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25-CIV-01919·sanmateo·Civil·Demurrer
SUSTAINED, with Leave to Amend

MAUSUMEE GUHA VS. ROOPA RAI, ET AL

Defendants’ Demurrer to Plaintiff’s First Amended Complaint

Hearing date
May 8, 2026
Department
20
Prevailing
Defendant

Motion type

Demurrer

Parties

PlaintiffMAUSUMEE GUHA
DefendantROOPA RAI
DefendantPRAKASH NARAIN

Attorneys

SCOTT J. KALTERfor Plaintiff

Ruling

For the reasons stated below, defendants Roopa Rai’s and Prakash Narain’s (collectively, “Defendants”) demurrer, filed Nov. 4, 2025, which is directed to Plaintiff Mausumee Guha First Amended Complaint (“FAC”), filed Oct. 20, 2025, is SUSTAINED, with Leave to Amend. (Code Civ. Proc. § 430.10(e).)

Background

Plaintiff’s initial Complaint (“Complaint”) alleged that in or prior to May 2021, Plaintiff and Defendant Rai began discussing the idea of forming a joint venture together. Part of their business idea/proposal contemplated identifying “drug targets,” which the Complaint defined as “molecules in the body that interact with drugs to target disease.” (Cmplt. ¶ 12.) As alleged, Plaintiff and Defendant Rai contemplated that Plaintiff would contribute to the joint venture her experience and knowledge in identifying promising drug targets, which was critical to, and the starting point, for the joint venture’s success. From May-Aug. 2021, Plaintiff dedicated significant time and effort educating and advising Rai about drug targets, and proposed several drug targets, including one entitled “KAT6.” (Cmplt. ¶¶ 15-18.) At some point, Defendant Rai’s husband, Defendant Narain, became involved in these discussions. (Id.) As alleged in the initial Complaint, the parties’ relationship began to sour in about July 2021, when Defendant Rai formed a company called Isosterix, without giving an ownership interest in Isosterix to Plaintiff. (¶¶ 21-23.) Rai also told Plaintiff that on the advice of Rai’s counsel, Rai would not take/accept Plaintiff’s financial contribution to the company. (Id.) After some back and forth, Rai told Plaintiff that she (Rai) wished to terminate the joint venture. (¶¶ 33- 34.) In response, Plaintiff told Rai to stop work on any drug targets that were suggested by Plaintiff. (¶ 34.) In March 2024, Plaintiff discovered, from a LinkedIn post, that despite Plaintiff’s prior admonition that Defendants were not to use Plaintiff’s drug target ideas, Defendants and Isosterix were in fact using Plaintiff’s prior drug target research. (¶ 35.) The LinkedIn post stated that Rai was taking Isosterix out of “stealth mode.” (Id.) Plaintiff learned that Rai was taking credit for Plaintiff’s drug target work and was “bragging about it.” (Id.) Around this same time, Plaintiff saw that Rai presented at a conference, at which Rai claimed that the KAT6 drug target (Plaintiff’s research) was Rai’s own idea. (¶ 36.)

May 8, 2026 Law and Motion Calendar PAGE 15 HONORABLE MICHAEL L. MAU, Department 20 ________________________________________________________________________

The Prior Demurrer to the Complaint. Defendants demurred to Plaintiff’s original Complaint, arguing that the Plaintiff’s five asserted claims were all time-barred, because (as argued) no later than Aug. 2021, Plaintiff had reason to suspect that she had been harmed by the Defendants. The Court then sustained the demurrer with leave to amend, stating, in part: Plaintiff’s Claims Are Insufficiently Pled At the pleading stage, the Court finds that Plaintiff’s asserted claims are not ‘clearly time-barred on their face,’ such that sustaining without leave to amend is warranted ... Nevertheless, Plaintiff alleges no facts whatsoever regarding her ‘inability to have made earlier discovery despite reasonable diligence.’ (Fox, supra.) There is a glaring void in the Complaint where Plaintiff simply jumps from August 2021 to March 2024. (Complaint ¶¶ 34 – 35.) Plaintiff alleges in conclusory fashion that Defendants ‘secretly’ pursued the drug tests at issue. (Complaint ¶ 40.) That does not suffice and Plaintiff must allege specific facts, if they exist, that there was an inability to discover Defendants’ alleged misconduct prior to March 2024. Accordingly, the Demurrer is SUSTAINED with leave to amend.

