Radioligand Therapy: Solid Tumors

In 2021, Molecular Partners announced a new collaboration with Novartis in the form of a license agreement to develop, manufacture and commercialize DARPin based radioligand therapies (DARPin-RLTs) for cancer. The collaboration will combine Molecular Partners’ industry-leading ability to rapidly generate high-affinity, high-specificity DARPins, and the RLT capabilities and expertise of Novartis. Further, Molecular Partners is exploring additional targets amenable to DARPin-based radioligand therapies internally and in future collaborations.


Conventional radiation therapy (e.g., external beam radiation) is a well-validated treatment for cancer that has been in use for over a century. However, cancer killing is non-specific and healthy cells are also affected, resulting in harmful side effects. This limits the amount of radiation patients can receive in their lifetimes, which can leave difficult to reach tumor lesions untreated. Ultimately, therapeutic effect is limited.


In contrast to conventional radiation therapy, radioligand therapies (RLTs) are targeted, specifically damaging tumor cells over healthy cells and thus, difficult to target small tumor lesions (micro-metastasis) can be treated more efficiently and safely.


Molecular Partners will develop DARPin-based RLTs that target specific tumor-associated antigens. DARPins have great potential to enable robust, tumor-specific delivery of therapeutic radionuclides owing to their small size – allowing for great tumor penetration – high specificity and long tumor residence time. Due to their robust architecture and high stability, DARPins can be efficiently coupled to various linker payloads for the specific delivery of radionuclides to the tumor site. The unique attributes of DARPins make them a powerful potential partner for radioligand therapies (RLTs).