USPTO.

A breach of the duty of disclosure generally is discovered during patent litigation, when an accused infringer raises an affirmative defense of inequitable conduct. If the court finds inequitable conduct, then the patent becomes unenforceable or invalid. This also extends to all progeny patents.

A finding of inequitable conduct can be the basis for awarding attorney's fees and court costs to the opposing party in litigation. To successfully defend inequitable conduct, the defendant must prove by clear and convincing evidence that the material information was withheld or misrepresented with intent to deceive the patent office. When examining deceitful intent, a court must weigh all evidence, including evidence of good faith. For this reason, patent counsel should ensure that good-faith efforts in complying with the duty to disclose are evident, such as the timely filing of Information Disclosure Statements (IDSs) or supplemental IDSs to cite any newly discovered information.

Compliance with the duty of disclosure is critical to obtaining valid and enforceable patents. When anyone involved with the preparation or prosecution of a patent application becomes aware of any information that a reasonable examiner may consider to be material to a determination of patentability, this information should be brought to the attention of the patent attorney or agent prosecuting the application promptly. Any legal or technical issues can be discussed and a good faith determination regarding the duty of disclosure can be made. Failure to make a proper disclosure can result in the application not issuing as a patent or, if issued as a patent, being deemed unenforceable or invalid.

Seidman, Ph.D., Miskiel, Ph.D., and Gerken, Ph.D., are attorneys in the biotechnology and pharmaceutical practice group of the San Diego office of Fish & Richardson.

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