As noted, the Complaint alleges that in August 2021, Defendant Rai informed Plaintiff that Rai wished to terminate the parties’ ‘joint venture’ and that Plaintiff would not be receiving any ownership interest in Isosterix. (Id., ¶¶ 34 – 35.) Plaintiff allegedly responded by warning Defendants not to use Plaintiff’s prior drug target research in operating Isosterix, since Plaintiff was not receiving an ownership interest. (Id., ¶ 34.) Plaintiff alleges it was not until Defendants took Isosterix out of ‘stealth mode’ in March 2024 that Plaintiff discovered that Isosterix was, in fact, despite Plaintiff’s prior admonition, using the KAT6 drug target that Plaintiff had previously proposed/contributed. (Id., at ¶¶ 35 – 36.) That ‘stealth mode’ comment is also conclusory. More importantly, the Complaint does not explain how Plaintiff could have reasonably assumed in August 2021 that Defendants were just going to follow her directive to not use Plaintiff’s information any further and shut down Isosterix, which apparently had no other information to continue work on. (Sept. 19, 2025 Minute Order).

Plaintiff thereafter filed her FAC. Defendants have demurred to the FAC, arguing that the FAC still does not allege facts showing that Plaintiff was diligent, between Aug. 2021 and March 2024, in trying to ascertain whether Defendants were using her drug target research. The FAC alleges, in part (new allegations are in italics emphasis, added by the Court): “... In August 2021, Defendant Rai called Plaintiff and told her she could not give Plaintiff 20% ownership in their joint venture and that she wanted to terminate their joint venture. Plaintiff was shocked because she had already shared the drug target information with Defendant Rai and spent countless hours after work in the evenings to help Defendant Rai form Isosterix. This work that Plaintiff provided regarding drug targets is worth millions of dollars ... Accordingly, Plaintiff told Defendant Rai to stop work on any drug targets that were suggested by Plaintiff ...” (FAC ¶ 34); (See also, Complaint ¶ 34)

May 8, 2026 Law and Motion Calendar PAGE 16 HONORABLE MICHAEL L. MAU, Department 20 ________________________________________________________________________

“[I]n or around August 2021, ... Plaintiff told Defendant Rai that if she used Plaintiff’ s drug target information without appropriately compensating Plaintiff, Plaintiff would file a lawsuit against Defendant Rai. Defendant Rai acknowledged that she did not want to be sued and said she understood and would not use the drug target information provided by Plaintiff. After this call, Plaintiff and Defendant Rai did not speak again.” (FAC ¶ 35)

“Plaintiff reasonably believed that Defendants would not use the drug target information she had provided because Defendant’ s company was still in very early stages and there are numerous drug targets that companies can perform research and chemistry on.” (FAC ¶ 36)

“Plaintiff, having been good friends with Defendant Rai, believed that Defendant Rai would not steal Plaintiff’ s ideas and call them her own. Plaintiff also thought the threat of a lawsuit would prevent Defendant Rai from using her work without properly compensating Plaintiff. Plaintiff never thought Defendant Rai would steal her ideas and call them her own.” (FAC ¶ 37)

“From August 2021 to the present date, Plaintiff and Defendant Rai continue to share connections on LinkedIn and Plaintiff often sees Defendant Rai’ s LinkedIn activity. Plaintiff would have seen any posts/updates posted by Defendants if any appeared from August 2021 through February 2024 about the company. No such posts appeared until March 2024.” (FAC ¶ 40)

“In or around March 2024, Plaintiff discovered that Defendant Rai and Isosterix were [using Plaintiff’s ideas/research]. Plaintiff discovered this due to Defendant Rai announcing on LinkedIn that she is taking Isosterix out of “stealth mode.” The post stated ‘Isosterix is coming out of stealth mode! W e have lead molecules as inhibitors of Kat6A, an epigenetic oncogene that is implicated in multiple...’ (FAC ¶ 41) See also, Complaint ¶ 35.

“This was the first time Defendant Rai posted about Isosterix on LinkedIn since [Aug. 2021] ... This was the first time Plaintiff could have discovered that Defendants mislead [sic] her and used her work/research without compensating her.” (FAC ¶ 42.)

“When a Company is in “Stealth Mode” they do not reveal anything publicly ... Defendants purposefully and intentionally kept Isosterix’ s research, activities, and updates hidden from the public and hidden from Plaintiff. Plaintiff has reason to believe that Defendants kept it a secret because they did not want to compensate Plaintiff. Defendant Rai was told that if she used the drug target information, Plaintiff would demand compensation and seek legal action. This is why Defendants kept the company going, in secret.” (FAC ¶ 44.)

“There was no reasonable way for Plaintiff to know what Defendants were doing because they admitted that they were operating their Company in secret until March 2024.” (FAC ¶ 45.)

