Association between TERT promoter mutations and clinical outcome with immune checkpoint inhibitor therapy for advanced urothelial cancer.

Abstract

561 Background: Recently published data suggests that the presence of a TERT promoter mutation is predictive of superior overall survival (OS) in patients (pts) with advanced/metastatic bladder cancer (mUC) treated with an immune checkpoint inhibitor (ICI) (Kouchkovsky et al, JITC 2021). We aim to validate the results of this study in a large independent cohort. Methods: Pts with mUC treated at two tertiary cancer centers with available genomic data collected in the course of routine clinical care were identified retrospectively. Pts that had received at least one line of ICI therapy in the metastatic setting were selected. Demographic and treatment data were collected, with pts divided into two groups based on the presence or absence of TERT mutation status ( TERTm or TERTwt, respectively). We evaluated OS from diagnosis of at least muscle invasive disease, progression free survival (PFS), and objective response rate (ORR) with ICI therapy across the two groups. OS in our cohort was compared with findings from pts with bladder cancer in The Cancer Genome Atlas (TCGA) database. Results: From our combined data sets, a total of 166 pts had available genomic data, with 64 TERTm pts (52:12 M:F) and 58 TERTwt pts (32:26 M:F) meeting criteria for inclusion. Median age at diagnosis was 67 in both groups. The site of primary disease was bladder in 54 (84%) TERTm vs. 41 (71%) in TERTwt; 10 (16%) and 17 (29%) had upper tract disease, respectively. 47 (73%) TERTm pts and 40 (69%) TERTwt pts had pure urothelial disease; 17 (27%) and 18 (31%) pts had mixed/pure variant histology, respectively. 37 (58%) and 42 (72%) pts received first-line ICI therapy whereas 27 (42%) and 16 (28%) received subsequent-line therapy in TERTm and TERTwt, respectively. At the time of analysis, there were 24 (38%) patients alive in TERTm, and 23 (40%) patients alive in TERTwt. OS was 35 vs. 36 mos (95% CI 0.62-1.51, P=0.66) in TERTm and TERTwt, respectively. PFS on ICI therapy was 4.6 vs. 5.3 mos (95% CI 0.58-1.34, P≥0.99) in TERTm and TERTwt, respectively. ORR was 75% in TERTm and 50% in TERTwt (P=.004). OS in the TCGA database was 35 mos in TERTm and 47 in TERTwt (P=0.19) from a total of 311 and 127 pts, respectively. Conclusions: In contrast to previously published data, our data show no difference in OS and PFS on the basis of TERT mutational status in pts with mUC treated with ICI therapy. Further analysis from larger datasets is needed to reconcile the role of TERT mutations within this patient population.