In defending against allegations of patent infringement, there are numerous avenues to invalidating an asserted patent or rendering it unenforceable. Invalidity contentions can include asserting that the claims are anticipated or rendered obvious over the prior art such that the patent should never have issued, or that the claims are indefinite, insufficiently described or not enabled by the specification. Inequitable conduct—asserting that the applicant breached its duty of candor and good faith before the United States Patent and Trademark Office (USPTO) with a specific intent to deceive through the omission of material information—may be used to render the asserted patent or family of patents unenforceable. Unlike invalidity contentions, which are analyzed and proven on a claim-by-claim basis, a finding of inequitable conduct can render the underlying patent or family of related patents unenforceable.
A recent case, Global Tubing LLC v. Tenaris Coiled Tubes LLC, Nos. 2023-1882, 2023-1883, 2026 WL 530911 (Fed. Cir. Feb. 26, 2026), provides an example of how certain conduct made during patent prosecution may be viewed and interpreted in consideration of whether there was inequitable conduct in obtaining the underlying asserted patents.
BackgroundTenaris purchased the assets of Southwestern Pipe Inc., which included disclosures related to a tubing manufacture process using quench and temper techniques that result in a stronger and more durable product, known as CYMAX. Such manufacturing processes were disclosed in a series of documents referred to as the “CYMAX Documents.” The CYMAX Documents disclosed one iteration of coiled tube product, CYMAX 100, that included a chemical composition of 0.13-0.17 weight percent carbon and a yield strength of 100 ksi. Tenaris developed its own product known as BlueCoil, having 0.17-0.35 weight percent carbon and a yield strength between 95 and 140 ksi.
Tenaris filed for and obtained grant of U.S. Patent No. 9,803,256 (’256 patent) directed to its coiled tubing product. The main independent claim of the ’256 patent recites a coiled steel tube having 0.17-0.35 weight percent carbon and a yield strength of greater than about 80 ksi, which overlaps with CYMAX 100 disclosed in the CYMAX Documents.
During prosecution of the ’256 patent, among the hundreds of documents submitted to the USPTO, Tenaris submitted a paper titled “High-Strength Coiled Tubing Expands Service Capabilities” (called “Chitwood” after one of the authors) co-authored by Southwestern Pipe Inc. engineers, which explicitly taught coiled steel tubing having the requisite yield strength and carbon content, namely a carbon range of at least 0.18 to 0.43 weight percent. The parties agreed that this disclosure is the CYMAX 100 product.
Tenaris submitted Chitwood to the USPTO for consideration during prosecution but did not submit the CYMAX Documents on the basis that Chitwood disclosed materially the same information as the CYMAX Documents.
During prosecution, Tenaris filed an inventor declaration to rebut an allegation of obviousness raised by the examiner. Prosecution counsel had asked the inventor declarant, “Is there any particular evidence of long felt need of a particular property of the coiled tube?”; “Can you provide any evidence or details of this long felt need?”; and “Do you have any evidence of people struggling to achieve the claimed coiled tube?” In a series of margin comments in response to the above inquiries in the draft declaration, the inventor declarant directed counsel to page 30 of the CYMAX Documents, disclosing CYMAX 100, and indicated “I am not sure it is a good idea to disclose this document.”
Nonetheless, the examiner, in response to the declaration, withdrew the obviousness rejection and allowed the underlying application to issue as the ’256 patent.
Tenaris obtained grant of two child patents claiming priority to the ’256 patent, U.S. Patent Nos. 10,378,074 (’074 patent) and 10,378,075 (’075 patent). Prosecution counsel for the ’074 and ’075 patents, different than counsel used to obtain grant of the ’256 patent, urged submission of the CYMAX Documents. While the CYMAX Documents were submitted, page 30 of the CYMAX Documents, which disclosed CYMAX Documents, was omitted from these submissions. Tenaris submitted the entirety of the CYMAX Documents, including page 30 disclosing CYMAX 100, in the prosecution of grandchild Application Nos. 16/538,326 and 16/538,407 along with the requisite terminal disclaimers such that the underlying issued patents would expire the same time as the ’256 patent.