Legal Standard. A demurrer is used to challenge defects that appear on the face of the pleading, or from matters outside the pleading that are judicially noticeable. (Blank v. Kirwan (1985) 39 Cal.3d 311, 318.) In ruling on a demurrer, the court assumes all facts pleaded in the complaint are true, no matter how improbable. (Serrano v. Priest (1971) 5 Cal. 3rd 584, 591.) The court construes the complaint liberally with a view of substantial justice between the parties. (Code Civ. Proc. Sect. 452; Cameron v. Wernick (1967) 251 Cal.App.2d 890.) A demurrer will not be sustained unless the complaint, liberally construed, fails to state a cause of action on any theory. (Brousseau v. Jarrett (1977) 73 Cal.App.3d 864.)

May 8, 2026 Law and Motion Calendar PAGE 17 HONORABLE MICHAEL L. MAU, Department 20 ________________________________________________________________________

A complaint that shows on its face, or from matters subject to judicial notice, that it is barred by the statute of limitations is subject to demurrer. (Minton v. Cavaney (1961) 56 Cal.2d 576, 581.) “A demurrer based on a statute of limitations will not lie where the action may be, but is not necessarily, barred. On demurrer, the defect must clearly and affirmatively appear on the face of the complaint; it is not enough that the complaint shows that the action may be barred.” (Committee for Green Foothills v. Santa Clara County Board of Supervisors (2010) 48 Cal.4th 32, 42; see The Rutter Group: Civ. Proc. Before Trial, stating: [W]here the complaint shows on its face that the claim would be time-barred without benefit of the discovery rule, plaintiff must ‘plead around’ the statute of limitations defense. Under these circumstances, if plaintiff relies on the discovery rule, the complaint must specifically allege facts showing ‘(1) the time and manner of discovery and (2) the inability to have made earlier discovery despite reasonable diligence.’ Fox v. Ethicon Endo-Surgery, Inc. (2005) 35 Cal.4th 797, 808. Conclusory allegations are insufficient and will not survive a demurrer. WA Southwest 2, LLC v. First American Title Ins. Co. (2015) 24 Cal.App.4th 148, 157.

Diligence allegations: In assessing allegations of delayed discovery, the court places the burden on plaintiff to allege facts showing diligence; conclusory allegations will not withstand demurrer. [Grisham v. Philip Morris U.S.A., Inc. (2007) 40 Cal.4th 623, 638]. (The Rutter Group: Civ. Proc. Before Trial, Sect. 3:170; 3:170.5) “Generally speaking, a cause of action accrues at the time when the cause of action is complete with all of its elements.” (Fox, supra, 35 Cal.4th at p. 806.) The California Supreme Court has stated: An important exception to the general rule of accrual is the ‘discovery rule,’ which postpones accrual of a cause of action until the plaintiff discovers, or has reason to discover, the cause of action ... A plaintiff has reason to discover a cause of action when he or she has reason at least to suspect a factual basis for its elements ... the uniform California rule is that a limitations period dependent on discovery of the cause of action begins to run no later than the time the plaintiff learns, or should have learned, the facts essential to his claim ... Under the discovery rule, suspicion of one or more of the elements of a cause of action, coupled with knowledge of any remaining elements, will generally trigger the statute of limitations period ... [b]y discussing the discovery rule in terms of a plaintiff’s suspicion of elements of a cause of action, it was referring to the generic elements of wrongdoing, causation, and harm ... In so using the term elements, we do not take a hyper-technical approach to the application of the discovery rule. Rather than examining whether the plaintiffs suspect facts supporting each specific legal element of a particular cause of action, we look to whether the plaintiffs have reason to at least suspect that a type of wrongdoing has injured them. The discovery rule only delays accrual until the plaintiff has, or should have, inquiry notice of the cause of action. The discovery rule does not encourage dilatory tactics because plaintiffs are charged with presumptive knowledge of an injury if they have information of circumstances to put them on inquiry or if they have the opportunity to obtain knowledge from sources open to their investigation ... In other words, plaintiffs are required to conduct a reasonable investigation after becoming aware of an injury, and are charged with knowledge of the information that would have been revealed by such an investigation.

May 8, 2026 Law and Motion Calendar PAGE 18 HONORABLE MICHAEL L. MAU, Department 20 ________________________________________________________________________

(Id., at pp. 807 – 808, citations/quotations omitted, emphasis in original.)

