Efficacy of enfortumab vedotin in advanced urothelial cancer: Analysis from the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study.

BACKGROUND: Enfortumab vedotin (EV) is a novel antibody-drug conjugate approved for advanced urothelial cancer (aUC) refractory to prior therapy. In the Urothelial Cancer Network to Investigate Therapeutic Experiences (UNITE) study, the authors looked at the experience with EV in patient subsets of interest for which activity had not been well defined in clinical trials. METHODS: UNITE was a retrospective study of patients with aUC treated with recently approved agents. This initial analysis focused on patients treated with EV. Patient data were abstracted from chart reviews by investigators at each site. The observed response rate (ORR) was investigator-assessed for patients with at least 1 post-baseline scan or clear evidence of clinical progression. ORRs were compared across subsets of interest for patients treated with EV monotherapy. RESULTS: The initial UNITE analysis included 304 patients from 16 institutions; 260 of these patients were treated with EV monotherapy and included in the analyses. In the monotherapy cohort, the ORR was 52%, and it was >40% in all reported subsets of interest, including patients with comorbidities previously excluded from clinical trials (baseline renal impairment, diabetes, and neuropathy) and patients with fibroblast growth factor receptor 3 (FGFR3) alterations. Progression-free survival and overall survival were 6.8 and 14.4 months, respectively. Patients with a pure urothelial histology had a higher ORR than patients with a variant histology component (58% vs 42%; P = .06). CONCLUSIONS: In a large retrospective cohort, responses to EV monotherapy were consistent with data previously reported in clinical trials and were also observed in various patient subsets, including patients with variant histology, patients with FGFR3 alterations, and patients previously excluded from clinical trials with an estimated glomerular filtration rate < 30 mL/min and significant comorbidities. LAY SUMMARY: Enfortumab vedotin, approved by the Food and Drug Administration in 2019, is an important new drug for the treatment of patients with advanced bladder cancer. This study looks at the effectiveness of enfortumab vedotin as it has been used at multiple centers since approval, and focuses on important patient populations previously excluded from clinical trials. These populations include patients with decreased kidney function, diabetes, and important mutations. Enfortumab vedotin is effective for treating these patients. Previously reported clinical trial data have been replicated in this real-world setting, and support the use of this drug in broader patient populations.

Longitudinal Evaluation of Circulating Tumor DNA Using Sensitive Amplicon-Based Next-Generation Sequencing to Identify Resistance Mechanisms to Immune Checkpoint Inhibitors for Advanced Urothelial Carcinoma.

Serial evaluation of circulating tumor DNA may allow noninvasive assessment of drivers of resistance to immune checkpoint inhibitors (ICIs) in advanced urothelial cancer (aUC). We used a novel, amplicon-based next-generation sequencing assay to identify genomic alterations (GAs) pre- and post-therapy in 39 patients with aUC receiving ICI and 6 receiving platinum-based chemotherapy (PBC). One or more GA was seen in 95% and 100% of pre- and post-ICI samples, respectively, commonly in TP53 (54% and 54%), TERT (49% and 59%), and BRCA1/BRCA2 (33% and 33%). Clearance of ≥1 GA was seen in 7 of 9 patients responding to ICI, commonly in TP53 (n = 4), PIK3CA (n = 2), and BRCA1/BRCA2 (n = 2). A new GA was seen in 17 of 20 patients progressing on ICI, frequently in BRCA1/BRCA2 (n = 6), PIK3CA (n = 3), and TP53 (n = 3), which seldom emerged in patients receiving PBC. These findings highlight the potential for longitudinal circulating tumor DNA evaluation in tracking response and resistance to therapy.

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.

Noninvasive Detection of Neuroendocrine Prostate Cancer through Targeted Cell-free DNA Methylation.

Castration-resistant prostate cancer (CRPC) is a heterogeneous disease associated with phenotypic subtypes that drive therapy response and outcome differences. Histologic transformation to castration-resistant neuroendocrine prostate cancer (CRPC-NE) is associated with distinct epigenetic alterations, including changes in DNA methylation. The current diagnosis of CRPC-NE is challenging and relies on metastatic biopsy. We developed a targeted DNA methylation assay to detect CRPC-NE using plasma cell-free DNA (cfDNA). The assay quantifies tumor content and provides a phenotype evidence score that captures diverse CRPC phenotypes, leveraging regions to inform transcriptional state. We tested the design in independent clinical cohorts (n = 222 plasma samples) and qualified it achieving an AUC > 0.93 for detecting pathology-confirmed CRPC-NE (n = 136). Methylation-defined cfDNA tumor content was associated with clinical outcomes in two prospective phase II clinical trials geared towards aggressive variant CRPC and CRPC-NE. These data support the application of targeted DNA methylation for CRPC-NE detection and patient stratification. SIGNIFICANCE: Neuroendocrine prostate cancer is an aggressive subtype of treatment-resistant prostate cancer. Early detection is important, but the diagnosis currently relies on metastatic biopsy. We describe the development and validation of a plasma cell-free DNA targeted methylation panel that can quantify tumor fraction and identify patients with neuroendocrine prostate cancer noninvasively. This article is featured in Selected Articles from This Issue, p. 384.

