Innate Lymphoid Cells in Bladder Cancer: From Mechanisms of Action to Immune Therapies

Bladder tumors have a high mutational burden and tend to be responsive to immune therapies; however, response rates remain modest. To date, immunotherapy in bladder cancer has largely focused on enhancing T-cell immune responses in the bladder tumor microenvironment. It is anticipated that other immune cells, including innate lymphoid cells (ILC), which play an important role in bladder oncogenesis and tumor suppression, could be targeted to improve response to existing therapies. ILCs are classified into five groups: natural killer cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer cells. ILCs are pleiotropic and play dual and sometimes paradoxical roles in cancer development and progression. Here, a comprehensive discussion of the current knowledge and recent advancements in understanding the role of ILCs in bladder cancer is provided. We discuss the multifaceted roles that ILCs play in bladder immune surveillance, tumor protection, and immunopathology of bladder cancer. This review provides a rationale for targeting ILCs in bladder cancer, which is relevant for other solid tumors.

Standardization of the evaluation and surveillance of patients with BCG unresponsive high grade non-muscle invasive bladder cancer clinical trials

There are multiple ongoing and planned clinical trials that are evaluating novel therapies to treat patients with BCG-unresponsive high grade nonmuscle invasive bladder cancer (NMIBC). Importantly, there is considerable variation in surveillance strategies between these clinical trials, specifically with regards to the use of advanced imaging, enhanced cystoscopy, and mandatory biopsies, which could impact landmark efficacy assessments of investigational agents. To present guideline recommendations for the standardization of cystoscopic evaluation, surveillance, and efficacy assessments for patients with BCG-unresponsive NMIBC participating in clinical trials. On September 29, 2023 at the annual meeting of the International Bladder Cancer Network, a breakout session was convened, during which representatives from various disciplines discussed potential guidance statements with opportunity for discussion and comment. A set of statements regarding use of white light and enhanced cystoscopy were developed to help guide a pragmatic approach to surveillance and efficacy assessments of patients in clinical trials. The use of "for cause" and "mandatory" biopsies was also addressed. A standard approach to evaluation of patients within the context of clinical trials is necessary to accurately assess the efficacy of novel agents, especially within single arm trials that lack an appropriate comparator. Additionally, the utilization and timing of mandatory biopsies is critical, as these biopsies may impact both disease evaluations and the determination of duration of response.

A comparative analysis of radical cystectomy with perioperative chemotherapy, chemoradiation therapy, or systemic therapy in patients with clinically advanced node-positive bladder cancer (cN2/N3)

Introduction

The management of non-metastatic clinically advanced lymph nodal (cN2/N3) bladder cancer (Stage IIIB) could involve radical cystectomy, chemoradiation, or systemic therapy alone. However, a definitive comparison between these approaches is lacking. This study aims to compare the outcomes of patients undergoing radical cystectomy with pelvic lymph node dissection (RC-PLND), chemoradiation therapy (CRT) or systemic therapy (including immunotherapy) (ST) only in patients with stage IIIB bladder cancer.

Materials and methods

A retrospective analysis of the National Cancer Database for patients with stage IIIB urothelial bladder cancer was done from 2004-2019. Patients were classified as Group A: Those who received RC-PLND with perioperative chemotherapy, Group B: Those who received CRT, and Group C: Those who received only ST alone. The primary outcome was overall survival (OS). Inverse probability weighting (IPW)-adjusted Kaplan Meier curves were utilized to compare overall survival (OS) and cox multivariate regression analysis was used to identify predictors for OS.

Results

Overall, 2,575 patients were identified. They were classified into Group A (n=1,278), Group B (n=317) and Group C (n=980). Compared to Group B, patients in Group A were younger (SMD=19.6%), had lower comorbidities (SMD=18.2%), had higher income (SMD=31.5%), had private insurance (SMD= 26.7%), were treated at academic centres (SMD=29.3%) and had higher percentage of N2 disease (SMD=31.1%). Using IPW-adjusted survival analysis, compared to Group C, the median OS was significantly higher in Group A (20.7 vs 14.2 months, p<0.001) and Group B (19.7 vs 14.2 months, p<0.001) but similar between Group A and Group B (20.9 vs 19.7 months, p=0.74). Both surgery (HR=0.72 (0.65-0.80), p<0.001) and CRT (0.70 (0.59-0.82), p<0.001) appeared to be independent predictors for OS on cox-regression analysis. The major limitations include bias due to retrospective analysis and non-assessment of cancer-specific survival.

Conclusion

In stage IIIB bladder cancer with advanced lymph nodal disease, both RC and CRT offer equivalent survival benefits and are superior to systemic therapy alone.

Impact of rural residence on the presentation, management and survival of patients with non-metastatic muscle-invasive bladder carcinoma

PURPOSE

To assess the impact of rural and remote residence on the receipt of guidelines-recommended treatment, quality of treatment and overall survival (OS) in patients with non-metastatic muscle-invasive bladder cancer (MIBC).

MATERIALS AND METHODS

Patients with MIBC were identified using National Cancer Database. Patients were classified into three residential areas. Logistic regression models were used to assess associations between geographic residence and receipt of radical cystectomy (RC) or chemoradiation therapy (CRT). Models were fitted to assess quality benchmarks of RC and CRT.

RESULTS

We identified 71,395 patients. Of those 58,874 (82.5%) were living in Metro areas, 8,534 (11.9%) in urban-rural adjacent (URA), and 3,987 (5.6%) in urban-rural remote to metro area (URR). URR residence was significantly associated with poor OS compared to URA and Metro residence (HR 0.87, 95% CI 0.81-0.94 and HR 0.90, 95% CI 0.87-0.93, p<0.001). There was no difference in the likelihood of receiving RC and CRT among different residential areas. Among patients who underwent RC; individuals living in URR were less likely to receive neoadjuvant chemotherapy and adequate lymph node dissection, and had a higher probability of positive surgical margin than those living in metro areas. For those who received CRT; individuals living in Metro areas were more likely to receive concomitant systemic therapy compared to URR.

CONCLUSIONS

Rural residence is associated with lower OS for MIBC patients and less likelihood of meeting quality benchmarks for RC and CRT. This data should be used to guide further health policy and allocation of resources for rural population.

Checkpoint Inhibitors in Urothelial Carcinoma-Future Directions and Biomarker Selection

CONTEXT

Several recent phase 2 and 3 trials have evaluated the efficacy and toxicity of checkpoint inhibitor (CPI) therapy for urothelial carcinoma (UC) in the metastatic, localized muscle-invasive UC (MIUC), upper tract UC, and non-muscle-invasive bladder cancer (NMIBC) disease state.

OBJECTIVE

To assess the outcomes and toxicity of CPIs across the treatment landscape of UC and contextualize their application to current real-world treatment.

EVIDENCE ACQUISITION

We queried PubMed, Web of Science, and EMBASE databases and conference abstracts to identify prospective trials examining CPIs in UC. The primary endpoints included overall survival, recurrence-free survival, and toxicity (when available). A secondary analysis included biomarker evaluation of response.

EVIDENCE SYNTHESIS

We identified 21 trials, 12 phase 2 and nine phase 3 trials, in which a CPI was used for metastatic UC (seven), MIUC (nine), and NMIBC (five). For first-line (1L) metastatic UC, concurrent chemotherapy with CPIs failed to show superiority. Improved overall and progression-free survival for switch maintenance avelumab (after achieving stable disease or response with induction systemic chemotherapy) has established the current standard of care for 1L metastatic UC. A single-agent CPI is a consideration for patients unable to tolerate chemotherapy. CPIs in the perioperative setting are limited to only the adjuvant treatment with nivolumab after radical surgery for MIUC in patients at a higher risk of recurrence based on pathologic stage. Only pembrolizumab is approved by the Food and Drug Administration for carcinoma in situ unresponsive to bacillus Calmette-Guérin (BCG) in patients who are not fit for or who refuse radical cystectomy. Trials investigating CPIs in combination with multiple immune regulators, antibody drug conjugates, targeted therapies, antiangiogenic agents, chemotherapy, and radiotherapy are enrolling patients and may shape the future treatment of patients with UC.

CONCLUSIONS

CPIs have an established role across multiple states of UC, with broadened applications likely to occur in the future. Several combinations are being evaluated, while the development of predictive biomarkers and their validation may help identify patients who are most likely to respond.

PATIENT SUMMARY

Our findings highlight the broad activity of checkpoint inhibitors in urothelial carcinoma, noting the need for further investigation for the best application of combinations and patient selection to patient care.

Volumetric Analysis of Renal Masses as Predictors of Partial Nephrectomy Outcomes

Objective: To examine the role of endophytic tumor volume (TV) assessment (endophycity) on perioperative partial nephrectomy (PN) outcomes. Patients and Methods: Retrospective review of 212 consecutive laparoscopic and open partial nephrectomies from single institution using preoperative imaging and 1-year follow-up. Demographics, comorbidities, RENAL nephrometry scores, and all peri- and postoperative outcomes were recorded. Volumetric analysis performed using imaging software, independently assessed by two blinded radiologists. Univariate and multivariate statistical analysis were completed to assess predictive value of endophycity for all clinically meaningful outcomes. Results: Among those undergoing minimally invasive surgery (MIS), lower tumor endophycity was associated with higher likelihood of trifecta outcome (negative surgical margin, <10% decline in estimated glomerular filtration rate, the absence of complications) irrespective of max tumor size. For MIS, estimated blood loss increased with greater tumor endophycity regardless of tumor size. Among those who underwent open partial nephrectomy, lower tumor endophycity was associated with trifecta outcomes for tumors >4 cm only. On multivariate analysis with log-scaled odds ratios (OR), tumor endophycity and total kidney volume had the strongest correlation with tumor-related complications (OR = 3.23, 2.66). The analysis identified that tumor endophycity and TV on imaging were inversely correlated with of trifecta outcomes (OR = 0.53 for both covariates). Conclusions: Volumetric assessment of tumor endophycity performed well in identifying PN outcomes. As automated imaging software improves, volumetric analysis may prove to be a useful adjunct in preoperative planning and patient counseling.

