Immutep to Present New Data from AIPAC-003 Phase II at the 2025 San Antonio Breast Cancer Symposium
MWN-AI** Summary
Immutep Limited (ASX: IMM; NASDAQ: IMMP) has announced that it will present new data from its AIPAC-003 Phase II trial at the upcoming 2025 San Antonio Breast Cancer Symposium (SABCS), scheduled for December 9-12 in San Antonio, Texas. The trial focuses on the combination of eftilagimod alfa (efti) with paclitaxel in heavily pretreated female patients suffering from metastatic breast cancer (MBC) resistant to standard therapies.
The AIPAC-003 study randomized 66 participants with hormone receptor-positive (HR+) and HER2-negative/low MBC or metastatic triple-negative breast cancer (mTNBC), evaluating two dosing regimens of efti: 30 mg and 90 mg. Both dosages demonstrated promising outcomes, achieving objective response rates (ORR) of 41.9% for the 30 mg group and 48.5% for the 90 mg group, alongside disease control rates (DCR) of 87.1% and 78.8%, respectively. Notably, the time to onset of response was consistent between the two dosages.
These outcomes align with the FDA's Project Optimus initiative, leading to the selection of 30 mg as the optimal biological dose (OBD) for efti. Dr. Nuhad Ibrahim from MD Anderson Cancer Center highlighted the trial's success in integrating clinical response data with pharmacodynamic readouts, reinforcing the potential of efti’s immunotherapy-chemotherapy combination.
Immutep's CEO, Marc Voigt, emphasized the significance of this trial for advancing cancer treatment, especially with its ongoing Phase III trial for first-line treatment of advanced non-small cell lung cancer (NSCLC) in combination with MSD's KEYTRUDA. The presentation of the AIPAC-003 data at SABCS marks a critical step in the development of efti and its future applications within oncology.
MWN-AI** Analysis
Immutep Limited (ASX: IMM; NASDAQ: IMMP) is on the cusp of significant market recognition following the presentation of new data from the AIPAC-003 Phase II study at the upcoming 2025 San Antonio Breast Cancer Symposium. The trial highlights the efficacy of eftilagimod alfa (efti) in combination with paclitaxel for heavily pretreated metastatic breast cancer patients, achieving strong objective response rates (41.9% with 30 mg and 48.5% with 90 mg) and high disease control rates (87.1% and 78.8%, respectively).
The strategic importance of selecting 30 mg as the optimal biological dose (OBD) aligns with the FDA’s Project Optimus initiative, underscoring Immutep's commitment to regulatory compliance and the development of efficacious therapies. The tolerability profile at 90 mg raised concerns, particularly dose-limiting toxicities (DLTs), reinforcing the decision to focus on 30 mg for future trials and applications.
Immutep's efforts in advancing its pipeline extend beyond breast cancer, as evidenced by the ongoing Phase III TACTI-004 study assessing efti in combination with Merck's KEYTRUDA® for first-line NSCLC treatment. The clarity on efti's OBD is a pivotal milestone that not only strengthens its position in the oncology market but may also facilitate future combinations with other therapies, enhancing its attractiveness to investors.
Given the promising phase II data and strong regulatory alignment, investors should look for a potential surge in Immutep's stock price as the SABCS presentation approaches on December 10. Its unique immunotherapy approach shows substantial promise, opening new avenues for revenue generation and boosting the company’s long-term growth prospects. With an ongoing commitment to innovative cancer treatments, Immutep represents a compelling opportunity within biotech investments.
**MWN-AI Summary and Analysis is based on asking OpenAI to summarize and analyze this news release.
- Immunotherapy-chemotherapy combination of eftilagimod alfa (efti) and paclitaxel led to strong objective response rates and immune activation in heavily pretreated metastatic breast cancer patients
- AIPAC-003 has resulted in successful completion of FDA’s Project Optimus requirements and selection of 30 mg as efti’s optimal biological dose
SYDNEY, AUSTRALIA, Dec. 02, 2025 (GLOBE NEWSWIRE) -- Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), a late-stage immunotherapy company targeting cancer and autoimmune diseases, today announces new data from the AIPAC-003 trial will be presented at the 2025 San Antonio Breast Cancer Symposium (SABCS) taking place in San Antonio, Texas, from December 9-12, 2025.
