Immutep Provides Clinical Update in 1st line NSCLC: Positive Mature Overall Survival Data from INSIGHT-003 and Update from TACTI-004

Rhea-AI Summary

Immutep (NASDAQ: IMMP) reported mature overall survival data from the INSIGHT-003 Phase I trial of eftilagimod alfa (efti) plus KEYTRUDA and chemotherapy in 1st line non-squamous NSCLC (N=51). Median overall survival (mOS) reached 30.9 months in both the overall population and patients with PD-L1 TPS <50% (N=47), and 37.8 months in TPS ≥50% (N=4). Approximately 92% of patients had TPS <50%, a group with significant unmet need, and outcomes continue to compare favourably with a 22.0‑month mOS historical benchmark for anti‑PD‑1 plus doublet chemotherapy. No new safety signal was seen.

Immutep also updated on the discontinued TACTI‑004 Phase III 1L NSCLC trial, where interim futility analysis showed an ORR of 42.9% for the efti arm versus 55.1% for control (N=173). Preliminary immune monitoring indicates a markedly different immune activation profile versus prior efti studies and INSIGHT‑003. Root cause analysis, including manufacturing factors, is ongoing, with further results expected in Q3 CY2026.

Positive

• INSIGHT-003 mOS 30.9 months in overall and TPS <50% 1L NSCLC population
• INSIGHT-003 ORR 62.7% despite ~92% of patients having PD-L1 TPS <50%
• INSIGHT-003 outcomes compare to 22.0-month mOS historical benchmark for anti-PD-1 plus chemotherapy
• No new safety signals observed to date in INSIGHT-003 and TACTI-004
• Root cause analysis supported by partners Dr. Reddy’s and WuXi Biologics, with further data expected Q3 CY2026

Negative

• TACTI-004 discontinued after futility analysis in 1L NSCLC
• TACTI-004 ORR 42.9% in efti arm vs 55.1% in control arm (N=173)
• Efti arm lacked superiority across squamous, non-squamous, and all TPS subgroups in TACTI-004
• Immune activation profile in TACTI-004 differed from almost 600 prior efti-treated patients and INSIGHT-003, requiring ongoing investigation

News Explained

The disclosure is mixed: mature INSIGHT-003 survival data add favorable clinical evidence, while TACTI-004 remains discontinued and under unresolved review.

The July 13, 2026 release changes Immutep's clinical-development record in two directions: it reports mature survival data from INSIGHT-003, while TACTI-004 is already discontinued after futility and remains under root-cause analysis.

INSIGHT-003, an investigator-initiated Phase I study, reported median overall survival of 30.9 months in both the overall population and patients with TPS below 50%. The release compares that result with 22.0 months from a registrational trial of anti-PD-1 therapy plus doublet chemotherapy in first-line non-squamous NSCLC.

At the TACTI-004 futility analysis, objective response was 42.9% with standard of care plus efti versus 55.1% with standard of care plus placebo, and the efti arm showed no superiority in any TPS subgroup. Preliminary immune-monitoring results also showed a different immune-activation profile from earlier studies, but the analysis remains ongoing.

Additional TACTI-004 root-cause results are expected in Q3 CY2026; that milestone is the next stated update on why the Phase III result differed from the earlier evidence.

News Market Reaction – IMMP

+7.52%

5 alerts

+7.52% Session close to close

+3.6% Peak in 7 hr 27 min

$61.97M Market Cap

1.0x Rel. Volume

In the Jul 13 session, IMMP gained 7.52%, reflecting a notable positive market reaction. Argus tracked a peak move of +3.6% during that session. Our momentum scanner triggered 5 alerts that day, indicating moderate trading interest and price volatility.

Data tracked by StockTitan Argus on the day of publication.

Market Context

The stock moved +7.5% in the session following this news. A strong upside reaction would be consiste...

Analysis

The stock moved +7.5% in the session following this news. A strong upside reaction would be consistent with the robust INSIGHT-003 data, where median overall survival reached 30.9 months versus a 22.0-month benchmark. Historically, good news has not always been rewarded, and relatively low short positioning limits squeeze-driven extensions.