Global Tubing manufactured a competing quenched and tempered coiled tubing product purported to be a copy of Tenaris’ product. Under the threat of litigation, Global Tubing sought a declaratory judgment asserting noninfringement of Tenaris’ patents. Tenaris counterclaimed asserting infringement of the ’256, ’074 and ’075 patents.
During discovery, Tenaris inadvertently produced communications that included the draft declaration containing the inventor declarant’s comments regarding his apprehension to disclose the CYMAX Documents pertaining to CYMAX 100. The magistrate judge rejected Tenaris’ attempt to claw back the inadvertently disclosed materials, holding that the declarant’s comment, “I am not sure it is a good idea to disclose this document,” as evidence of intent to defraud. Global Tubing subsequently amended its complaint to assert inequitable conduct and fraud under Walker Process Equipment, Inc. v. Food Machine & Chemical Corp., 382 U.S. 172, 177 (1965) in utilizing patents to monopolize the market.[1]
As further part of the discovery process, Global Tubing deposed the declarant regarding his views on the comment regarding his apprehension to disclose the CYMAX Documents. The declarant attested to the product claimed in the ’256 patent as having a different chemical composition, namely, the lower carbon content, such that the properties of the resulting coiled tubing product would be different and disclosure of the CYMAX Documents would not be helpful to prosecution and instead lead to confusion. Further, the declarant attested that the content of the CYMAX Documents was sufficiently disclosed in Chitwood, the Chitwood publication being a public record of CYMAX.
The parties filed cross motions for summary judgment at the close of discovery, with Global Tubing seeking summary judgment for its inequitable conduct claim and Tenaris seeking summary judgment of no liability as to inequitable conduct and Walker Process fraud. The district court held that Global Tubing had proved by clear and convincing evidence that Tenaris intended to deceive the USPTO by withholding and not disclosing the CYMAX Documents, granting summary judgment to Global Tubing’s inequitable conduct claim.
Tenaris appealed the district court’s grant of summary judgment as to inequitable conduct to the United States Court of Appeals for the Federal Circuit.
The Federal Circuit’s Decision
On appeal, Tenaris argued that there are genuine issues of material fact in whether the inventor declarant acted with the specific intent to defraud the USPTO, and that disclosure of the CYMAX Documents would have been cumulative in view of Tenaris’ disclosure of Chitwood and thus not material to patentability. Global Tubing asserted that the inventor declarant’s comment is an admission of fraudulent intent to deceive and that the CYMAX Documents were material to patentability.
With respect to the intent to deceive, an “accused infringer must prove by clear convincing evidence that the applicant knew of the [withheld] reference, knew that it was material, and made a deliberate decision to withhold it.” Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1290 (Fed. Cir. 2011) (en banc) (internal quotation marks omitted).
The Federal Circuit, in its determination to vacate the grant of summary judgment, held that the district court failed to consider the evidence and drew all reasonable inferences in the light most favorable to the nonmoving party (i.e., Tenaris). Rather, the Federal Circuit focused on the series of inquiries posed to the declarant in preparing his statements for the declaration, namely “Do you have any evidence of people struggling to achieve the claimed coiled tube?” Based on such inquiries, the court held that patent prosecution counsel was merely soliciting evidence of secondary considerations of nonobvioussness. While the trial court could determine that the declarant’s comments could indeed confirm disclosure of the overlapping carbon content of the CYMAX Documents, leading to the claims being finally rejected in prosecution, a reasonable factfinder could also infer, in the light most favorable to Tenaris, that the disclosed ranges in the CYMAX Documents related to a different carbon content [2] and range and that the disclosed Chitwood reference sufficiently disclosed CYMAX 100 as in the withheld CYMAX Documents and disclosure of the CYMAX Documents would be cumulative with Chitwood. The court further noted that the declarant provided the documents to prosecution counsel to allow counsel to make the decision as to disclosure based on the declarant’s comments.
