[6-K] IMMUTEP Ltd Current Report (Foreign Issuer)

Rhea-AI Filing Summary

Immutep Limited reported that the Independent Data Monitoring Committee for its TACTI-004 Phase III trial in first-line non-small cell lung cancer has recommended discontinuing the study after a planned interim futility analysis. Enrolment will stop and the company will wind down the trial with patient follow up and site close out.

The study tested eftilagimod alfa in combination with pembrolizumab and chemotherapy versus pembrolizumab, chemotherapy and placebo, targeting about 756 patients across more than 150 sites in over 25 countries. Following the discontinuation, Immutep now anticipates its cash runway will extend well beyond its prior Q2 CY2027 guidance and plans to reassess capital allocation once data review is complete.

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Biotechnology equity analyst

Key lung cancer Phase III for efti is being stopped for futility.

Immutep is discontinuing the TACTI-004 Phase III trial in first-line non-small cell lung cancer after an interim futility analysis by an independent committee found the study should not continue. This is a pivotal setting, combining eftilagimod alfa with pembrolizumab and chemotherapy.

The decision follows review of available safety and efficacy data, implying the regimen was unlikely to meet its dual primary endpoints of progression-free and overall survival. While management highlights efti’s prior performance in other trials, they are now conducting a comprehensive data review to determine next steps for the program.

Operationally, halting a global trial planned for approximately 756 patients across more than 150 sites reduces future trial costs. The company now expects its cash runway to extend well beyond its earlier Q2 CY2027 guidance, and will update its runway outlook and capital allocation priorities after completing operational assessments and full data analysis.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Date as Mar 13, 2026

Commission File Number 001-35428

IMMUTEP LIMITED

(Exact Name as Specified in its Charter)

N/A

(Translation of Registrant’s Name)

Level 32, Australia Square

264 George Street, Sydney

NSW 2000, Australia

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒   Form 40-F ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes ☐   No ☒

If “Yes” is marked, indicated below the file number assigned to the registrant in connection with Rule 12g3-2(b): Not applicable.

EXHIBIT INDEX

Exhibit		Description of Exhibit
99.1		TACTI-004 Phase III Study in First Line NSCLC to be discontinued following Futility Analysis

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: Mar 13, 2026

IMMUTEP LIMITED
By:		/s/ Marc Voigt
Name:		Marc Voigt
Title:		Chief Executive Officer

Exhibit 99.1

TACTI-004 Phase III Study in First Line NSCLC to be discontinued following Futility Analysis

Independent Data Monitoring Committee Recommends Discontinuation of Phase III Trial Following Futility Analysis

SYDNEY, AUSTRALIA – March 13, 2026 – Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), today announced that the Independent Data Monitoring Committee (IDMC) for the TACTI-004 Phase III study evaluating eftilagimod alfa (“efti”) in patients in 1^st line non-small cell lung cancer has recommended the discontinuation of the trial following a planned interim futility analysis in accordance with the study protocol.

Based on its review of the available safety and efficacy data, the IDMC recommended that the trial be discontinued for futility.

In response to the IDMC’s recommendation, enrolment in the study will be halted and the Company will implement an orderly wind down of the study, including appropriate patient follow up and site close out in accordance with regulatory and ethical obligations.

“We are very disappointed and surprised with the outcome of the futility analysis, in light of efti’s performance in every other clinical trial” said Marc Voigt, Chief Executive Officer. “We would like to thank the patients, investigators, and clinical teams who contributed to this important study. We are currently conducting a comprehensive review of the available data to better understand the results and determine the appropriate next steps for the program.”

Immutep remains focused on advancing its pipeline of innovative therapies including efti. Following the discontinuation of TACTI-004, Immutep now anticipates its cash runway will be extended well beyond the previously guided timeframe of Q2 CY2027, which was set prior to the trial’s cessation. The Company will provide an updated outlook on its revised cash runway and will reassess capital allocation priorities once operational assessments and a full analysis of the study data have been finalised.