Key Figures

Median overall survival: 30.9 months Median overall survival: 30.9 months Median overall survival: 37.8 months +5 more

8 metrics

Median overall survival 30.9 months INSIGHT-003 overall 1L non-squamous NSCLC population (N=51)

Median overall survival 30.9 months INSIGHT-003 TPS <50% subgroup (N=47)

Median overall survival 37.8 months INSIGHT-003 TPS ≥50% subgroup (N=4)

Comparator mOS 22.0 months Registrational anti-PD-1 plus doublet chemotherapy in 1L non-squamous NSCLC

Low PD-L1 patients 92% INSIGHT-003 patients with TPS <50% at enrolment

Objective response rate 42.9% TACTI-004 efti arm in futility analysis (N=173)

Objective response rate 55.1% TACTI-004 control arm in futility analysis (N=173)

Objective response rate 62.7% INSIGHT-003 1L non-squamous NSCLC study

Historical Context

5 past events · Latest: Jun 04 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Jun 04	Phase I data	Positive	-4.5%	Encouraging interim IMP761 Phase I safety and pharmacodynamic data in autoimmune setting.
May 28	Pooled clinical data	Positive	+2.3%	Pooled efti data showed increased ALC and +7.7 months median OS benefit.
Apr 30	Quarterly update	Neutral	-3.2%	Activities report with TACTI-004 discontinuation, strong cash of A$110.6 million and cost controls.
Apr 30	Listing compliance	Negative	-3.2%	Nasdaq minimum bid price deficiency notice and 180-day compliance window disclosure.
Apr 22	Conference abstract	Positive	-4.8%	ASCO 2026 abstract acceptance highlighting efti-driven lymphocyte activation and survival benefits.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Recent news, even when clinically positive, has often coincided with share price weakness for Immutep.

Key Terms

median overall survival, objective response rate, immune activation profile, absolute lymphocyte counts, +1 more

5 terms

median overall survival medical

"With a minimum of 30 months of follow-up, median Overall Survival (mOS) was 30.9 months"

Median overall survival is the middle point of how long patients live after starting treatment, meaning half live longer and half live shorter. It helps doctors understand how effective a treatment is and gives patients an idea of what to expect about their future.

objective response rate medical

"the objective response rate (ORR) in the overall patient population receiving standard of care plus efti"

The objective response rate (ORR) is the percentage of patients in a clinical trial whose tumors measurably shrink or disappear according to preset rules. Investors use it as a quick, objective signal of a drug’s ability to produce a clear treatment effect—like counting how many plants visibly respond after applying a new fertilizer—and higher ORR can improve odds of regulatory approval, commercial success, and company valuation.

immune activation profile medical

"patients treated with efti exhibited a markedly different immune activation profile compared with that observed"

A set of measurable immune system signals—such as levels of specific cells, proteins, or inflammatory markers—that together show how strongly and in what way the immune system is responding. Think of it as a dashboard or fingerprint that summarizes immune activity. Investors watch these profiles because they help predict a therapy’s effectiveness, safety risks, clinical trial outcomes, and regulatory or market potential.

absolute lymphocyte counts medical

"based on analyses of absolute lymphocyte counts (ALC) and circulating monocyte counts in blood"

Absolute lymphocyte count is the actual number of lymphocytes — a type of white blood cell that helps fight infections — measured per volume of blood (usually cells per microliter). Think of it as counting how many soldiers are on patrol in the bloodstream. Investors watch this measure because changes can signal a drug’s effect on the immune system, inform safety and efficacy assessments in clinical trials, and influence regulatory and commercial outcomes.

independent data monitoring committee regulatory

"based on a recommendation from the Independent Data Monitoring Committee (IDMC)"

A panel of independent medical, statistical and ethical experts who review ongoing clinical trial data to judge participant safety, study integrity and whether the trial should continue, change or stop. Like impartial referees or safety inspectors, their decisions can speed, delay or halt a drug’s development and therefore materially affect a company’s timelines, regulatory chances and investment risk.

