Impact of DNA Repair Deficiency in the Evolving Treatment Landscape of Bladder Cancer.

PURPOSE OF REVIEW: This review explores the current landscape of treatments which target the DNA damage response (DDR) in metastatic and muscle-invasive bladder cancer. It emphasizes recent clinical trials which integrate DDR inhibitors with standard chemotherapy and immunotherapy. RECENT FINDINGS: Noteworthy findings include the ATLANTIS trial, which demonstrated prolonged progression-free survival (PFS) in DDR biomarker-selected patients using PARP inhibitors as maintenance after standard chemotherapy. Trials such as BAYOU, which combined immunotherapy with PARP inhibition, similarly suggested a potential therapeutic benefit in DDR biomarker-selected patients with bladder cancer. Efforts to develop bladder-sparing treatment regimens based on DDR-associated mutational profiles, such as the RETAIN and HCRN 16-257 trials, have had mixed outcomes to date. There are now ongoing efforts to combine DDR inhibitors with the newest bladder cancer therapies, such as antibody-drug conjugates. This review highlights the most recent advances in targeting DNA repair deficiency in the evolving treatment landscape of bladder cancer.

Molecular characterization of metastatic penile squamous cell carcinoma in developing countries and its impact on clinical outcomes: LACOG 2018 translational study.

BACKGROUND: Penile squamous cell carcinoma (PSCC) is a rare malignancy. However, in developing countries the incidence rate is higher. The understanding of molecular alterations is essential for evaluating possible targets for more effective systemic therapies. METHODS: We retrospectively collected clinical data of metastatic PSCC (mPSCC) patients who had received at least one prior systemic treatment from 3 Brazilian hospitals. Tumor samples were evaluated using the next-generation sequencing (NGS) Foundation One DX and immunohistochemistry (IHC). The objective was to identify and describe somatic genomic alterations known to be functional or pathogenic and their association with survival outcomes. RESULTS: Twenty-three patients were identified, 22 and 18 patients had tumor samples analyzed by IHC and NGS, respectively. PD-L1 expression (CPS ≥ 1%) was positive in 14 patients (63.6%). Regarding the genomic alterations, 16 patients (88.9%) had some clinically relevant genomic alterations. TP53, TERT, CDKN2A, PIK3CA, NOTCH1, and CDKN2B loss were identified in 66.7%, 50%, 50%, 33.3%, 27.8%, and 22.2% of the patients, respectively. No MSI or TMB high (≥10 mutations/MB) cases were identified. NOTCH1 mutation was identified only in HPV-negative patients and it was associated with worse OS (yes: 5.5 vs no: 12.8 months, P = .049) and progression-free survival (yes: 5.5 vs no: 11.7 months, P = .032). CONCLUSION: This study demonstrated that molecular alterations in mPSCC from developing countries are similar to those from developed countries. Predictive biomarkers for immunotherapy response such as TMB high or MSI were not identified. Specific gene mutations may identify patients with worse prognoses and open new avenues for therapeutic development.

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.

Enhancing immunotherapy through PD-L1 upregulation: the promising combination of anti-PD-L1 plus mTOR inhibitors.

Immune checkpoint inhibitors (ICIs) targeting the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) pathway have transformed urothelial cancer (UC) therapy. The correlation between PD-L1 expression and ICI effectiveness is uncertain, leaving the role of PD-L1 as a predictive marker for ICI efficacy unclear. Among several ways to enhance the efficacy of ICI, trials are exploring combining ICIs with serine/threonine-protein kinase mTOR (mTOR) inhibitors in different tumor types. The potential interaction between mTOR inhibitors and PD-L1 expression in UC has not been well characterized. In our study, we investigated how phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway inhibitors (TAK-228, everolimus and TAK-117) affect PD-L1 expression and function in preclinical bladder cancer cell models. TAK-228 increased cell surface levels of glycosylated PD-L1 in all but one of the seven cell lines, regardless of baseline levels. TAK-228 promoted the secretion of epidermal growth factor (EGF) and interferon-ß (IFNß), both linked to PD-L1 protein induction. Blocking EGF and IFNß receptors reversed the TAK-228-induced PD-L1 increase. Additionally, TAK-228 enhanced IFN-γ-induced PD-L1 expression and intracellular HLA-I levels in some cells. TAK-228-treated bladder cancer cells exhibited resistance to the cytotoxic effects of peripheral blood mononuclear cells (PBMCs) and cluster of differentiation 8 (CD8)+ T cells. The addition of an anti-PD-L1 antibody diminished this resistance in T24 cells. Increased expression of PD-L1 under TAK-228 exposure was confirmed in patient-derived explants (PDEs) treated ex vivo. These preclinical findings suggest that mTOR inhibition with TAK-228 can increase PD-L1 levels, potentially impacting the specific immune response against UC cells. This highlights the rationale for exploring the combination of mTOR inhibitors with ICIs in patients with advanced UC.