Adjuvant immunotherapy for patients with renal cell carcinoma at increased risk of recurrence following resection: A National Cancer Database analysis

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Background: Radical nephrectomy is the standard management for locoregional renal cell carcinoma (RCC); however, patients with adverse pathological features are at increased risk of recurrence. IMmotion010 and KeyNote 564 trials investigated the adjuvant role of immune checkpoint inhibitors (ICI) for high-risk clear cell RCC (ccRCC) and have yielded conflicting results. We aimed to investigate real-world survival outcomes associated with the adjuvant use of ICI in high-risk ccRCC using the National Cancer Database Methods: In this nationwide contemporary cohort study, patients with newly diagnosed non-metastatic high-risk clear cell RCC undergoing radical nephrectomy between 2015-2019 were included. High-risk RCC was defined as cT2 with Fuhrman grade 4 or cT3a with Fuhrman grade 3/4 or cT3b/T3c/T4 with any grade, or TxN+ any grade. Patients receiving adjuvant ICI were classified as Group A and patients who did not receive adjuvant ICI were classified as Group B. Inverse probability weighting (IPW)-adjusted Kaplan Meier curves were utilized to compare overall survival (OS) between the groups and cox proportional hazard models were utilized to identify the predictors for OS. Results: Overall, 768 patients met the inclusion criteria; 270 patients in Group A and 498 patients in Group B. The mean age was 60.5(10.6) years, and 70.8% of patients were males (Table). The use of ICI in the adjuvant setting for high-risk RCC increased from 17.4% in 2015 to 61.8% in 2019. The unadjusted and IPW-adjusted Kaplan Meier 5-year overall survival was similar in the two groups [Unadjusted: 36.8% in Group A vs 50.1% in Group B, p=0.30 and adjusted: 39.5% in Group A vs 47.9% in Group B, p=0.17]. The use of adjuvant ICI did not appear to be an independent predictor for OS on multivariable cox regression analysis (HR=1.14, p=0.31) Conclusions: Adjuvant ICI therapy in non-metastatic high-risk ccRCC might not be associated with a benefit in overall survival. [Table: see text]

Patency outcomes of primary inferior vena cava repair in radical nephrectomy and tumor thrombectomy

OBJECTIVE

The reconstruction of inferior vena cava (IVC) during radical nephrectomy and venous tumor thrombectomy (RN-VTT) is mostly performed with primary repair or with a patch/graft. We sought to systematically evaluate the outcomes of IVC patency over short- to intermediate-term follow-up for patients undergoing primary repair of IVC and to assess the association with survival.

METHODS

A retrospective review of patients undergoing RN-VTT between January 2013 and August 2018 was conducted. Patients were followed until death, last available follow-up, or March 2022. The patency outcomes and IVC diameters were studied using follow-up cross-sectional imaging. The χ² test, Student t test, and Kaplan-Meier survival analysis were used.

RESULTS

Seventy-seven patients were included. The mean age was 59.2 ± 12.2 years and 45.4% had Mayo classification level III thrombus or higher. At a median follow-up of 36.5 months (13.3-60.7 months), the 3-year overall survival (OS) was 64%. Sixty patients underwent primary repair of the IVC and 48 of these patients were assessed for IVC patency. Ten patients (20.8%) developed caval occlusion, either from recurrent tumor (8.3%), new-onset bland thrombus (8.3%), or stenosis (4.2). The IVC patency seemed to be a significant predictor of OS (hazard ratio, 2.85; P = .021). Although the IVC diameters decreased significantly at the 3-month postoperative scan at the infrarenal (P = .019), renal (P < .001), and suprarenal (P < .001) levels, they did not decrease further on long-term follow-up imaging.

CONCLUSIONS

IVC reconstruction with primary repair results in an overall patency rate of 80.2% with only a 4.0% rate of stenosis. Recurrence of tumor thrombus (8.3%) or bland thrombus (8.3%) are the predominant reasons for IVC occlusion after RN-VTT, and this outcome is associated with poor OS.

Revisiting current National Comprehensive Cancer Network (NCCN) high-risk prostate cancer stratification: a National Cancer Database analysis

BACKGROUND

High-risk prostate cancer includes heterogenous populations with variable outcomes. This study aimed to compare the prognostic ability of individual high-risk factors, as defined by National Comprehensive Cancer Network (NCCN) risk stratification, in prostate cancer patients undergoing radical prostatectomy.

METHODS

We queried the National Cancer Database from 2004 to 2018 for patients with non-metastatic high-risk prostate cancer who underwent radical prostatectomy and stratified them as Group H1: Prostate specific antigen (PSA) > 20 ng/ml alone, Group H2: cT3a stage alone and Group H3: Gleason Grade (GG) group 4/5 as per NCCN guidelines. The histopathological characteristics and rate of adjuvant therapy were compared between different groups. Inverse probability weighting (IPW)-adjusted Kaplan-Meier curves were utilized to compare overall survival (OS) in group H1 and H2 with H3.

RESULTS

Overall, 61,491 high-risk prostate cancer patients were identified, and they were classified into Group H1 (n = 14,139), Group H2 (n = 2855) and Group H3 (n = 44,497). Compared to group H1 or H2, pathological GG group > 3 (p < 0.001), pathological stage pT3b or higher (p < 0.001), lymph nodal positive disease (pN1) (p < 0.001) and rate of adjuvant therapy (p < 0.001) were significantly in Group H3. IPW-adjusted Kaplan-Meier curves showed significantly better 5-year OS in group H1 compared to group H3 [95.1% vs 93.3%, p < 0.001] and group H2 compared to group H3 [94.4% vs 92.9%, p < 0.001].

CONCLUSION

PSA > 20 ng/ml or cT3a stage in isolation have better oncologic and survival outcomes compared to GG > 3 disease and sub-stratification of 'High-risk' category might lead to better patient prognostication.

Selective delipidation of Mycobacterium bovis BCG retains antitumor efficacy against non-muscle invasive bladder cancer

PURPOSE

Repeated instillations of bacillus Calmette et Guérin (BCG) are the gold standard immunotherapeutic treatment for reducing recurrence for patients with high-grade papillary non-muscle invasive bladder cancer (NMIBC) and for eradicating bladder carcinoma-in situ. Unfortunately, some patients are unable to tolerate BCG due to treatment-associated toxicity and bladder removal is sometimes performed for BCG-intolerance. Prior studies suggest that selectively delipidated BCG (dBCG) improves tolerability of intrapulmonary delivery reducing tissue damage and increasing efficacy in preventing Mycobacterium tuberculosis infection in mice. To address the lack of treatment options for NMIBC with BCG-intolerance, we examined if selective delipidation would compromise BCG's antitumor efficacy and at the same time increase tolerability to the treatment.

MATERIALS AND METHODS

Murine syngeneic MB49 bladder cancer models and in vitro human innate effector cell cytotoxicity assays were used to evaluate efficacy and immune impact of selective delipidation in Tokyo and TICE BCG strains.

RESULTS

Both dBCG-Tokyo and dBCG-TICE effectively treated subcutaneous MB49 tumors in mice and enhanced tumor-infiltrating CD8+ T and natural killer cells, similar to conventional BCG. However, when compared to conventional BCG, only dBCG-Tokyo retained a significant effect on intratumoral tumor-specific CD8+ and γδ T cells by increasing their frequencies in tumor tissue and their production of antitumoral function-related cytokines, i.e., IFN-γ and granzyme B. Further, dBCG-Tokyo but not dBCG-TICE enhanced the function and cytotoxicity of innate effector cells against human bladder cancer T24 in vitro.

CONCLUSIONS

These data support clinical investigation of dBCG-Tokyo as a treatment for patients with BCG-intolerant NMIBC.

KLRF1, a novel marker of CD56bright NK cells, predicts improved survival for patients with locally advanced bladder cancer

BACKGROUND

Bladder tumor-infiltrating CD56^bright NK cells are more tumor cytotoxic than their CD56^dim counterparts. Identification of NK cell subsets is labor-intensive and has limited utility in the clinical setting. Here, we sought to identify a surrogate marker of bladder CD56^bright NK cells and to test its prognostic significance.

METHODS

CD56^bright and CD56^dim NK cells were characterized with the multiparametric flow (n = 20) and mass cytometry (n = 21) in human bladder tumors. Transcriptome data from bladder tumors (n = 351) profiled by The Cancer Genome Atlas (TCGA) were analyzed. The expression levels of individual markers in intratumoral CD56^bright and CD56^dim NK cells were visualized in tSNE plots. Expressions of activation markers were also compared between Killer Cell Lectin-Like Receptor Subfamily F Member 1 (KLRF1)⁺ and KLRF1^- NK cells.

