ASX/Media Release Immutep Publishes AIPAC, TACTI-002 and TACTI-003 Trial Posters at SITC with Positive New Data for LAG-3 Therapy, Eftilagimod Alpha AIPAC poster presentation includes new data and graphs showing: Very en

Immutep Publishes AIPAC, TACTI-002 and TACTI-003 Trial Posters at SITC

Positive New Data for LAG-3 Therapy, Eftilagimod Alpha

15 November 2021 Immutep Limited (ASX: IMM; NASDAQ: IMMP) ( Immutep or the Company ), a biotechnology company developing novel LAG-3 related immunotherapy

treatments for cancer and autoimmune disease, announces new data has been published in poster presentations at the Society for Immunotherapy of Cancer (SITC) Annual Meeting 2021 which took place from 10-14

November 2021 in the US. The new data relates to the Company s Phase IIb AIPAC trial and Part C of its Phase II TACTI-002 study (also designated KEYNOTE-798). In

addition, a poster presentation of the trial design of the Company s new randomised Phase IIb study in 1st line HNSCC was also presented at SITC.

All three poster presentations relate to Immutep s lead candidate efti and are available on the Company s website:

https://www.immutep.com/investors-media/presentations.html. New data which is shown in addition to the data from the abstracts released on 9 November 2021 is summarised below.

Immutep will present data from the posters in a global webcast for investors on Wednesday, 17 November 2021 at 8.00 am AEDT / Tuesday, 16 November

2021 at 4.00 pm EST. Details are below.

PHASE IIB AIPAC POSTER PRESENTATION

In addition to the final OS data announced on 10 November 2021, Immutep reports new Quality of Life (QoL) data from AIPAC. QoL is a secondary endpoint of

the study. In the total trial population, a statistically significant QoL preservation was observed in the first 6 months in the efti group of patients who were treated with efti in combination with paclitaxel. This compares favourably to the

comparator group (paclitaxel and placebo) where a significant deterioration in these measures were reported at 6 months (see Figure 1). QoL is generally very important for patient compliance and forms part of reimbursement discussions after any

potential marketing approval.

Figure 1. Quality of Life at 3 and 6 months of treatment (Global Health Status / QoL QLQC30-B23)2

As previously announced, the AIPAC trial demonstrates a statistically significant and clinically meaningful OS benefit in

now three prespecified (prior to unblinding) patient subgroups. A majority of patients fall into at least one of the patient subgroups and therefore derive a statistically significant benefit (Table 1).

Kaplan-Meier curve for OS in patients < 65 years of age

Table 1 Overall Survival in key patient subgroups at final analysis at 72.5% of events in the

Pleasingly, these results have improved since interim data were reported at the San Antonio Breast Cancer Symposium (SABCS) in

December 2020. A comparison is provided in Table 2.

Table 2 Comparison of interim Overall Survival data and final Overall Survival data

In addition, as briefly reported on 10 November 2021, immune monitoring studies showed an increase in peripheral CD8 T

cells in patients from the efti group of the total population (N=36/31 comparator group/efti group).1 This increase is statistically significant and is also significantly correlated with improved

OS, demonstrating strong proof-of-concept. New data and graphs are provided below (see Figures 3 & 4).

Immutep CEO, Marc Voigt commented: The combination of the OS data in the prespecified subgroups, immune

monitoring data and Quality of Life data, which were all statistically significant, give us confidence as we move forward with the development of efti in various late-stage settings. The results here are particularly noteworthy because Her2-HR+ metastatic breast cancer is not a particularly immunogenic tumour and so does not always respond to treatment with modern immunotherapies such

as anti-PD-1 therapy. Indeed, we have seen across our various studies that efti, with its unique mechanism of action, has the potential to benefit many cancer patients,

including those with more limited treatment options.

PHASE II TACTI-002 POSTER PRESENTATION

Immutep s TACTI-002 is being conducted in collaboration with Merck & Co., Inc., Kenilworth, NJ, USA

(known as MSD outside the United States and Canada). The study is evaluating the combination of efti with MSD s anti-PD-1 therapy KEYTRUDA (pembrolizumab) in 183 patients with non-small cell lung cancer (NSCLC) in 1st and 2nd line (Parts A and B, respectively) or 2nd line head and neck

squamous cell carcinoma (HNSCC, Part C). The results announced today relate to Part C only.

Immutep CSO and CMO, Dr Frederic Triebel said:

It is encouraging to see deep and durable responses in low PD-L1 expressing patients who may not typically respond to

anti-PD-1 therapy when given on its own. When given in combination with efti, we are seeing an ORR of about 30%. Results from

TACTI-002 demonstrate an encouraging ORR combined with a durable response and good safety. This was key to securing Fast Track Designation with the US FDA in April this year.

Key Findings 2nd line HNSCC Part C

Table 3 TACTI-002 Interim ORR Results for Part C (data cut-off date: 4 August 2021)

Conclusion: The more mature data from 2nd line HNSCC patients continues to be encouraging, including when compared to

historical studies with checkpoint inhibitor monotherapy in comparable patient groups. These results are supportive of Immutep s randomised Phase IIb TACTI-003 study in the 1st line HNSCC indication

conducted in collaboration with MSD. The trial design for the new TACTI-003 study is outlined below.

(data cut-off date 16 April 2021)

The combination treatment continues to be safe and well tolerated with

no new safety signals reported thus far.

Further data from TACTI-002 are planned to be reported in H1 of calendar year 2022.