Impact of Prior Chemotherapy on Response to Second-line Pembrolizumab in Urothelial Cancer: Exploratory Analysis of the Phase 3 KEYNOTE-045 Trial.

BACKGROUND AND OBJECTIVE: Until recently, the standard first-line treatment for advanced urothelial carcinoma (UC) was platinum-based combination chemotherapy followed by avelumab maintenance therapy for patients without progressive disease (PD). For patients with advanced UC who experience PD or recurrence, standard-of-care treatment is pembrolizumab monotherapy based on the phase 3 KEYNOTE-045 study. This post hoc analysis of the KEYNOTE-045 study evaluated the efficacy of pembrolizumab compared with chemotherapy by the best response to prior platinum-based chemotherapy. METHODS: Patients with advanced UC that progressed or recurred after first-line platinum-based chemotherapy were randomly assigned 1:1 to receive either pembrolizumab 200 mg every 3 wk (Q3W) for ≤2 yr or investigator's choice of chemotherapy (paclitaxel [175 mg/m2], docetaxel [75 mg/m2], or vinflunine [320 mg/m2], each Q3W). Endpoints included overall survival (OS) from the initiation of the last treatment prior to death, objective response rate (ORR), and duration of response (DOR) as per Response Evaluation Criteria in Solid Tumors version 1.1 from the date of the first response. KEY FINDINGS AND LIMITATIONS: An objective response to pembrolizumab was observed in all groups in terms of a prior response to first-line platinum-based chemotherapy. Median OS, ORR, and median DOR were numerically greater with pembrolizumab than with chemotherapy across subgroups. Patients with PD as the best response to prior platinum-based chemotherapy had the poorest OS outcomes. Limitations include a lack of formal hypothesis testing. CONCLUSIONS AND CLINICAL IMPLICATIONS: When compared with chemotherapy, prolonged OS and durable responses to second-line pembrolizumab were observed independently of the response to or type of prior platinum-based chemotherapy. These findings further support pembrolizumab as second-line treatment for advanced UC.

Epacadostat plus pembrolizumab versus placebo plus pembrolizumab for advanced urothelial carcinoma: results from the randomized phase III ECHO-303/KEYNOTE-698 study.