RESULTS

Intratumoral CD56^bright NK cells displayed a more activated phenotype compared to the CD56^dim subset. Multiple intratumoral cell types expressed CD56, including bladder tumor cells and nonspecific intratumoral CD56 expression was associated with worse patient survival. Thus, an alternative to CD56 as a marker of CD56^bright NK cells was sought. The activation receptor KLRF1 was significantly increased on CD56^bright but not on CD56^dim NK cells. Intratumoral KLRF1⁺ NK cells were more activated and expressed higher levels of activation molecules compared with KLRF1^- NK cells, analogous to the distinct effector function of NK cells across CD56 expression. High intratumoral KLRF1 was associated with improved recurrence-free survival (hazard ratio [HR] 0.53, p = 0.01), cancer-specific survival (HR 0.47, p = 0.02), and overall survival (HR 0.54, p = 0.02) on multivariable analyses that adjusted for clinical and pathologic variables.

CONCLUSIONS

KLRF1 is a promising prognostic marker in bladder cancer and may guide treatment decisions upon validation.

First-in-human Intravesical Delivery of Pembrolizumab Identifies Immune Activation in Bladder Cancer Unresponsive to Bacillus Calmette-Guérin

BACKGROUND

Intravenous immune checkpoint inhibition is an effective anticancer strategy for bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer (NMIBC) but may be associated with greater systemic toxicity compared with localized therapies.

OBJECTIVE

We assessed the safety and antitumor activity of intravesical pembrolizumab combined with BCG.

DESIGN, SETTING, AND PARTICIPANTS

A 3 + 3 phase 1 trial of pembrolizumab + BCG was conducted in patients with BCG-unresponsive NMIBC (NCT02808143).

INTERVENTION

Pembrolizumab was given intravesically (1-5 mg/kg for 2 h) beginning 2 weeks prior to BCG induction until recurrence. Urine profiling during treatment and spatial transcriptomic profiling of pre- and post-treatment tumors were conducted to identify biomarkers that correlated with response.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Safety and tolerability of immune checkpoint inhibition were assessed, and Kaplan-Meier survival analysis was performed.

RESULTS AND LIMITATIONS

Nine patients completed therapy. Median follow-up was 35 months for five patients still alive at the end of the trial. The trial was closed due to the COVID-19 pandemic. Grade 1-2 urinary symptoms were common. The maximum tolerated dose was not reached; however, one dose-limiting toxicity was reported (grade 2 diarrhea) in the only patient who reached 52 weeks without recurrence. One death occurred from myasthenia gravis that was deemed potentially related to treatment. The 6-mo and 1-yr recurrence-free rates were 67% (95% confidence interval [CI]: 42-100%) and 22% (95% CI: 6.5-75%), respectively. Pembrolizumab was detected in the urine and not in blood. CD4⁺ T cells were significantly increased in the urine after treatment, and a transcriptomic analysis identified decreased expression of T-cell exhaustion markers in late recurrences.

CONCLUSIONS

We demonstrate that intravesical pembrolizumab is safe, feasible, and capable of eliciting strong immune responses in a clinical setting and should be investigated further.

PATIENT SUMMARY

Direct application of pembrolizumab to the bladder is a promising alternative for non-muscle-invasive bladder cancer unresponsive to Bacillus Calmette-Guérin and should be investigated further.

Impact of Finasteride on survival in bladder cancer: A retrospective multi-institutional database analysis

INTRODUCTION

Androgen suppression therapy has been associated with a lower incidence of bladder cancer (BCa) or improved overall/cancer-specific survival. Results are ofent conflicting; therefore, we aim to assess the impact of use of finasteride on overall survival (OS) for BCa using multi-institutional database.

METHODS

The South Texas Veterans Healthcare System from 5 medical centers was queried for patients with BCa with or without use of finasteride after diagnosis of BCa. The primary outcome was the impact of finasteride use after diagnosis on the OS in BCa and in the high-risk Non-muscle invasive BCa (NMIBC) cohort.

RESULTS

A total of 1890 patients were included, amongst which 619 (32.8%) men were classified as finasteride users and 1271 (67.2%) men as controls. At a median (IQR) follow up of 53.8 (27.4, 90.9) months, death due to any cause was noted in 272 (43.9%) finasteride-treated, and 672 (49.3%) control groups (P = .028). The patients in the finasteride group had significantly better OS in overall cohort (112.1 months vs. 84.8 months, P < .001) as well as in the NMIBC cohort (129.3months vs. 103.2 months, P = .0046). The use of finasteride was independently associated with improved OS in both, overall cohort (HR 0.74, 95% CI 0.63-0.86; P < .001) and in the NMIBC cohort (HR = 0.71, 95% CI 0.55-0.93; P = .011).

CONCLUSION

Finasteride use is associated with the improved overall survival in patients with BCa, specifically in patients with NMIBC. We, further, propose a randomized clinical trial to investigate the use of finasteride in BCa patients.

A Decade of Robotic-Assisted Radical Nephrectomy with Inferior Vena Cava Thrombectomy: A Systematic Review and Meta-Analysis of Perioperative Outcomes

PURPOSE

Open radical nephrectomy with inferior vena cava thrombectomy (O-CT) is standard management for renal cell carcinoma with inferior vena cava thrombus. First reported a decade ago, robotic-assisted radical nephrectomy with inferior vena cava thrombectomy (R-CT) is a minimally invasive option for this disease. We aimed to perform a systematic review to assess the safety and feasibility of R-CT in terms of perioperative outcomes and compare the outcomes between R-CT and O-CT.

MATERIALS AND METHODS

The PubMed®, Scopus®, Cochrane Central Register of Controlled Trials and Web of ScienceTM databases were searched using the free-text and MeSH terms "renal cell carcinoma," "inferior vena cava," "thrombosis" or "thrombus," "robot" and "thrombectomy." Studies reporting perioperative outcomes of R-CT and studies comparing R-CT with O-CT were included. The review was done in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

The search retrieved 28 articles describing R-CT, including 7 comparative studies. This systematic review included 1,375 patients, out of which 329 patients were in single-arm studies and 1,046 patients were in comparative studies. Of the 329 patients who underwent R-CT, 14.7% were level I, 60.9% level II, 20.4% level III and 2.5% level IV thrombus. Operative time ranged from 150 to 530 minutes; blood transfusion was administered in 38.2% (126). The overall complication rate was 30.3% (99). R-CT, in comparison to O-CT, was associated with a lower blood transfusion rate (18.4% vs 64.3%, p=0.002) and a lower complication rate (14.5% vs 36.7%, p=0.005). Major complication and 30-day mortality rates were similar in both groups.

CONCLUSIONS

R-CT has acceptable perioperative outcomes in carefully selected patients. Compared with O-CT, R-CT is associated with a lower blood transfusion rate and fewer overall complications. In experienced hands with carefully selected patients, R-CT is feasible and safe, with acceptable outcomes; however, selection bias limits definitive inference of these results, and optimal patient selection criteria remain to be described.

Tumor Intrinsic PD-L1 Promotes DNA Repair in Distinct Cancers and Suppresses PARP Inhibitor-Induced Synthetic Lethality

BRCA1-mediated homologous recombination is an important DNA repair mechanism that is the target of FDA-approved PARP inhibitors, yet details of BRCA1-mediated functions remain to be fully elucidated. Similarly, immune checkpoint molecules are targets of FDA-approved cancer immunotherapies, but the biological and mechanistic consequences of their application are incompletely understood. We show here that the immune checkpoint molecule PD-L1 regulates homologous recombination in cancer cells by promoting BRCA1 nuclear foci formation and DNA end resection. Genetic depletion of tumor PD-L1 reduced homologous recombination, increased nonhomologous end joining, and elicited synthetic lethality to PARP inhibitors olaparib and talazoparib in vitro in some, but not all, BRCA1 wild-type tumor cells. In vivo, genetic depletion of tumor PD-L1 rendered olaparib-resistant tumors sensitive to olaparib. In contrast, anti-PD-L1 immune checkpoint blockade neither enhanced olaparib synthetic lethality nor improved its efficacy in vitro or in wild-type mice. Tumor PD-L1 did not alter expression of BRCA1 or its cofactor BARD1 but instead coimmunoprecipitated with BARD1 and increased BRCA1 nuclear accumulation. Tumor PD-L1 depletion enhanced tumor CCL5 expression and TANK-binding kinase 1 activation in vitro, similar to known immune-potentiating effects of PARP inhibitors. Collectively, these data define immune-dependent and immune-independent effects of PARP inhibitor treatment and genetic tumor PD-L1 depletion. Moreover, they implicate a tumor cell-intrinsic, immune checkpoint-independent function of PD-L1 in cancer cell BRCA1-mediated DNA damage repair with translational potential, including as a treatment response biomarker.

SIGNIFICANCE

PD-L1 upregulates BRCA1-mediated homologous recombination, and PD-L1-deficient tumors exhibit BRCAness by manifesting synthetic lethality in response to PARP inhibitors, revealing an exploitable therapeutic vulnerability and a candidate treatment response biomarker. See related commentary by Hanks, p. 2069.

Clinical outcomes and patterns of population-based management of urachal carcinoma of the bladder: An analysis of the National Cancer Database

BACKGROUND

Given the low incidence of urachal carcinoma of the bladder (UCB), there is limited published data from contemporary population-based cohorts. This study aimed to describe demographic, clinicopathological features, and survival outcomes of patients diagnosed with UCB.

