ASX/Media Release Immutep Reports Positive Data from its TACTI-002 Phase II Study of LAG-3 Therapy, Efti, at ASCO 2021 Combination therapy with eftilagimod alpha and pembrolizumab demonstrates very favourable overall res

Immutep Reports Positive Data from its

TACTI-002 Phase II Study of LAG-3 Therapy, Efti, at ASCO 2021

SYDNEY, AUSTRALIA 4 June 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 interim data from its Phase II

TACTI-002 study (also designated KEYNOTE-798) with a data cut-off date of 16 April 2021. The data will be presented in two

poster presentations by Dr Tim Clay, Investigator, St John of God Subiaco Hospital, Perth, Australia and Dr Irene Brana, Investigator, Vall d Hebron Institute of Oncology, Barcelona, Spain at the American Society of Clinical Oncology s

(ASCO) 2021 Annual Meeting in on-demand sessions available from 9 am on 4 June 2021, US Eastern Time at this year s virtual conference. The posters will also be made available on Immutep s

website from that time at:

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 Immutep s lead product candidate eftilagimod alpha ( efti or IMP321 ) with MSD s KEYTRUDA (pembrolizumab) in up to 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).

Immutep CSO and CMO, Dr Frederic Triebel said: As more and more industry focus is on LAG-3 therapies and

it is in the spotlight of this year s ASCO, we are very pleased to be reporting such robust and exciting results from our TACTI-002 study of efti in combination with pembrolizumab. We are seeing nearly

50% of the evaluable 1st line NSCLC patients responding to the therapy, as scored by a blinded independent central review committee, with responses in all

PD-L1 subgroups and a favourable median PFS. Overall, the NSCLC patients receiving this 1st line therapy are living 8.2 months without their disease

progressing, a promising improvement for a chemo-free 1st line regimen. In effect, we are seeing an improvement in patient outcomes compared with that historically seen with anti-PD-1 monotherapy but with a similar safety profile and, also, comparable results in terms of ORR and PFS to chemo + anti-PD-1 combination therapy but, importantly, with a longer duration of response and lower toxicity.

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Investigator, A/Prof Tim Clay, St John of God

Subiaco Hospital, Perth, Australia said: The median PFS of 8.2 months in 1st line NSCLC patients is very encouraging compared to historical studies where pembrolizumab has been given as

monotherapy in comparable patient groups. There remains a great need for more effective chemotherapy free regimens in the treatment of NSCLC. These data are exciting and as a result, we will be expanding recruitment with 74 additional patients

Investigator, Dr Irene Brana, Vall d Hebron Institute of Oncology, Barcelona, Spain,

said: The sustained and durable responses reported in 2nd line HNSCC patients are improving as TACTI-002 progresses, with about 14% of patients

now benefiting from a complete disappearance of all their tumour lesions. Responses are particularly good in PD-L1 expressing patients (CPS 1) where an ORR of

45.8% is reported. The strength of these results validates the decision to explore the combination of efti and pembrolizumab in a new Phase IIb study, TACTI-003 in 1st line HNSCC patients which is starting in the coming months.

Table 1 TACTI-002 Interim ORR Results for Part A and C (data cut-off date: 16 April 2021)

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Conclusion: The data presented for 1st line NSCLC is very encouraging and will be broadened by the

ongoing recruitment in this patient population to form a solid basis for late-stage clinical development.

2nd line HNSCC - Part C

Conclusion: The 2nd line HNSCC data is mature and continues to be very encouraging and forms an excellent basis to move into the 1st line HNSCC indication via

Immutep s randomised Phase IIb TACTI-003 study which is expected to start in mid-2021.

2nd line NSCLC - Part B

Stage 1 results were reported in

November 2020 at SITC and Overall Survival is trending favourably. Stage 2 recently opened for patient enrolment and combined results from Stages 1 & 2 are expected to be reported later this year.

The combination treatment continues to be safe

and well tolerated with no new safety signals reported thus far.

Trial recruitment continues to progress well, with 127 patients out of up to 183 already participating at 12 clinical sites across Australia, Europe, the UK

and US. At present, recruitment is ongoing for the expansion stage of Part A and Stage 2 of Part B.

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Recruitment details for each Part of the trial are

shown below and are current as at 1 June 2021.

Table 2 TACTI-002 Recruitment (as at

currently expects to report further interim data from Part A, final data from Part C, and new results from Stages 1 & 2 of Part B in 2H calendar year 2021 or early calendar year 2022.

Immutep will present this data in a

global webcast for investors. Details are as follows:

Thursday, 10 June 2021, at 7:00 am Australian Eastern Daylight Time (AEDT) (Wednesday, 9 June, at 5:00 p.m. U.S. ET)

Investors are invited to submit questions in advance via immutep@citadelmagnus.com.

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

About the TACT-002 Trial

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.

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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 significantly less responsive.

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

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

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.

Further information can be

found on the Company s website www.immutep.com or by contacting:

Australian Investors/Media:

Catherine Strong, Citadel-MAGNUS

McCarthy, LifeSci Advisors

+1 (212) 915.2564; tim@lifesciadvisors.com

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

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