Tectonic Therapeutic, Inc. is a clinical-stage biotechnology company. The Company is focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of G-protein coupled receptors (GPCRs). Its technology platform called GEODe (GPCRs Engineered for Optimal Discovery), is focused on developing biologic medicines that overcome the existing challenges of GPCR-targeted drug discovery and harness the human body to modify the course of disease. Its product candidates are TX45, a Fc-relaxin fusion molecule that activates the RXFP1 receptor, the GPCR target of the hormone relaxin. Its second development candidate, TX2100, is a VHH-Fc fusion antagonist antibody that binds to the APJ receptor (APLNR), also known as the apelin receptor. Its APJ is a differentiated approach for the treatment of hereditary hemorrhagic telangiectasia (HHT) and is a selective anti-angiogenic target that is primarily expressed in endothelial cells.