Bio-miR: A prognostic microRNA-based signature for localized clear cell renal cell carcinoma

e16519

Background: Prognosis of localized clear cell renal cell carcinoma (ccRCC) patients is estimated by nomograms based on clinico-pathological factors. However, clinical guidelines do not recommend their use. Recently, pembrolizumab has demonstrated benefit in disease-free survival (DFS) in medium-high risk localized ccRCC, increasing the need for better patient stratification tools. In this study, we have defined and validated a molecular signature, Bio-miR, based on the expression of nine microRNAs, with prognostic value in ccRCC. Methods: The discovery and two validation cohorts (Leeds-UK and Spain) consisted of patients with resected localized (stage Ib-III) ccRCC and no adjuvant therapy. miRNA expression was analyzed using microarrays and validated using qPCR in FFPE nephrectomy tissues. Cox regression was used to define the best microRNAs combination to predict risk of relapse. Results: In the discovery cohort (n = 71), DFS at 5 years was 93.9% amongst Bio-miR-defined low-risk patients and 61.6% in high-risk patients (HR = 6.9 (3.4-42.9), p < 0.001). Cancer-specific survival at 5 years was 95.7% and 86.4% in low- and high-risk patients, respectively (HR = 7.7 (1.7-35.1), p < 0.01). Bio-miR compared favorably with different histopathological factors and UISS and Karakiewicz´s nomograms. In the Leeds validation cohort (n = 75/95 passing qPCR quality control), patients defined as low-risk had a 5-year DFS rate of 94% versus 62% in high-risk defined disease. In this cohort Bio-miR was able to divide the Leibovich intermediate-risk population into two groups with divergent five-year DFS rates (100% vs 71%). In the Spanish validation cohort (n = 180), DFS rates at 5 years were 82.9% in the low-risk group and 58.7% in the high-risk group (HR = 2.4 (1.4-4.4); p < 0.005). Applying the inclusion criteria from the phase III KEYNOTE-564 trial, Bio-miR identifies a small low-risk population who could be spared adjuvant treatment. Conversely, amongst patients excluded from the study due to low-risk features, Bio-miR defines a high-risk population (DFS at five years of 50%) who should be prioritized for adjuvant therapy. Conclusions: We define and validate a nine-microRNA based signature capable of dichotomizing patients with localized ccRCC into low- and high-risk groups based on risk of relapse. Importantly, Bio-miR acts independently of tumor stage and grade and could, therefore, help refine the selection of patients for adjuvant therapy as well as inform the design of future adjuvant ccRCC trials.

Association of immune gene expression profiling with vinflunine clinical benefit in metastatic urothelial cancer (mUC)

e16034

Background: There are limited treatment options for mUC after platinum-based chemotherapy failure. Immune checkpoint inhibitors (ICI) have shown a durable benefit but only in a minority of patients (20-25%). Vinflunine remains as a therapeutic option without validated biomarkers. In this study, we sought to analyze the molecular determinants of vinflunine response in mUC. Methods: mUC patients from 4 University Hospitals in Spain who received second-line vinflunine after platinum-based chemotherapy were classified in non-responders (NR: progressive disease ≤3 months; N = 10) or responders (R: response ≥ 6 months, N = 14). Targeted- sequencing of 275 cancer-related genes and a PanCancer Immune Profiling Panel were performed on pre-treatment tumors. Selected genes were evaluated by RT-qPCR and protein expression was detected by immunohistochemistry. Results: The most common alteration, TP53 mutations, had a similar frequency in R (7/14, 50%) and NR (4/10, 40%). Mutations in 5 genes: ERBB3 (4/14; 28,6%), KTM2C (4/14; 28,6%), PI3KCA (4/14; 28,6%), ARID2 (3/14; 21,4%) and FGFR3 (3/14; 21,4%) were identified only in R. Mutations in ERBB4 (3/10, 33,3%) and BCOR (2/10, 20%) were identified only in NR. Estimated TMBs were not significantly different among the R (13 per Mb) and NR (9 per Mb) samples. According to gene expression profiling, NR had high cytotoxic cells infiltrate and T cells as well as high counts of TILs compared to R. In addition, expression of IDO, MAGE A4, and SOCS1, that has been associated with response to ICIs, were down-regulated in R compared with NR. Conclusions: Gene profiling showed that low-expression levels of immune-related genes are significantly associated with clinical benefit from vinflunine. Validation and complementary studies are ongoing in patients treated with ICIs.