Teplizumab

Teplizumab, sold under the brand name Tzield, is a humanized anti-CD3 monoclonal antibody that is the first approved treatment indicated to delay the onset of stage 3 type 1 diabetes in people with stage 2 type 1 diabetes.

Teplizumab's mechanism of action involves binding to CD3 protein complexes (a molecule involved in recognising antigens and activating T cells) on the surface of T-cells and modifying T-cell immune behaviour to reduce cytotoxicity. This appears to involve weak agonistic activity on signaling via the T cell receptor-CD3 complex associated with the development of anergy, unresponsiveness, and/or apoptosis, particularly of unwanted activated T effector cells. In addition, regulatory cytokines are released and regulatory T cells are expanded that may lead to the reestablishment of immune tolerance. To avoid overly stimulating cytokine release, the Fc region of this antibody has been engineered to have Fc receptor non-binding (FNB) properties.

Teplizumab was approved for medical use in the United States in November 2022. The US Food and Drug Administration (FDA) considers it to be a first-in-class medication.