Immutep gets FDA orphan status for efti

Immutep Limited reports that the U.S. FDA has granted Orphan Drug Designation to its immunotherapy candidate eftilagimod alfa (efti) for treating Soft Tissue Sarcoma, a rare cancer with significant unmet need.

Rhea-AI Filing Summary

Immutep Limited reports that the U.S. FDA has granted Orphan Drug Designation to its immunotherapy candidate eftilagimod alfa (efti) for treating Soft Tissue Sarcoma, a rare cancer with significant unmet need. Orphan status can provide regulatory support, potential tax credits, fee exemptions, and seven years of market exclusivity upon approval.

The designation is supported by Phase II EFTISARC-NEO trial data in 38 evaluable patients, where efti with radiotherapy and KEYTRUDA achieved a median tumour hyalinization/fibrosis of 51.5%, beating the pre-set 35% target and historical ~15% with radiotherapy alone, with immune activation signals and a favourable safety profile.

Positive

• FDA Orphan Drug Designation for efti in Soft Tissue Sarcoma adds regulatory support, potential tax credits, fee exemptions, and up to seven years of U.S. market exclusivity upon approval, materially enhancing the asset’s development and commercial profile in a rare cancer with significant unmet medical need.
• Strong Phase II EFTISARC-NEO data for efti combination therapy showed median tumour hyalinization/fibrosis of 51.5% in 38 evaluable Soft Tissue Sarcoma patients, surpassing the 35% pre-specified target and historical ~15% with radiotherapy alone, with immune activation signals and a favourable safety profile.

Negative

• None.

Insights

Biotech regulatory and clinical analyst

FDA orphan status validates efti’s STS potential and supports late-stage development.

The FDA’s Orphan Drug Designation for eftilagimod alfa in Soft Tissue Sarcoma is a meaningful regulatory milestone. Orphan status can bring fee exemptions, potential tax credits, and seven years of market exclusivity after approval, improving the economic case for further development.

The decision is anchored in Phase II EFTISARC-NEO data: efti plus radiotherapy and KEYTRUDA produced median tumour hyalinization/fibrosis of 51.5% in 38 evaluable patients, above the 35% target and roughly 15% seen with radiotherapy alone. Immune activation consistent with efti’s mechanism and a favourable safety profile strengthen the rationale.

Management notes they are conducting a comprehensive review after discontinuing the Phase III TACTI-004 trial, and that the orphan designation, together with the EFTISARC-NEO results, may provide a direct path toward a late-stage neoadjuvant study in resectable Soft Tissue Sarcoma, subject to future strategic decisions.

Key Figures

Orphan disease prevalence threshold: fewer than 200,000 people EFTISARC-NEO evaluable patients: 38 patients Median tumour hyalinization/fibrosis with efti combo: 51.5% +3 more

6 metrics

Orphan disease prevalence threshold fewer than 200,000 people U.S. patient limit for FDA Orphan Drug program

EFTISARC-NEO evaluable patients 38 patients Phase II neoadjuvant Soft Tissue Sarcoma trial

Median tumour hyalinization/fibrosis with efti combo 51.5% Primary endpoint result in EFTISARC-NEO Phase II

Pre-specified target for primary endpoint 35% Benchmark used in EFTISARC-NEO trial design

Historical radiotherapy-alone benchmark ~15% Tumour hyalinization/fibrosis with radiotherapy alone

Market exclusivity period seven years U.S. exclusivity upon approval under Orphan Drug rules

Key Terms

Orphan Drug Designation, Soft Tissue Sarcoma, neoadjuvant setting, Phase II, +1 more

5 terms

Orphan Drug Designation regulatory

"the United States Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) for eftilagimod alfa"

Orphan drug designation is a special status given to medicines developed to treat rare diseases affecting only a small number of people. This status often provides benefits like faster approval processes and financial incentives, making it more attractive for companies to develop these drugs. For investors, it signals potential for exclusive market rights and reduced competition, which can impact the drug’s profitability.

Soft Tissue Sarcoma medical

"Orphan Drug Designation (ODD) for eftilagimod alfa (“efti”) for the treatment of Soft Tissue Sarcoma (STS)"

A soft tissue sarcoma is a type of cancer that starts in the body’s soft tissues — such as muscles, fat, nerves, blood vessels or connective tissue — rather than in organs or bones. For investors, it matters because treatments for these cancers drive drug development, clinical trial results and regulatory decisions; a successful therapy can create a meaningful commercial market while trial failures or safety issues can affect a company’s valuation and prospects.

neoadjuvant setting medical

"evaluating efti in combination with radiotherapy and KEYTRUDA in the neoadjuvant setting in patients with resectable soft tissue sarcoma"

Phase II medical

"Phase II EFTISARC-NEO trial which has been evaluating efti in combination"

Phase II is the mid-stage clinical trial where a potential drug or medical treatment is tested in a larger group of patients to see if it works and to help determine the best dose and common side effects. For investors, Phase II results matter because they give the first meaningful evidence about effectiveness and safety—like a road test that shows whether a product has real promise before a much bigger, costly final trial and potential regulatory approval.

Lymphocyte Activation Gene-3 (LAG-3) medical

"a pioneer in the understanding and advancement of therapeutics related to Lymphocyte Activation Gene-3 (LAG-3)"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Immutep (IMMP) announce regarding eftilagimod alfa and the FDA?