METHODS

The National Cancer Database (2004-2016) was queried for UCB patients. Descriptive analyses characterized demographics and clinicopathologic features. We assessed 5-year overall survival (OS) rates of the entire cohort and subgroups of localized/locally advanced and metastatic disease. We utilized Cox proportional hazards models to assess the association between covariates of interest and all-cause mortality and to examine the impact of surgical technique and chemotherapy.

RESULTS

We identified 841 patients with UCB. The most common histologic subtype was non-mucinous adenocarcinoma (39.6%). Approximately 50% had ≥cT2 disease, and 14.3% were metastatic at diagnosis. Altogether, partial cystectomy (60%) was most performed, and lymph node dissection was performed in 377 patients (44.8%), with specific temporal increase in utilization over the study period (p < 0.001). Overall, median OS was 59 months, and 5-year OS was 49%. In patients with localized/locally advanced disease, we found no association between partial and radical cystectomy (Hazards ratio [HR] 1.75; 95% CI 0.72-4.3) as well as receipt of perioperative chemotherapy (HR 1.97, 95% CI 0.79-4.90) and outcomes. Lastly, receipt of systemic therapy was not associated with survival benefit (HR 0.785, 95% CI 0.37-1.65) in metastatic disease cohort.

CONCLUSION

This large population-based cohort provides insight into the surgical management and systemic therapy, without clear evidence on the association of chemotherapy and survival in the perioperative and metastatic setting.

Nitration of CCL2 disrupts the tumor-protective function of CCL2 in bladder cancer

The chemokine CCL2 (C-C motif ligand 2) is best known for its ability to induce trafficking of immune cells by binding its primary receptor, CCR2. The recruitment of immunosuppressive monocytes by CCL2 promotes cancer in several tumor types. Surprisingly, we previously found an unanticipated protective role for CCL2 signaling in bladder cancer (BC). To determine if CCL2’s effect to suppress bladder tumor growth is dependent on T cells, we examined the effects of α-CCL2 antibody in wild-type versus T cell-deficient mice. The protective effect of CCL2 was lost in T cell-deficient mice and on T cell depletion in wild-type mice. Mixed bone marrow chimera experiments also showed that CCR2+ T cells were preferentially recruited by CCL2 to the bladder compared with CCR2− T cells suggesting that the protective effect of CCL2 in BC is through CCR2+ T cells. Most studies researching chemokines, including CCL2, in cancer assume the chemokine to be completely active and do not consider their different modified states which may be one of the critical reasons behind the failure of chemokines in clinical trials. We show for the first time that bladder tumors induce post-translational nitration of CCL2 and block T cell recruitment to the bladder which is restored by exogenous recombinant (r) CCL2 treatment. However, the chemical nitration of rCCL2 abolished this therapeutic efficacy of rCCL2 and was associated with decreased bladder T cell infiltration and more monocytes infiltration in BC. Our study analyzed the role of nitrated CCL2 in BC which explained certain paradoxes between CCL2 levels and patient outcomes in cancer. We also developed a novel BC treatment strategy using rCCL2 which should lead to effective combinations with existing BC immunotherapies.

Supported by (1) the Mays Family Cancer Center at University of Texas Health San Antonio (P30 CA054174), (2) the Roger L. And Laura D. Zeller Charitable Foundation Chair in Urologic Cancer, (3) the Glenda and Gary Woods Distinguished Chair in GU Oncology, (4) the Max & Minnie Tomerlin Voelcker Fund, (5) CDMRP CA170270/P1P2, (6) Bladder Cancer Advocacy Network (BCAN), (7) Research Training Award (RP170345) from the Cancer Prevention & Research Institute of Texas (8) MSTP Program (NIH T32GM113896)

The Latinx Disparity in Surgery for Kidney Cancer: Data from The South Texas Region

The South Texas region, with a predominantly Latinx population, has a very high incidence of renal cell carcinoma (RCC), including those with tumor extending into the major blood vessels called venous tumor thrombus (VTT). There is currently no data on outcomes of Latinx patients with VTT as most published studies are from predominantly Caucasian population. Therefore, we performed this study to fill an urgent, unmet need. We reviewed patients who underwent radical nephrectomy with removal of VTT (called tumor thrombectomy) between 2015 and 2020. We collected data on demographics, clinical, pathological characteristics and outcomes of patients. Univariate and multivariate Cox regression analyses were used to evaluate the associations between ethnicity and disease progression or survival. We identified 112 patients, of which 67 (62%) were Latinx, and 41 (38%) were non-Latinx. Approximately 60% of patients had Level II-IV VTT; Latinx presented with a higher level of tumor thrombus (p=0.046). Latinx patients had a higher rate of no insurance (11% vs. 27%, p=0.04) and were more likely to lost to follow-up after surgery (22.4% vs. 13.3%, p=0.23) compared to non-Latinx. Fewer Latinx received systemic therapy (28% vs. 42%; p=0.13). Ninety-day mortality for the entire cohort was 3.8%. The Latinx population in the South Texas region present late, with advanced thrombus level, and do not have access to systemic therapy. Given symptomatic disease, surgical treatment, if feasible, is their only option. Our results highlight disparate treatment patterns which require further investigation and health-care policy changes.

Antiadenovirus Antibodies Predict Response Durability to Nadofaragene Firadenovec Therapy in BCG-unresponsive Non-muscle-invasive Bladder Cancer: Secondary Analysis of a Phase 3 Clinical Trial

A recent phase 3 trial of intravesical nadofaragene firadenovec reported a promising complete response rate for patients with bacillus Calmette-Guérin-unresponsive non-muscle-invasive bladder cancer. This study examined the ability of antiadenovirus antibody levels to predict the durability of therapeutic response to nadofaragene firadenovec. A standardized and validated quantitative assay was used to prospectively assess baseline and post-treatment serum antibody levels among 91 patients from the phase 3 trial, of whom 47 (52%) were high-grade recurrence free at 12 mo (responders). While baseline titers did not predict treatment response, 3-mo titer >800 was associated with a higher likelihood of durable response (p = 0.026). Peak post-treatment titers >800 were noted in 42 (89%) responders versus 26 (59%) nonresponders (p = 0.001; assay sensitivity, 89%; negative predictive value, 78%). Moreover, 22 (47%) responders compared with eight (18%) nonresponders had a combination of peak post-treatment titers >800 and peak antibody fold change >8 (p = 0.004; assay specificity, 82%; positive predictive value, 73%). A majority of responders continued to have post-treatment antibody titers >800 after the first 6 mo of therapy. In conclusion, serum antiadenovirus antibody quantification may serve as a novel predictive marker for nadofaragene firadenovec response durability. Future studies will focus on large-scale validation and clinical utility of the assay. PATIENT SUMMARY: This study reports on a planned secondary analysis of a phase 3 multicenter clinical trial that established the benefit of nadofaragene firadenovec, a novel intravesical gene therapeutic, for the treatment of patients with bacillus Calmette-Guérin (BCG)-unresponsive high-risk non-muscle-invasive bladder cancer. Prospective assessment of serum anti-human adenovirus type-5 antibody levels of patients in this trial indicated that a combination of post-treatment titers and fold change from baseline can predict treatment efficacy. While this merits additional validation, our findings suggest that serum antiadenovirus antibody levels can serve as an important predictive marker for the durability of therapeutic response to nadofaragene firadenovec.

Reduced Dose Intravesical Bacillus Calmette-Guérin: Why It Might Not Matter

When it comes to the treatment of patients with non-muscle-invasive bladder cancer (NMIBC) with intravesical bacillus Calmette-Guérin (BCG), two questions must be considered: 1) what dose to give, and 2) for how long? The issue of optimal dose and duration has been the subject of several randomized trials and is especially pertinent in the context of a global BCG shortage. Despite this, there appears to be uncertainty as to whether BCG dose or duration may be compromised in the event of shortage. As such, we wish to summarize the available evidence as an aid to the practicing urologist.

Comparison of Robot-Assisted and Open Radical Cystectomy in Recovery of Patient-Reported and Performance-Related Measures of Independence: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

No data exist on time to recovery of patient-reported and performance-related measures of functional independence after radical cystectomy (open or robotic).

OBJECTIVE

To determine recovery of functional independence after radical cystectomy and whether robot-assisted radical cystectomy (RARC) is associated with any advantage over open procedures.

DESIGN, SETTING, AND PARTICIPANTS

Data for this secondary analysis from the RAZOR (Randomized Open vs Robotic Cystectomy) trial were used. RAZOR was a phase 3 multicenter noninferiority trial across 15 academic medical centers in the US from July 1, 2011, to November 18, 2014, with a median follow-up of 2 years. Participants included the per-protocol population (n = 302). Data were analyzed from February 1, 2017, to May 1, 2021.

INTERVENTIONS

Robot-assisted radical cystectomy or open radical cystectomy (ORC).

MAIN OUTCOMES AND MEASURES

Patient-reported (activities of daily living [ADL] and independent ADL [iADL]) and performance-related (hand grip strength [HGS] and Timed Up & Go walking test [TUGWT]) measures of independence were assessed. Patterns of postoperative recovery for the entire cohort and comparisons between RARC and ORC were performed. Exploratory analyses to assess measures of independence across diversion type and to determine whether baseline impairments were associated with 90-day complications or 1-year mortality were performed.