BACKGROUND: Indoleamine 2,3-dioxygenase 1 (IDO1) levels correlate with poor outcomes in urothelial carcinoma (UC). IDO1 and programmed death-ligand 1 (PD-L1) are often co-expressed. Epacadostat is a potent and highly selective inhibitor of IDO1. In a subgroup analysis of patients with advanced UC participating in a phase I/II study, epacadostat-pembrolizumab treatment produced an objective response rate (ORR) of 35%. METHODS: ECHO-303/KEYNOTE-698 was a double-blinded, randomized phase III study of adults with metastatic or unresectable locally advanced UC with recurrence or progression following first-line platinum-based chemotherapy. Participants were randomized to epacadostat 100 mg twice daily (BID) plus pembrolizumab or placebo plus pembrolizumab until completion of 35 pembrolizumab infusions, disease progression, or unacceptable toxicity. The primary endpoint was investigator-assessed ORR per Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: Target enrollment was 648 patients; enrollment was halted early based on efficacy results from the phase III ECHO-301/KEYNOTE-252 study in metastatic melanoma. Forty-two patients were randomized to each treatment arm. Median duration of follow-up was 62 days in each arm. The investigator-assessed ORR (unconfirmed) was 26.2% (95% CI 16.35-48.11) for epacadostat plus pembrolizumab and 11.9% (95% CI 4.67-29.50) for placebo plus pembrolizumab. Two complete responses were reported, both in the placebo-plus-pembrolizumab arm. Circulating kynurenine levels increased from C1D1 to C2D1 in the placebo-plus-pembrolizumab arm and numerically decreased in the epacadostat-plus-pembrolizumab arm. The safety profile of epacadostat plus pembrolizumab was similar to that of pembrolizumab monotherapy, although a numerically greater proportion of patients in the combination vs. control arm experienced treatment-related grade ≥ 3 adverse events (16.7% vs. 7.3%). One patient in each arm died due to cardiovascular events, which were not deemed drug-related. No new safety concerns were identified for either agent. CONCLUSIONS: Epacadostat plus pembrolizumab demonstrated anti-tumor activity and was generally tolerable as second-line treatment of patients with unresectable locally advanced or recurrent/progressive metastatic UC. Epacadostat 100 mg BID, when administered with pembrolizumab, did not normalize circulating kynurenine in most patients. Further study of combined IDO1/PD-L1 inhibition in this patient population, particularly with epacadostat doses that result in durable normalization of circulating kynurenine, may be warranted. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03374488. Registered 12/15/2017.

Enfortumab vedotin and pembrolizumab combination as a relevant game changer in urothelial carcinoma: What is left behind?

The EV-302 study1 marks a pivotal leap in the management of advanced urothelial carcinoma, setting a new benchmark for frontline therapy. Enfortumab vedotin plus pembrolizumab is the first combination therapy that has ever outperformed standard chemotherapy. The degree of benefit and the reported safety profile should make this combination a first-choice option for most patients with advanced-stage urothelial carcinoma.

Dual mTOR1/2 Inhibitor Sapanisertib (FTH-003/TAK-228) in Combination With Weekly Paclitaxel in Patients With Previously Treated Metastatic Urothelial Carcinoma: A Phase II Open-Label Study.

BACKGROUND: The PI3K/AKT/mTOR pathway is frequently altered at genomic level in metastatic urothelial carcinoma (mUC). Since mTOR is the last protein in the PI3K signaling cascade, it may have the largest impact on the pathway and has been a focus of targeted therapies. Sapanisertib (FTH-003/TAK-228) is an oral highly selective mTOR1 and mTOR2 inhibitor. NFE2L2 mutations have been described as predictive biomarkers of response in patients with advanced squamous cell lung cancer treated with sapanisertib. PATIENTS AND METHODS: This was an open-label, investigator-initiated phase II study evaluating safety and efficacy of sapanisertib plus paclitaxel in patients with mUC who had progressed to prior platinum therapy, and the correlation with NFE2L2 mutations in responders. Primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. Patients were treated with weekly paclitaxel at dose of 80 mg/m2 on days 1, 8, and 15 in combination with sapanisertib 4 mg administered orally 3 days per week on days 2-4, 9-11, 16-18, and 23-25 of a 28-day cycle. NFE2L2 mutations were analyzed by Sanger sequencing in responders. RESULTS: 22 patients were enrolled from May 2018 to April 2020; the trial was halted early due to slow accrual and the COVID-19 pandemic. ORR was 18.2% (n = 4). Disease control rate was 50% (7 SD and 4 PR). Median PFS was 3.4 months (95% CI: 1.8-6.1) and median OS was 6.1 months (95% CI: 1.8-13.4). Adverse events (AE) of grade 3-4 were seen in 86% of patients, but no patients discontinued treatment due to AEs. NFE2L2 mutations were not found in responders. CONCLUSIONS: Although the primary endpoint was no met, sapanisertib and paclitaxel combination demonstrated clinical activity in a heavily pretreated population of mUC. This trial generates insight for future combination of sapaniserib with immunotherapy and/or antibody drug conjugates.

Safety profile of pembrolizumab monotherapy based on an aggregate safety evaluation of 8937 patients.