Immutep announced that the U.S. FDA granted Orphan Drug Designation to eftilagimod alfa for treating Soft Tissue Sarcoma. This status supports development of therapies for rare diseases and can bring regulatory assistance, potential tax credits, fee exemptions, and seven years of market exclusivity after approval.

What benefits does FDA Orphan Drug Designation provide to Immutep’s efti program?

Orphan Drug Designation can provide regulatory support, potential tax credits, certain FDA fee exemptions, and seven years of U.S. market exclusivity upon approval. These incentives are designed to make developing treatments for rare diseases like Soft Tissue Sarcoma more attractive and economically feasible for companies.

What clinical data supported Immutep’s orphan designation for efti in Soft Tissue Sarcoma?

The designation was supported by Phase II EFTISARC-NEO data in 38 evaluable patients receiving efti with radiotherapy and KEYTRUDA. The study met its primary endpoint, showing median tumour hyalinization/fibrosis of 51.5%, exceeding a pre-specified 35% target and historical ~15% with radiotherapy alone, with encouraging immune activation signals.

How does eftilagimod alfa perform compared to radiotherapy alone in Soft Tissue Sarcoma?

In the EFTISARC-NEO Phase II trial, efti plus radiotherapy and KEYTRUDA achieved median tumour hyalinization/fibrosis of 51.5% in 38 evaluable patients. This result significantly exceeded both the 35% target and historical benchmarks of about 15% typically seen with radiotherapy alone in Soft Tissue Sarcoma.

What is Immutep’s development focus for efti following the orphan designation?

Immutep is conducting a comprehensive review after discontinuing its Phase III TACTI-004 trial, and this analysis will influence decisions on any future efti trials. Management notes that the FDA orphan designation and EFTISARC-NEO data offer a potential direct step toward a late-stage neoadjuvant study in Soft Tissue Sarcoma.

What type of company is Immutep (IMMP) and what is its core science focus?

Immutep is a clinical-stage biotechnology company developing novel immunotherapies for cancer and autoimmune diseases. It is a pioneer in therapeutics related to Lymphocyte Activation Gene-3 (LAG-3), leveraging this pathway to stimulate or suppress immune responses through a diversified product portfolio targeting unmet medical needs.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/15/2026 - 08:42 PM EDT Learn about SEC filing dates

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 April 15, 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		Immutep Receives FDA Orphan Drug Designation for Eftilagimod Alfa in Soft Tissue Sarcoma

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: April 15, 2026

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

Exhibit 99.1

Immutep Receives FDA Orphan Drug Designation for

Eftilagimod Alfa in Soft Tissue Sarcoma

SYDNEY, AUSTRALIA – April 15, 2026 – Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), a clinical-stage biotechnology company targeting cancer and autoimmune diseases, today announces that the United States Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) for eftilagimod alfa (“efti”) for the treatment of Soft Tissue Sarcoma (STS), a rare cancer with significant unmet medical need.

The FDA’s Orphan Drug Designation program is designed to encourage development of therapies for rare diseases affecting fewer than 200,000 people in the United States. Benefits of ODD may include regulatory support, potential tax credits, fee exemptions, and seven years of market exclusivity upon approval.

This designation recognises the potential therapeutic relevance of efti in STS, supported by encouraging clinical data from the investigator-initiated Phase II EFTISARC-NEO trial which has been evaluating efti in combination with radiotherapy and KEYTRUDA^® (pembrolizumab) in the neoadjuvant setting in patients with resectable soft tissue sarcoma. In 38 evaluable patients, the study met its primary endpoint, demonstrating a median tumour hyalinization/fibrosis of 51.5%, significantly exceeding the pre-specified target of 35% and historical benchmarks of ~15% with radiotherapy alone.¹

These results were observed across multiple sarcoma subtypes and were supported by translational data showing immune activation consistent with efti’s mechanism of action, with a favourable safety profile and no delays to planned surgery.²

CEO of Immutep, Marc Voigt said: “We are pleased that the FDA has recognised the potential of efti for patients with soft tissue sarcoma, a rare and difficult to treat cancer. As previously communicated, the Company is currently undertaking a comprehensive review and analysis following the discontinuation of its Phase III TACTI-004 trial and the outcome will influence the decision regarding any potential future clinical trial with efti. The FDA’s designation, based on very encouraging data from the EFTISARC-NEO trial, provides us with a potential direct step forward into a late-stage study in the neoadjuvant setting for STS.”

About Immutep

Immutep is a clinical-stage biotechnology company developing novel immunotherapies for cancer and autoimmune diseases. 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 maximise value for shareholders. For more information, please visit www.immutep.com.

1. ESMO Congress 2025 Proffered Paper presentation, “EFTISARC-NEO: A phase II study of neoadjuvant eftilagimod alpha, pembrolizumab and radiotherapy in patients with resectable soft tissue sarcoma”.

2. CTOS 2025 Annual Meeting Oral Presentation, “Primary endpoint and translational correlates from EFTISARC-NEO: Phase II trial of neoadjuvant eftilagimod alfa (efti), pembrolizumab and radiotherapy in patients with resectable soft tissue sarcoma”.

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

Australian Investors/Media:

Eleanor Pearson, Sodali & Co.

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

U.S. Investors/Media:

Matthew Beck, astr partners

Ph: +1 (917) 415-1750; matthew.beck@astrpartners.com

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

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 EX-99.1 7.4 KB