Clinical outcomes and safety of immune checkpoint inhibitors in patients with solid tumors and paraneoplastic syndromes.

BACKGROUND: Patients with paraneoplastic syndromes (PNS) are excluded from clinical trials involving immune checkpoint inhibitors (ICIs) due to safety concerns. Moreover, real-world data on efficacy and safety is scarce. METHODS: In this retrospective study, data were collected on patients with PNS and solid tumors receiving ICI between 2015 and 2022 at nine institutions. Patients were classified into: Cohort 1 (pre-existing PNS before ICI initiation), cohort 2 (PNS during ICI treatment), and cohort 3 (PNS after ICI discontinuation). Patients with metastatic non-small cell lung cancer (NSCLC) (mNSCLC) from cohort 1 were matched to patients who were PNS-free at each institution up to a 1:3 ratio for age, sex, type of ICI, use of concurrent chemotherapy, and number of lines of systemic therapy prior to ICI initiation. Kaplan-Meier method was used to assess overall survival (OS) and time-to-next treatment (TTNT). RESULTS: Among 109 patients with PNS treated with ICIs, median age at ICI initiation was 67 years (IQR: 58-74). The most represented cancer type was NSCLC (n=39, 36%). In cohort 1 (n=55), PNS exacerbations occurred in 16 (29%) patients with median time to exacerbation after ICI of 1.1 months (IQR: 0.7-3.3). Exacerbation or de novo PNS prompted temporary/permanent interruption of ICIs in 14 (13%) patients. For cohort 2 (n=16), median time between ICI initiation and de novo PNS was 1.2 months (IQR: 0.4-3.5). Treatment-related adverse events (trAEs) occurred in 43 (39%) patients. Grade ≥3 trAEs occurred in 18 (17%) patients. PNS-directed immunosuppressive therapy was required in 55 (50%) patients. We matched 18 patients with mNSCLC and PNS (cohort 1) to 40 without PNS, treated with ICIs. There was no significant difference in OS or TTNT between patients with mNSCLC with and without PNS, although a trend was seen towards worse outcomes in patients with PNS. TrAEs occurred in 6/18 (33%) and 14/40 (35%), respectively. Grade ≥3 trAEs occurred in 4 (22%) patients with PNS and 7 (18%) patients without PNS. CONCLUSIONS: Exacerbations of pre-existing PNS occurred in 29% of patients treated with ICIs and both exacerbations and de novo PNS occur early in the ICI course. TrAE from ICIs were similar between patients with and without PNS. Our data suggest that pre-existing PNS should not preclude consideration of ICI therapy although patients may not derive the same clinical benefit compared with patients without PNS.

Epigenomic signatures of sarcomatoid differentiation to guide the treatment of renal cell carcinoma.

Renal cell carcinoma with sarcomatoid differentiation (sRCC) is associated with poor survival and a heightened response to immune checkpoint inhibitors (ICIs). Two major barriers to improving outcomes for sRCC are the limited understanding of its gene regulatory programs and the low diagnostic yield of tumor biopsies due to spatial heterogeneity. Herein, we characterized the epigenomic landscape of sRCC by profiling 107 epigenomic libraries from tissue and plasma samples from 50 patients with RCC and healthy volunteers. By profiling histone modifications and DNA methylation, we identified highly recurrent epigenomic reprogramming enriched in sRCC. Furthermore, CRISPRa experiments implicated the transcription factor FOSL1 in activating sRCC-associated gene regulatory programs, and FOSL1 expression was associated with the response to ICIs in RCC in two randomized clinical trials. Finally, we established a blood-based diagnostic approach using detectable sRCC epigenomic signatures in patient plasma, providing a framework for discovering epigenomic correlates of tumor histology via liquid biopsy.

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.

A genetic basis for cancer sex differences revealed in Xp11 translocation renal cell carcinoma.

