Prognostic role of PD-L1 expression in patients with advanced renal cell carcinoma (RCC) treated with sunitinib.

603 Background: the prognosis and treatment of advanced RCC has improved over the last decade due to a number of effective anti-angiogenic and immune checkpoint inhibitors (ICPI) therapies. Certain clinical factors, such as low Karnofsky status (≤ 70%); less than a one year period from diagnosis to treatment administration; low serum hemoglobin; high corrected serum calcium; high lactate dehydrogenase; elevated neutrophil count or platelet count exceeding the upper limit of the normal range, have been able to stratify patients into three distinct prognostic groups: favorable (zero risk factors), intermediate (one to two), and poor risk (more than two). Nowadays, the relationship between PD-L1 expression with treatment response and the survival rate of RCC is a current topic of interest. Methods: a retrospective analysis of 182 patients with advanced RCC who received sunitinb in a single Institution has been conducted with the aim of analyzing PD-L1 as a prognostic factor. To carry out the immunohistochemical analysis, microscopy samples have been treated with the PD-L1 IHC 22C3 pharmDx assay, which is intended to measure the percentage of PD-L1 expression in the primary tumor tissue. Results: a total of 65 patients with primary tumor tissue sampling, who were never treated with (ICPI), were analyzed. Among these, 95% were considered as intermediate or poor risk and 47% had PD-L1 expression. The results have shown that PD-L1 expression is associated with worse progression-free survival (PFS) and overall survival (OS). In patients with no expression of PD-L1, the median PFS was 16.89 months (95% confidence interval 11.0 – 40.87 months) and 12.61 months for those with some % of PD-L1 expression (4.43 – 53.09). (χ² = 1.16; Pr > χ² = 0.20). Likewise, the median OS was 42.28 months (13.76 – 68.13) for patients with no expression of PD-L1 and 24.60 months for those with some % of PD-L1 expression (13.76- not reached) ( χ ² = 0.12; Pr > χ ² = 0.73). Conclusions: patients treated with sunitinib who express PD-L1, have shown shorter PFS and OS. Its validation as an independent prognostic factor, with regard to other standard clinical parameters, must be considered in order to develop a more tailored approach to treatment decision.