Immutep is a late-stage Australian biotech focused entirely on a single biological target: LAG-3 (Lymphocyte Activation Gene-3), a protein that regulates immune activity. Immutep's core insight is that LAG-3 can be engaged in two opposite ways — to amplify immune responses against cancer, or to suppress overactive immune responses in autoimmune disease. The lead asset, eftilagimod alfa (efti), is a soluble LAG-3 fusion protein that activates antigen-presenting cells, which in turn drive T cell proliferation to attack tumors. Efti is a first-in-class APC agonist, distinct from checkpoint inhibitors like Keytruda, and is being developed as a complement to, not a replacement for, those drugs. The most important program is the Phase III TACTI-004 trial, which dosed its first patient in March 2025 and is evaluating efti combined with Keytruda and chemotherapy in non-small cell lung cancer. Efti is also being developed in head and neck cancer and metastatic breast cancer. A second pipeline asset, IMP761, is an early-stage LAG-3 agonist antibody for autoimmune disease, with Phase I data showing meaningful T cell suppression. Immutep has out-licensed a third LAG-3 asset to Novartis and received back a fourth from GSK. Immutep is pre-revenue, generating only modest income from milestones, licensing fees, and research reagent sales. The company outsources manufacturing and clinical operations, running a lean 51-person internal team. If efti is approved, Immutep would sell directly in markets where it retains rights and collect royalties from its China partner, EOC Pharma.