Guangdong Cell Biotechnology Ltd v. Thomas Christian Sudhof

District Court, N.D. California·Decided February 20, 2026·No. 5:25-cv-08953·Unknown

Opinion

GUANGDONG CELL Case No. 25-cv-08953-VKD BIOTECHNOLOGY LTD, Plaintiff, ORDER GRANTING IN PART AND DENYING IN PART DEFENDANT'S v. MOTION TO DISMISS AND DENYING DEFENDANT’S MOTION TO STRIKE THOMAS CHRISTIAN SUDHOF, Re: Dkt. Nos. 5, 6 Defendant.

On September 9, 2025, plaintiff Guangdong Cell Biotechnology Ltd. (“Cell Biotech”) filed this action against defendant Thomas Christian Sudhof in the Superior Court for the County of Santa Clara, asserting state law claims for breach of contract and breach of the implied covenant of good faith and fair dealing. Dkt. No. 1, Ex. A. On October 17, 2025, Dr. Sudhof removed the action to federal court, invoking the Court’s diversity jurisdiction, 28 U.S.C. § 1332. Dkt. No. 1 ¶ 3. Dr. Sudhof moves to dismiss all claims for lack of standing and failure to state a claim under Rule 12(b)(6) and to strike certain allegations and requests for relief in the complaint under Rule 12(f). Dkt. Nos. 5, 6. Cell Biotech opposes the motions. Dkt. Nos. 10, 12. The Court held a hearing on both motions on January 20, 2026. Dkt. No. 25.1 Upon consideration of the moving and responding papers and oral arguments presented, the Court grants in part and denies in part Dr. Sudhof’s motion to dismiss, and denies Dr. Sudhof’s motion to strike. According to the complaint, Cell Biotech is a Chinese corporation “dedicated to the research, development, application, and promotion of stem cell technology and immune cell technology.” Dkt. No. 1, Ex. A ¶ 7. Cell Biotech alleges that it was formerly known as Dongguan Cell Biotechnology Ltd. Id. ¶ 5. It changed its corporate name to its current name on July 31, 2020. Id. Cell Biotech alleges that Dr. Sudhof is a professor at Stanford University’s School of Medicine. Id. ¶ 6. Cell Biotech alleges that on November 8, 2017, one of its representatives invited Dr. Sudhof to serve as a scientific advisor for Cell Biotech. Id. ¶ 8. According to Cell Biotech, on December 7, 2017, two representatives of Cell Biotech met with Dr. Sudhof at Stanford University. Id. ¶ 9. Cell Biotech alleges that it arranged for Dr. Sudhof to travel to China on March 9 and 10, 2018 to “meet with [p]laintiff’s management team, discuss future cooperation plans, and execute a cooperation agreement.” Id. ¶ 10. Cell Biotech alleges that on March 9, 2018, Cell Biotech and Dr. Sudhof executed a memorandum of understanding (“MOU”) in China. Id. ¶ 11. According to the complaint, the MOU contains several provisions, including: Article 2: “Defendant agreed to serve as [p]laintiff’s Chief Scientific Advisor and to provide advice to [p]laintiff and its scientific projects.” Id. ¶ 12. Article 5: “Plaintiff paid [d]efendant USD 50,000 in cash as the remuneration provided under the [MOU].” Id. ¶ 17. Article 7: “If [d]efendant foresaw a potential conflict of interest, he was required to inform [p]laintiff.” Id. ¶ 13. Cell Biotech alleges that on March 9, 2018, following execution of the MOU, Cell Biotech issued a letter of appointment to Dr. Sudhof which he “accepted on site.” Id. ¶ 14. The complaint alleges that the letter of appointment states, “This letter is to confirm that [sic] Thomas C. Sudhof’s appointment in Cell Biotechnology Inc. of Dongguan and Cells Group as Chief Scientific Advisor.” Id. ¶ 15. by Cell Biotech in China, including visiting a partner clinical cooperation hospital, attending a forum titled the “Medical Biotechnology Forum with Nobel Laureate Thomas C. Sudhof,” and participating in scientific seminars. Id. ¶ 16. On March 10, 2018, Cell Biotech paid Dr. Sudhof $50,000 in cash, pursuant