FINDINGS

Of the 302 patients included in the analysis (254 men [84.1%]; mean [SD] age at consent, 68.0 [9.7] years), 150 underwent RARC and 152 underwent ORC. Baseline characteristics were similar in both groups. For the entire cohort, ADL, iADL, and TUGWT recovered to baseline by 3 postoperative months, whereas HGS recovered by 6 months. There was no difference between RARC and ORC for ADL, iADL, TUGWT, or HGS scores at any time. Activities of daily living recovered 1 month after RARC (mean estimated score, 7.7 [95% CI, 7.3-8.0]) vs 3 months after ORC (mean estimated score, 7.5 [95% CI, 7.2-7.8]). Hand grip strength recovered by 3 months after RARC (mean estimated HGS, 29.0 [95% CI, 26.3-31.7] kg) vs 6 months after ORC (mean estimated HGS, 31.2 [95% CI, 28.8-34.2] kg). In the RARC group, 32 of 90 patients (35.6%) showed a recovery in HGS at 3 months vs 32 of 88 (36.4%) in the ORC group (P = .91), indicating a rejection of the primary study hypothesis for HGS. Independent ADL and TUGWT recovered in 3 months for both approaches. Hand grip strength showed earlier recovery in patients undergoing continent urinary diversion (mean HGS at 3 months, 31.3 [95% CI, 27.7-34.8] vs 33.9 [95% CI, 30.5-37.3] at baseline; P = .09) than noncontinent urinary diversion (mean HGS at 6 months, 27.4 [95% CI, 24.9-30.0] vs 29.5 [95% CI, 27.2-31.9] kg at baseline; P = .02), with no differences in other parameters. Baseline impairments in any parameter were not associated with 90-day complications or 1-year mortality.

CONCLUSIONS AND RELEVANCE

The results of this secondary analysis suggest that patients require 3 to 6 months to recover baseline levels after radical cystectomy irrespective of surgical approach. These data will be invaluable in patient counseling and preparation. Hand grip strength and ADL tended to recover to baseline earlier after RARC; however, there was no difference in the percentage of patients recovering when compared with ORC. Further study is needed to assess the clinical significance of these findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01157676.

CD122-targeted interleukin-2 and αPD-L1 treat bladder cancer and melanoma via distinct mechanisms, including CD122-driven natural killer cell maturation

Bladder cancer (BC) and melanoma are amenable to immune checkpoint blockade (ICB) therapy, yet most patients with advanced/metastatic disease do not respond. CD122-targeted interleukin (IL)-2 can improve ICB efficacy, but mechanisms are unclear. We tested αPD-L1 and CD122-directed immunotherapy with IL-2/αIL-2 complexes (IL-2c) in primary and metastatic bladder and melanoma tumors. IL-2c treatment of orthotopic MB49 and MBT-2 BC generated NK cell antitumor immunity through enhanced activation, reduced exhaustion, and promotion of a mature, effector NK cell phenotype. By comparison, subcutaneous B16-F10 melanoma, which is IL-2c sensitive, requires CD8⁺ T and not NK cells, yet we found αPD-L1 efficacy requires both CD8⁺ T and NK cells. We then explored αPD-L1 and IL-2c mechanisms at distinct metastatic sites and found intraperitoneal B16-F10 metastases were sensitive to αPD-L1 and IL-2c, with IL-2c but not αPD-L1, increasing CD122⁺ mature NK cell function, confirming conserved IL-2c effects in distinct cancer types and anatomic compartments. αPD-L1 failed to control tumor growth and prolong survival in B16-F10 lung metastases, yet IL-2c treated B16-F10 lung metastases effectively even in T cell and adaptive immunity deficient mice, which was abrogated by NK cell depletion in wild-type mice. Flow cytometric analyses of NK cells in B16-F10 lung metastases suggest that IL-2c directly boosts NK cell activation and effector function. Thus, αPD-L1 and IL-2c mediate nonredundant, immune microenvironment-specific treatment mechanisms involving CD8⁺ T and NK cells in primary and metastatic BC and melanoma. Mechanistic differences suggest effective treatment combinations including in other tumors or sites, warranting further studies.

γδ T Cells Support Antigen-Specific αβ T cell-Mediated Antitumor Responses during BCG Treatment for Bladder Cancer

Bacillus Calmette-Guérin (BCG) is the most effective intravesical agent at reducing recurrence for patients with high-grade, non-muscle-invasive bladder cancer. Nevertheless, response to BCG is variable and strategies to boost BCG efficacy have not materialized. Prior work demonstrated a requirement for either conventional αβ or nonconventional γδ T cells in mediating BCG treatment efficacy, yet the importance of T-cell antigen specificity for BCG's treatment effect is unclear. Here, we provide direct evidence to show that BCG increases the number of tumor antigen-specific αβ T cells in patients with bladder cancer and protects mice from subsequent same-tumor challenge, supporting BCG induction of tumor-specific memory and protection. Adoptive T-cell transfers of antigen-specific αβ T cells into immunodeficient mice challenged with syngeneic MB49 bladder tumors showed that both tumor and BCG antigen-specific αβ T cells contributed to BCG efficacy. BCG-specific antitumor immunity, however, also required nonconventional γδ T cells. Prior work shows that the mTOR inhibitor rapamycin induces the proliferation and effector function of γδ T cells. Here, rapamycin increased BCG efficacy against both mouse and human bladder cancer in vivo in a γδ T cell-dependent manner. Thus, γδ T cells augment antitumor adaptive immune effects of BCG and support rapamycin as a promising approach to boost BCG efficacy in the treatment of non-muscle-invasive bladder cancer.

Effects of Mycobacterium bovis Calmette et Guérin (BCG) in oncotherapy: Bladder cancer and beyond

The Mycobacterium bovis Bacillus Calmette et Guérin (BCG) vaccine was generated in 1921 with the efforts of a team of investigators, Albert Calmette and Camille Guérin, dedicated to the determination to develop a vaccine against active tuberculosis (TB) disease. Since then, BCG vaccination is used globally for protection against childhood and disseminated TB; however, its efficacy at protecting against pulmonary TB in adult and aging populations is highly variable. Due to the BCG generated immunity, this vaccine later proved to have an antitumor activity; though the standing mechanisms behind are still unclear. Recent studies indicate that both innate and adaptive cell responses may play an important role in BCG eradication and prevention of bladder cancer. Thus, cells such as natural killer (NK) cells, macrophages, dendritic cells, neutrophils but also MHC-restricted CD4 and CD8 T cells and γδ T cells may play an important role and can be one the main effectors in BCG therapy. Here, we discuss the role of BCG therapy in bladder cancer and other cancers, including current strategies and their impact on the generation and sustainability of protective antitumor immunity against bladder cancer.

Bladder tumor ILC1s undergo Th17-like differentiation in human bladder cancer

PURPOSE

Human innate lymphoid cells (hILCs) are lineage-negative immune cells that do not express rearranged adaptive antigen receptors. Natural killer (NK) cells are hILCs that contribute to cancer defense. The role of non-NK hILCs in cancer is unclear. Our study aimed to characterize non-NK hILCs in bladder cancer.

EXPERIMENTAL DESIGN

Mass cytometry was used to characterize intratumoral non-NK hILCs based on 35 parameters, including receptors, cytokines, and transcription factors from 21 muscle-invasive bladder tumors. Model-based clustering was performed on t-distributed stochastic neighbor embedding (t-SNE) coordinates of hILCs, and the association of hILCs with tumor stage was analyzed.

RESULTS

Most frequent among intratumoral non-NK hILCs were hILC1s, which were increased in higher compared with lower stage tumors. Intratumoral hILC1s were marked by Th17-like phenotype with high RORγt, IL-17, and IL-22 compared to Th1 differentiation markers, including Tbet, perforin, and IFN-γ. Compared with intratumoral hILC2s and hILC3s, hILC1s also had lower expression of activation markers (NKp30, NKp46, and CD69) and increased expression of exhaustion molecules (PD-1 and Tim3). Unsupervised clustering identified nine clusters of bladder hILCs, which were not defined by the primary hILC subtypes 1-3. hILC1s featured in all the nine clusters indicating that intratumoral hILC1s displayed the highest phenotypic heterogeneity among all hILCs.

CONCLUSIONS

hILC1s are increased in higher stage tumors among patients with muscle-invasive bladder cancer. These intratumoral hILC1s exhibit an exhausted phenotype and Th17-like differentiation, identifying them as potential targets for immunotherapy.

CD122-directed interleukin-2 treatment mechanisms in bladder cancer differ from αPD-L1 and include tissue-selective γδ T cell activation

BACKGROUND

Anti-programmed death-ligand 1 (αPD-L1) immunotherapy is approved to treat bladder cancer (BC) but is effective in <30% of patients. Interleukin (IL)-2/αIL-2 complexes (IL-2c) that preferentially target IL-2 receptor β (CD122) augment CD8⁺ antitumor T cells known to improve αPD-L1 efficacy. We hypothesized that the tumor microenvironment, including local immune cells in primary versus metastatic BC, differentially affects immunotherapy responses and that IL-2c effects could differ from, and thus complement αPD-L1.

METHODS

We studied mechanisms of IL-2c and αPD-L1 efficacy using PD-L1⁺ mouse BC cell lines MB49 and MBT-2 in orthotopic (bladder) and metastatic (lung) sites.