PHASE II TACTI-003 POSTER PRESENTATION

TACTI-003 is a Phase IIb multicentre, open label, randomised and controlled, trial enrolling approximately 154 patients

with 1st line HNSCC.

Patients will be enrolled into two cohorts (see Figure 5):

Figure 5. TACTI-003 trial design

Pembrolizumab will be given at a dose of 400 mg via intravenous infusion on day 1 of each

6-week treatment cycle (maximum of 18 infusions). Efti will be subcutaneously injected at a dose of 30 mg every 2 weeks for the first 6 months (4 cycles) and thereafter at a dose of 30 mg every 3 weeks for up

to 2 years in total.

The primary endpoint of the study is ORR according to RECIST 1.1. and iRECIST will be used for treatment decisions. Secondary

endpoints include OS and Progression Free Survival (PFS). The TACTI-003 study is open for patient recruitment in the US and Ukraine, with further clinical sites expected to be opened in the coming months.

A replay of the webcast will also be available at www.immutep.com from the day after the event.

Active Immunotherapy Paclitaxel (AIPAC) is a multicentre, placebo-controlled, double-blind, 1:1 randomised Phase IIb clinical trial in HER2-negative/HR

positive metastatic breast cancer.

The study is evaluating the combination of efti with paclitaxel chemotherapy. 227 HER2-negative/HR positive metastatic

breast cancer patients are randomised 1:1 to a chemo-immunotherapy arm (efti plus paclitaxel) or to a comparator arm (placebo plus paclitaxel). Patients receive weekly paclitaxel at days 1, 8 and 15, with either efti or placebo injected

subcutaneously on days 2 and 16 of each 4-week cycle, repeated for 6 cycles. Thereafter, patients pass over to the maintenance phase with efti alone.

For more information regarding the AIPAC trial, visit clinicaltrials.gov (identifier: NCT02614833)

and https://www.ncbi.nlm.nih.gov/pubmed/30977393.

TACTI-002 (Two ACTive Immunotherapies) is being conducted in collaboration with Merck & Co., Inc., Kenilworth,

NJ, USA (known as MSD outside the United States and Canada). The study is evaluating the combination of efti with MSD s KEYTRUDA (pembrolizumab) in up to 183 patients with

second line head and neck squamous cell carcinoma or non-small cell lung cancer in first and second line.

trial is a Phase II, Simon s two-stage, non-comparative, open-label, single-arm, multicentre clinical study that is taking

place in study centres across Australia, Europe, the UK and US.

Patients participate in one of the following:

TACTI-002 is an all-comer study in terms of PD-L1 status, a well-known predictive marker for response to pembrolizumab monotherapy especially in NSCLC and HNSCC. PD-L1 expression is typically reported in three groups

for NSCLC: < 1%, 1-49% and 50% (Tumour Proportion Score or TPS) and in HNSCC: < 1, 1-19 and 20 (Combined Positive Score or CPS). Patients with a high PD-L1 status are typically more responsive to

anti-PD-1 therapy such as pembrolizumab, whereas those with low PD-L1 status are overall less responsive.

More information about the trial can be found on Immutep s website or on ClinicalTrials.gov (Identifier: NCT03625323).

KEYTRUDA is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of

Merck & Co., Inc., Kenilworth, NJ, USA.

TACTI-003 is a Phase IIb clinical trial in first line head and neck squamous cell carcinoma (HNSCC) in collaboration

with Merck & Co., Inc., Kenilworth, NJ, USA, known as MSD outside the United States and Canada. It will evaluate efti in combination with MSD s KEYTRUDA

(pembrolizumab) as a first line therapy in unresectable recurrent or metastatic HNSCC patients with PD-L1 negative and PD-L1 positive (CPS

1) tumours. It will be a randomised, controlled clinical study in approximately 154 first line HNSCC patients and will take place across Australia, Europe and the US in up to 35 clinical sites.

The study will evaluate the safety and efficacy of efti in combination with pembrolizumab, compared to

pembrolizumab alone in first line metastatic or recurrent HNSCC patients with PD-L1 positive (CPS 1) tumours (cohort A), and determine the efficacy and safety of

efti plus pembrolizumab in patients with PD-L1 negative tumours (CPS < 1) (cohort B). According to the current plans, about 130 patients in cohort A will be randomised 1:1 to receive either efti plus

pembrolizumab or pembrolizumab alone. Subjects in cohort B (up to 24 patients) will receive a combination of efti and pembrolizumab.

The primary endpoint

of the study is the Overall Response Rate (ORR) according to RECIST 1.1. and iRECIST will be used for treatment decisions. Secondary endpoints include OS and Progression Free Survival (PFS).

Immutep is a globally active biotechnology

company that is a leader in the development of LAG-3 related immunotherapeutic products for the treatment of cancer and autoimmune disease. Immutep is dedicated to leveraging its technology and expertise to

bring innovative treatment options to market for patients and to maximise value to shareholders.

Immutep s current lead product candidate is

eftilagimod alpha (efti or IMP321), a soluble LAG-3 fusion protein (LAG-3Ig), which is a

first-in-class antigen presenting cell (APC) activator being explored in cancer and infectious disease. Immutep is also developing an agonist of LAG-3 (IMP761) for autoimmune disease. Additional LAG-3 products, including antibodies for immune response modulation, are being developed by Immutep s large

pharmaceutical partners.

Immutep is listed on the Australian Securities Exchange (IMM), and on the NASDAQ (IMMP) in the United States.

Further information can be found on the Company s website www.immutep.com or by contacting: