Molecular imaging of immunotherapy biodistribution and the tumor immune environment

The major anticancer effects of cancer immune checkpoint inhibitors changed treatment options for patients with several tumor types. Durable responses and cures have been observed in the metastatic setting. However, not all patients respond to currently available immunotherapies. To optimally exploit the effects of cancer-immunotherapy it is paramount to identify as early as possible the patients that will and will not respond, and to understand why patients respond. Furthermore, developing novel strategies beneficial to patients that previously did not respond is critical to further advance cancer care. A novel approach is the application of bispecific T-cell engager molecules. They, in contrast to other cancer drugs, actively involve and bind immune cells to induce T-cell mediated tumor cell killing. Understanding their biodistribution will provide insight into their application in the clinic. Molecular imaging can be used to non-invasively visualize the tumor immune microenvironment and show how it changes in response to cancer-immunotherapy. In addition, molecular imaging can facilitate drug development by providing information on drug biodistribution and tumor targeting. The research performed in this thesis uses molecular imaging and aims to evaluate the biodistribution of novel immunotherapies, with a focus on bispecific T-cell engager molecules, and to visualize the tumor immune microenvironment