Lemko Corporation v. AT&T Inc. et al

IN THE UNITED STATES DISTRICT COURT
FOR THE EASTERN DISTRICT OF TEXAS
MARSHALL DIVISION
LEMKO CORPORATION,
Plaintiff,
v.
AT&T ENTERPRISES LLC, AT&T
MOBILITY LLC, AT&T MOBILITY LLC II,
and AT&T SERVICES, INC.,
Defendants.
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CASE NO. 2:25-CV-00305-JRG
MEMORANDUM OPINION AND ORDER
Before the Court is the Motion to Transfer Venue to the Northern District of Texas (the
“Motion”) filed by Defendants AT&T Enterprises LLC, AT&T Mobility LLC, AT&T Mobility
LLC II, and AT&T Services, Inc. (the “Defendants”). (Dkt. No. 33). In the Motion, Defendants
move to transfer the above-captioned case to the United States District Court for the Northern
District of Texas (the “NDTX”) pursuant to the first-to-file rule. (Id. at 1). Specifically,
Defendants assert that this case substantially overlaps with the earlier-filed Lemko Corp. v.
Microsoft Corp. et al, Case No. 3:22-cv-363-K (the “NDTX Case”). (Dkt. No. 31, at 1). Plaintiff
Lemko Corporation (“Plaintiff”) opposes the Motion. (See Dkt. No. 37). Having considered the
Motion and its related briefing, and for the reasons set forth herein, the Court finds that it should
be DENIED.
I. BACKGROUND
On February 14, 2022, Plaintiff filed suit against non-parties Microsoft Corporation and
Affirmed Networks Inc. (the “Non-Parties”) in the NDTX. (NDTX Case, Dkt. No. 1). There,
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Plaintiff alleges that the Non-Parties infringe eight (8) of its patents1 that generally relate to a
distributed mobile architecture structure for use in a 4G (LTE) or 5G Network (the “NDTX
Patents”). (See NDTX Case, Dkt. No. 80 ¶ 38). Specifically, Plaintiff accuses the Affirmed
Mobile Core (software) and the Azure Stack Edge (a common-off-the-shelf server (“COTS”)) of
infringement. (Dkt. No. 33, at 7).
Then, on March 17, 2025, Plaintiff filed this case. (Dkt. No. 1). Here, Plaintiff alleges that
Defendants infringe seven (7) of its patents2 that are related to but distinct from the NDTX Patents
(the “Asserted Patents”). (Id. ¶¶ 27–33; see also Dkt. No. 33-13, at 2). Particularly, Plaintiff
accuses the AT&T Private 5G Edge of infringement. (Dkt. No. 33, at 7). The Private 5G Edge
runs Azure Private 5G software on a variety of COTS, including the Azure Stack Edge. (Id.).
II. LEGAL STANDARD
“Under the first-to-file rule, when related cases are pending before two federal courts, the
court in which the case was last filed may refuse to hear it if the issues raised by the cases
substantially overlap.” Cadle Co. v. Whataburger of Alice, Inc., 174 F.3d 599, 603 (5th Cir. 1999)
(citations omitted); see also Int’l Fidelity Ins. Co. v. Sweet Little Mexico Corp., 665 F.3d 671, 677–
678 (5th Cir. 2011). “The rule rests on principles of comity and sound judicial administration.”
Cadle, 174 F.3d at 603 (citations omitted). “The concern manifestly is to avoid the waste of
duplication, to avoid rulings which may trench upon the authority of sister courts, and to avoid
piecemeal resolution of issues that call for a uniform result.” Id. (quotation omitted). In
determining whether cases “substantially overlap,” the Court may look to “factors such as whether
1 Plaintiff asserts the following patents in the NDTX Case: U.S. Patent No. 7,548,763; U.S. Patent No. 7,653,414;
U.S. Patent No. 7,855,988; U.S. Patent No. 8,107,409; U.S. Patent No. 8,688,111; U.S. Patent No. 9,191,980; U.S.
