Immutep Limited (IMMP) said its lung cancer treatment could change everything, according to a lawsuit recently filed. Strong trial data. Strong safety results. A possible new standard of care. But the lawsuit alleges that, behind the scenes, the company knew or recklessly disregarded the material risks that its pivotal Phase III trial faced, which investors did not know.
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A federal securities lawsuit filed in the Southern District of New York alleges that Immutep Limited and several of its senior executives misled investors about the viability of the company’s TACTI-004 Phase III clinical trial, which was evaluating eftilagimod alfa (“efti”) in combination with Merck’s pembrolizumab and chemotherapy as a first-line treatment for advanced or metastatic non-small cell lung cancer. According to the complaint, defendants repeatedly characterized the trial as exhibiting strong operational progress and highlighted favorable efficacy and safety readouts from earlier studies, while allegedly concealing material risks that the study could fail to meet its primary endpoints. The proposed class period runs from March 24, 2025, through March 12, 2026.
The alleged corrective disclosure arrived on March 13, 2026, when Immutep announced that the trial’s Independent Data Monitoring Committee had recommended discontinuing the TACTI-004 study following a planned interim futility analysis. The complaint alleges that Immutep’s ADRs dropped from a closing price of $2.76 per share on March 12, 2026, to $0.48 per share on March 13, 2026, representing a single-day decline of approximately 83%.
Immutep investors can learn more about the IMMP securities lawsuit and check eligibility.
Immutep and Its Lead Oncology Program
Immutep Limited is an Australian biotechnology company focused on developing LAG-3-related immunotherapies for cancer and autoimmune diseases. The company’s principal executive offices are located in Sydney, Australia, and its ADRs traded on the NASDAQ Stock Market under the symbol IMMP during the class period.
The TACTI-004 program involved eftilagimod alfa (“efti”), which the complaint describes as a first-in-class MHC Class II agonist. The TACTI-004 Phase III trial, also known as KEYNOTE-F91, was evaluating efti in combination with Merck’s pembrolizumab and chemotherapy as a first-line treatment for patients with advanced or metastatic non-small cell lung cancer, one of the largest indications in oncology with over two million diagnoses annually worldwide, according to statements cited in the complaint.
What the Lawsuit Alleges
The complaint alleges that Immutep and its senior executives made materially false and misleading statements throughout the class period concerning the efficacy, safety, and overall prospects of the TACTI-004 Phase III trial. Specifically, the lawsuit alleges that defendants touted positive data from earlier efti studies, including TACTI-002 and INSIGHT-003, to support optimistic assertions about TACTI-004’s future success while allegedly concealing information that materially increased the risk the study would not meet its primary endpoints.
The complaint further alleges that defendants were aware of, or were reckless, based on access to internal clinical data, analyses, and reports concerning TACTI-004 and its planned interim futility evaluation, that the then-existing information materially increased the risk that the study would fail to meet its primary endpoints. It is alleged that this conduct artificially inflated Immutep’s ADR price during the class period, causing investors to purchase shares at prices that did not reflect the true risk profile of the TACTI-004 program.
Purchased IMMP ADRs? Review the Immutep lawsuit and check shareholder eligibility details.
What Management Said During the Class Period
The complaint cites a series of public statements made by Immutep executives throughout the class period. On March 24, 2025, CEO Marc Voigt stated that dosing the first patient in the Phase III trial ranked among the most significant milestones in the company’s history and expressed excitement about TACTI-004’s potential to deliver a new standard-of-care therapy for patients with metastatic or advanced non-small cell lung cancer.
Also on March 24, 2025, Chief Scientific Officer Frederic Triebel stated that efti in combination with pembrolizumab had demonstrated the ability to activate the immune system and fight non-small cell lung cancer regardless of PD-L1 expression across multiple clinical trials, and characterized the combination as having an excellent safety profile while delivering strong efficacy that compares favorably to standard-of-care therapies.
On October 9, 2025, Chief Medical Officer Stephan Winckels stated that feedback from principal investigators and physicians had consistently resulted in constructive feedback, and that their favorable assessments of the trial design and of efti as an innovative immunotherapy provided a strong basis for ongoing positive enrollment trends. On February 6, 2026, Voigt stated that the excellent global enrollment pace speaks to the promise of efti and the need for more efficacious therapies, and expressed that the team looks forward to delivering on additional important upcoming milestones, including the futility analysis in the first quarter.
How the Alleged Truth Emerged
According to the complaint, the alleged truth began to emerge on March 13, 2026, when Immutep issued a press release announcing that the Independent Data Monitoring Committee for the TACTI-004 Phase III study had recommended discontinuing the trial following a planned interim futility analysis. The IDMC’s recommendation was based on its review of available safety and efficacy data, and the committee recommended discontinuation for futility.
Following that announcement, Immutep’s ADR price fell from $2.76 per share at the close of trading on March 12, 2026, to $0.48 per share on March 13, 2026, a decline of approximately 83% in a single session. The complaint notes that multiple analysts who had been covering Immutep publicly described the outcome as surprising and disappointing, citing the previously reported efficacy and safety data from earlier efti studies that had informed their expectations for TACTI-004.
Why This Development May Matter to Shareholders
The core of the lawsuit is the allegation that Immutep and its executives portrayed the TACTI-004 trial as progressing soundly and supported by favorable prior data, while allegedly failing to disclose information that materially elevated the risk of trial failure. Investors who purchased ADRs during the class period and held through the March 13, 2026, corrective disclosure suffered significant losses as the stock fell approximately 83% in a single trading day.
The complaint argues that had investors been aware of the full picture regarding the trial’s risk profile, they would not have purchased shares at the prices paid during the class period. The case could raise broader questions about disclosure obligations for clinical-stage biopharmaceutical companies regarding interim data and the known limitations of ongoing trials.
Legal Framework and Claims Asserted
The lawsuit asserts claims under Section 10(b) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder against all defendants, alleging that they engaged in a scheme to deceive investors through materially false and misleading statements and omissions regarding TACTI-004’s viability. The complaint also asserts claims under Section 20(a) of the Exchange Act against the individual defendants, Marc Voigt, Frederic Triebel, and Stephan Winckels, alleging that as senior officers with control over the company’s public disclosures, they are liable as controlling persons for the alleged violations committed by Immutep.
The plaintiff, Yves Dhaenens, purchased Immutep ADRs on April 23 and April 24, 2025, at prices of $1.53 and $1.66 per share, respectively, and seeks to represent a class of all investors who purchased or acquired Immutep ADRs during the class period.
IMMP investors can review the securities lawsuit and learn whether they may be eligible.
About Levi & Korsinsky, LLP
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