Xp11 translocation renal cell carcinoma (tRCC) is a female-predominant kidney cancer driven by translocations between the TFE3 gene on chromosome Xp11.2 and partner genes located on either chrX or on autosomes. The rearrangement processes that underlie TFE3 fusions, and whether they are linked to the female sex bias of this cancer, are largely unexplored. Moreover, whether oncogenic TFE3 fusions arise from both the active and inactive X chromosomes in females remains unknown. Here we address these questions by haplotype-specific analyses of whole-genome sequences of 29 tRCC samples from 15 patients and by re-analysis of 145 published tRCC whole-exome sequences. We show that TFE3 fusions universally arise as reciprocal translocations with minimal DNA loss or insertion at paired break ends. Strikingly, we observe a near exact 2:1 female:male ratio in TFE3 fusions arising via X:autosomal translocation (but not via X inversion), which accounts for the female predominance of tRCC. This 2:1 ratio is at least partially attributable to oncogenic fusions involving the inactive X chromosome and is accompanied by partial re-activation of silenced chrX genes on the rearranged chromosome. Our results highlight how somatic alterations involving the X chromosome place unique constraints on tumor initiation and exemplify how genetic rearrangements of the sex chromosomes can underlie cancer sex differences.

Safety and efficacy of immune checkpoint inhibitors in advanced penile cancer: report from the Global Society of Rare Genitourinary Tumors.

BACKGROUND: Treatment options for penile squamous cell carcinoma are limited. We sought to investigate clinical outcomes and safety profiles of patients with penile squamous cell carcinoma receiving immune checkpoint inhibitors. METHODS: This retrospective study included patients with locally advanced or metastatic penile squamous cell carcinoma receiving immune checkpoint inhibitors between 2015 and 2022 across 24 centers in the United States, Europe, and Asia. Overall survival and progression-free survival were estimated using the Kaplan-Meier method. Objective response rates were determined per Response Evaluation Criteria in Solid Tumours 1.1 criteria. Treatment-related adverse events were graded per the Common Terminology Criteria for Adverse Events, version 5.0. Two-sided statistical tests were used for comparisons. RESULTS: Among 92 patients, 8 (8.7%) were Asian, 6 (6.5%) were Black, and 24 (29%) were Hispanic and/or Latinx. Median (interquartile range) age was 62 (53-70) years. In all, 83 (90%) had metastatic penile squamous cell carcinoma, and 74 (80%) had received at least second-line treatment. Most patients received pembrolizumab monotherapy (n = 26 [28%]), combination nivolumab-ipilimumab with or without multitargeted tyrosine kinase inhibitors (n = 23 [25%]), or nivolumab (n = 16 [17%]) or cemiplimab (n = 15 [16%]) monotherapies. Median overall and progression-free survival were 9.8 months (95% confidence interval = 7.7 to 12.8 months) and 3.2 months (95% confidence interval = 2.5 to 4.2 months), respectively. The objective response rate was 13% (n = 11/85) in the overall cohort and 35% (n = 7/20) in patients with lymph node-only metastases. Visceral metastases, Eastern Cooperative Oncology Group (ECOG) performance status of 1 or higher, and a higher neutrophil/lymphocyte ratio were associated with worse overall survival. Treatment-related adverse events occurred in 27 (29%) patients, and 9.8% (n = 9) of the events were grade 3 or higher. CONCLUSIONS: Immune checkpoint inhibitors are active in a subset of patients with penile squamous cell carcinoma. Future translational studies are warranted to identify patients more likely to derive clinical benefit from immune checkpoint inhibitors.

Impact of renin-angiotensin system inhibitors on outcomes in patients with metastatic renal cell carcinoma treated with immune-checkpoint inhibitors.