BACKGROUND: Pembrolizumab has a manageable safety profile as described in its label, which was primarily based on 2799 patients who participated in clinical trials for melanoma or non-small cell lung cancer. Here, we evaluated the safety of pembrolizumab in a broader population of patients from 31 advanced cancer clinical trials across 19 cancer types. METHODS: Safety was analyzed in patients who received at least one dose of pembrolizumab (200 mg every 3 weeks [Q3W], 10 mg/kg Q2W or Q3W, or 2 mg/kg Q3W). Adverse events (AEs) and immune-mediated AEs and infusion reactions were evaluated. RESULTS: Safety data from 8937 patients in 31 trials of pembrolizumab monotherapy were pooled (median, seven administrations; range, 1-59). Median duration on treatment was 4.1 months (range, 0.03-40.1). AEs occurred in 96.6% of patients. Grade 3-5 AEs occurred in 50.6% of patients. AEs led to pembrolizumab discontinuation in 12.7% of patients and death in 5.9%. Immune-mediated AEs and infusion reactions occurred in 23.7% of patients (4.6% experienced multiple immune-mediated AEs/infusion reactions) and led to pembrolizumab discontinuation in 3.6% and death in 0.2%. Grade 3-5 immune-mediated AEs occurred in 6.3% of patients. Serious immune-mediated AEs and infusion reactions occurred in 6.0% of patients. Median time to immune-mediated AE onset was 85 days (range, 13-163). Of 2657 immune-mediated AEs, 22.3% were initially treated with prednisone ≥ 40 mg/day or equivalent, and 8.3% were initially treated with lower steroid doses. CONCLUSIONS: This pooled analysis of 31 clinical trials showed that pembrolizumab has a consistent safety profile across indications.

Progress in systemic therapy for advanced-stage urothelial carcinoma.

Despite recent advances, advanced-stage urothelial carcinoma (aUC) remains incurable, with 5-year survival rates of approximately 10%. Platinum-based chemotherapy has a major role as first-line therapy for most patients with aUC. The approval of the anti-PD-L1 antibody avelumab as maintenance therapy for patients without initial disease progression on platinum-based chemotherapy is an important development that has improved the survival outcomes of patients with this disease. Otherwise, the use of first-line immune-checkpoint inhibitors (ICIs) targeting PD-1 or PD-L1 has been restricted to patients who are ineligible for platinum-containing chemotherapy regimens. Other important developments include the FDA-accelerated approval of first-line enfortumab vedotin plus pembrolizumab for patients ineligible to receive cisplatin and the availability of FGFR inhibitors, enfortumab vedotin and sacituzumab govitecan for subsequent lines of therapy. Several research questions remain unaddressed including the lack of adequate biomarkers, how to assign priority to the different treatment options for individual patients and which agents can be effective as monotherapies. The future is promising with the emergence of modalities such as antibody-drug conjugate-like drugs, next-generation ICIs, bispecific antibodies and cellular therapies. In this Review, we summarize the evolution of systemic therapy for patients with aUC and provide insights into the unmet needs.

Updated Overall Survival by Circulating Tumor DNA Status from the Phase 3 IMvigor010 Trial: Adjuvant Atezolizumab Versus Observation in Muscle-invasive Urothelial Carcinoma.