RESULTS

IL-2c reduced orthotopic tumor burden and extended survival in MB49 and MBT-2 BC models, similar to αPD-L1. Using antibody-mediated cell depletions and genetically T cell-deficient mice, we unexpectedly found that CD8⁺ T cells were not necessary for IL-2c efficacy against tumors in bladder, whereas γδ T cells, not reported to contribute to αPD-L1 efficacy, were indispensable for IL-2c efficacy there. αPD-L1 responsiveness in bladder required conventional T cells as expected, but not γδ T cells, altogether defining distinct mechanisms for IL-2c and αPD-L1 efficacy. γδ T cells did not improve IL-2c treatment of subcutaneously challenged BC or orthotopic (peritoneal) ovarian cancer, consistent with tissue-specific and/or tumor-specific γδ T cell contributions to IL-2c efficacy. IL-2c significantly altered bladder intratumoral γδ T cell content, activation status, and specific γδ T cell subsets with antitumor or protumor effector functions. Neither IL-2c nor αPD-L1 alone treated lung metastatic MB49 or MBT-2 BC, but their combination improved survival in both models. Combination treatment efficacy in lungs required CD8⁺ T cells but not γδ T cells.

CONCLUSIONS

Mechanistic insights into differential IL-2c and αPD-L1 treatment and tissue-dependent effects could help develop rational combination treatment strategies to improve treatment efficacy in distinct cancers. These studies also provide insights into γδ T cell contributions to immunotherapy in bladder and engagement of adaptive immunity by IL-2c plus αPD-L1 to treat refractory lung metastases.

Rapamycin enhances BCG-specific γδ T cells during intravesical BCG therapy for non-muscle invasive bladder cancer: a randomized, double-blind study

BACKGROUND

Although intravesical BCG is the standard treatment of high-grade non-muscle invasive bladder cancer (NMIBC), response rates remain unsatisfactory. In preclinical models, rapamycin enhances BCG vaccine efficacy against tuberculosis and the killing capacity of γδ T cells, which are critical for BCG's antitumor effects. Here, we monitored immunity, safety, and tolerability of rapamycin combined with BCG in patients with NMIBC.

METHODS

A randomized double-blind trial of oral rapamycin (0.5 or 2.0 mg daily) versus placebo for 1 month was conducted in patients with NMIBC concurrently receiving 3 weekly BCG instillations (NCT02753309). The primary outcome was induction of BCG-specific γδ T cells, measured as a percentage change from baseline. Post-BCG urinary cytokines and immune cells were examined as surrogates for local immune response in the bladder. Secondary outcomes measured were adverse events (AEs) and tolerability using validated patient-reported questionnaires.

RESULTS

Thirty-one patients were randomized (11 placebo, 8 rapamycin 2.0 mg, and 12 rapamycin 0.5 mg). AEs were similar across groups and most were grade 1-2. One (12.5%) patient randomized to 2.0 mg rapamycin was taken off treatment due to stomatitis. No significant differences in urinary symptoms, bowel function, or bother were observed between groups. The median (IQR) percentage change in BCG-specific γδ T cells from baseline per group was as follows: -26% (-51% to 24%) for placebo, 9.6% (-59% to 117%) for rapamycin 0.5 mg (versus placebo, p=0.18), and 78.8% (-31% to 115%) for rapamycin 2.0 mg (versus placebo, p=0.03). BCG-induced cytokines showed a progressive increase in IL-8 (p=0.02) and TNF-α (p=0.04) over time for patients on rapamycin 2.0 mg, whereas patients receiving placebo had no significant change in urinary cytokines. Compared with placebo, patients receiving 2.0 mg rapamycin had increased urinary γδ T cells at the first week of BCG (p=0.02).

CONCLUSIONS

Four weeks of 0.5 and 2.0 mg oral rapamycin daily is safe and tolerable in combination with BCG for patients with NMIBC. Rapamycin enhances BCG-specific γδ T cell immunity and boosts urinary cytokines during BCG treatment. Further study is needed to determine long-term rapamycin safety, tolerability and effects on BCG efficacy.

Bladder cancer cell-intrinsic PD-L1 signals promote mTOR and autophagy activation that can be inhibited to improve cytotoxic chemotherapy

Tumor cell-intrinsic programmed death-ligand 1 (PD-L1) signals mediate immunopathologic effects in breast, colon, and ovarian cancers and in melanomas, but bladder cancer (BC) effects are unreported. We show here that BC cell-intrinsic PD-L1 signals in mouse MB49 and human RT4, UM-UC3, and UM-UC-14 BC cells regulate important pathologic pathways and processes, including effects not reported in other cancers. α-PD-L1 antibodies reduced BC cell proliferation in vitro, demonstrating direct signaling effects. BC cell-intrinsic PD-L1 promoted mammalian target of rapamycin complex 1 (mTORC1) signals in vitro and augmented in vivo immune-independent cell growth and metastatic cancer spread, similar to effects we reported in melanoma and ovarian cancer. BC cell-intrinsic PD-L1 signals also promoted basal and stress-induced autophagy, whereas these signals inhibited autophagy in melanoma and ovarian cancer cells. BC cell-intrinsic PD-L1 also mediated chemotherapy resistance to the commonly used BC chemotherapy agents cis-platinum and gemcitabine and to the mTORC1 inhibitor, rapamycin. Thus, BC cell-intrinsic PD-L1 signals regulate important virulence and treatment resistance pathways that suggest novel, actionable treatment targets meriting additional studies. As a proof-of-concept, we showed that the autophagy inhibitor chloroquine improved cis-platinum treatment efficacy in vivo, with greater efficacy in PD-L1 null versus PD-L1-replete BC.

A Randomized Feasibility Trial Comparing Surveillance Regimens for Patients with Low and Low-Intermediate Risk Non-Muscle Invasive Bladder Cancer

BACKGROUND

Surveillance regimens for non-muscle invasive bladder cancer (NMIBC) are disparate and controlled trials could inform guidelines. The feasibility of randomizing patients to variable frequency surveillance is unknown.

OBJECTIVES

To determine patient willingness to randomization to high frequency (HF) versus low frequency (LF) surveillance regimen for NMIBC and compare patient comfort and healthcare costs across regimens.

METHODS

A non-blinded, two-arm, randomized-controlled study of patients with low or low-intermediate risk NMIBC was conducted at two institutions where patients were offered randomization to HF vs. LF surveillance following initial tumor resection. The HF group underwent cystoscopy every three months for 2 years, then every 6 months for 2 years, then annually. The LF group underwent cystoscopy at 9 months following the 3-month cystoscopy, then annually. Assuming 75% of patients approached would agree to enrollment, a sample size of n = 35 patients per arm provided a one-sided 95% exact Clopper-Pearson confidence lower-limit of 60%.

RESULTS

Of 70 patients approached, 45 (64.3%) agreed to participate and 25 (35.7%) declined enrollment due to preference for HF. Twelve biopsies were performed, including 4 (19%) of 21 patients in the HF group and 8 (33.3%) of 24 patients in the LF group. Disease recurrence (low grade Ta) was observed in 3 (14.3%) and 5 (20.8%) patients in the HF and LF groups, respectively. No patients experienced high grade recurrence or progression. Both groups had similar patient-reported procedure-related discomfort and quality of life measures over time. Patient out-of-pocket cost and healthcare systems costs were $383.80 more per patient annually in the HF group.

CONCLUSIONS

Randomization to variable frequency surveillance is challenging as over a third of patients declined participation. However, these data provide important preliminary insights into the potential effects of surveillance frequency on oncologic and economic outcomes in patients with low and low-intermediate risk bladder cancer.

Intravesical nadofaragene firadenovec gene therapy for BCG-unresponsive non-muscle-invasive bladder cancer: a single-arm, open-label, repeat-dose clinical trial

BACKGROUND

BCG is the most effective therapy for high-risk non-muscle-invasive bladder cancer. Nadofaragene firadenovec (also known as rAd-IFNa/Syn3) is a replication-deficient recombinant adenovirus that delivers human interferon alfa-2b cDNA into the bladder epithelium, and a novel intravesical therapy for BCG-unresponsive non-muscle-invasive bladder cancer. We aimed to evaluate its efficacy in patients with BCG-unresponsive non-muscle-invasive bladder cancer.

METHODS

In this phase 3, multicentre, open-label, repeat-dose study done in 33 centres (hospitals and clinics) in the USA, we recruited patients aged 18 years or older, with BCG-unresponsive non-muscle-invasive bladder cancer and an Eastern Cooperative Oncology Group status of 2 or less. Patients were excluded if they had upper urinary tract disease, urothelial carcinoma within the prostatic urethra, lymphovascular invasion, micropapillary disease, or hydronephrosis. Eligible patients received a single intravesical 75 mL dose of nadofaragene firadenovec (3 × 1011 viral particles per mL). Repeat dosing at months 3, 6, and 9 was done in the absence of high-grade recurrence. The primary endpoint was complete response at any time in patients with carcinoma in situ (with or without a high-grade Ta or T1 tumour). The null hypothesis specified a complete response rate of less than 27% in this cohort. Efficacy analyses were done on the per-protocol population, to include only patients strictly meeting the BCG-unresponsive definition. Safety analyses were done in all patients who received at least one dose of treatment. The study is ongoing, with a planned 4-year treatment and monitoring phase. This study is registered with ClinicalTrials.gov, NCT02773849.

FINDINGS

Between Sept 19, 2016, and May 24, 2019, 198 patients were assessed for eligibility. 41 patients were excluded, and 157 were enrolled and received at least one dose of the study drug. Six patients did not meet the definition of BCG-unresponsive non-muscle-invasive bladder cancer and were therefore excluded from efficacy analyses; the remaining 151 patients were included in the per-protocol efficacy analyses. 55 (53·4%) of 103 patients with carcinoma in situ (with or without a high-grade Ta or T1 tumour) had a complete response within 3 months of the first dose and this response was maintained in 25 (45·5%) of 55 patients at 12 months. Micturition urgency was the most common grade 3-4 study drug-related adverse event (two [1%] of 157 patients, both grade 3), and there were no treatment-related deaths.