Application. The demurrer is SUSTAINED. The Court agrees with Defendants that the FAC is not significantly changed from the original Complaint, which the Court previously found did not plead sufficient facts regarding delayed discovery to avoid the applicable statute(s) of limitations. The Court agrees that the FAC does not allege facts showing diligence between August 2021 and March 2024. Based on the allegations, by August 2021, Plaintiff had been shut out of the company (Isosterix) that Plaintiff had helped form, despite having already given Defendants drug target research that Plaintiff contends was “worth millions.” Plaintiff had already threatened Defendants with litigation in the event that Defendants used Plaintiff’s drug research without compensating her. As alleged, Defendant Rai had responded to Plaintiff’s threat of litigation by stating that Defendants did not want to get sued, and therefore, that Defendants would not use Plaintiff’s research. (FAC ¶ 35.) Plaintiff alleges that Isosterix was “still in very early stages,” and there were numerous other drug targets that Defendants could have used going forward, instead of using Plaintiff’s proposed drug targets. (FAC ¶ 36)

As with the original Complaint, the FAC does not allege facts showing that Plaintiff was diligent between August 2021 and March 2024. It does not allege that during that time period, Plaintiff conducted any searches of any kind to try to ascertain what Defendants or Isosterix was/were doing. There are no allegations that Plaintiff made any inquiries from anyone to try to determine whether Defendants were keeping their promise, and were refraining from using Plaintiff’s research. There are no allegations of actual investigative steps taken by Plaintiff in this regard. Perhaps there are none, but it is arguably still unclear. Instead, the FAC alleges that (1) Plaintiff believed that Defendants, out of their expressed fear of being sued, were keeping their word and were not using Plaintiff’s research, and (2) until March 2024, Defendants were operating Isosterix in “stealth mode,” which means operating in private without publicly disclosing any of their activities. There is a difference between a reasonable investigation, versus the mere lack of public disclosures. As Defendants point out, the statute of limitations generally starts to run when a plaintiff has reason to suspect it has been harmed, not upon confirmation of harm. (Fox v. Ethicon Endo-Surgery, Inc. (2005) 35 Cal. 4th 797, 807.) Plaintiff clearly knew (in August 2021) that Defendants had the ability to harm Plaintiff (because they possessed her drug target research). Under the discovery rule, a plaintiff is required to conduct a reasonable investigation after becoming aware of an injury, and is “charged with knowledge of the information that would have been revealed by such an investigation.” (Id. at 808.)

Plaintiff’ s Claims are Still Insufficiently Pled As in the original Complaint, the FAC still alleges no facts regarding her “inability to have made earlier discovery despite reasonable diligence.” Fox, supra. There remains a glaring void in the FAC with no specific facts of diligence from August 2021 to March 2024. As stated before, Plaintiff must allege specific facts, if they exist, that there was an inability to discovery Defendants’ alleged misconduct prior to March 2024. In the FAC, Plaintiff essentially alleges she monitored LinkedIn from August 2021 to March 2024, with nothing more. Plaintiff then jumps to a conclusion that there “was no reasonable way for Plaintiff to know what Defendants were doing” (FAC ¶ 45) for that same period of years, without any other allegations, detail or supporting facts.

May 8, 2026 Law and Motion Calendar PAGE 19 HONORABLE MICHAEL L. MAU, Department 20 ________________________________________________________________________

The Court is certainly cognizant of the Defense argument, that this now repeated omission is a basis to Sustain the Demurrer without leave to amend. However, because such a ruling will effectively end Plaintiff’s entire case, the Court is hesitant to make that ruling without giving the Plaintiff one final opportunity to cure this defect.

Leave to Amend Leave to amend is generally liberally granted. (Tarrar Enterprises, Inc. v. Associated Indemnity Corp. (2022) 83 Cal.App.5th 685, 689, “Unless the complaint shows on its fact that it is incapable of amendment, denial of leave to amend constitutes an abuse of discretion, irrespective of whether leave to amend is requested or not.”) “It is an abuse of discretion to deny a party leave to amend a complaint if there is a reasonable probability the pleading can be cured by amendment.” Brenner v. City of El Cajon (2003) 113 Cal.App.4th 434, 444. “Denial of leave to amend is appropriate only when it conclusively appears that there is no possibility of alleging facts under which recovery can be obtained.” Tarrar Enterprises, supra, pg. 688 (citation omitted).

Here we are no longer dealing with an original complaint, but a FAC after a prior sustaining of a demurrer. This FAC has the same defects of inadequate allegations as the original Complaint. It is not an abuse of discretion to sustain a demurrer without leave to amend, if plaintiff is unable to show there is a reasonable possibility that the defect can be cured by amendment. Aubry v. Tri-City Hospital Dist. (1992) 2 Cal.4th 962, 967. “The plaintiff bears the burden of demonstrating a reasonable possibility to cure any defect by amendment.” Lazar v. Hertz Corp. (1999) 69 Cal.App.4th 1494, 1501. Plaintiffs are thus on notice, their next amended complaint may be the last one allowed. Plaintiff shall file its Second Amended Complaint within ten (10) days after service of the Order after hearing.

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