Texas Round-Up: November 2025

Our November 2025 Texas Round-Up covers three cases from the Eastern District addressing claim construction of “whereby” clauses, motions to compel, and motions to transfer.

Robert Bosch, LLC v. Westport Fuel Systems Canada, Inc., No. 2:23-cv-00038 (E.D. Tex.), Dkt. No. 38 (Payne, J.)

On November 6, 2025, Judge Payne denied Robert Bosch’s motion to compel Westport Fuel Systems Canada to substantively respond to an interrogatory concerning obviousness-type double patenting (OTDP). Specifically, the interrogatory concerned Westport's factual and legal bases for contending that the asserted patent was not invalid for OTDP.

In response to the motion, Westport countered that Bosch never properly pleaded OTDP. Westport pointed to Bosch’s answer, which asserted only statutory invalidity grounds “under one or more sections of Title 35.” Beyond this "perfunctory, single-sentence" reference to solely statutory invalidity theories, id. at 2, Bosch otherwise failed to identify where it had timely notified Westport of its OTDP theory.

Given Bosch's failure, Judge Payne agreed with Westport that Bosch’s OTDP theory was untimely. The court noted that Bosch’s pleading contained a single sentence listing statutory invalidity provisions but “nowhere . . . state[d], or even hint[ed], that any non-statutory invalidity bases are asserted.” Id. at 2. Because OTDP is a “judicially-created doctrine,” not a statutory § 101 defense, the court held that Bosch’s answer could not reasonably be read to include it. Id. (citing Eli Lilly & Co. v. Barr Labs., Inc., 251 F.3d 955, 967 (Fed. Cir. 2001)).

The court was also unpersuaded by Bosch’s alternative argument — that Bosch lacked a basis to raise OTDP until after claim construction. According to Judge Payne, Westport’s infringement contentions were enough to put Bosch on notice years earlier, and raising OTDP for the first time in a supplemental damages interrogatory response — after the amended-pleadings deadline, after fact discovery, and with expert reports imminent — constituted undue delay. With OTDP not properly in the case, the motion to compel was denied as moot.

PLS IV, LLC v. GDC Technology Limited, No. 2:24-cv-00466 (E.D. Tex.), Dkt. No. 62 (Gilstrap, J.)

On November 24, 2025, Judge Gilstrap issued a claim construction order resolving four disputes across two digital security-related patents. In its order, the court applied an exception to a lesser-known claim construction rule involving "whereby" clauses. Specifically, the court considered whether the disputed claim's “whereby” clause limits the scope of the method. The method involves generating and transmitting an "encoded block of data" to a "user's system,"

whereby the user’s system is able to receive and authenticate portions of the encoded block of data before the entire encoded block of data is received

Id. at 4–5 (quoting U.S. Patent No. 7,340,602 at Cl. 25). The parties disagreed over whether this whereby clause should be treated merely as an intended result of the method steps (i.e., the general rule for whereby clauses) or as a substantive claim limitation (i.e., an exception to the general rule).

Judge Gilstrap applied the exception, holding that the clause is limiting. Relying on Hoffer v. Microsoft Corp., 405 F.3d 1326, 1329–30 (Fed. Cir. 2005), the court explained that while “‘whereby’ clauses often recite intended results, they cannot be disregarded when they supply a condition material to the invention.” The court went on to explain that here, “the clause ‘clearly describes a capability of the user’s system,’ and the applicant chose to pair the encoding method with a transmission step and a receiving system that must have the specified ability.”

Gatekeeper Solutions, Inc. v. Darktrace, Inc., No. 4:24-cv-00723 (E.D. Tex.), Dkt. No. 39 (Jordan, J.)

We now transfer from Marshall to Sherman, but we may not be there long. This November, Judge Jordan granted Darktrace’s motion to transfer Gatekeeper Solutions’ email security patent case to the Northern District of California. Applying Fifth Circuit § 1404(a) principles, the court held that Darktrace had demonstrated that the Northern District of California is “clearly the more convenient venue” for this action, finding that no factors weighed against transfer.

Gatekeeper, a New York company, accuses Darktrace's email protection feature of patent infringement. This email protection feature prevents users from sending messages to conflicting recipients. Darktrace, headquartered in San Francisco, supported its motion with uncontroverted evidence that all of its "likely witnesses" work in or near San Francisco, none are located in the Eastern District of Texas, and the accused product’s technical documentation resides on servers in Darktrace’s San Francisco and Cambridge, UK, offices.

Gatekeeper had some evidentiary hooks at its disposal. Darktrace maintained a small sales office in Plano at the time the lawsuit was filed, though that office closed by the time of the court's decision. Moreover, even though two dozen of Darktrace's clients were located in the transferee district, it did have a customer in the Eastern District of Texas.

But these small hooks were insufficient to warrant keeping the case. Judge Jordan found that most of the private interest factors favored transfer or were neutral.

1. The first factor — access to proof — favored California because of Darktrace's uncontested testimony that all relevant technical documents are stored on servers in San Francisco and none in the Eastern District of Texas.
2. The second factor — the availability of compulsory process — likewise favored transfer. Nearly two dozen Darktrace customers who use the accused product and former employees (i.e., "potential" third-party witnesses) are located in the Northern District of California, compared to only one customer in the Eastern District of Texas. The court even considered the fact that current employees may leave before trial as favoring transfer.
3. The third factor — cost for willing witnesses — favored California because all putative willing witnesses resided there, while Gatekeeper identified none in Texas.

For the public interest factors, the court found that the local interest factor also tilted westward, with the remaining factors being neutral.

1. Though the court concluded that the congestion factor was neutral, it noted that the Sherman Division faces an unusually high caseload. Indeed, despite its finding of neutrality, the court spent a page discussing district-wide statistics and their inconclusive nature, all while suggesting that the Eastern District of Texas is, in fact, quite congested.
2. The local interest factor weighed decisively in favor of transfer. Darktrace is headquartered in San Francisco, relevant witnesses and documents are located there, and several of the accused acts occurred in that district. By contrast, neither party resides in the Eastern District and Darktrace has no remaining presence there.
3. The parties agreed that the remaining public-interest factors were neutral.

Finding four factors favoring transfer and none weighing against it, the court concluded that Darktrace met its burden to show that the Northern District of California is “clearly more convenient.”