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

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• INSIGHT-003 demonstrates mature mOS of 30.9 months in both the overall population (N=51) and patients with TPS <50% (N=47) in 1L non-squamous NSCLC
• Outcomes continue to compare favourably with historical benchmarks
• Preliminary immune monitoring data indicate that patients treated with efti in TACTI-004 exhibited a different immune activation profile compared with previous studies
• TACTI-004 root cause analysis is ongoing with additional results expected in Q3 CY2026

SYDNEY, AUSTRALIA, July 13, 2026 (GLOBE NEWSWIRE) -- Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), a biotechnology company developing novel immunotherapies, today announced a significant positive update of the investigator-initiated INSIGHT-003 Phase I trial evaluating eftilagimod alfa (efti) in combination with MSD’s (Merck & Co. Inc., Rahway, NJ, USA) anti-PD-1 therapy KEYTRUDA^® (pembrolizumab) and chemotherapy as 1^st line therapy for advanced/metastatic non-small cell lung cancer (1L NSCLC) in 51 evaluable non-squamous patients.

Key Results from INSIGHT-003 – Data Cutoff – 27 March 2026
Approximately 92% of patients enrolled in INSIGHT-003 had no or low PD-L1 expression (Tumour Proportion Score: TPS <50%), representing a population with significant unmet medical need. With a minimum of 30 months of follow-up, median Overall Survival (mOS) was 30.9 months in the overall population regardless of PD-L1 expression (N=51), with the same mOS observed in patients with TPS <50% (N=47) and 37.8 months in TPS>=50% (N=4).

These mature results continue to compare favourably to the 22.0 month mOS from a registrational trial of anti-PD-1 and doublet chemotherapy in non-squamous 1L NSCLC regardless of PD-L1 expression.¹ Notably, patients with TPS <50%, for whom PD-L1 inhibitor-based therapies typically perform suboptimally, were overrepresented in INSIGHT-003 compared with historical benchmarks (~92% versus ~68%¹). No new safety signal was identified since the previous data cut-off.

Update on TACTI-004 Root Cause Analysis
In March 2026, following a planned interim futility analysis, Immutep announced that it would discontinue the TACTI-004 Phase III trial in 1^st line NSCLC based on a recommendation from the Independent Data Monitoring Committee (IDMC). In the TACTI-004 futility analysis (N=173), the objective response rate (ORR) in the overall patient population receiving standard of care plus efti (“efti arm”) was 42.9% compared with 55.1% in patients receiving standard of care plus placebo (“control arm”). The difference was observed across both squamous and non-squamous histologies, and the efti arm did not demonstrate superiority in any TPS subgroup. By comparison, the ORR in INSIGHT-003 has been 62.7%, despite the high proportion of patients with TPS <50%. Pending a final analysis of all patients, to date no new safety signals have been observed in TACTI-004.

Preliminary immune monitoring data generated from TACTI-004 indicate that patients treated with efti exhibited a markedly different immune activation profile compared with that observed in previous studies. This assessment is based on analyses of absolute lymphocyte counts (ALC) and circulating monocyte counts in blood. In particular, these findings contrast with observations from almost 600 patients treated with efti in five earlier studies (AIPAC, AIPAC-003, TACTI-mel, TACTI-002 and TACTI-003), which were presented at ASCO 2026², and also contrast with observations from INSIGHT-003.

The TACTI-004 analysis, which includes all recruited and evaluable patients who received a minimum of 12 weeks of treatment, remains ongoing, with additional results expected in Q3 CY2026. The Company will continue to analyse this data as part of its ongoing root cause analysis of a range of potential factors, including manufacturing, and will share the outcome of that analysis as soon as it becomes available. Immutep is being assisted in this process by its partners, including Dr. Reddy’s and WuXi Biologics.

Marc Voigt, CEO of Immutep, said: “We are encouraged by the mature overall survival data from INSIGHT-003 in 1^st line non-squamous NSCLC, which continue to compare favourably with historical benchmarks, particularly given the high proportion of patients in this study with no or low PD-L1 expression. The observed median overall survival of 30.9 months especially in patients with no or low PD-L1 expression reinforces our confidence in efti’s potential to enhance anti-tumour immune responses, including in patient populations that have historically experienced less favourable outcomes.

At the same time, we are completing a comprehensive root cause analysis of TACTI-004 to better understand the factors underlying the outcome of that trial and their implications for the potential future development of efti. Importantly, the differences observed in the immune activation profile between TACTI-004 and prior studies are providing valuable insights to inform our strategy as we evaluate efti’s potential path forward.”