to Article 5 of the MOU. Id. ¶ 17. Cell Biotech alleges that on July 27, 2018, Dr. Sudhof attended the International Summit Forum on Biotechnology and Translational Medicine in his capacity as Cell Biotech’s Chief Scientific Advisor. Id. ¶ 18. Cell Biotech paid Dr. Sudhof an additional $50,000 in cash, pursuant to Article 5 of the MOU. Id. Cell Biotech alleges that, at some point,2 it learned that during and around the same time of Dr. Sudhof’s appointment as Cell Biotech’s Chief Scientific Advisor, Dr. Sudhof had been engaging with competitors in violation of the MOU. Id. ¶ 19. Specifically, a report dated January 15, 2025 indicates that Dr. Sudhof serves as Chief Scientific Advisor to Cell Biotech’s direct competitor Guangdong Wanhai Cell Biotechnology Co., Ltd. (“Wanhai”). Id. ¶ 20. Cell Biotech claims that Dr. Sudhof never informed it of his engagement with Wanhai, and this failure constitutes a breach of the conflict-of-interest provision in Article 7 of the MOU. Id. ¶ 21. Cell Biotech alleges that Dr. Sudhof’s conduct “has caused, and continues to cause, irreparable harm to [Cell Biotech’s] business operations, competitive position, and goodwill.” Id. ¶ 22. In this action, Cell Biotech asserts claims for (1) breach of contract, and (2) breach of the implied covenant of good faith and fair dealing. Id. ¶¶ 7-26. Cell Biotech seeks specific performance, restitution, compensatory damages, punitive damages, and attorneys’ fees and costs. Id. at 7. A. Rule 12(b)(1) “[L]ack of Article III standing requires dismissal for lack of subject matter jurisdiction under Federal Rule of Civil Procedure 12(b)(1).” Maya v. Centex Corp., 658 F.3d 1060, 1067 (9th Cir. 2011). To establish standing, a plaintiff must plausibly allege (1) an “injury in fact,” (2) that is fairly traceable to the challenged conduct of the defendant, and (3) likely to be redressed by a favorable judicial decision. Lujan v. Defs. of Wildlife, 504 U.S. 555, 560-61 (1992). “To establish injury in fact, a plaintiff must show that he or she suffered an invasion of a legally protected interest that is concrete and particularized and actual or imminent, not conjectural or hypothetical.” Spokeo, Inc. v. Robins, 578 U.S. 330, 339 (2016) (internal quotation marks omitted). To be particularized, an injury “must affect the plaintiff in a personal and individual way,” and to be concrete, the injury must be real and not abstract. Id. at 339-40 (internal quotation marks omitted). B. Rule 12(b)(6) A Rule 12(b)(6) motion to dismiss for failure to state a claim tests the legal sufficiency of the claims in the complaint. Navarro v. Block, 250 F.3d 729, 732 (9th Cir. 2001). Dismissal is appropriate where there is no cognizable legal theory or an absence of sufficient facts alleged to support a cognizable legal theory. Id. (citing Balistreri v. Pacifica Police Dep’t, 901 F.2d 696, 699 (9th Cir. 1988)). In such a motion, all material allegations in the complaint must be taken as true and construed in the light most favorable to the claimant. Id. Rule 8(a)(2) requires only “a short and plain statement of the claim showing that the pleader is entitled to relief.” Fed. R. Civ. P. 8(a)(2). However, “[t]hreadbare recitals of the elements of a cause of action, supported by mere conclusory statements, do not suffice,” Ashcroft v. Iqbal, 556 U.S. 662, 678 (2009), and “[f]actual allegations must be enough to raise a right to relief above the speculative level,” Bell Atl. Corp. v. Twombly, 550 U.S. 544, 555 (2007) (citations omitted). On

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Guangdong Cell Biotechnology Ltd v. Thomas Christian Sudhof, (N.D. Cal. 2026).

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