Actithera

Actithera is a radiopharmaceutical biotech developing next-generation radioligand therapies (RLTs) for cancer. Founded in 2021 by medicinal chemist Andreas Goutopoulos and based in Cambridge, Massachusetts and Oslo, Norway, the company uses a proprietary, chemistry-led platform to design covalent small-molecule radioligands that lodge inside tumors, deliver targeted radiation, and clear quickly from healthy tissue. Its isotope-agnostic approach is engineered to match the residence time of a drug in a tumor to the half-life of long-lived radionuclides, with a lead program targeting Fibroblast Activation Protein (FAP). Actithera raised an oversubscribed $75.5M Series A in July 2025.