Prostate Cancer With OligometaSTatic Relapse: Combining Stereotactic Ablative Radiotherapy and Durvalumab (MEDI4736)

As in other solid tumours, increasing evidence indicates that patients diagnosed with a limited number of prostate cancer metastases, so-called oligometastases, have a better prognosis compared with patients with extensive metastatic disease. Survival of patients with three or fewer metastases was superior compared with patients with more than three lesions. The introduction of novel imaging modalities such as Fluorocholine (FCH), Fuciclovine or Ga-PSMA PET CT has increased the detection of oligometastatic prostate cancer (PCa) recurrence, potentially justifying the use of a metastasis-directed therapy with radiotherapy (RT). Based on several studies, SBRT is now considered as a strongly validated option in oligometastatic prostate cancer. It is increasingly understood that cancers are recognized by the immune system, and, under some circumstances, the immune system may control or even eliminate tumors. Programmed death-ligand 1 (PD-L1) is transmembrane protein that has been speculated to play a major role in suppressing the immune system during particular events. PD-L1 is expressed in a broad range of cancers. Based on these findings, an anti-PD-L1 antibody could be used therapeutically to enhance antitumor immune responses in patients with cancer. Experimental data from multiple cancer models have provided cumulative evidence of an interaction of ionizing radiation with the systemic antitumor immunity and this has created several opportunities in the field. The oligometastatic setting appears to be the most relevant clinical situation to evaluate the immune response generated by radiotherapy and immune modifiers in patients with an intact immune system. The hypothesize is that Durvalumab will enhance immune response following SBRT targeting oligometastatic lesions. In this randomized 2:1 phase II trial of Stereotactic Body Radiation Therapy with or without durvalumab in oligometastatic hormone sensitive prostate cancer patients, Durvalumab will be started