The Phase II study randomised female participants (N=66) with HR+ and HER2-negative/HER2-low metastatic breast cancer (MBC) resistant to endocrine-based therapy (ET) including cyclin-dependent kinase 4/6 (CDK4/6) inhibitors or metastatic triple-negative breast cancer (mTNBC) not eligible for PD-(L)1-based therapy. Patients were randomised 1:1 to receive either 30 or 90 mg eftilagimod alfa (efti) in combination with paclitaxel to determine the optimal biological dose (OBD) consistent with the FDA’s Project Optimus initiative.
Both efti dosing levels on top of weekly paclitaxel in heavily pretreated metastatic breast cancer patients, who received a median of three prior lines of systemic therapy, led to strong objective response rates (ORR) and disease control rates (DCR) of 41.9% and 87.1% (30 mg efti) and 48.5% and 78.8% (90 mg efti), respectively, in the evaluable population (N=64). Time to onset of response (TTR) was comparable at 2.0 months (30 mg) versus 1.9 months (90 mg).
Additionally, both dosing levels elicited the desired pharmacodynamic (PD) response in line with efti’s mechanism of action with substantial increases in immune activation biomarkers including absolute-lymphocyte count (ALC) and interferon-gamma (IFN-?). Data cut-off date for efficacy results was 15 September 2025.
Dr. Nuhad Ibrahim, Professor, Department of Breast Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center noted, “Evaluating two biologically active doses allowed us to integrate clinical response data with meaningful pharmacodynamic readouts. In keeping with Project Optimus principles, the study generated rigorous comparative data in heavily pretreated metastatic breast cancer patients showing consistent efficacy measures and immune-activation signals across both arms, reinforcing efti’s novel mechanism of action and the clinical potential of this immunotherapy-chemo combination.”
Tolerability at 90 mg was suboptimal including dose-limiting toxicities (DLT) and a higher proportion of local injection site reactions (LISR). In line with FDA guidance/advice and as previously reported on 13 October 2025, 30 mg of efti administered subcutaneously has been defined as the OBD.
Marc Voigt, CEO of Immutep said, “We are pleased to conclude this important phase of efti’s clinical development and are fully committed to advancing this novel immunotherapy to address the needs of cancer patients globally, especially in light of our ongoing Phase III in 1 st line NSCLC. This study holds significant importance in satisfying FDA’s Project Optimus requirements and defining efti’s OBD across our entire oncology clinical pipeline and potential future combinations with new therapeutic agents such as ADCs and bispecifics as well as for a potential future Biological Licence Application.”
The AIPAC-003 trial has resulted in the successful completion of the FDA’s Project Optimus requirements and agreement on 30 mg as efti’s OBD carries strategic importance in ongoing and future clinical programs in oncology. This includes the global TACTI-004 (KEYNOTE-F91) Phase III trial evaluating efti in combination with MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy KEYTRUDA ® (pembrolizumab), and chemotherapy as first-line treatment for advanced or metastatic non-small cell lung cancer (1L NSCLC), regardless of PD-L1 expression, which is now in the process of opening sites in the United States.
Details on the SABCS 2025 presentation are as follows:
Title : Optimal biological dose of eftilagimod alpha, a soluble LAG-3 protein, in metastatic breast cancer patients receiving weekly paclitaxel in AIPAC-003
Presenter : Dr. Nuhad Ibrahim, Professor, Department of Breast Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center
Presentation number : PS1-09-16
Abstract number : 315
Date and time : Wednesday, December 10 th at 12:30-2:30 p.m. CST
The poster presentation is available on the Posters & Publications section of Immutep’s website.
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 maximise value for shareholders. For more information, please visit www.immutep.com .
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:
Chris Basta, VP, Investor Relations and Corporate Communications
+1 (631) 318 4000; chris.basta@immutep.com
FAQ**
How does the combination of eftilagimod alfa (efti) and paclitaxel demonstrate enhanced objective response rates in heavily pretreated metastatic breast cancer patients, according to the findings from Immutep Limited IMMP?
What implications does the selection of 30 mg as the optimal biological dose (OBD) have for Immutep Limited IMMP's future clinical trials beyond the AIPAC-003 study?
How did the AIPAC-003 trial's outcomes align with the FDA’s Project Optimus initiative, and what does this mean for the regulatory landscape regarding Immutep Limited IMMP's treatments?
What are the anticipated steps for Immutep Limited IMMP following the data presentation at the San Antonio Breast Cancer Symposium regarding the future development of eftilagimod alfa?
**MWN-AI FAQ is based on asking OpenAI questions about Immutep Limited (NASDAQ: IMMP).
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