Our lead candidate PH1154 is a breakthrough in cancer treatment. It has shown remarkable results in preclinical studies in mice in a hard-to-treat tumor model. Here, selective elimination of hypoxic tumor cells by PH1154 perfectly complemented the eradication of the normoxic bulk tumor by radiotherapy. This result demonstrates the importance of eliminating hypoxic cancer cells and suggests groundbreaking clinical potential of our approach. Thus, PH1154 has the potential to enhance the effectiveness of immunotherapy and radiation by removing the most resilient cancer cells from the tumor.