Immutep Limited Lawsuit Submission Form

Introduction

A securities class action lawsuit has been filed against Immutep Limited (NASDAQ: IMMP) and three of its senior executives in the United States District Court for the Southern District of New York. The complaint, filed by plaintiff Yves Dhaenens through Levi & Korsinsky, LLP, alleges that defendants made materially false and misleading statements throughout the Class Period of March 24, 2025 through March 12, 2026 regarding the efficacy and safety prospects of the company's TACTI-004 Phase III clinical trial evaluating eftilagimod alfa (efti) in patients with advanced non-small cell lung cancer. On March 13, 2026, Immutep disclosed that the trial's Independent Data Monitoring Committee (IDMC) recommended discontinuing the study following a planned interim futility analysis, revealing that the available safety and efficacy data did not support continuation. Immutep's ADR price collapsed from $2.76 to $0.48 per share — a decline of approximately 83% — as analysts across major firms expressed shock at the outcome and downgraded the stock.

Company Profile

Immutep Limited is an Australian-based biotechnology company focused on developing LAG-3 (Lymphocyte Activation Gene-3) related immunotherapies for cancer and autoimmune diseases. The company's lead program, eftilagimod alfa (efti), is a first-in-class MHC Class II agonist that was being evaluated in combination with Merck's KEYTRUDA (pembrolizumab) and chemotherapy for the treatment of first-line advanced or metastatic non-small cell lung cancer.

Class Period

March 24, 2025 – March 12, 2026

Investors who purchased or acquired Immutep Limited (IMMP) American Depositary Receipts during the Class Period may be entitled to seek recovery under the federal securities laws.

Allegations

The complaint alleges that throughout the Class Period, Immutep and its senior executives — CEO Marc Voigt, Chief Scientific Officer Frédéric Triebel, and Chief Medical Officer Stephan Winckels — made materially false and misleading statements about the TACTI-004 Phase III trial's prospects. Defendants repeatedly characterized the trial as exhibiting "strong operational progress" and emphasized that prior studies, TACTI-002 and INSIGHT-003, demonstrated compelling efficacy and safety results that supported expectations for TACTI-004's success. These statements, according to the complaint, created an artificially positive picture of the trial's trajectory while concealing material adverse information about the risk that the study would fail to meet its primary endpoints.

Beginning with the March 24, 2025 announcement that the first patient had been dosed, the complaint alleges defendants engaged in a sustained pattern of positive statements designed to maintain investor confidence. Defendant Voigt described the dosing as "among the most significant milestones in the Company's history" and stated that the trial could be "practice changing." Defendant Triebel asserted that efti's ability to fight non-small cell lung cancer "has been demonstrated across multiple clinical trials" with "an excellent safety profile while delivering strong efficacy." In subsequent press releases through February 2026, defendants continued to tout enrollment progress, expanding site activations across 27 countries, and the potential for efti to establish a "new standard of care" — while repeatedly affirming that the planned futility analysis remained "on track."

The complaint alleges that defendants knew or recklessly disregarded that then-existing internal clinical data, analyses, and reports materially increased the risk that TACTI-004 would fail its primary efficacy and safety endpoints. Despite having access to non-public interim data from the trial, defendants allegedly continued to frame the TACTI-004 program in exclusively positive terms, omitting material safety concerns and the deteriorating likelihood of success. As late as February 6, 2026 — just weeks before the trial's discontinuation — Defendant Voigt described the enrollment pace as "excellent" and highlighted the "promise of efti," while the complaint alleges the underlying data told a fundamentally different story.

The Truth Emerges

On March 13, 2026, Immutep issued a press release disclosing that the IDMC for the TACTI-004 Phase III study had recommended discontinuing the trial following the planned interim futility analysis. Based on its review of the available safety and efficacy data, the IDMC concluded that the trial should be stopped for futility — meaning the data indicated the study was unlikely to demonstrate a meaningful treatment benefit even if carried to completion. Defendant Voigt acknowledged the company was "very disappointed and surprised with the outcome of the futility analysis, in light of efti's performance in every other clinical trial."

The disclosure directly contradicted months of positive statements from defendants about TACTI-004's progress and prospects. Multiple major analysts expressed shock at the result. Jefferies called it "a very surprising outcome, given previous efficacy and safety readouts." Baird noted that prior efti data "had shown numerically higher ORR, OS, and PFS vs. pembro + chemo alone regardless of PD(L)-1 expression levels" and stated it did "not see a clear path forward for efti." Citizens observed that "very few studies fail at the futility analysis level" and suggested the mechanism of action for efti itself would now be called into question. Maxim Group characterized the result as creating "a significant lack of clarity on the path forward for Immutep, including its efti-based pipeline programs," noting potential negative read-through across the company's entire pipeline.

Market Reaction

Immutep's ADR price suffered a catastrophic decline following the disclosure. From a closing price of $2.76 per share on March 12, 2026, IMMP fell to $0.48 per share on March 13, 2026 — a single-day decline of approximately 83%, erasing the vast majority of shareholder value. The scale of the collapse reflected the degree to which the market had relied on defendants' prior positive statements about TACTI-004's prospects. Analysts uniformly downgraded the stock: Baird slashed its price target from $7.00 to $1.00, while Maxim Group removed its prior $12.00 target entirely, underscoring the market's reassessment of the company's value following the loss of its primary pipeline asset.

Next Steps

●      Lead Plaintiff Deadline: July 6, 2026

●      The Court will issue its order for lead plaintiff and counsel in the weeks after submissions are due.

●      The Court will then consider motion for class certification.

●      The Court will later consider a motion to dismiss.

Disclaimer

This shareholder alert is for informational purposes only and does not constitute legal advice. Consult a qualified attorney for personalized guidance. No specific outcomes are guaranteed.

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