Australia-based Immutep has signed a collaboration and supply agreement with Merck, Darmstadt, Germany to conduct a Phase I/IIa clinical trial of eftilagimod alpha (efti/IMP321) for solid tumours.

Immutep’s efti is a soluble LAG-3 fusion protein (LAG-3Ig) designed to activate antigen-presenting cells (APC) to potentially treat cancer and infectious diseases.

During the Phase I/IIa trial, dubbed INSIGHT-005, efti will be assessed in combination with bintrafusp alfa (M7824), a bifunctional fusion protein immunotherapy candidate.

Merck is co-developing bintrafusp alfa with GlaxoSmithKline (GSK).

Bintrafusp alfa is meant to inhibit immunosuppressive TGF-β and PD-L1 pathways, while the APC activator efti acts through the LAG-3 – MHC II pathway.

Immutep CEO Marc Voigt said: “Through INSIGHT-005, we plan to explore the effect of releasing the brakes and pushing the accelerator of the body’s immune system in three different positions of the cancer immunity cycle.

“The new trial builds on our knowledge and the encouraging data from the INSIGHT trial of efti, also in solid tumours.”

To be performed by the Institute of Clinical Cancer Research at Krankenhaus Nordwest in Frankfurt, Germany, INSIGHT-005 will assess the combination treatment’s safety, efficacy and feasibility.

The trial will be carried out as a modification to the ongoing Phase I INSIGHT study’s protocol as the fifth arm (Stratum E).

It will take place at two German sites with patient enrolment scheduled to begin in the coming months after receiving necessary approvals.

INSIGHT-005 lead investigator Dr Salah-Eddin Al-Batran said: “Our experience and knowledge of efti, combined with our extensive nationwide network of more than 500 German clinical facilities, means we are well equipped to lead the INSIGHT-005 study.”

Immutep is funding the trial operation and Merck is financially supporting the biomarker activities. Initial results are expected to be available next year.