BACKGROUND: Renin-angiotensin system inhibitors (RASi) have been shown to improve outcomes in studies of multiple malignancies by effects on the tumor microenvironment to enhance the immune repertoire and improve drug delivery. Repurposing RASi to treat metastatic renal cell carcinoma (mRCC) in combination with immune-checkpoint inhibitors (ICI) may improve survival coupled with tolerability and cost efficacy. We evaluated the impact of RASi on outcomes in mRCC patients receiving ICI. METHODS: This multicenter, retrospective cohort study included mRCC patients treated with ICI with or without RASi. The patients from Dana-Farber Cancer Institute (DFCI) were used as a discovery cohort, and the patients from University of California San Diego (UCSD) were used for validation. Receipt of an ICI (PD1/L1 and/or CTLA-4 inhibitors) was required. RASi use was defined as receipt of a RASi at baseline and for a minimum of 30 days after ICI initiation. For both the discovery and validation cohorts, the primary outcome assessed was overall survival (OS) and the secondary endpoints were time-to-treatment failure (TTF), and objective response rate (ORR). RESULTS: Overall, 229 patients who received an ICI were included: 100 patients from DFCI and 129 patients from UCSD. Concomitant RASi were administered in 30 patients (30%) in the DFCI cohort and 59 (45%) in the UCSD cohort. Median age at ICI initiation was 62.5 years in both cohorts. Median follow-up was 3.8 [IQR 3-5.3] years in the DFCI cohort, and 2.3 [IQR 1.4-3.6] years in the UCSD cohort. In the DFCI cohort, RASi was significantly associated with longer OS (adjusted-HR 0.35 [95% CI, 0.17-0.70], P = .003) and TTF (adjusted-HR 0.57 [0.36-0.92], P = .02). In the validation cohort, RASi was associated with TTF (adjusted HR, 0.60 [0.39-0.92], P = .02) and not statistically associated with OS (adjusted-HR 0.60 [0.34-1.06], P = .07). The propensity analysis, matching 83 patients from both cohorts receiving RASi while on ICI with 83 who did not, showed that RASi significantly improved OS (HR 0.59 [0.37-0.95], P = .03) and TTF (HR 0.60 [0.43-0.85], P = .0034). CONCLUSIONS: RASi was associated with improved OS and TTF in mRCC patients receiving ICI. This provides a rationale for prospective randomized studies combining ICI and RASi in mRCC patients.

FGFR2/3 genomic alterations and response to Enfortumab Vedotin in metastatic urothelial carcinoma.

Enfortumab Vedotin (EV) is approved for metastatic urothelial carcinoma (mUC) progressing post-platinum and PD1/L1 inhibitor therapy. Erdafitinib is approved for post-platinum mUC with activating somatic genomic alterations (GAs) in FGFR2/3. Information on the activity of EV in mUC with FGFR2/3 alterations will facilitate optimal clinical management. In this multi-center, retrospective analysis, we assessed the overall survival (OS), progression-free survival (PFS) and objective response rate (ORR) to EV in mUC patients with and without FGFR2/3 GAs including mutations and fusions. Multivariable cox-regression and logistic regression analyses with 2-tailed p-values were used to evaluate the association of GAs with outcomes. A majority of the evaluable 60 patients were male (44/60, 78%), exhibited ECOG performance score 0-1 (53/60, 88.3%) and had a median age of 70.5 (range 48 - 88) years when starting EV. GAs in FGFR2/3 did not influence the ORR (p=0.32), OS (p=0.79) or PFS (p = 0.32) with EV. In conclusion, FGFR2/3 GAs did not appear to compromise major outcomes with EV in mUC. Larger studies are required to further evaluate the impact of FGFR2/3 GAs on the activity of EV and the optimal sequencing of EV and erdafitinib in mUC.

Genomic Features of Muscle-invasive Bladder Cancer Arising After Prostate Radiotherapy.

BACKGROUND: Muscle-invasive bladder cancer (MIBC) is a rare but serious event following definitive radiation for prostate cancer. Radiation-associated MIBC (RA-MIBC) can be difficult to manage given the challenges of delivering definitive therapy to a previously irradiated pelvis. The genomic landscape of RA-MIBC and whether it is distinct from non-RA-MIBC are unknown. OBJECTIVE: To define mutational features of RA-MIBC and compare the genomic landscape of RA-MIBC with that of non-RA-MIBC. DESIGN, SETTING, AND PARTICIPANTS: We identified patients from our institution who received radiotherapy for prostate cancer and subsequently developed MIBC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We performed whole exome sequencing of bladder tumors from RA-MIBC patients. Tumor genetic alterations including mutations, copy number alterations, and mutational signatures were identified and were compared with genetic features of non-RA-MIBC. We used the Kaplan-Meier method to estimate recurrence-free (RFS) and overall (OS) survival. RESULTS AND LIMITATIONS: We identified 19 RA-MIBC patients with available tumor tissue (n = 22 tumors) and clinical data. The median age was 76 yr, and the median time from prostate cancer radiation to RA-MIBC was 12 yr. The median RFS was 14.5 mo and the median OS was 22.0 mo. Compared with a cohort of non-RA-MIBC analyzed in parallel, there was no difference in tumor mutational burden, but RA-MIBCs had a significantly increased number of short insertions and deletions (indels) consistent with previous radiation exposure. We identified mutation signatures characteristic of APOBEC-mediated mutagenesis, aging, and homologous recombination deficiency. The frequency of mutations in many known bladder cancer genes, including TP53, KDM6A, and RB1, as well as copy number alterations such as CDKN2A loss was similar in RA-MIBC and non-RA-MIBC. CONCLUSIONS: We identified unique mutational properties that likely contribute to the distinct biological and clinical features of RA-MIBC. PATIENT SUMMARY: Bladder cancer is a rare but serious diagnosis following radiation for prostate cancer. We characterized genetic features of bladder tumors arising after prostate radiotherapy, and identify similarities with and differences from bladder tumors from patients without previous radiation.

