Immutep Reports 61% Response Rate In Lung Cancer Trial With Keytruda-Based Triple Combo

Immutep Limited IMMP on Thursday announced additional data from the investigator-initiated INSIGHT-003 trial evaluating a triple combination therapy in front-line non-small cell lung cancer patients consisting of efti administered in conjunction with Merck & Co Inc’s MRK Keytruda (pembrolizumab) and chemotherapy (carboplatin and pemetrexed).

The company said it achieved a 60.8% response rate and 90.2% disease control rate as of the data cut-off date of May 6, 2025.

Marc Voigt, CEO of Immutep, stated, “Our level of confidence in efti driving a new standard of care for patients with non-small cell lung cancer via our pivotal TACTI-004 trial continues to rise with the strength of the data from INSIGHT-003 and TACTI-002. Across two trials we have now efficacy data from 165 patients with 1L NSCLC who have been treated with efti and KEYTRUDA, either with or without chemotherapy. In multi-national settings, efti has generated consistent and remarkable improvements in response rates. In particular, the interim ORR data in patients with PD-L1 expression below 50% in the ongoing INSIGHT-003 trial, who represent over two-thirds of the 1L NSCLC patient population, is very encouraging.”

Data from all evaluable patients demonstrates significant improvement of Overall Response Rate (ORR) across all levels of PD-L1 expression compared to historical control from a registrational trial of anti-PD-1 and doublet chemotherapy in non-squamous 1L NSCLC1:

• 75.0% ORR versus 62.1% ORR in patients with high PD-L1 expression (TPS >50%).
• 64.0% ORR versus 49.2% ORR in patients with low PD-L1 expression (TPS 1-49%).
• 54.5% ORR versus 32.3% ORR in patients with negative PD-L1 (TPS <1%).

The 60.8% response rate, regardless of PD-L1 expression (TPS 0-100%), represents a substantial improvement compared to the historical control of 48.0%.

The relative outperformance is particularly strong given the registrational trial has four times as many patients with high PD-L1 expression (~32% of patients versus ~8% in INSIGHT-003), who have the highest response rates.

In patients with TPS <50% (N=47), who have a high unmet need and represent over two-thirds of the 1L NSCLC patient population, the triple combination with efti achieved a 59.6% response rate compared to a historical control of 40.8%.

Safety continues to be favorable for the triple combination in 1L NSCLC with no new safety signals.

Additional data updates from this trial are expected to be presented at a medical conference in 2025 and beyond.

In May, Immutep announced that the median Overall Survival (OS) of 17.6 months had been achieved in Cohort B of the TACTI-003 (KEYNOTE-C34) Phase 2b trial.

This part of the Phase 2 study evaluates eftilagimod alfa (efti) in combination with Keytruda as first-line therapy in recurrent/metastatic head and neck squamous cell carcinoma.

Immutep dosed the first patient in its pivotal TACTI-004 Phase 3 trial in March.

TACTI-004 will evaluate Immutep’s eftilagimod alfa in combination with Keytruda as first-line treatment for patients with advanced or metastatic non-small cell lung cancer.

Price Action: IMMP stock is up 9.2% at $2.00 at last check on Thursday.

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