About TACTI-004

TACTI-004 (Two ACTive Immunotherapies) is a randomised, double-blind, controlled Phase III study evaluating eftilagimod alfa (efti), a first-in-class MHC Class II agonist, in combination with MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy, KEYTRUDA^® (pembrolizumab), and chemotherapy as first line therapy for patients with advanced or metastatic non-small cell lung cancer with no EGFR, ALK or ROS1 genomic tumour aberrations. The global trial was to enrol approximately 756 patients regardless of PD-L1 expression and with non-squamous or squamous tumours at over 150 clinical sites in over 25 countries. Patients were being randomised 1:1 to receive either efti in combination with pembrolizumab and chemotherapy in the treatment arm or pembrolizumab in combination with chemotherapy and placebo in the control arm. The study’s dual primary endpoints were progression-free survival and overall survival.

About Eftilagimod Alfa (Efti)

Efti is a novel immunotherapy that directly activates antigen-presenting cells or APCs (e.g. dendritic cells, monocytes) via the MHC Class II pathway to fight cancer. As an MHC Class II agonist, its activation of APCs engages the adaptive and innate immune system to initiate a broad anti-cancer immune response. This includes priming and activating cytotoxic T cells as well as generating important co-stimulatory signals & cytokines that further boost the immune system’s ability to combat cancer.

Efti is under evaluation for a variety of solid tumours including non-small cell lung cancer (NSCLC), as well as head and neck squamous cell carcinoma (HNSCC), soft tissue sarcoma, and breast cancer. Its favourable safety profile has enabled various combinations like with anti-PD-[L]1 immunotherapy, radiotherapy, and/or chemotherapy. Efti has received Fast Track designation in first line HNSCC and in first line NSCLC from the United States Food and Drug Administration (FDA).

About Immutep

Immutep is a late-stage biotechnology company developing novel immunotherapies for cancer and autoimmune disease. The Company is a pioneer in the understanding and advancement of therapeutics related to Lymphocyte Activation Gene-3 (LAG-3), and its diversified product portfolio harnesses LAG-3’s ability to stimulate or suppress the immune response. Immutep is dedicated to leveraging its expertise to bring innovative treatment options to patients in need and to maximize value for shareholders. For more information, please visit www.immutep.com.

Investors/Media:

Eleanor Pearson, Sodali & Co.

+61 2 9066 4071; eleanor.pearson@sodali.com

This announcement was authorised for release by the Board of Immutep Limited.

KEYTRUDA^® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

FAQ

What did Immutep Limited (IMMP) announce regarding the TACTI-004 Phase III trial?

Immutep announced that its TACTI-004 Phase III trial in first-line non-small cell lung cancer will be discontinued. An Independent Data Monitoring Committee recommended stopping the study after a planned interim futility analysis of safety and efficacy data under the trial’s protocol.

Why is the TACTI-004 Phase III study for IMMP being discontinued?

The TACTI-004 study is being discontinued because an Independent Data Monitoring Committee, after a planned interim futility analysis, recommended stopping the trial for futility. Their review of available safety and efficacy data indicated the study was unlikely to achieve its predefined clinical endpoints.

How will discontinuing TACTI-004 affect Immutep Limited’s cash runway?

Immutep now anticipates its cash runway will extend well beyond the previously guided timeframe of Q2 CY2027. This change reflects reduced future spending as the TACTI-004 trial is halted and wound down, with updated runway guidance to follow once operational assessments are complete.

What was the design of Immutep’s TACTI-004 Phase III lung cancer trial?

TACTI-004 was a randomized, double-blind, controlled Phase III study in first-line advanced or metastatic non-small cell lung cancer without EGFR, ALK or ROS1 aberrations. It planned to enroll about 756 patients across more than 150 sites, comparing an eftilagimod alfa combination regimen against a pembrolizumab-based control.

What are the primary endpoints of the discontinued TACTI-004 trial for IMMP?

The dual primary endpoints of TACTI-004 were progression-free survival and overall survival. These measures were intended to evaluate whether adding eftilagimod alfa to pembrolizumab and chemotherapy improved outcomes versus pembrolizumab, chemotherapy and placebo in first-line non-small cell lung cancer patients.

Does Immutep plan to continue developing eftilagimod alfa after TACTI-004?

Immutep states it remains focused on advancing its pipeline, including eftilagimod alfa. The company is conducting a comprehensive review of TACTI-004 data to better understand the results and to determine appropriate next steps for the program across its various solid tumour indications.

Filing Exhibits & Attachments

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Press Releases

• EX-99.1 EX-99.1 8.8 KB