BACKGROUND: Interim results from IMvigor010 showed an overall survival (OS) benefit for adjuvant atezolizumab (anti-PD-L1) versus observation in patients with circulating tumor DNA (ctDNA)-positive muscle-invasive urothelial carcinoma (MIUC). OBJECTIVE: To report updated OS and safety by ctDNA status. DESIGN, SETTING, AND PARTICIPANTS: This ad hoc analysis from a global, open-label, randomized, phase 3 trial (NCT02450331) included intention-to-treat (ITT) population with evaluable cycle 1 day 1 (C1D1) ctDNA samples. INTERVENTION: Atezolizumab (1200 mg every 3 wk) or observation for ≤1 yr. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: OS, relapse rates, and safety by ctDNA status were assessed. RESULTS AND LIMITATIONS: Among 581 of 809 ITT patients included, 214 (37%) were ctDNA positive. Atezolizumab did not improve OS versus observation in ITT patients (hazard ratio [HR] 0.91 [95% confidence interval {CI} 0.73-1.13]; median follow-up 46.8 mo [interquartile range, 36.1-53.6]). In the observation arm, ctDNA positivity versus negativity was associated with shorter OS (HR 6.3 [95% CI 4.3-9.3]). The ctDNA positivity identified patients with an OS benefit favoring atezolizumab versus observation (HR 0.59 [95% CI 0.42-0.83]). A greater reduction in ctDNA levels with atezolizumab (C3D1) was associated with longer OS (100% clearance, 60.0 mo [95% CI 35.5-not estimable]; 50-99% reduction, 34.3 mo [95% CI 15.2-not estimable]; <50% reduction, 19.9 mo [95% CI 16.4-32.2]). The ctDNA positivity at C1D1 + C3D1 was associated with relapse with greater sensitivity than C1D1 alone (68% vs 57%). Adverse events were more frequent with atezolizumab than with observation, regardless of ctDNA status. A study limitation was its exploratory design. CONCLUSIONS: Evidence suggests that ctDNA positivity in MIUC predicts a benefit with atezolizumab. An in-progress prospective study will further evaluate these findings. PATIENT SUMMARY: Among patients with urothelial cancer after surgery, survival was poorer if tumor-derived DNA was detected in their bloodstream; these patients' survival was longer with atezolizumab versus observation. Bloodstream tumor-derived DNA may identify patients who benefit from atezolizumab.

Avelumab First-line Maintenance for Advanced Urothelial Carcinoma: Analysis from JAVELIN Bladder 100 by Duration of First-line Chemotherapy and Interval Before Maintenance.

BACKGROUND: In the JAVELIN Bladder 100 phase 3 trial, avelumab first-line maintenance + best supportive care (BSC) prolonged overall survival (OS) and progression-free survival (PFS) versus BSC alone in patients with advanced urothelial carcinoma (advanced UC) without progression after first-line platinum-based chemotherapy. OBJECTIVE: To report post hoc analyses of subgroups defined by the duration of first-line chemotherapy and interval before maintenance. DESIGN, SETTING, AND PARTICIPANTS: Patients with advanced UC without progression after four to six cycles of platinum-based chemotherapy and a 4-10-wk interval after chemotherapy (n = 700) were randomized to receive avelumab + BSC or BSC alone. Subgroups were defined by duration (quartile [Q]) and estimated number of cycles of chemotherapy, and interval between chemotherapy and maintenance. The median follow-up was >19 mo in both arms. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: OS (primary endpoint), PFS, and safety were assessed. RESULTS AND LIMITATIONS: Hazard ratios (95% confidence interval) for OS with avelumab + BSC versus BSC alone were as follows: by chemotherapy duration-Q3: 0.63 (0.39-1.00); by number of cycles-four cycles: 0.69 (0.48-1.00), five cycles: 0.98 (0.57-1.71), and six cycles: 0.66 (0.47-0.92); and by interval-4-<6 wk: 0.75 (0.54-1.04), 6-<8 wk: 0.67 (0.43-1.06), and 8-10 wk: 0.69 (0.47-1.02). Results were similar for PFS. Safety was similar across subgroups. All analyses were exploratory. CONCLUSIONS: Post hoc analyses of OS and PFS in subgroups defined by first-line chemotherapy duration and interval before maintenance were generally consistent with the results in the overall population, with similar safety findings. Prospective trials are warranted to confirm these findings. PATIENT SUMMARY: Avelumab maintenance treatment helped patients with advanced urothelial cancer without disease progression after at least four cycles of prior chemotherapy, and who started maintenance treatment at least 4 wk after chemotherapy, to live longer.

Immunohistochemical markers as predictors of prognosis in multifocal prostate cancer.

