Peripheral blood correlates of outcomes with adjuvant tremelimumab plus durvalumab for patients with renal cell carcinoma at high or intermediate risk of relapse: Initial results from the TransRAMPART study.

527 Background: Despite optimal surgery, approximately 1/3 of patients with renal cell carcinoma (RCC) develop incurable relapse. Adjuvant pembrolizumab reduces the risk of relapse in patients with clear cell RCC and is considered standard care. Post nephrectomy plasma KIM-1 levels have been shown to be prognostic in RCC in the ASSURE instead, various immune cell lineages showed differential phenotypic enrichment according to baseline KIM-1. Tracking these phenotypes through the treatment period revealed divergence between Arm A and Arm C patients. Conclusions: We confirm that baseline KIM-1 levels are prognostic in RCC in an independent population. Although this exploratory analysis only assessed a subset of the whole trial population, this prognostic effect seems to be negated by adjuvant immunotherapy. There is an immune signature associated with KIM-1 levels distinct from the impact of treatment, suggesting an interplay between KIM-1 and immune activity in the postoperative period. Deeper characterization of these immune changes is ongoing. Clinical trial information: NCT03288532 .