Additional results from the root cause analysis related to TACTI-004 are expected in Q3 CY2026.

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 and 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), head and neck squamous cell carcinoma (HNSCC), soft tissue sarcoma, and breast cancer. Its favourable safety profile has enabled various combinations including with anti-PD-[L]1 immunotherapy, radiotherapy, and/or chemotherapy. Efti has received Fast Track designation in 1st line HNSCC and in 1st line NSCLC from the United States Food and Drug Administration (FDA).

About Immutep
Immutep is a clinical-stage biotechnology company targeting cancer and autoimmune diseases. The Company is developing novel immunotherapies based on Lymphocyte Activation Gene-3 (LAG-3). For more information, please visit www.immutep.com.

Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding anticipated clinical development, regulatory progress and potential benefits of eftilagimod alfa. These forward-looking statements are based on current expectations, estimates and projections, and involve known and unknown risks, uncertainties and other important factors that could cause actual results to differ materially from those expressed or implied in such statements.

Factors that could cause actual results to differ materially include risks associated with clinical trial outcomes, regulatory developments, and the Company’s ability to advance its product candidates.
Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date of this release. Immutep undertakes no obligation to update or revise such statements, except as required by applicable law.

Disclaimer
This announcement has been prepared for informational purposes only and does not constitute an offer to sell, or a solicitation of an offer to buy, securities in any jurisdiction.

1. Shirish Gadgeel et al., Updated Analysis From KEYNOTE-189: Pembrolizumab or Placebo Plus Pemetrexed and Platinum for Previously Untreated Metastatic Nonsquamous Non–Small-Cell Lung Cancer. JCO 38, 1505-1517(2020).
   DOI:10.1200/JCO.19.03136
   
   
2. Immutep press release – 28 May 2026
   
   

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

FAQ

What overall survival did Immutep (IMMP) report from the INSIGHT-003 1st line NSCLC trial?

Immutep reported a median overall survival of 30.9 months in INSIGHT-003. According to Immutep, this mOS applied to both the overall population (N=51) and patients with PD-L1 TPS <50% (N=47), and exceeded a 22.0‑month historical benchmark.

How did INSIGHT-003 outcomes for efti in 1L NSCLC compare with historical benchmarks for anti-PD-1 plus chemotherapy?

INSIGHT-003 showed a median overall survival of 30.9 months, above the 22.0‑month historical benchmark. According to Immutep, this comparison uses a registrational trial of anti-PD-1 plus doublet chemotherapy in non-squamous 1L NSCLC regardless of PD-L1 expression.

Why was Immutep’s Phase III TACTI-004 trial in 1st line NSCLC discontinued?

TACTI-004 was discontinued after a planned futility analysis recommended by the IDMC. According to Immutep, the efti arm’s objective response rate was 42.9% versus 55.1% in the placebo control arm, with no superiority in any TPS subgroup.

What objective response rates were observed in Immutep’s INSIGHT-003 and TACTI-004 NSCLC studies?

INSIGHT-003 recorded an objective response rate of 62.7%. According to Immutep, the TACTI-004 interim futility analysis showed an ORR of 42.9% for the efti arm compared with 55.1% for the standard-of-care plus placebo control arm (N=173).

What did Immutep (IMMP) report about safety in INSIGHT-003 and TACTI-004?

No new safety signals have been observed in either INSIGHT-003 or TACTI-004 to date. According to Immutep, safety findings since the previous data cut-off remained consistent, while further analyses and monitoring continue as part of the root cause investigation.

What is Immutep’s plan for the TACTI-004 root cause analysis and when are more results expected?

Immutep is conducting a comprehensive root cause analysis of TACTI-004, including potential manufacturing factors. According to Immutep, the analysis covers all eligible patients and immune monitoring, with additional results expected in Q3 CY2026, supported by partners Dr. Reddy’s and WuXi Biologics.

How did PD-L1 expression levels influence patient makeup in Immutep’s INSIGHT-003 NSCLC trial?

Approximately 92% of INSIGHT-003 patients had PD-L1 TPS <50%. According to Immutep, this represents a population with significant unmet medical need and is higher than about 68% reported in historical benchmarks, yet the study still achieved a 30.9‑month median overall survival.