Insulin-like growth factor- receptor (IGF-1R) is a transmembrane tyrosine kinase receptor that plays a role in development, metabolism, and immune regulation, and is overexpressed in orbital fibroblasts (OFs), B, and T cells of thyroid ophthalmopathy in Graves' disease. Blocking IGF-1(R) signalling reduces the expression of downstream inflammatory factors, thereby inhibiting the synthesis of hyaluronic acid and other glycosaminoglycans caused by OFs activation, as well as related inflammatory reactions including tissue congestion and edema; inhibit adipocyte cellularization of OFs, thereby reducing the disease activity of patients with active thyroid ophthalmopathy and improving proptosis, diplopia, ocular congestion and edema and other symptoms and signs. Clinical and commercial validation of IGF-1R as a target for treatment of thyroid eye disease (TED) is highlighted by 2024 global sales of nearly US$ 1.9 bln of the first approved anti-IGF-1R therapeutic antibody Tepezza.
IGF-1R has also emerged as a critical target in oncology due to its pivotal role in tumor growth, progression, and therapeutic resistance. IGF-1R was among the most intensively pursued kinase targets in oncology. However, even after a slew of small-molecule and antibody therapeutics reached clinical trials for a range of solid tumors, the initial promise remains unfulfilled. Mechanisms of resistance to, and toxicities resulting from, IGF-1R-targeted drugs are well-catalogued, and there is general appreciation of the fact that a lack of biomarker-based patient stratification was a limitation of previous clinical trials. But no next-generation therapeutic strategies have yet successfully exploited this understanding in the clinic.
Currently there is emerging interest in re-visiting IGF-1R targeted therapeutics in combination-treatment protocols with predictive biomarker-driven patient-stratification.