INTERPRETATION

Intravesical nadofaragene firadenovec was efficacious, with a favourable benefit:risk ratio, in patients with BCG-unresponsive non-muscle-invasive bladder cancer. This represents a novel treatment option in a therapeutically challenging disease state.

FUNDING

FKD Therapies Oy.

CD122-selective IL-2 complexes target γδ T and NK cells to reduce tumor-promoting Th17 effects and synergize with αPD-L1 to treat primary and metastatic bladder cancer

αPD-L1 bladder cancer (BC) immunotherapy is effective in &lt;30% of cases. To address the large αPD-L1-unresponsive subset of patients, we tested αIL-2/IL-2 complexes (IL-2c) that block IL-2 from binding high-affinity IL-2Rα (CD25) for preferential IL-2Rβ (CD122) binding. Regulatory T cells (Tregs) capture IL-2 by CD25 whereas CD8+T, γδ T, and NK cells use CD122. We hypothesized that the tumor microenvironment, including local immune cells in primary versus metastatic BC, differentially affects immunotherapy responses. We used PD-L1+ mouse BC cell lines MB49 and MBT-2, for intravesical ([IVe] in bladder) and intravenous (IV) challenge studies of local versus metastatic BC. αPD-L1 or IL-2c alone reduced tumor burden and extended survival in IVe MB49 and MBT-2. Treg depletion using FOXP3DTR mice further enhanced IVe IL-2c effects, consistent with the known tumor-promoting role of Tregs in human BC. Using in vivo cell depletion approaches, we found that γδ T cells and NK cells, but not CD8+ T cells, were necessary for IL-2c efficacy in bladder. γδ T cells also reduced intratumoral Th17 cells that promote MB49 growth and are elevated in human BC. We confirmed γδ T cell effects in δ TCR KO mice, which abrogated IL-2c efficacy but not αPD-L1 efficacy. Neither αPD-L1 nor IL-2c alone treated metastatic MB49 and MBT-2 BC but the combination improved survival in both. These data are consistent with our recent findings in human BC patients in whom γδ T cell and NK cell cytotoxicity improved BCG immunotherapy. Thus, IL-2c is a promising novel BC immunotherapy that can improve bladder-specific immunity in primary BC. In metastatic BC, combination with αPD-L1 may also be a successful BC treatment strategy due to engagement of innate and adaptive immune responses.

CCL2/CCR2 signaling protects against bladder cancer growth in a T cell dependent manner

The chemokine CCL2 (C-C motif ligand 2) is an important signaling axis underlying recruitment of pro-tumorigenic myeloid cells and is associated with worse outcomes in several tumor models. Currently, anti-CCL2 antibodies are being tested in cancer trials for solid tumors. To test CCL2 signaling in bladder carcinogenesis, wild type (WT) mice and mice deficient in CCL2 (CCL2KO) were given the urothelial carcinogen N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Surprisingly, tumor incidence was higher in CCL2KO mice demonstrating an unanticipated protective role for CCL2 signaling in bladder cancer (BC). We then orthotopically challenged WT, CCL2KO, and CCR2KO mice (lacking the major CCL2 receptor) with MB49 BC and confirmed the protective effect of CCL2/CCR2. WT mice had significantly more intratumoral T cells compared to CCL2KO mice suggesting that CCL2 is involved in recruiting T cells to the bladder. Further, depletion of T cells abolished this protective effect of CCL2. Adoptive transfer of CCR2+ T cells into CCR2KO mice restored protection against MB49. CCR2+ T cells were also more activated, functional and tumor specific compared to their CCR2− counterparts. We found that anti-CCL2 promotes BC growth highlighting a concern for use of anti-CCL2 in BC. Moreover, intravesical recombinant CCL2 (rCCL2) either alone or in combination with intravesical gemcitabine reduced bladder tumor and improved survival of mice with MB49 BC. We further developed a slow-release encapsulated nanoparticle formulation of rCCL2 which successfully treated MB49, C3H mice with MBT-2 BC and reduced urine hematuria in our first ever humanized model of orthotopic BC. Our results are rapidly translatable and identify a novel treatment strategy in BC.

Distribution of Molecular Subtypes in Muscle-invasive Bladder Cancer Is Driven by Sex-specific Differences

Muscle-invasive bladder cancer (MIBC) is a sex-biased cancer with a higher incidence in men but worse outcomes in women. The root cause behind these observations remains unclear. To investigate whether sex-specific tumor biology could explain the differences in clinical behavior of MIBC, we analyzed the transcriptome profiles from transurethral resected bladder tumors of 1000 patients. Female tumors expressed higher levels of basal- and immune-associated genes, while male tumors expressed higher levels of luminal markers. Using molecular subtyping, we found that the rates of the basal/squamous subtype were higher in females than in males. Males were enriched with tumors of the luminal papillary (LumP) and neuroendocrine-like subtypes. Male MIBC tumors had higher androgen response activity across all luminal subtypes and male patients with LumP tumors were younger. Taken together, these data confirm differences in molecular subtypes based on sex. The role of the androgen response pathway in explaining subtype differences between men and women should be studied further. PATIENT SUMMARY: We explored the sex-specific biology of bladder cancer in 1000 patients and found that women had more aggressive cancer with higher immune activity. Men tended toward less aggressive tumors that showed male hormone signaling, suggesting that male hormones may influence the type of bladder cancer that a patient develops.

Evidence-based Assessment of Current and Emerging Bladder-sparing Therapies for Non-muscle-invasive Bladder Cancer After Bacillus Calmette-Guerin Therapy: A Systematic Review and Meta-analysis

CONTEXT

Currently, there is no standard of care for patients with non-muscle-invasive bladder cancer (NMIBC) who recur despite bacillus Calmette-Guerin (BCG) therapy. Although radical cystectomy is recommended, many patients decline to undergo or are ineligible to receive it. Multiple agents are being investigated for use in this patient population.

OBJECTIVE

To systematically synthesize and describe the efficacy and safety of current and emerging treatments for NMIBC patients after treatment with BCG.

EVIDENCE ACQUISITION

A systematic literature search of MEDLINE, Embase, and the Cochrane Controlled Register of Trials (period limited to January 2007-June 2019) was performed. Abstracts and presentations from major conference proceedings were also reviewed. Randomized controlled trials were assessed using the Cochrane risk of bias tool. Data for single-arm trials were pooled using a random-effect meta-analysis with the proportions approach. Trials were grouped based on the minimum number of prior BCG courses required before enrollment and further stratified based on the proportion of patients with carcinoma in situ (CIS).

EVIDENCE SYNTHESIS

Thirty publications were identified with data from 23 trials for meta-analysis, of which 17 were single arm. Efficacy and safety outcomes varied widely across studies. Heterogeneity across trials was reduced in subgroup analyses. The pooled 12-mo response rates were 24% (95% confidence interval [CI]: 16-32%) for trials with two or more prior BCG courses and 36% (95% CI: 25-47%) for those with one or more prior BCG courses. In a subgroup analysis, inclusion of ≥50% of patients with CIS was associated with a lower response.

CONCLUSIONS

The variability in efficacy and safety outcomes highlights the need for consistent endpoint reporting and patient population definitions. With promising emerging treatments currently in development, efficacious and safe therapeutic options are urgently needed for this difficult-to-treat patient population.

PATIENT SUMMARY

We examined the efficacy and safety outcomes of treatments for non-muscle-invasive bladder cancer after bacillus Calmette-Guerin therapy. Outcomes varied across studies and patient populations, but emerging treatments currently in development show promising efficacy.

Urinary Diversion Disparity Following Radical Cystectomy for Bladder Cancer in the Hispanic Population

OBJECTIVE

To determine if disparities in quality of surgical care exist between Hispanics and non-Hispanics undergoing radical cystectomy for bladder cancer.

MATERIALS AND METHODS

An observational cohort study was conducted retrospectively on patients who underwent radical cystectomy for urothelial carcinoma of the bladder at our institution between January 2005 and July 2018. Data was collected on demographic, clinical, and pathological characteristics of patients, including self-reported ethnicity. Univariable and multivariable logistic or linear regression analyses were used to evaluate the association of ethnicity with receipt of neoadjuvant chemotherapy, utilization of laparoscopic surgery, number of lymph nodes removed, and continent urinary diversion.

RESULTS

We identified 507 patients in our database out of which, 136 (27%) were Hispanic and 371 (73%) were non-Hispanic. Compared to non-Hispanics, Hispanics had a higher body mass index (26.9 kg/m2 vs 28.2 kg/m2, P = .006) and lived further away from site of surgery (34 vs 96 miles, P = .02). No significant differences were observed in receipt of neoadjuvant chemotherapy, laparoscopic surgery, or number of lymph nodes removed during cystectomy between ethnicity groups. However, Hispanics were less likely than non-Hispanics to receive a continent urinary diversion on multivariable analysis (odds ratio 0.30, 95% confidence interval 0.10 - 0.92, P = .03).

CONCLUSION

Disparity exists in the delivery of continent urinary diversions for Hispanic patients undergoing radical cystectomy for bladder cancer. Further investigation is needed to determine the potential causes for this disparity in care delivered.

