Enfortumab Vedotin Following Platinum Chemotherapy and Avelumab Maintenance in Patients with Metastatic Urothelial Carcinoma: A Retrospective Data from the ARON-2EV Study.

BACKGROUND: Enfortumab vedotin (EV) has been approved for the treatment of patients with locally advanced/metastatic urothelial carcinoma (la/mUC) who previously received platinum-based chemotherapy followed by immune checkpoint inhibitors. However, the pivotal clinical trials did not include patients previously treated with avelumab maintenance therapy. OBJECTIVE: The aim of the present retrospective analysis was to assess the effectiveness of EV following avelumab in patients with mUC enrolled in the ARON-2EV study. PATIENTS AND METHODS: The study included 182 patients with mUC treated with EV following avelumab maintenance. The primary objective was to assess clinical outcomes, including progression-free survival (PFS), overall survival (OS), overall response rate (ORR), and duration of response (DoR). Statistical analysis involved Fisher exact test, Kaplan-Meier method, log-rank test, and univariate/multivariate Cox proportional hazard regression models. RESULTS: Median OS and PFS were 12.7 (95% CI 10.2-14.1) and 7.9 (95% CI 6.4-9.9) months, respectively. Complete response (CR) was achieved in 5% and partial response (PR) in 34% of patients, with an ORR of 39%. The DoR in patients who achieved CR/PR was 10.9 months (95% CI 8.1-11.4). The incidence of grade ≥ 3 peripheral neuropathy and skin rash was 9%, followed by 8% of grade ≥ 3 diarrhea and 4% of grade ≥ 3 hyperglycemia. CONCLUSIONS: The results of our large international retrospective study confirm the effectiveness of EV and endorse its use in the population of patients with mUC treated with EV following the frontline platinum-based chemotherapy and subsequent maintenance treatment with avelumab.

Association of Tumor Mutational Burden and Microsatellite Instability With Response and Outcomes in Patients With Urothelial Carcinoma Treated With Immune Checkpoint Inhibitor.

BACKGROUND: Microsatellite Instability (MSI) and Tumor Mutational Burden (TMB) are associated with immune checkpoint inhibitor (ICI) efficacy. We examined the association between TMB and MSI status with survival in patients with urothelial carcinoma (UC) treated with ICI. METHODS: Patients from 15 institutions were treated with ICI monotherapy. Primary endpoint was overall survival and secondary endpoints included observed response rate (ORR), and progression-free (PFS) calculated from ICI initiation. TMB was analyzed as dichotomous (≥10 vs. <10 mut/Mb) and continuous variable. RESULTS: We identified 411 patients: 203 were treated with ICI 1L/upfront; 104 with 2 + L. For the 1L/upfront: median [m] OS was numerically longer in patients with TMB ≥10 versus TMB <10: mOS 35 versus 26 months (HR = 0.6) and with MSI-H and MSI-S (mOS NR vs. 22 months), though neither association was statistically significant. A statistically significant association was found between TMB (continuous variable) and OS (HR = 0.96, P = .01). For 2 + L: mOS was numerically longer in patients with TMB ≥10 versus TMB <10: (20 vs. 12 months; HR = 0.9); mOS was 12 and 17 months for patients with MSI-H and MSI-S, respectively. Eighty-nine patients received maintenance avelumab (mAV): mOS was longer in patients with TMB ≥10 versus TMB <10: 61 versus 17 months; (HR = 0.2, P = .02) and with MSI-H and MSI-S (NR vs. 24 months). CONCLUSIONS: Although not reaching statistical significance in several subsets, patients with high TMB and MSI-H had numerically longer OS with ICI, especially with mAV. Further validation is needed.

Comprehensive multiplexed autoantibody profiling of patients with advanced urothelial cancer.

BACKGROUND: Comprehensive profiling of autoantibodies (AAbs) in metastatic urothelial cancer (mUC) has not been performed to date. This may aid in diagnosis of UC, uncover novel therapeutic targets in this disease as well as identify associations between AAbs and response and toxicity to systemic therapies. METHODS: We used serum from patients with mUC collected prior to and after systemic therapy (immune checkpoint inhibitor (ICI) or platinum-based chemotherapy (PBC)) at Dana-Farber Cancer Institute. 38 age-matched and sex-matched healthy controls (HCs) from healthy blood donors were also evaluated. The SeroTag immuno-oncology discovery array (Oncimmune) was used, with quantification of the AAb reactivity toward 1132 antigens. Bound AAbs were detected using an anti-immunoglobulin G-specific detection antibody conjugated to the fluorescent reporter dye phycoerythrin. The AAb reactivity was reported as the median fluorescence intensity for each color and sample using a Luminex FlexMAP3D analyzer. Clinical outcomes of interest included radiographic response and development of immune-related adverse events (irAEs). Significance analysis of microarray was used to compare mUC versus HC and radiographic response. Associations with irAE were evaluated using a logistic regression model. P<0.05 was considered statistically significant. RESULTS: 66 patients were included with a median age of 68 years; 54 patients (82%) received ICI and 12 patients (18%) received PBC. Compared with HCs, AAbs against the cancer/testis antigens (CTAG1B, CTAG2, MAGEB18), HSPA1A, TP53, KRAS, and FGFR3 were significantly elevated in patients with mUC. AAbs against BRCA2, TP53, and CTNBB1 were associated with response, and those against BICD2 and UACA were associated with resistance to ICI therapy. AAbs against MITF, CDH3, and KDM4A were associated with development of irAEs in patient who received an ICI. A higher variance in pre-to-post treatment fold change in AAb levels was seen in patients treated with ICI versus PBC and was associated with response to ICI. CONCLUSIONS: This is the first report of comprehensive AAb profiling of patients with mUC and identified key AAbs that were elevated in patients with mUC versus HCs as well as AAbs associated with therapeutic response to ICI. These findings are hypothesis generating and further mechanistic studies evaluating humoral immunity in UC are required.

ATM deficiency confers specific therapeutic vulnerabilities in bladder cancer.

Ataxia-telangiectasia mutated (ATM) plays a central role in the cellular response to DNA damage and ATM alterations are common in several tumor types including bladder cancer. However, the specific impact of ATM alterations on therapy response in bladder cancer is uncertain. Here, we combine preclinical modeling and clinical analyses to comprehensively define the impact of ATM alterations on bladder cancer. We show that ATM loss is sufficient to increase sensitivity to DNA-damaging agents including cisplatin and radiation. Furthermore, ATM loss drives sensitivity to DNA repair-targeted agents including poly(ADP-ribose) polymerase (PARP) and Ataxia telangiectasia and Rad3 related (ATR) inhibitors. ATM loss alters the immune microenvironment and improves anti-PD1 response in preclinical bladder models but is not associated with improved anti-PD1/PD-L1 response in clinical cohorts. Last, we show that ATM expression by immunohistochemistry is strongly correlated with response to chemoradiotherapy. Together, these data define a potential role for ATM as a predictive biomarker in bladder cancer.