Patent No. 9,332,478; and U.S. Patent No. 9,755,931. (NDTX Case, Dkt. No. 80 ¶¶ 20–36).
2 Plaintiff asserts the following patents in the this case: U.S. Patent No. 7,840,230; U.S. Patent No. 7,979,066; U.S.
Patent No. 8,224,322; U.S. Patent No. 8,310,990; U.S. Patent No. 8,340,667; U.S. Patent No. 8,359,029; and U.S.
Patent No. 9,198,020. (Dkt. No. 1 ¶¶ 28–34).
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‘the core issue . . . was the same’ or if ‘much of the proof adduced . . . would likely be identical.’”
Int’l Fidelity, 665 F.3d at 678 (quotations omitted). “The first-to-file rule is a discretionary
doctrine,” and a district court’s decision to apply the rule is reviewed for abuse of discretion. Id.
at 677–678 (citation omitted).
“In patent cases, courts determining whether cases were substantially [overlapping] have
examined whether they involved the same parties, the same technology, the same inventors,
overlapping remedies, the same witnesses, or overlapping issues in claim construction.” SIPCO,
LLC v. Emerson Electric Co., 2016 WL 7743496, at *2 (E.D. Tex. Jul. 1, 2016) (citing E-Z-EM,
Inc. v. Mallinckrodt, Inc., 2010 WL 1378820, at *2 (E.D. Tex. Feb. 26, 2010)). For example, this
Court has found “substantial[] overlap” between cases that involved closely related patents and
“many of the same products.” Robert Bosch Healthcare Sys., Inc. v. Cariocom, 2014 WL
12618095, at *1 (E.D. Tex. Mar. 10, 2014). In another example, the Court has found that
“[s]ubstantial overlap does not exist” between cases that involved “the same patents” because “the
plaintiff assert[ed] different claims against different defendants and accuse[d] different technology
platforms” of infringement. Personalized Media Communications, L.L.C. v. Motorola, Inc. , 2009
WL 10643344, at *2 (E.D. Tex. Sep. 30, 2009).
III. ANALYSIS
Substantial overlap does not exist here. First, this case and the NDTX case involve
different defendants. See Personalized Media, 2009 WL 10643344 at *2. Second, the cases
involve different technology platforms. Id. Specifically, the underlying software is different in
this case (Azure Private 5G Core) than in the NDTX Case (Affirmed Mobile Core). (See Dkt. No.
33, at 7). Further, and whereas Plaintiff has identified Azure Stack Edge servers as an accused
product in the NDTX Case, the Private 5G Edge at issue here is not required to use the Azure Stack
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Edge. (See id. (“The servers may be common-off-the-shelf servers (COTS), including [Microsoft]
Azure Stack Edge servers, or other COTS servers”) (quotation omitted)). A potential but not
assured overlap in a mere subcomponent of a system is not substantial. Third, and as a result of
having different defendants and different accused products, this case and the NDTX Case are
unlikely to have substantial overlap in discovery. Indeed, patent cases have an “assumption” that
most discovery “comes from the infringer . . . [that] is now so engrained in the case law.” Affinity
Labs of Texas v. Samsung Electronics Co., Ltd., 968 F.Supp.2d 852, 857 (E.D. Tex. 2013).
At best, the cases involve related patents.3 However, given the significant differences in
parties, accused products, and expected discovery, transferring this case to the NDTX “will
produce only minimal gains in judicial economy, if any at all.” Personalized Media, 2009 WL
10643344 at *2.
Accordingly, the Court finds that transfer under the first-to-file rule is not warranted here.
IV. CONCLUSION
For the foregoing reasons, the Court finds that the Motion should be and hereby is
DENIED.
3 The Court notes that none of the Asserted Patents are asserted in the NDTX Case. See supra notes 1–2.
.
____________________________________
RODNEY GILSTRAP
UNITED STATES DISTRICT JUDGE
So ORDERED and SIGNED this 6th day of March, 2026.
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