Association of myeloid suppressor cells with resistance to checkpoint blockade immunotherapy in urothelial carcinoma

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Background: Myeloid immune cells such as myeloid derived suppressor cells (MDSC) and tumor associated macrophages (TAM) have been hypothesized to cause resistance to immune checkpoint blockade (ICB). This is a pressing clinical problem for patients with bladder cancer. Here we determined if we could identify immune cells associated with resistance to ICB in the BBN963 mouse model, and if we could identify therapeutic strategies to target those same suppressor immune cells from patients with bladder cancer. Methods: BBN963 subcutaneous allografts were established in C57BL6/J mice. Response to anti-PD-L1 ICB was classified as partial or complete response according to RECIST criteria. Immune cell subsets with the tumors was evaluated by gene expression profiling and flow cytometry. Peripheral blood from patients with bladder cancer was collected under an IRB-approved protocol. MDSC were purified by flow sorting (CD11b+ CD33+ HLA-DRlow/neg) and screened for viability (Annexin-V staining) after 24 hours of exposure to a panel potential MDSC inhibitors. Results: 16/22 (72%) subjects met criteria for partial or complete response, while 6/22 (28%) were classified as anti-PD-L1 non-responders. Mice in the control group had a 0/10 (0%) response to isotype control (IgG) treatment. Monocytic MDSC (CD11b+ Ly6C+) were much more frequent among the intratumoral CD45+ cells of non-responding subjects as compared to control mice. Nanostring immune panel gene expression profiling revealed that combination treatment of tumor bearing mice with anti-PD-L1 plus ibrutinib (a putative MDSC inhibitor) decreased mRNA biomarkers of tumor-infiltrating macrophages. In vitro screening of patient-derived peripheral blood mononuclear cells showed that an inhibitor of the bromodomain and extraterminal domain (BET) family BRD4 specifically decreased MDSC viability. Conclusions: Monocytic MDSC appear to be associated with resistance to anti-PD-L1 ICB in a new murine model. Analysis of MDSC from patients with bladder cancer suggests that these myeloid suppressor cells can be specifically targeted.

The utilization status of neoadjuvant chemotherapy in muscle-invasive bladder cancer: a systematic review and meta-analysis

INTRODUCTION

To give a comprehensive depiction of the utilization status of neoadjuvant chemotherapy (NAC) in muscle invasive bladder cancer (MIBC) worldwide.

EVIDENCE ACQUISITION

Potential relevant research papers of Pubmed, Embase, Web of Science, and the Cochrane Library were reviewed to identify eligible studies. Primary outcomes of this meta-analysis were utilization rate of NAC and its utility distribution in different genders, races, ages, countries and temporal trends. The utilization rates of NAC were calculated as 'Proportion (s)' with 95% confidence intervals (CIs) and pooled estimates were calculated by using a random-effect model.

EVIDENCE SYNTHESIS

A total of thirteen studies and 35,738 patients were included. The total proportion of NAC applied in MIBC populations prior to radical cystectomy (RC) was 17.2% (95% CI: 12.5-21.9%, I²=99.7%). The comparative analyses showed there were no significant differences existing in different genders or races on NAC utilization rates. In terms of age distribution, <60 age group conferred higher utilization rate of NAC than the older (OR=1.919, 95% CI: 1.671-2.202, P=0.0001). As for regional distribution, our meta-analysis showed that Japan (Proportion: 44.0%, 95% CI: 6.5-81.5%, I²=99.6%) and Sweden (37.9%, 95% CI: 34.9-40.8%) were the top two leading countries which contributed to the most frequent application of NAC. In respect of pathologic responses after NAC, complete, partial and down-staged pathologic responses were achieved in 16.6% (95% CI: 7.4-25.9%, I²=89.7%), 14.6% (95% CI: 0.8-28.5%, I²=89.7%) and 45.0% (95% CI: 17.8-72.2%, I²=98.8%) patients, respectively.

CONCLUSIONS

The present study shows the low utilization rate of NAC in MIBC patients. Standardization of the treatment modality of MIBC and promotion of guidelines might be necessary to expedite the adoption of NAC in near future.

The utilization status of neoadjuvant chemotherapy in muscle-invasive bladder cancer: a systematic review and meta-analysis

INTRODUCTION

To give a comprehensive depiction of the utilization status of neoadjuvant chemotherapy (NAC) in muscle invasive bladder cancer (MIBC) worldwide.

EVIDENCE ACQUISITION

Potential relevant research papers of Pubmed, Embase, Web of Science, and the Cochrane Library were reviewed to identify eligible studies. Primary outcomes of this meta-analysis were utilization rate of NAC and its utility distribution in different genders, races, ages, countries and temporal trends. The utilization rates of NAC were calculated as 'Proportion (s)' with 95% confidence intervals (CIs) and pooled estimates were calculated by using a random-effect model.

EVIDENCE SYNTHESIS

A total of thirteen studies and 35,738 patients were included. The total proportion of NAC applied in MIBC populations prior to radical cystectomy (RC) was 17.2% (95% CI: 12.5-21.9%, I²=99.7%). The comparative analyses showed there were no significant differences existing in different genders or races on NAC utilization rates. In terms of age distribution, <60 age group conferred higher utilization rate of NAC than the older (OR=1.919, 95% CI: 1.671-2.202, P=0.0001). As for regional distribution, our meta-analysis showed that Japan (Proportion: 44.0%, 95% CI: 6.5-81.5%, I²=99.6%) and Sweden (37.9%, 95% CI: 34.9-40.8%) were the top two leading countries which contributed to the most frequent application of NAC. In respect of pathologic responses after NAC, complete, partial and down-staged pathologic responses were achieved in 16.6% (95% CI: 7.4-25.9%, I²=89.7%), 14.6% (95% CI: 0.8-28.5%, I²=89.7%) and 45.0% (95% CI: 17.8-72.2%, I²=98.8%) patients, respectively.

CONCLUSIONS

The present study shows the low utilization rate of NAC in MIBC patients. Standardization of the treatment modality of MIBC and promotion of guidelines might be necessary to expedite the adoption of NAC in near future.

Chemoradiation Vs Radical Cystectomy for Muscle-invasive Bladder Cancer: A Propensity Score-weighted Comparative Analysis Using the National Cancer Database

OBJECTIVE

To address the overarching question whether chemoradiation therapy (CMT) offers overall survival (OS) similar to that of radical cystectomy (RC) in muscle-invasive bladder cancer (MIBC), we performed analyses using the National Cancer Database.

MATERIALS AND METHODS

Patients diagnosed with MIBC in 2004-2014 who underwent RC or received primary CMT were identified in the National Cancer Database. Survival was estimated using the weighted Kaplan-Meier method, and propensity score-weighted Cox proportional hazards model were used to evaluate association of clinicopathologic features with outcome.

RESULTS

Of 484,367 patients with a diagnosis of bladder cancer, 35,856 underwent RC and 4050 received CMT. After applying the exclusion/inclusion criteria, data for 15,854 patients who underwent RC and 2083 who received CMT were available for analysis. Five-year OS was 40.4% in the RC group and 29.4% in the CMT group (P <.001). OS was significantly shorter in the CMT group than in the RC group in both multivariate analysis (hazards ratio [HR] 1.15, 95% CI 1.08-1.22; P <.001) and propensity score-weighted analysis (HR 1.18, 95% CI 1.07-1.30; P <.001). Interaction terms indicated better survival after RC in patients younger than 70 years (HR 1.61, 95% CI 1.34-1.93; P <.001); subgroup analyses identified a survival benefit in patients with N0/N1 disease who underwent RC (HR 1.21, 95% CI 1.09-1.33; P <.001).

CONCLUSION AND RELEVANCE

OS after 1 year of treatment was increased in RC group compared to CMT group in patient with MIBC. Further studies are required to identify optimal treatment for specific patients.

Percutaneous BCG enhances innate effector antitumor cytotoxicity during treatment of bladder cancer: a translational clinical trial

Background: Intravesical bacillus Calmette-Guérin (BCG) is the gold standard immunologic agent for treating patients with high-grade non-muscle invasive bladder cancer (NMIBC). Nevertheless, relapse rates remain high and BCG unresponsive NMIBC often requires bladder removal. Preclinical data suggest that priming with percutaneous BCG vaccine could improve response to intravesical BCG. Methods: A single-arm trial (NCT02326168) was performed to study the safety, immunogenicity, and preliminary efficacy of priming. Percutaneous BCG was given 21 days prior to intravesical BCG instillation in patients (n = 13) with high-risk NMIBC. Immune responses were monitored and compared to a sequentially enrolled cohort of nine control patients receiving only intravesical BCG. The effect of BCG on natural killer (NK) and γδ T cell in vitro cytotoxicity was tested. γδ T cell subsets were determined by T cell receptor gene expression with NanoString. Results: Priming was well tolerated and caused no grade ≥3 adverse events. The 3-month disease-free rate for prime patients was 85% (target goal ≥ 75%). Priming boosted BCG-specific immunity at 3 months and increased the activation status of in vitro expanded circulating NK and γδ T cells and their cytotoxicity against bladder cancer cells through receptor NKG2D. BCG enhanced the cytotoxicity of NK and γδ T cells against K562, RT4, and UM-UC6 but not against T24, UM-UC-3, or UM-UC-14 cells. Infiltrating γδ T cell subsets identified in the bladder includes γ9δ2 and γ8δ2. Conclusions: BCG priming is safe and tolerable. Poor sensitivity to NK and γδ T cell cytotoxicity by some bladder tumors represents a potential BCG-resistance mechanism.