Immutep doses first patient in Phase II/III efti trial to treat metastatic breast cancer

Biotechnology company Immutep (ASX: IMM) has safely dosed the first patient at a European clinical site for its integrated Phase II/III AIPAC-003 trial to treat metastatic breast cancer.

AIPAC-003 is evaluating the company’s soluble LAG-3 protein and first-in-class MHC Class II agonist known as eftilagimod alpha (efti) in combination with standard-of-care paclitaxel for the treatment of metastatic HER2-neg/low breast cancer and triple-negative breast cancer.

The open label trial will take place at 17 sites across Europe and the US, with patients receiving same-day administration of efti and paclitaxel which will continue until disease progression.

A lead-in to the trial will see up to 12 patients dosed at 90 milligrams efti, followed by a randomised (1:1) portion of the Phase II consisting of up to 58 patients who will receive 30mg efti or 90mg efti to determine the optimal biological dose in combination with paclitaxel.

A randomised, double-blinded, placebo-controlled Phase III portion may follow (pending Phase II results), where overall survival will be the primary objective.

Immutep’s previous efti trial showed encouraging efficacy and safety results including a 2.9-month median overall survival benefit and significant median overall survival improvements of between 4.2 to 19.6 months across pre-specified subgroups.

Milestone development

Immutep chief scientific officer Prof Frédéric Triebel said dosing of the first patient was considered a milestone development for the company.

“Our aim is to improve clinical outcomes, focusing on a robust primary endpoint of overall survival in Phase III for patients with standard-of-care chemotherapy,” he said.

“We look forward to seeing how 90mg efti dosing along with same-day administration of efti plus paclitaxel until disease progression may build on the results of our previous trials.”

Treatment of cancer

Efti is Immutep’s proprietary soluble LAG-3 protein and MHC Class II agonist which stimulates both innate and adaptive immunity for the treatment of cancer.

As a first-in-class antigen presenting cell (APC) activator, efti binds to MHC (major histocompatibility complex) Class II molecules leading to activation and proliferation of CD8+ cytotoxic T lymphocytes, CD4+ helper T cells, dendritic cells, natural killer (NK) cells and monocytes.

It also upregulates the expression of key biological molecules like IFN-y (Interferon gamma) and CXCL10 which further boost the immune system’s ability to fight 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) and metastatic breast cancer.

It has previously received fast track designation in 1st line HNSCC and in 1st line NSCLC from the US Food and Drug Administration.