Clinical Benefit and Biomarker Analysis of Combination of PD-1/PD-L1 Immune Checkpoint Inhibitors and Radiotherapy

Inhibitors of the programmed cell death protein 1 (PD-1)/PD-L1 immune checkpoint signaling pathway are already approved in the treatment of various tumor entities in relapsed or metastatic stages. Different exploratory trials suggest that the combination of radiotherapy and PD-1/PD-L1 inhibitors is highly effective, especially in oligometastatic stages and if all lesions are treated with ablative radiotherapy. In addition, the role of predictive biomarkers is becoming increasingly important for future therapy algorithms. First data, also from our group, indicate clearly that dynamic changes of immune cells and their activation markers in the peripheral blood (immune matrix) can be used as predictive biomarkers. During the planned STICI-02 trial predictive immune matrix derived from the STICI01 trial (NCT03453892) will be validated in the groups of patient suffering from HNSCC (palliative