Incidence of Germline Variants in Familial Bladder Cancer and Among Patients With Cancer Predisposition Syndromes.

BACKGROUND: The familial aggregation of bladder cancers has been observed, but the incidence and association of familial bladder cancer with germline pathogenic and likely pathogenic (P/LP) variants is unknown. PATIENTS AND METHODS: A retrospective analysis was conducted of patients with bladder cancer treated at the Dana-Farber Cancer Institute to identify those with a first-degree relative with bladder cancer. A second cohort of patients referred to DFCI for suspicion of a cancer predisposition syndrome was analyzed for candidate P/LP germline variants. Descriptive statistics were generated. RESULTS: Among 885 patients with bladder cancer, 38 patients (4.3%) had a family history of bladder cancer in a first-degree relative. No significant association of age of diagnosis was observed between patients with and without a first-degree family history of bladder cancer (P = .3). In the second cohort, 27 of 80 (34%) patients with bladder cancer evaluated for cancer predisposition syndromes harbored a P/LP germline variant. P/LP variants were identified most commonly in the following genes: BRCA1 (n = 5), MSH2 (n = 5), MLH1 (n = 4), ATM (n = 3), and CHEK2 (n = 2). Of the 27 patients with identified germline P/LP variants, 20 (74%) had a family history of a tumor component syndrome in a first- or second-degree relative and 3 were subsequently diagnosed with another genetically-linked associated cancer. CONCLUSION: Familial bladder cancer defined as bladder cancer in the proband and a first-degree relative, was present in 4.3% of patients with bladder cancer and was not associated with age of diagnosis. Additionally, among patients suspected to have a familial cancer syndrome, one-third harbored a germline P/LP variant. Further study of germline variants in patients with familial bladder cancer including somatic testing for loss of heterozygosity may provide insights regarding disease pathogenesis and inform therapy.

Angiotensin Blockade Modulates the Activity of PD1/L1 Inhibitors in Metastatic Urothelial Carcinoma.

BACKGROUND: The renin-angiotensin system is involved in the regulation of angiogenesis and cell proliferation. Angiotensin inhibition may improve drug delivery by enhancing tumor perfusion partly by downregulating transforming growth factor (TGF)-ß. Because TGF-ß is associated with resistance in patients with metastatic urothelial carcinoma (mUC) receiving programmed cell death protein 1/programmed cell death ligand 1 (PD1/L1) inhibitors, we hypothesized that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) may enhance the outcomes of patients with mUC who receive PD1/L1 inhibitors. PATIENTS AND METHODS: Data from patients with mUC who received PD1/L1 inhibitors as monotherapy were obtained; patients from the Dana-Farber Cancer Institute constituted the discovery dataset, and data from Moffitt Cancer Center served as the validation dataset. A logistic regression investigated the impact of concurrent ACEI/ARB primarily on any regression of tumor (ART) after controlling for prognostic factors. RESULTS: Data were available for 178 patients from the discovery dataset, of whom 153 (86%) had received prior platinum and 33 (18.5%) concurrent ACEIs/ARBs. Multivariable logistic regression analysis revealed that ACEIs/ARBs were associated with greater probability of ART (odds ratio [OR] = 2.69; 95% confidence interval [CI], 1.15-6.30; P = .022). In the validation dataset, 101 patients were available, of whom 59 (58.4%) had received prior platinum and 22 (21.8%) concurrent ACEIs/ARBs. ACEI/ARB demonstrated a trend for association with ART (OR = 3.28; 95% CI, 0.98-10.99; P = .054) on multivariable analysis of the validation dataset. CONCLUSIONS: Concurrent angiotensin blockade was associated with a higher rate of tumor regression in patients with mUC receiving PD1/L1 inhibitors. Validation is warranted in a prospective trial, especially given the cost efficacy of ACEIs/ARBs.