Immutep announces improved results in two parallel clinical trials into lead drug eftilagimod alpha

Biotechnology company Immutep (ASX: IMM) has unveiled results from two parallel clinical studies into its lead drug eftilagimod alpha, citing “improving results” and “encouraging” early anti-tumour activity signals a variety of cancer indications not typically sensitive to immune checkpoint inhibitor (ICI) therapy.

In Immutep’s INSIGHT-004 phase I clinical trial was conducted in Frankfurt, Germany, in collaboration with pharma giants Merck and Pfizer.

The trio is co-developing and co-commercialising avelumab under the brand name Bavencio,which is a fully human monoclonal antibody.

Immutep’s INSIGHT-004 drug serves as the fourth arm of the investigator-initiated INSIGHT trial.

The trial is designed to evaluate the combination of efti with avelumab in 12 patients with different solid tumours, primarily gastrointestinal.

In a statement to the market, Immutep said that 41.7% of patients showed a partial response to the therapy, compared to 33% recorded previously. Moreover, the trial indicated a disease control rate of 50%.

In a presentation at the ESMO Virtual Congress yesterday, INSIGHT-004 trial investigator and IKF director Professor Salah-Eddin Al-Batran said: “It is encouraging to see the range of patients with different solid cancers that are responding to the combination of efti and avelumab, including PD-L1-negative cervical cancer, squamous anal cell carcinoma and mesothelioma. These tumours are not typically responsive to immune checkpoint therapy and warrant further investigation.”

Skin cancer study

In parallel to INSIGHT-004, Immutep has also progressed its TACTI-002 trial, also being conducted in collaboration with Merck, evaluating the combination of efti with Merck’s drug pembrolizumab, better known as Keytruda, in around 109 patients with second line head and neck squamous cell carcinoma or non-small cell lung cancer in first and second line.

The trial is a phase 2, Simon’s two-stage, non-comparative, open-label, single-arm, multicentre clinical study that is taking place in up to 12 centres across Australia, Europe, the UK and the US.

Patients are participating in three parts – part A investigates first-line non-small cell lung cancer (NSCLC) PD-X naïve, part B investigates second-line NSCLC PD-X refractory, and part C investigates second line head and neck squamous cell carcinoma (HNSCC) PD-X naïve.

INSIGHT-004 showed 47.1% of patients were progression-free at six months of treatment with a maintained iORR rate of 38.9%. Results also showed that two patients recorded a complete response and five patients recorded a partial response.

According to study’s principal investigator Dr Martin Foster, the results are encouraging and improving, especially with respect to resistant late-stage head and neck cancers, where the likelihood of response to other treatments is small.

Furthermore, the durability of responses and the two patients with a complete response was characterised as “extremely promising signals”, thereby justifying further investigation.

“The combination of efti and pembrolizumab is reporting encouraging progression-free survival in patients with HNSCC and NSCLC, improving on the results from separate historical trials,” Immutep’s chief scientific and medical officer Dr Frederic Triebel said.

“In comparable studies, HNSCC patients receiving pembrolizumab monotherapy had a PFS of 2.1 months, or 2.3 months if given chemotherapy.”

“This compares to a PFS of 4.3 months in HNSCC patients from the TACTI-002 trial, thus far. To have these very good and durable responses in both groups and without the use of chemotherapy is highly encouraging for efti,” he said.

Immutep expects to report the first data from the stage 2 and more mature data from stage 1 trial at a conference later this year.