Thus, because there are issues of material fact regarding the intent of the declarant to be resolved at the trial court, the grant of summary judgment for inequitable conduct was not appropriate.
The Federal Circuit next turned to its analysis of whether the CYMAX Documents were material to patentability. A prior art reference is material if demonstrated by a preponderance of the evidence that, but for withholding of the reference, the underlying patent would not have issued. See Belcher Pharms., LLC v. Hospira, Inc., 11 F.4th 1345, 1352 (Fed. Cir. 2021). Thus, Global Tubing must show that the withheld CYMAX Documents are but-for material to patentability.
In further finding genuine issues of material fact, the court focused on the disclosure of Chitwood, which did not specifically identify the chemical composition of the embodiment disclosed in page 30 of the withheld CYMAX Documents. However, the court noted Tenaris presented evidence that the skilled artisan, in interpreting Chitwood, would have been able to discern that the steel used in the Chitwood publication utilized a chemical composition that was the same as that disclosed on page 30 of the withheld CYMAX Documents. Because a reasonable inference could be found in the light most favorable to the nonmoving party, namely that Chitwood is cumulative of the withheld CYMAX Documents, there are genuine issues of material fact as to whether the withheld CYMAX Documents are indeed cumulative to Chitwood or, instead, material to patentability such that granting summary judgment was not proper. The court further noted that despite disclosing the entirety of the CYMAX Documents during prosecution of grandchild Application Nos. 16/538,326 and 16/538,407, these applications were still allowed and granted such that the USPTO may have granted the asserted patents even with complete disclosure of the CYMAX Documents.
Based on viewing the evidence in the light most favorable to the nonmoving party (i.e., Tenaris) in which reasonable inferences can be drawn favorable to the nonmoving party, there are genuine issues of material fact as to the specific intent of the inventor declarant in his comments about his apprehension to not disclose the CYMAX Documents and whether the CYMAX Documents are cumulative to Chitwood and thus not material to patentability, the grant of summary judgment as to a finding of inequitable conduct was not proper. The court vacated the grant of summary judgment and remanded the case to the district court for further proceedings.
Conclusion and Practice Points
Here, the grant of summary judgment as to inequitable conduct was not proper because the Federal Circuit was able to draw reasonable inferences in the light most favorable to Tenaris such as the mistaken conclusion of the declarant that the CYMAX Documents involved a different carbon range. From such inferences, the court reasoned that the resulting product would have different properties and the intent to not disclose was to avert potential confusion or that the disclosures of the CYMAX Documents could be fully ascertained from Chitwood and render the disclosures of the former cumulative. Because there are issues of material fact from making these reasonable inferences, the grant of summary judgment in finding inequitable conduct was inappropriate. However, other patentees may not be as lucky.
The underlying situation as to the disclosure of the draft declaration containing the inventor’s comments to patent prosecution counsel may have been avoided in the first place if Tenaris had thoroughly reviewed the communications between the inventors and prosecution counsel. Communications that would invoke the attorney-client privilege or are deemed attorney work product should have been clearly marked as such.
However, if faced with the decision of whether to disclose or not disclose a particular reference or set of references, it is recommended to disclose in an abundance of caution to also avoid the instant situation in which the accused infringer asserts inequitable conduct to render the underlying asserted patent unenforceable. The examiner having the requisite technical background and training, in reviewing the disclosed reference, may also come to the conclusion that such disclosed reference is either immaterial to patentability or is cumulative with the disclosures of other prior art submitted for consideration during prosecution. Even if the examiner were to formulate an appropriate rejection of the claims, applicants may choose to continue to work with the examiner through continued examination to discuss the distinctions and unexpected results between the disclosed reference in advocating for patentability versus facing a protracted dispute as to the specific intent of the applicant during prosecution and the materiality of the withheld references to patentability.