The impact of tumor focality on prostate cancer (PCa) prognosis has been addressed in several studies with conflicting results. Tumor foci from multifocal (MF) PCa can show highly heterogeneous molecular features. Our aim was to analyze the protein expression of PTEN, SPOP, SLC45A3, ETV1, ERG and the "triple hit" (ERG overexpression, PTEN plus SLC45A3 loss) in unifocal (UF) and MF PCa, to evaluate their value as prognostic markers according to focality, and the role of tumor heterogeneity in MF disease. PTEN, SPOP, SLC45A3, ETV1 and ERG immunohistochemical expression was evaluated in 185 PCa from 9 TMAs, 51 UF and 134 MF. In a subset of 69 MF cases, the dominant and secondary foci (DF and SF) were compared. Heterogeneity was considered when both tumor foci presented different expression patterns. Relationship with clinicopathological features was also analyzed. MF PCa was diagnosed in significantly younger patients when compared to UF ones (p = 0.007). ETV1 overexpression was associated with UF disease (p = 0.028). A shorter time to PSA recurrence was related to SLC45A3 wt expression in UF PCa (p = 0.052), and to SPOP expression loss (p = 0.043) or "triple hit" phenotype in MF PCa (p = 0.041). In MF cases, PTEN loss, SLC45A3 loss and "triple hit" phenotype were associated with the DF and had significant heterogeneity. In conclusion, our results indicate that UF and MF PCa have relevant and consistent molecular differences. The analysis of an immunohistochemical panel, composed by PTEN, SPOP, SLC45A3, ETV1 and ERG, could be useful to predict outcome in MF cases.

Bone targeting agents, but not radiation therapy, improves survival in patients with bone metastases from advanced urothelial carcinoma receiving pembrolizumab: results from the ARON-2 study.

The ARON-2 study (NCT05290038) aimed to assess the real-world efficacy of pembrolizumab in patients recurred or progressed after platinum-based chemotherapy. This retrospective analysis reports the outcomes of urothelial carcinoma (UC) patients with bone metastases (BM). Medical records of patients with documented metastatic UC treated by pembrolizumab as second-line therapy were reviewed from60 institutions in 20 countries. Patients were assessed for Overall Response Rate (ORR), Progression-Free Survival (PFS), and Overall Survival (OS). Univariate and multivariate analyses were used to explore the association of variables of interest with OS and PFS. 881 patients were included; of them, 263 (30%) presented BM. Median follow-up time was 22.7 months. Patients with BM showed both shorter median OS (5.9 months vs 13.1 months, p < 0.001) and PFS (3.5 months, vs 7.3 months, p < 0.001) compared to patients without BM. Patients who received bone targeted agents (BTAs) showed a significantly longer median OS (8.5 months vs 4.6 months, p = 0.003) and PFS (6.1 months vs 3.2 months, p = 0.003), while no survival benefits were observed among patients who received radiation therapy for BM during pembrolizumab treatment compared to those who did not. In multivariate analysis, performance status, concomitant liver metastases, and the lack of use of BTAs were significantly associated with worse OS and PFS. Bone involvement in UC patients treated with pembrolizumab predicts inferior survival. Poor performance status and liver metastases may further worsen outcomes, while the use of BTAs is associated with improved outcomes.

The impact of mutational clonality in predicting the response to immune checkpoint inhibitors in advanced urothelial cancer.

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment and can result in complete remissions even at advanced stages of the disease. However, only a small fraction of patients respond to the treatment. To better understand which factors drive clinical benefit, we have generated whole exome and RNA sequencing data from 27 advanced urothelial carcinoma patients treated with anti-PD-(L)1 monoclonal antibodies. We assessed the influence on the response of non-synonymous mutations (tumor mutational burden or TMB), clonal and subclonal mutations, neoantigen load and various gene expression markers. We found that although TMB is significantly associated with response, this effect can be mostly explained by clonal mutations, present in all cancer cells. This trend was validated in an additional cohort. Additionally, we found that responders with few clonal mutations had abnormally high levels of T and B cell immune markers, suggesting that a high immune cell infiltration signature could be a better predictive biomarker for this subset of patients. Our results support the idea that highly clonal cancers are more likely to respond to ICI and suggest that non-additive effects of different signatures should be considered for predictive models.

A Plea for the Use of Video-recorded Cystoscopy for Blinded Independent Central Review of Tumor Response in Open-label Non-muscle invasive Bladder Cancer Trials.

Given that most of non-muscle invasive bladder cancer trials available in the literature share the same limitation of an open-label design, they are likely prone to detection bias. Indeed, tumor response is currently assessed by unblinded investigators, mainly via follow-up cystoscopy, which has well-known intraobserver and interobserver variability. Thus, we believe that the use of video-recorded cystoscopy for blinded independent central review of tumor response could help to minimize detection bias in open-label NMIBC trials.